chapter06

Getting Familiar

To start, go ahead and try these four Strengthen and Weaken questions. Give yourself no more than six minutes total. We'll revisit these questions later on in the chapter.

PT38, S4, Q15

Loggerhead turtles live and breed in distinct groups, of which some are in the Pacific Ocean and some are in the Atlantic. New evidence suggests that juvenile Pacific loggerheads that feed near the Baja peninsula hatch in Japanese waters 10,000 kilometers away. Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from turtles at the Japanese nesting sites.

Which one of the following, if true, most seriously weakens the reasoning above?

(A) Nesting sites of loggerhead turtles have been found off the Pacific coast of North America several thousand kilometers north of the Baja peninsula.

(B) The distance between nesting sites and feeding sites of Atlantic loggerhead turtles is less than 5,000 kilometers.

(C) Loggerhead hatchlings in Japanese waters have been declining in number for the last decade while the number of nesting sites near the Baja peninsula has remained constant.

(D) Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from Atlantic loggerhead turtles.

(E) Commercial aquariums have been successfully breeding Atlantic loggerheads with Pacific loggerheads for the last five years.

PT29, S4, Q24

Medical researcher: As expected, records covering the last four years of ten major hospitals indicate that babies born prematurely were more likely to have low birth weights and to suffer from health problems than were babies not born prematurely. These records also indicate that mothers who had received adequate prenatal care were less likely to have low birth weight babies than were mothers who had received inadequate prenatal care. Adequate prenatal care, therefore, significantly decreases the risk of low birth weight babies.

Which one of the following, if true, most weakens the medical researcher's argument?

(A) The hospital records indicate that many babies that are born with normal birth weights are born to mothers who had inadequate prenatal care.

(B) Mothers giving birth prematurely are routinely classified by hospitals as having received inadequate prenatal care when the record of that care is not available.

(C) The hospital records indicate that low birth weight babies were routinely classified as having been born prematurely.

(D) Some babies not born prematurely, whose mothers received adequate prenatal care, have low birth weights.

(E) Women who receive adequate prenatal care are less likely to give birth prematurely than are women who do not receive adequate prenatal care.

PT36, S1, Q8

It has been claimed that television networks should provide equal time for the presentation of opposing views whenever a television program concerns scientific issues—such as those raised by the claims of environmentalists—about which people disagree. However, although an obligation to provide equal time does arise in the case of any program concerning social issues, it does so because social issues almost always have important political implications and seldom can definitely be settled on the basis of available evidence. If a program concerns scientific issues, that program gives rise to no such equal time obligation.

Which one of the following, if true, most seriously weakens the argument?

(A) No scientific issues raised by the claims of environmentalists have important political implications.

(B) There are often more than two opposing views on an issue that cannot be definitely settled on the basis of available evidence.

(C) Some social issues could be definitely settled on the basis of evidence if the opposing sides would give all the available evidence a fair hearing.

(D) Many scientific issues have important political implications and cannot be definitely settled on the basis of the available evidence.

(E) Some television networks refuse to broadcast programs on issues that have important political implications and that cannot be definitely settled by the available evidence.

PT37, S2, Q20

Antarctic seals dive to great depths and stay submerged for hours. They do not rely solely on oxygen held in their lungs, but also store extra oxygen in their blood. Indeed, some researchers hypothesize that for long dives these seals also store oxygenated blood in their spleens.

Each of the following, if true, provides some support for the researchers’ hypothesis EXCEPT:

(A) Horses are known to store oxygenated blood in their spleens for use during exertion.

(B) Many species of seal can store oxygen directly in their muscle tissue.

(C) The oxygen contained in the seals’ lungs and bloodstream alone would be inadequate to support the seals during their dives.

(D) The spleen is much larger in the Antarctic seal than in aquatic mammals that do not make long dives.

(E) The spleens of Antarctic seals contain greater concentrations of blood vessels than are contained in most of their other organs.

One Extra Layer

Thus far, we've looked at two Assumption Family question types—Assumption and Identify a Flaw—and we've discussed the general process for attacking Assumption Family problems. Hopefully, you are feeling more and more comfortable with identifying the argument core and evaluating the issues that it might present.

We will continue to reinforce those skills in this chapter. Like Assumption and Identify a Flaw questions, Strengthen and Weaken questions test your ability to evaluate the reasoning in an argument—that is, the connection between the premises and the conclusion. However, Strengthen and Weaken questions present us with an additional and unique challenge. Whereas Assumption and Identify a Flaw questions primarily require us to identify the argument core and assess it, Strengthen and Weaken questions require us to identify, assess, and then consider ways to address the issues in the argument core. For Assumption and Identify a Flaw questions, we select answers that directly represent our understanding of the reasoning within the argument. For Strengthen and Weaken questions, we must consider how different bits of new information might relate to that reasoning.

Let's use a simple example to illustrate the impact of this additional layer. Consider the following argument:

Sally owns more cookbooks than Finn. Therefore, Sally is a better cook than Finn.

It's clear the argument is flawed, but success on the LSAT requires that we understand this type of flaw in a specific way. The subjects, Sally and Finn, don't change from premise to conclusion, but what is discussed about these subjects does:

Sally owns more cookbooks than Finn

Sally is a better cook than Finn

What are the gaps or flaws?

For one, the argument is assuming that owning more cookbooks equates to being a better cook. This is a pretty big assumption. One needs to do more than own cookbooks to be a good cook—at the least, one should probably read them. And learn from them. And incorporate what is learned into the cooking. Furthermore, the number of cookbooks is not indicative of the knowledge these books have to offer—it's likely that one great cookbook has more valuable information than 10 bad ones.

We can also say that the argument is assuming that owning more cookbooks is enough, by itself, to justify the conclusion. That is, that there are no other factors that significantly influence how well Sally and Finn cook. Again, that's a pretty big assumption. We know from our own lives that there are plenty of other factors that could be considered here: experience in the kitchen, teachers, parents, natural aptitude, taste, and even exposure to various foods of various cultures.

We can generalize the flaws in the argument as follows:

The author takes for granted that owning more cookbooks has a direct impact on being a better cook.
The author fails to consider that other factors could be involved in determining who is the better cook.

Most commonly, correct answers to Strengthen questions help the argument by helping to plug a gap in the core. This gap can relate to how the elements of the premise and conclusion equate to one another, or to the “What else?” the author should have considered but didn't. Correct answers to Weaken questions will most commonly expose these gaps.

With that in mind, take a look at some ways that we might strengthen or weaken the argument, by helping to plug one of the two gaps we just discussed:

Assumption	Valid Strengthen Answers	Valid Weaken Answers
Owning more cookbooks is related to being a better cook.	The number of cookbooks one owns is an accurate gauge of how much one knows about cooking. Owning cookbooks inspires people to practice cooking, and, in turn, to become better cooks. In Sally's collection are some of the greatest cookbooks in the world, and she has read and learned from them.	Sally has not read any of her cookbooks. None of Sally's cookbooks describe anything aside from different ways of decorating gingerbread houses. People often misread cookbooks and end up becoming worse cooks after reading them.
There are not other significant factors in being a good cook.	A recent study found that owning cookbooks was the most significant factor in determining a person's understanding of cooking. Experience in the kitchen and exposure to foods of other cultures are not factors that significantly influence knowledge of cooking.	Finn is a cooking school instructor and the books Sally owns were written by Finn. Finn has been apprenticing for a world-renowned chef for the past three years. Sally was born without taste buds and cannot accurately gauge the flavor of her cooking.

Keep in mind two factors in thinking about the above samples:

1. You do not have to consider whether the answer could be valid in real life or not. In fact, most question stems will explicitly ask that you consider the answers as if they are true.

So, even if you think it's not possible that reading cookbooks might make Sally a worse cook, it's not your job here to make that judgment. Even if you know that it's rare for people not to have taste buds, when evaluating an answer you should work off the assumption that the statement is true.

2. A Strengthen answer doesn't have to make the argument perfect, and a Weaken answer doesn't have to destroy the argument entirely. In fact, for some of the most challenging questions, a Strengthen answer will still leave the argument with significant gaps, and a Weaken answer may address the slightest of many issues in the core.

Consider this Weaken answer:

Finn is a cooking school instructor and the books Sally owns were written by Finn.

Does this mean Sally isn't a better cook than Finn? Does this prove Finn is a better cook? No, certainly not if we are considering this with the strict reasoning eye the LSAT requires. Finn can be an instructor and a book writer—and a terrible cook! It's possible Sally has never been to cooking school but is a phenomenal cook (we all know people like this in real life).

Furthermore, this answer has some characteristics that would, with good reason, cause us to shy away from it if it appeared on an Assumption or Identify a Flaw problem. If we think about one component of the answer—Finn teaches cooking—is this something that could play a critical role in an Assumption or Flaw answer? No. In making his argument, the author need not assume one thing or another about whether Finn teaches cooking, nor would any assumption about Finn teaching cooking be sufficient to make the argument sound. It's also not a flaw that, in reaching his conclusion, the author didn't consider whether Finn teaches cooking. There is no way that the author could anticipate that that is something he would have to consider, and, more importantly, because it's not an assumption that is required, it wouldn't be a flaw in reasoning not to consider it.

So, why could this be the correct answer to a Weaken question? Because it dents an assumption the author is making. In thinking that the evidence is sufficient to prove the conclusion, the author is assuming that the relative number of cookbooks Sally and Finn respectively own is enough, by itself, to determine which of the two is the better cook—the author is assuming that there must be no other significant factors. An answer choice such as this one exposes the issue with that assumption simply by showing that there could be other factors.

This leads us to a subtle but significant point. The answers to Strengthen and Weaken questions can address an assumption by bringing in new and unexpected information, like the lack of taste buds or being a cooking instructor. Because answer choices can bring in new information, it is often true that correct answers to these questions will relate less obviously to the argument core than most Assumption and Flaw answers do. In a certain way, this is similar to what we face with some questions asking for a necessary assumption; the correct answer to those can address an obvious gap in an unpredictable manner, or address a gap that is itself unpredictable.

This freedom of scope is important on two fronts. First, you want to cast a wider net when it comes to thinking about what could be the right answer to a Strengthen or Weaken question. The answer's relation to the core can be less obvious than for other Assumption Family questions. We've also noticed that correct Strengthen and Weaken answers are more likely than correct Assumption and Flaw answers to address secondary, or perhaps less significant, gaps in the reasoning of the argument.

Second, you want to make sure that the skills you develop for connecting tangential answers does not take away from the sharp eye you've developed for spotting ones that are truly out of scope. Right answers to Assumption and Flaw questions tend to relate more directly to the core—and a lot of the work we've done has been designed to help you better separate the answers that relate to the core from the answers that don't. We'd hate for the work you do on Strengthen and Weaken questions to take away from the work you've done on Assumption and Flaw questions. Again, if you think of Strengthen and Weaken questions as questions that add an additional layer to the tasks required of you in Assumption and Flaw questions, you can keep these characteristics clear.

Consider this potential weakener of our argument about Sally owning more cookbooks than Finn and thus being a better cook than him:

Finn is a good cook.

Why is this not a correct weakener? For one, it doesn't tell us if Finn is a better cook than Sally is. Also—and this is crucial—Finn being a good cook does not weaken the connection between the premises and conclusion. Our job is not to weaken the conclusion but to weaken the argument. We'll look at some rare questions where we're specifically asked to weaken the conclusion, but for the overwhelming majority of Strengthen and Weaken questions we're expected to focus on the reasoning.

Let's now practice our process on a real LSAT question. Remember to identify the conclusion, evaluate the premises, find the gaps and flaws, and choose an answer that addresses one of those gaps or flaws.

PT36, S1, Q25

A 1991 calculation was made to determine what, if any, additional health-care costs beyond the ordinary are borne by society at large for people who live a sedentary life. The figure reached was a lifetime average of $1,650. Thus people's voluntary choice not to exercise places a significant burden on society.

Which one of the following, if true and not taken into account by the calculation, most seriously weakens the argument?

(A) Many people whose employment requires physical exertion do not choose to engage in regular physical exercise when they are not at work.

(B) Exercise is a topic that is often omitted from discussion between doctor and patient during a patient's visit.

(C) Physical conditions that eventually require medical or nursing-home care often first predispose a person to adopt a sedentary life-style.

(D) Individuals vary widely in the amount and kind of exercise they choose, when they do exercise regularly.

(E) A regular program of moderate exercise tends to increase circulation, induce a feeling of well-being and energy, and decrease excess weight.

In the previous chapter, we deconstructed a thought process that aligns with, and works effectively for, almost all Assumption Family questions. Let's use it to break down this problem.

DECISION #1: What is my task?

We're asked to find an answer that most weakens the argument. We know this is an Assumption Family question, and we're going to need to understand the argument core well in order to efficiently arrive at the correct answer.

DECISION #2: What is the conclusion?

Let's model how this process might go in real time:

A 1991 calculation was made to determine what, if any, additional health-care costs beyond the ordinary are borne by society at large for people who live a sedentary life.

This is background information. It gives us the context for the argument.

The figure reached was a lifetime average of $1,650.

Still background? Unclear what role this plays.

Thus people's voluntary choice not to exercise places a significant burden on society.

This is definitely the conclusion. It is the author's main point, and, in fact, it's the only claim in the argument.

DECISION #3: How is this conclusion supported?

Once we identify the conclusion, it's easier to see that the information in the previous sentence—that the figure reached was a lifetime average of $1,650—is being used to support that conclusion. Furthermore, the sentence before that tells us what “the figure” stands for: “additional health-care costs beyond the ordinary that are borne by society at large for people who live a sedentary life.” Thus, we can think of the argument core as follows:

Additional health-care costs beyond the ordinary borne by society at large for people who live a sedentary life averages $1,650

Thus, people's voluntary choice not to exercise places a significant burden on society

DECISION #4: What is the gap?

Perhaps you notice the mismatch between the people who are discussed in the premises and those who are discussed in the conclusion.

The premises are specifically about people who live a sedentary life.

The conclusion is specifically about people who voluntarily choose not to exercise.

Do we know that those who live a sedentary life do so because they choose not to exercise? Absolutely not! There are a variety of other reasons why people must live a sedentary life. This is a significant mismatch, and it is very likely the correct answer will have to address this discrepancy.

Furthermore, it's unclear whether an average of $1,650 represents a significant burden. We've been given no tools to decide. A correct weaken answer could expose this gap by showing us why, for any of a variety of reasons, this would NOT be a significant burden.

With a clear understanding of these gaps, we are ready to evaluate the answer choices.

DECISION #5: Which answer choices are clearly wrong?

(A) Many people whose employment requires physical exertion do not choose to engage in regular physical exercise when they are not at work.

This answer is about an apparently related subject. Let's keep it for now.

(B) Exercise is a topic that is often omitted from discussion between doctor and patient during a patient's visit.

In real life this might be relevant to the discussion, but, for the purposes of the LSAT, this is completely out of scope. We can eliminate this quickly.

(C) Physical conditions that eventually require medical or nursing-home care often first predispose a person to adopt a sedentary life-style.

This answer relates directly to a gap we saw initially in the argument—the idea that the sedentary lifestyle must be voluntary. This is evidence that shows that perhaps the sedentary lifestyle is not always voluntary. Let's keep it.

(D) Individuals vary widely in the amount and kind of exercise they choose, when they do exercise regularly.

We're interested in people who do not exercise. And this answer doesn't address core issues. Let's eliminate it.

(E) A regular program of moderate exercise tends to increase circulation, induce a feeling of well-being and energy, and decrease excess weight.

And for the same reasons as (D), this answer can be eliminated quickly as well.

DECISION #6: What is the best available answer?

Keep in mind that even when a question asks for an answer that MOST weakens, there will typically only be one answer that actually weakens. This is the same for Strengthen questions as well. Down to two answers, your focus ought not to be on which one weakens more, but rather, on which answer actually does weaken, and which one does not. Let's evaluate the remaining choices one more time:

(A) Many people whose employment requires physical exertion do not choose to engage in regular physical exercise when they are not at work.

Does this answer help convince us that voluntarily lack of exercise doesn't place a significant burden on society? Perhaps indirectly, but the connection certainly isn't clear.

More importantly, keep in mind that the author is claiming that his conclusion is true because of additional health-care costs due to people who live a sedentary life. Those mentioned in this answer are not ones who live a sedentary lifestyle! This answer has no clearly definable impact on the reasoning—the connection between premise and conclusion—in this argument.

That leaves us with (C), the correct answer. Let's take one more look at it:

(C) Physical conditions that eventually require medical or nursing-home care often first predispose a person to adopt a sedentary life-style.

Does this answer destroy the argument? No. Perhaps such physical conditions as those described in this answer choice are exceedingly rare, and perhaps the vast majority of people adopt a sedentary lifestyle voluntarily, in which case the argument still could be pretty strong (at least in respect to the “voluntary” aspect). However, this answer does weaken the reasoning within the argument. It shows that something the author is assuming to be true—that people choose to be sedentary—may in fact not be.

Let's take a look at another question. Try solving it and analyzing the answers you didn't choose before reading further.

PT36, S3, Q2

Several companies will soon offer personalized electronic news services, delivered via cable or telephone lines and displayed on a television. People using these services can view continually updated stories on those topics for which they subscribe. Since these services will provide people with the information they are looking for more quickly and efficiently than printed newspapers can, newspaper sales will decline drastically if these services become widely available.

Which one of the following, if true, most seriously weakens the argument?

(A) In reading newspapers, most people not only look for stories on specific topics but also like to idly browse through headlines or pictures for amusing stories on unfamiliar or unusual topics.

(B) Companies offering personalized electronic news services will differ greatly in what they charge for access to their services, depending on how wide a range of topics they cover.

(C) Approximately 30 percent of people have never relied on newspapers for information but instead have always relied on news programs broadcast on television and radio.

(D) The average monthly cost of subscribing to several channels on a personalized electronic news service will approximately equal the cost of a month's subscription to a newspaper.

(E) Most people who subscribe to personalized electronic news services will not have to pay extra costs for installation since the services will use connections installed by cable and telephone companies.

The core of this argument comes at the end:

These (electronic news) services will provide people with the information they are looking for more quickly and efficiently than printed newspapers can

newspaper sales will decline drastically if these services become widely available.

Perhaps, at least the first time through, this argument seems pretty sound! However, since it's an Assumption Family question, we know it's got to have some issues, and, in this case, it's helpful to think about the conclusion in terms of “What else?” Why else do people buy and read papers? Do people primarily read newspapers searching for stuff they already know about?

No.

People often read with no idea of what's going to be in the paper—we read in part to see what's in the paper. People also buy newspapers for other reasons—for the crossword or for coupons, for example. The fact that people can identify information they are looking for faster through other forms is not the sole characteristic that needs to be considered in determining whether newspaper sales will drastically decrease.

Let's evaluate the answer choices:

(A) In reading newspapers, most people not only look for stories on specific topics but also like to browse idly through headlines or pictures for amusing stories on unfamiliar or unusual topics.

Perhaps you predicted this, or perhaps you didn't. In either case, you ought to be able to recognize that this answer presents an alternative reason that needs to be considered when thinking about whether newspaper sales will drastically decline. If (A) is true, people may want to continue buying the paper.

(B) Companies offering personalized electronic news services will differ greatly in what they charge for access to their services, depending on how wide a range of topics they cover.

A comparison within companies offering personalized electronic news services (as opposed to a comparison between such companies and newspapers) is of no relevance to this argument. We can quickly eliminate this answer choice.

(C) Approximately 30 percent of people have never relied on newspapers for information but instead have always relied on news programs broadcast on television and radio.

It's unclear how this relates to the conclusion. We're concerned about the people who do currently buy newspapers. Will they switch to the new medium? This answer is out of scope.

(D) The average monthly cost of subscribing to several channels on a personalized electronic news service will approximately equal the cost of a month's subscription to a newspaper.

Ahh. This answer perhaps brings to light a potential gap in the argument. Perhaps newspaper sales won't decline because electronic services will be more costly. However, this answer choice states the opposite, it states that the costs are equal. This answer eliminates a potential gap we didn't see initially. In doing so, it strengthens the argument.

This answer touches on the same issue as (D)—cost. But again, it doesn't weaken the argument because it's information about how people won't have to pay additional costs to switch away from the paper.

(A) is the best available answer, and it is the correct answer.

Hopefully these two questions have helped place Strengthen and Weaken questions in context relative to the Assumption Family questions discussed in previous chapters. Keep in mind, though, that there is more variation in Strengthen and Weaken questions than there is in both Assumption and Identify a Flaw questions. The arguments have gaps that are less absolute—often wider and often harder to clearly define, and the connection between argument and answer choice, for reasons discussed above, can be less obvious.

Let's look at one more challenging example, one that you tried at the start of the chapter:

PT38, S4, Q15

Which one of the following, if true, most seriously weakens the reasoning above?

(A) Nesting sites of loggerhead turtles have been found off the Pacific coast of North America several thousand kilometers north of the Baja peninsula.

(B) The distance between nesting sites and feeding sites of Atlantic loggerhead turtles is less than 5,000 kilometers.

(C) Loggerhead hatchlings in Japanese waters have been declining in number for the last decade while the number of nesting sites near the Baja peninsula has remained constant.

(D) Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from Atlantic loggerhead turtles.

(E) Commercial aquariums have been successfully breeding Atlantic loggerheads with Pacific loggerheads for the last five years.

We can take what the new evidence suggests as the conclusion of the argument: juvenile Pacific loggerheads that feed near the Baja peninsula hatch in Japanese waters 10,000 kilometers away. What is the reasoning given? DNA. Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from turtles at the Japanese nesting sites.

We can think of the core as follows:

Ninety-five percent of the DNA matches

Pacific loggerhead turtles that feed near the Baja peninsula hatch in Japanese waters 10,000 kilometers away

What would we need to know in order for this argument to be valid? We would need to know that a 95 percent match is significant enough to prove the connection. Perhaps these loggerheads also have a 95 percent DNA match with cabbage (unlikely, we realize). We don't know the exact significance of 95 percent, not based on the information we are given. Therefore, we can say the author is assuming that 95 percent is enough of a match to prove a relation. It's likely an answer meant to weaken will exploit this assumption.

One of the things that makes this question more challenging is that several of the answer choices are very attractive. Let's look at them in depth:

(A) Nesting sites of loggerhead turtles have been found off the Pacific coast of North America several thousand kilometers north of the Baja peninsula.

This answer choice doesn't address the exact gap we identified, but it does present an intriguing, alternative location from which these turtles in question could have come. Perhaps the turtles came from somewhere else…

But there is no proof that these sites are more likely places for the turtles to have been born, and, more significantly, this answer does not address any gap in reasoning between the premise and conclusion. We're looking for something that shows us that the DNA evidence is perhaps not as significant as the author believes.

(B) The distance between nesting sites and feeding sites of Atlantic loggerhead turtles is less than 5,000 kilometers.

This answer is related to an opposing point presented in the argument (the distance between the Baja peninsula and Japanese waters is over 10,000 kilometers). However, does this particular distance being 5,000 kilometers mean that 5,000 kilometers is a norm, or a maximum? Not at all. Therefore, this doesn't help us evaluate the reasoning in the argument, and this answer has no direct bearing on the conclusion.

(C) Loggerhead hatchlings in Japanese waters have been declining in number for the last decade while the number of nesting sites near the Baja peninsula has remained constant.

This is another somewhat tempting answer, but we haven't been told, or been given any indication, that all the hatchlings from Japanese waters come to the Baja peninsula. Therefore, it's unclear what relevance this decline would have for those particular turtles. Perhaps the decline in numbers is connected to turtles that end up going elsewhere. We can eliminate it.

(D) Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from Atlantic loggerhead turtles.

It's unclear what this answer means in terms of where the Baja turtles came from.

The point of this answer is NOT that the turtles in question could have come from the Atlantic. We are told explicitly in the argument that Atlantic turtles and Pacific turtles are distinct.

However, this is a clever way to address the gap that we identified. If the turtles in the Baja peninsula have just as strong a DNA match with the Atlantic turtles—turtles that we know for certain are a distinct group—as they do with the Japanese hatchlings, this puts a big dent into the premise-conclusion relationship. This makes it seem the DNA evidence is NOT strong enough to justify the conclusion. (D) seems like the correct answer.

(E) Commercial aquariums have been successfully breeding Atlantic loggerheads with Pacific loggerheads for the last five years.

This is out of scope. We can eliminate it quickly, leaving us with (D).

Notice that the right answer is the one that is most directly relevant to the gap that we identified—specifically the author's assumption that a 95 percent DNA match is adequate proof that the Baja turtles hatched in Japanese waters. If we were just to look for an answer that matches “keywords,” we'd be in trouble here. Without a clear understanding of the argument core, and the gap therein, it's very difficult to see which answers can play a more significant role than others.

Unique Strengthen and Weaken Questions

Though most—in fact, almost all—Strengthen and Weaken questions will develop in a manner that is fairly consistent with other Assumption Family questions, as exampled by the problems above, there are certain Strengthen and Weaken questions that do not agree neatly with what we traditionally associate with Assumption Family questions. Again, these questions are fairly rare, but it's important that you are familiar with their characteristics:

Argument, Minus Core

Take a look at the following question. In addition to solving it, consider what makes this argument different from others we've been looking at.

PT 43, S2, Q8

Criminologist: Increasing the current prison term for robbery will result in no significant effect in discouraging people from committing robbery.

Each of the following, if true, supports the criminologist's claim EXCEPT:

(A) Many people who rob are motivated primarily by thrill-seeking and risk-taking.

(B) An increase in the prison term for embezzlement did not change the rate at which that crime was committed.

(D) Most people committing robbery believe that they will not get caught.

(E) Most people committing robbery have no idea what the average sentence for robbery is.

This is an EXCEPT question. There is a specific way that we want you to approach EXCEPT questions, and we'll discuss this approach in greater detail later in the chapter.

For now, let's focus on the argument. Did you notice something unique about it? We're given a conclusion, but nothing else!

There is no supporting premise and, therefore, no reasoning to evaluate, strengthen, or weaken. Notice the question stem itself makes no mention of “author's reasoning” or “argument,” it simply asks us to evaluate the answers relative to the conclusion. Again, this type of question is fairly rare, but it does show up once every few exams. So, if you see an argument on the exam that just doesn't seem to have a core, don't force it.

Let's finish considering this question.

This is really a conclusion about causation—the author is saying that a certain trigger (lengthening sentences) won't have a particular direct impact (discouragement) on a certain action (robbery).

How do we strengthen such an argument? In one of two ways:

By showing that there is indeed little or no causal connection between lengthening term sentences and discouraging crime.
By showing that there are other factors that more strongly influence the rate of robbery (and in so doing showing that the particular trigger in question is not primary, or significant, to the likelihood of the outcome).

Let's take a look at the answer choices:

(A) Many people who rob are motivated primarily by thrill-seeking and risk-taking.

This addresses the second of our concerns. If this is the primary reason people are robbing, the increase in jail term is less likely to have an impact. This strengthens the claim.

(B) An increase in the prison term for embezzlement did not change the rate at which that crime was committed.

This addresses the first of our concerns. In a similar scenario, we can see that a lengthening of the term didn't impact the rate of crime. This strengthens the claim.

So what? Would an increase deter crime or not? The impact of this answer is unclear.

(D) Most people committing robbery believe that they will not get caught.

If this is true, it's likely robbers are not thinking about prison term length. This would also strengthen the conclusion.

(E) Most people committing robbery have no idea what the average sentence for robbery is.

This addresses the first of our issues. If people don't know how long the term is, it won't matter to them if it is lengthened. This strengthens the claim that increasing the term won't deter crime.

Four of the answers clearly strengthen the conclusion. (C) has an uncertain impact on the conclusion, and is therefore the correct answer.

Beware of Claims within Premises

Another way in which Strengthen and Weaken questions can differ from other typical Assumption Family questions is that they can address the validity of a claim made within a premise. That is, a correct answer can strengthen or weaken something that the premise assumes to be true.

To illustrate, let's take a look at the following example:

My child says she can see ghosts

Therefore, my child can see ghosts

Notice, as with all other premises for Assumption Family questions, the truth of the full premise is not what needs evaluating—we should take it to be true that the child does indeed say this. Our job is not to evaluate whether the child said she can see ghosts.

What needs to be evaluated here is the claim within the premise—the child's claim that she can see ghosts. This is suspect. Perhaps she is seeing shadows. A strengthen answer might validate the fact that she does indeed see ghosts, and a weaken answer might give a reason to believe she does not see ghosts.

Again, we want to be clear—it is not necessary for you to evaluate the truth of the vast majority of claims you see within premises—in fact, in general this will distract you from the far more important task, which is to evaluate the relationship between the premises and the conclusion. However, for certain Strengthen and Weaken questions—you'll see no more than one such problem on your exam—you may need to evaluate the truth of elements within a premise.

Let's take a look at an example from the “Getting Familiar” section:

PT29, S4, Q24

Which one of the following, if true, most weakens the medical researcher's argument?

(A) The hospital records indicate that many babies that are born with normal birth weights are born to mothers who had inadequate prenatal care.

(B) Mothers giving birth prematurely are routinely classified by hospitals as having received inadequate prenatal care when the record of that care is not available.

(C) The hospital records indicate that low birth weight babies were routinely classified as having been born prematurely.

(D) Some babies not born prematurely, whose mothers received adequate prenatal care, have low birth weights.

(E) Women who receive adequate prenatal care are less likely to give birth prematurely than are women who do not receive adequate prenatal care.

The medical researcher gives us a lot of information, then arrives at his main point at the end of the argument: Adequate prenatal care significantly decreases the risk of low birth weight babies.

Like many long arguments, this one has its core at the end. The first sentence perhaps gives us more information about the subjects in the conclusion, and the consequences of the conclusion, but it has no bearing on the reasoning used to reach the conclusion.

The primary evidence he uses comes in the sentence prior to the conclusion, and we can think of the argument core as follows:

Records indicate mothers who received adequate prenatal care are less likely to give birth to low birth weight babies than mothers who received inadequate prenatal care

Adequate prenatal care significantly decreases risk of low birth weight babies

If we heard this argument in real life, it might seem very reasonable to many of us. In critical debater mode, perhaps you noticed a jump from correlation (in the premise) to causation (in the conclusion). It could be true that there is a correlation between adequate prenatal care and the likelihood of giving birth to a low birth weight baby, but that the prenatal care has no direct impact on that outcome. Perhaps another element—such as mother's diet—is most important to birth weight, and those who are likely to follow the proper diet, for a variety of indirect reasons, such as socioeconomic status, happen to be those who get adequate prenatal care. If that were the case, it would be incorrect to say that the prenatal care is what decreases risk.

Let's evaluate the answer choices to see which ones weaken the conclusion:

(A) The hospital records indicate that many babies that are born with normal birth weights are born to mothers who had inadequate prenatal care.

The fact that “many” babies are born of normal weight to mothers who had inadequate prenatal care does not impact the relative likelihood of giving birth to low birth weight babies. This can be a tricky concept to understand, so let's take a look at a simpler example.

Suppose that at a certain ice cream shop those who order the sundae are far more likely to request peanuts than those who order the banana split. This would not mean that all those who order the sundae request peanuts—just that ordering the sundae makes the request more likely. We can image the following results for 100 orders:

	Requested Peanuts	Didn't Request Peanuts
Ordered Sundae	40	10
Ordered Banana Split	10	40

In the above situation, it's true that many people who ordered the banana split requested peanuts, but it doesn't change the fact that those who ordered the sundae were more likely to request peanuts.

The same thing is happening with answer (A). Even if those who get inadequate care give birth to many normal weight babies, it's unclear what impact this has on the conclusion, so we can eliminate it.

(B) Mothers giving birth prematurely are routinely classified by hospitals as having received inadequate prenatal care when the record of that care is not available.

This doesn't address a gap we discussed, but it does impact the premise—it provides an alternative reason for why the difference between likelihoods exists. Let's keep it for now.

(C) The hospital records indicate that low birth weight babies were routinely classified as having been born prematurely.

It's tough to see how this impacts the argument. This answer addresses the relationship between low birth weight and prematurity, but it does not address the relationship between prenatal care and birth weight. Let's eliminate it.

(D) Some babies not born prematurely, whose mothers received adequate prenatal care, have low birth weights.

This answer is similar to (A). “Some” is very vague, and so this gives us no insight into the relative likelihood for the different groups.

(E) Women who receive adequate prenatal care are less likely to give birth prematurely than are women who do not receive adequate prenatal care.

If anything, this answer would strengthen the argument by connecting the factors in the premise and giving another reason why women who receive adequate prenatal care are going to be less likely to give birth to a low weight baby.

We can eliminate this answer because it certainly doesn't weaken.

That leaves us only with answer choice (B). It certainly wasn't what we expected, but it does impact the conclusion. Let's review it one more time:

(B) Mothers giving birth prematurely are routinely classified by hospitals as having received inadequate prenatal care when the record of that care is not available.

In what way does this specifically impact our core? It's essentially telling us that the records themselves are not accurate. In other words, the support for the conclusion is not reliable! This answer choice weakens the reliability of a premise, and thus the argument. Usually we expect an answer that more obviously attacks the connection between the premise and conclusion, but we should expect some curveballs in Strengthen and Weaken questions.

Here's another question with a similar issue. Try it completely before reading further.

PT44, S2, Q20

Scientist: My research indicates that children who engage in impulsive behavior similar to adult thrill-seeking behavior are twice as likely as other children to have a gene variant that increases sensitivity to dopamine. From this, I conclude that there is a causal relationship between this gene variant and an inclination toward thrill-seeking behavior.

Which one of the following, if true, most calls into question the scientist's argument?

(A) Many impulsive adults are not unusually sensitive to dopamine.

(B) It is not possible to reliably distinguish impulsive behavior from other behavior.

(D) Many people exhibit behavioral tendencies as adults that they did not exhibit as children.

(E) The gene variant studied by the scientist is correlated with other types of behavior in addition to thrill-seeking behavior.

Here's the argument core:

Research indicates children who engage in impulsive behavior similar to adult thrill-seeking twice as likely to have gene variant

Causal connection between gene variant and inclination towards thrill-seeking

Once again, this argument is one that would seem quite reasonable in real life. Reading as a debater, perhaps you notice the causal flaw—correlation doesn't prove causation! Perhaps the likelihood is twice as great, but maybe there is another explanation, and there is no causal relationship between the two at all.

Let's evaluate the answer choices:

(A) Many impulsive adults are not unusually sensitive to dopamine.

This answer choice is very similar to a couple from the previous example—“many” does not, in any direct way, impact the likelihood of a characteristic in one group versus another. We can eliminate this quickly.

(B) It is not possible to reliably distinguish impulsive behavior from other behavior.

Hmmm. Interesting. Certainly doesn't have to do with any issue we saw, but, if this were true, it might weaken the argument. Let's keep it.

This may be true, but it is irrelevant to the facts of this argument. The research was not based on such adult characterizations. We can eliminate this.

(D) Many people exhibit behavioral tendencies as adults that they did not exhibit as children.

The research is about children—tendencies that develop later are irrelevant. Eliminate it.

(E) The gene variant studied by the scientist is correlated with other types of behavior in addition to thrill-seeking behavior.

This answer, if anything, would strengthen the connection between the genes and the behavior. We can eliminate it.

Once again, we're left with just one viable answer. Let's evaluate it again:

(B) It is not possible to reliably distinguish impulsive behavior from other behavior.

What would the significance of this answer be? If it's not possible to reliably distinguish impulsive behavior, the research is far less likely to be accurate. If the research is not accurate, it doesn't provide compelling support for the conclusion.

(B) is correct.

This last problem is a perfect example of a difficult Strengthen and Weaken question. The right answer is tough to predict and is presented in a surprising manner. For this type of question, it is critical that you stay open-minded as you evaluate the answer choices. With that in mind, your elimination process becomes even more critical, so let's discuss it in more depth.

The Elimination Process for Strengthen and Weaken Questions

The characteristics of incorrect answers for Strengthen and Weaken questions are fairly consistent with the characteristics of incorrect answers for other Assumption Family questions, and they are answers that are flawed either because of language issues or reasoning issues.

We've already discussed many incorrect answers in this chapter—let's try to organize our understanding of them. You can think of almost all wrong answers to Strengthen and Weaken questions as falling into one of three categories:

1. The answer has no direct bearing on the conclusion. Often, these answers are related to a vague, or slightly incorrect, understanding of the author's point. If you don't have a clear sense of the core, or if you've generalized beyond what the author is specifically discussing, you'll be in trouble with these. If you do have a strong sense of the core, you can often spot an incorrect answer that falls in this category because there is a subtle but significant shift (often a mismatch of terms) between the argument and the answer.

If you have a clear understanding of the core and, most importantly, the conclusion, these answers can be the simplest to eliminate. They also happen to be the most common wrong choices.

2. The answer has an unclear bearing on the conclusion. A slightly more tempting wrong answer is one that is related to the elements of the conclusion, but has an unclear impact on the author's point. We'll discuss these types of answers in more depth in the “EXCEPT” section. These answers may discuss the same subject matter as the argument, but in a manner that doesn't relate directly to the point that the author is making or to the reasoning that the author is using to reach that conclusion. If you can't see how the answer impacts the author's point, or if you can see the answer either strengthening or weakening the argument, depending on how you interpret the answer choice or on what assumptions you make, that's a good sign it neither strengthens nor weakens.

3. The answer plays the opposite role relative to the argument. Let's imagine you are given a Strengthen question, you read through the argument, immediately see one significant flaw, then go to the answer choices. Answers (A) through (C) have no direct impact on the author's point. You get to answer (D)—it is an example that accurately and absolutely proves the flaw you saw in the argument, and so you pick it…

But wait…wouldn't that mean answer choice (D) weakens the argument? We're supposed to strengthen!

As we've said before, answers that express an assumption when we should be looking for a flaw, or answers that weaken an argument when we're looking for something that should strengthen—answers that play the opposite role of what we're looking for—can often be the most tempting and most attractive. This is particularly true for “EXCEPT” questions!

Let's take a look at a real LSAT question. For each wrong choice, take the extra time to try to determine exactly why it is incorrect.

PT36, S3, Q7

Medical doctor: Sleep deprivation is the cause of many social ills, ranging from irritability to potentially dangerous instances of impaired decision making. Most people today suffer from sleep deprivation to some degree. Therefore we should restructure the workday to allow people flexibility in scheduling their work hours.

Which one of the following, if true, would most strengthen the medical doctor's argument?

(A) The primary cause of sleep deprivation is overwork.

(B) Employees would get more sleep if they had greater latitude in scheduling their work hours.

(D) More people would suffer from sleep deprivation today than did in the past if the average number of hours worked per week had not decreased.

(E) The extent of one's sleep deprivation is proportional to the length of one's workday.

The argument begins with a general statement about the consequences of sleep deprivation. The second sentence shows how widespread the issue is, and the author's conclusion comes at the end.

We can think of the core of the doctor's argument as follows:

Most people today suffer from sleep deprivation
+
Sleep deprivation is the cause of many social ills

Should restructure workday to allow more flexibility in scheduling work hours

There is a fairly big gap in this argument. It's unclear what the relationship is between sleep deprivation and flexibility in scheduling work hours.

It's easy to misinterpret, or generalize, this argument to mean that workdays should be set up in such a way as to prevent people from overworking and not getting enough sleep. Notice though that that's NOT what this argument says. If you thought of the conclusion in this way, many of the answer choices could have seemed a lot more attractive than they should have.

Let's go through them now:

(A) The primary cause of sleep deprivation is overwork.

This may be true, but it's unclear what overwork has to do with flexibility in the schedule. This answer is not relevant to the conclusion.

(B) Employees would get more sleep if they had greater latitude in scheduling their work hours.

This answer seems to help bridge the gap between elements in the premises (amount of sleep) and the conclusion (flexibility). Let's keep it for now.

It's unclear what impact, if any, this could have on our conclusion. We can eliminate it.

(D) More people would suffer from sleep deprivation today than did in the past if the average number of hours worked per week had not decreased.

Again, if you had generalized the conclusion to be about a workload that allowed for more sleep, this answer would seem tempting. However, it's unclear what connection there is between a decrease in work hours and the flexibility in hours discussed in the conclusion. You can have flexible work hours and still work a lot!

(E) The extent of one's sleep deprivation is proportional to the length of one's workday.

Again, it's unclear what impact this has on an argument that has to do with flexibility.

That leaves us with (B), the correct answer. Let's review it one more time:

(B) Employees would get more sleep if they had greater latitude in scheduling their work hours.

How does this strengthen the argument, exactly? If (B) is true, then giving more flexibility would allow employees to not be as sleep deprived. This is a good thing, since we're told that sleep deprivation is the cause of many social ills. This answer connects the premises to the conclusion, and helps the premises justify that conclusion.

Note that in this case, there was only one answer that had any direct bearing at all on the conclusion. A careful understanding of the core should have helped you knock off the incorrect choices fairly quickly. Here's another challenging problem for which many incorrect choices will have no relation to the core. Try to eliminate these answers first, before moving on to decide which answer choice is correct.

PT16, S3, Q18

Because dinosaurs were reptiles, scientists once assumed that, like all reptiles alive today, dinosaurs were cold-blooded. The recent discovery of dinosaur fossils in the northern arctic, however, has led a number of researchers to conclude that at least some dinosaurs might have been warm-blooded. These researchers point out that only warm-blooded animals could have withstood the frigid temperatures that are characteristic of arctic winters, whereas cold-blooded animals would have frozen to death in the extreme cold.

Which one of the following, if true, weakens the researchers’ argument?

(A) Today's reptiles are generally confined to regions of temperate or even tropical climates.

(B) The fossils show the arctic dinosaurs to have been substantially smaller than other known species of dinosaurs.

(C) The arctic dinosaur fossils were found alongside fossils of plants known for their ability to withstand extremely cold temperatures.

(D) The number of fossils found together indicates herds of dinosaurs so large that they would need to migrate to find a continual food supply.

(E) Experts on prehistoric climatic conditions believe that winter temperatures in the prehistoric northern arctic were not significantly different from what they are today.

Before reading the explanation, please think again about the answer choices that do not relate to the argument core and notate them in some way.

We can think of the core of this argument as follows:

Dinosaur fossils discovered in northern arctic
+
Only warm-blooded animals can withstand artic winters

Some dinosaurs were warm-blooded

You may have considered the core slightly differently, but by this point your understanding of the core should in general be consistent with ours.

What are the gaps in this argument?

For one, perhaps the winters may have been different when the dinosaurs were around. Perhaps arctic winters weren't as cold back then as they are now, and cold-blooded dinosaurs could have survived. For another, perhaps the dinosaurs migrated north in the warmer summer, and migrated to warmer areas in the south for the winter. In this case, they wouldn't need to survive arctic winters.

Simple enough, perhaps, to see the issues once the argument is dissected, but we know this is a difficult argument to understand the first time through. We can do ourselves a big favor by first getting rid of answers that do not impact the reasoning in any way.

Here are two answer choices we feel you can eliminate even when you don't have a perfect understanding of the core, answer choices that simply have no relationship to the reasoning in the argument:

(A) Today's reptiles are generally confined to regions of temperate or even tropical climates.

Does this generalization have any impact on our conclusion? No. The fact that the reptiles generally live in temperate or tropical climates has no impact on our argument—this doesn't mean reptiles don't live in cold climates. Furthermore, we're assuming a lot in connecting the behavior of reptiles today with the behavior of dinosaurs.

(B) The fossils show the arctic dinosaurs to have been substantially smaller than other known species of dinosaurs.

It's unclear what relevance the size of the dinosaurs has for this argument. So what if they were small? Perhaps you can imagine some relationship between size and heat retention. However, that requires assumptions that go too far beyond the text.

The other answer choices are a bit more tempting. Let's evaluate them in depth:

(C) The arctic dinosaur fossils were found alongside fossils of plants known for their ability to withstand extremely cold temperatures.

Hmmm. If this is true, it would seem the dinosaurs died during very cold temperatures. It supports the idea, perhaps, that the dinosaurs died in the winter. Let's leave it for now.

But wait a minute! That would make it so the author's argument sounds better, and we're looking to weaken. We can eliminate this answer because it plays a reverse role.

By the way, we can also eliminate this answer because it doesn't actually indicate whether these plants (and thus the dinosaurs) actually died in extremely cold temperatures; we simply know that these plants were capable of withstanding cold temperatures. If you noticed this, perhaps you also noticed that this answer has no direct bearing on the conclusion—that some dinosaurs may have been warm-blooded. It's often true that answers are wrong for multiple reasons.

(D) The number of fossils found together indicates herds of dinosaurs so large that they would need to migrate to find a continual food supply.

The first part, about the size of the herds, makes this answer seem out of scope, but the second part is relevant—these herds migrated. If they migrated, perhaps they were in the north only during the summer months. Notice how this answer seems out of scope, but actually helps to break the bond between premise and conclusion. Thus, this answer weakens the author's argument by deflecting the impact of evidence the author uses to prove that there were warm-blooded dinosaurs.

(D) is correct. Let's finish this off by looking at (E):

(E) Experts on prehistoric climatic conditions believe that winter temperatures in the prehistoric northern arctic were not significantly different from what they are today.

This is a very tempting answer. Of all the choices, this one addresses a gap in the argument most directly. However, notice that this is an answer that would strengthen the argument. It's another answer that's the opposite of what we're looking for.

Clearly, this is a difficult question, especially if you didn't anticipate the gap about migration when you initially read the argument. However, even if you didn't see the gap, an answer like (D) should be attractive to you, because it presents an alternative explanation for why bones could be found in an area where dinosaurs seemingly shouldn't be able to survive the winter—because the dinosaurs migrated. In so doing, it directly addresses a gap in the core. Does it make it so that the argument is 100 percent wrong? Absolutely not. Is it the type of answer we expect you can predict every time? Absolutely not. Again, having the ability to quickly eliminate answers that don't directly relate to the core will give you a better chance of zeroing in on such an unlikely correct answer.

Here is a final question you tried earlier. Take the time to solve it again and to classify the wrong answer choices before moving forward.

PT36, S1, Q8

Which one of the following, if true, most seriously weakens the argument?

(A) No scientific issues raised by the claims of environmentalists have important political implications.

(B) There are often more than two opposing views on an issue that cannot be definitely settled on the basis of available evidence.

(C) Some social issues could be definitely settled on the basis of evidence if the opposing sides would give all the available evidence a fair hearing.

(D) Many scientific issues have important political implications and cannot be definitely settled on the basis of the available evidence.

(E) Some television networks refuse to broadcast programs on issues that have important political implications and that cannot be definitely settled by the available evidence.

It's very easy to get distracted in this argument, because it is long, and because the author uses claims that we might disagree with. It's great to read like a debater, but be sure to apply that to the entire core, not just to the premises or just to the conclusion.

Let's evaluate the argument core:

There is obligation to provide equal time for programs involving social issues because they almost always have important political implications and can rarely be solved with available evidence.

If program is about scientific issues, there is no such equal time obligation.

There are many flaws with this argument, and it's dangerous to be overly specific. For example, it's unclear exactly which obligation “no such equal time obligation” refers to—the obligation for equal time, or the obligation for equal time because of these same reasons.

Furthermore, the argument has many gaps. Can't a program be both scientific and social? How do we know scientific problems don't have the characteristics the author describes? Depending on how you read that conclusion, who is to say an obligation doesn't exist to present equal sides for scientific issues for other reasons?

Again, because the argument is vague and heavily flawed, we want to cast a wide net in terms of what could strengthen or what could weaken. Indeed, it will be far more effective to start by finding reasons why four of the answers don't work.

Let's review the answers one at a time:

(A) No scientific issues raised by the claims of environmentalists have important political implications.

This seems to be something the author is assuming, and we know the author is wrong in assuming this—and so this answer can be very tempting. However, this answer is NOT one that, if true, would weaken the argument. If this were true, the argument would be strengthened. We must be careful to be clear about our task. If we are, we can eliminate this answer.

(B) There are often more than two opposing views on an issue that cannot be definitely settled on the basis of available evidence.

This may be true, but it has an unclear impact on our conclusion, because we don't know that scientific issues have views that definitely cannot be settled on the basis of available evidence. Though we are told that people disagree on scientific issues, that's not the same thing, and it would be an assumption to say these people definitely could not settle the dispute using all the available evidence. Furthermore, why does it matter if the number of opposing views is two or more than two? We can eliminate this answer.

(C) Some social issues could be definitely settled on the basis of evidence if the opposing sides would give all the available evidence a fair hearing.

This answer has no bearing on the author's conclusion about scientific issues and can be eliminated quickly. If you were tempted by this answer, make sure you keep your eyes on the core.

(D) Many scientific issues have important political implications and cannot be definitely settled on the basis of the available evidence.

This answer directly addresses the gap, and, if this were true, then the author's point would be weakened. Scientific issues would have the same characteristics that obligate networks to air equal time for social issues.

(E) Some television networks refuse to broadcast programs on issues that have important political implications and that cannot be definitely settled by the available evidence.

Whether they “refuse” is irrelevant to this argument (this is a mismatch with “obligation”) and you can quickly eliminate this answer.

Answer choice (D) is correct.

To be clear, we do not want you to spend precious time during the exam categorizing incorrect choices. However, we think it's very useful for you to go into the exam knowing, in as clear a way as possible, why wrong answer choices are wrong. In reviewing your work, even for problems that you confidently answered correctly, take the time to consider exactly how each wrong choice is “made” incorrect. A strong sense of how wrong answers are built will allow you to go through Strengthen and Weaken questions more efficiently and effectively.

EXCEPT

EXCEPT questions can often be some of the most challenging questions in a Logical Reasoning section. They cause careless errors, are easily misunderstood, and can cause us to get all twisted around.

It's understandable! EXCEPT questions require us to think in the reverse of what we've grow accustomed to doing for solving other types of problems. Answers that directly relate to core, and clearly strengthen or weaken—answers that we typically ought to be attracted to—are going to be the ones we'll generally want to eliminate.

Therefore, it's important that you consider EXCEPT questions as a distinct subcategory of Strengthen and Weaken, and that you practice a process that is specific to these types of questions.

Here are a few key points to remember:

1. Make sure you clearly understand what you are looking for. Let's take a look at a typical phrasing of an EXCEPT question:

“Each of the following, if true, would weaken the argument EXCEPT:”

A common misconception is that the answer choices for such a question will break down as follows: four answer choices that weaken and one answer choice that strengthens.

It's critical to remember that the right answer to this type of question need not, and often will not, strengthen the conclusion. The right answer will simply be the only one that does not weaken. It may strengthen, or it may have no direct bearing on the conclusion. For the most challenging questions, the tendency will be that the right answer has no clearly discernable impact on the conclusion. So, remember that there are three categories of answers:

Weaken

No/Unclear bearing

Strengthen

For a question such as “Each of the following, if true, would strengthen the argument EXCEPT,” four answers will strengthen, and the right answer will either weaken or, more commonly, have no clearly discernable impact on the conclusion.

How can this be? How can the LSAT outsmart you with answers that don't have an impact on the conclusion, and how can it do so to such a degree that these can be some of the most challenging questions on the exam? The key to these well-cloaked answers is that they will relate directly to some other part of the argument, often the primary premise, but not in a way that impacts the author's point. Remember, your job in most Strengthen and Weaken questions is to strengthen or weaken the argument, not the premises or conclusion alone. Your ability to recognize and focus in on the argument core is critical.

To illustrate, let's go back to the sample argument that started the chapter:

Sally owns more cookbooks than Finn

Sally is a better cook than Finn

Here are a few examples of answers that, if true, would strengthen the argument:

“The number of cookbooks one owns is an accurate gauge of how much one knows about cooking.”

“Owning cookbooks inspires people to practice cooking, and, in turn, to become better cooks.”

“Experience in the kitchen and exposure to foods of other cultures are not factors that significantly influence knowledge of cooking.”

Here are a few examples of answers that would, if true, weaken the argument:

“Sally has not read any of her cookbooks.”

“Sally often misreads cookbooks and ends up becoming a worse cook after reading them.”

“Sally was born without taste buds and cannot accurately gauge the flavor of her cooking.”

Each of these answers has a direct impact on the conclusion either because it supports the reasoning used in connecting the premise to the conclusion, or because it exposes gaps in this reasoning. We can see how each of these answers would have a direct impact on our judgment of whether Sally is a better cook than Finn.

Now here is an answer that seems related to the argument, but neither strengthens nor weakens the author's reasoning:

“Sally unexpectedly got all the cookbooks from her mother when her mother moved into a smaller house.”

Note that this answer relates directly to our premise—in fact, it gives us a reason why our premise is true.

But does this answer impact the author's conclusion? Does it impact the reasoning used? Not in a clear, direct way.

The fact that Sally inherited the books could mean she didn't have any interest in owning them, or it could mean she wanted the books. If we try to connect this answer to the argument in a way that impacts whether Sally is a better cook than Finn, we could only do so by adding significant conjectures, or assumptions. Therefore, we can say that this answer does not have a clearly definable impact on our argument.

Let's now take a look back at a question from the start of the chapter. Please solve it again now so that your process will be fresh in your mind as we continue the discussion:

PT37, S2, Q20

Each of the following, if true, provides some support for the researchers’ hypothesis EXCEPT:

(A) Horses are known to store oxygenated blood in their spleens for use during exertion.

(B) Many species of seal can store oxygen directly in their muscle tissue.

(C) The oxygen contained in the seals’ lungs and bloodstream alone would be inadequate to support the seals during their dives.

(D) The spleen is much larger in the Antarctic seal than in aquatic mammals that do not make long dives.

(E) The spleens of Antarctic seals contain greater concentrations of blood vessels than are contained in most of their other organs.

We discussed earlier that arguments for Strengthen and Weaken questions can stray farther from the norm than arguments for Assumption and Identify a Flaw questions—this isn't very common, but here's an example of an argument that doesn't fit the argument core model.

We could think of the core in this way:

Seals stay submerged for hours
+
Don't rely solely on oxygen in lungs
+
Store oxygen in blood

Store oxygenated blood in spleens

However, a more accurate representation of this argument is that the first two sentences present background for a hypothesis that doesn't have a supporting premise. Here we have another argument without a core:

Seals store oxygenated blood in their spleens.

Again, we want to stress that being asked to strengthen or weaken an argument without a premise-conclusion is fairly unusual. Something you should expect to see no more than once, if that, on any given exam. By the way, it's no coincidence that both “core-free” arguments we've discussed in this chapter have come in the form of EXCEPT questions. Also, note that we were given a subtle clue in the way the question is asked:

“Each of the following, if true, provides some support for the researchers’ hypothesis EXCEPT:”

The words in bold are of note because of what is missing—typically we are asked to evaluate what would strengthen or weaken reasoning, or an argument. In this case, we're asked to identify answers that simply support the hypothesis, or conclusion. We know we just need to compare the answers to the conclusion.

Now it's time to look at the answer choices. Your frame of mind is critical to your success and efficiency. Here's our second tip:

2. Eliminate the four that weaken or strengthen! This may seem like obvious advice—incredibly obvious advice, perhaps. However, the reason we make a point of stating this is that by the time you are done practicing all the Strengthen and Weaken questions that we hope you will practice, your default mind-set is going to be to look for the one answer that weakens or the one answer that strengthens. If you are not careful, this habit will slow you down or distract you on EXCEPT questions.

It is important that you change your mind-set for EXCEPT questions. What you know going in to the answer choices is that almost all of the answers, 80 percent, in fact, will strengthen or will weaken.

Let's focus in on the hypothesis one more time before going into the answer choices:

Seals store oxygenated blood in their spleens.

We know almost all the answers will support this idea, and we want to cast a wide net. Let's evaluate each in depth:

(A) Horses are known to store oxygenated blood in their spleens for use during exertion.

This strengthens the argument because it shows that such a thing—an animal storing oxygenated blood in its spleen—is possible.

It's important to note that this is the type of answer that most likely would be considered out of scope for an Assumption or Identify a Flaw question. The author doesn't need to assume anything about horses to make her claim about seals, nor is it a flaw that she didn't. This is another example of how answers that strengthen or weaken can feel a bit further separated from the text than answers that represent assumptions or flaws.

(B) Many species of seal can store oxygen directly in their muscle tissue.

How does this impact the conclusion? It's unclear. Let's leave it for now.

(C) The oxygen contained in the seals’ lungs and bloodstream alone would be inadequate to support the seals during their dives.

This strengthens the conclusion. It means that they need to store oxygen someplace else, and that supports the idea that they could store it in the spleen.

(D) The spleen is much larger in the Antarctic seal than in aquatic mammals that do not make long dives.

This also strengthens. If the spleen for these seals is larger, it's possible this difference is due to using the spleen for storing oxygenated blood.

(E) The spleens of Antarctic seals contain greater concentrations of blood vessels than are contained in most of their other organs.

This also strengthens. This difference in the spleen is more evidence that the spleens are used to store extra oxygen.

In the initial read, you may have felt that many of these answers did not strengthen the argument. If so, it's likely you are setting the bar too high. Remember that answers that strengthen need not make an argument perfect, or anywhere near that. Especially for an EXCEPT question, strengthen answers simply have to give you a stronger sense that the conclusion is true than that the conclusion is false.

There is only one answer that doesn't have any discernable impact on the conclusion:

(B) Many species of seal can store oxygen directly in their muscle tissue.

This is the correct answer. How does the fact that seals can store oxygen in their muscles support the idea that they can store it in their spleens? It doesn't.

Let's try another challenging example:

PT33, S1, Q20

Recently discovered prehistoric rock paintings on small islands off the northern coast of Norway have archaeologists puzzled. The predominant theory about northern cave paintings was that they were largely a description of the current diets of the painters. This theory cannot be right, because the painters must have needed to eat the sea animals populating the waters north of Norway if they were to make the long journey to and from the islands, and there are no paintings that unambiguously depict such creatures.

Each of the following, if true, weakens the argument against the predominant theory about northern cave paintings EXCEPT:

(A) Once on these islands, the cave painters hunted and ate land animals.

(B) Parts of the cave paintings on the islands did not survive the centuries.

(D) Those who did the cave paintings that were discovered on the islands had unusually advanced techniques of preserving meats.

(E) The cave paintings on the islands were done by the original inhabitants of the islands who ate the meat of land animals.

The author's conclusion is that the predominant theory cannot be right, and this predominant theory is that northern cave paintings were largely a description of the current diets of the painters. The premises are given in the sentence that follows in the argument, and we can think of the argument core as follows:

Needed to eat sea animals during journey to islands
+
No unambiguous paintings of sea animals

False that cave paintings largely describe current diets of painters.

There are some significant gaps in the argument—we don't actually know anything about the diets of the painters once they are on the island, and we don't know if the paintings that have been discovered are representative of all the paintings on the island. It's certainly helpful to consider these gaps as we go into the answer choices.

We want to make sure to focus on eliminating answers that weaken this core. In this case—because we are asked specifically to weaken a claim that another claim is false—it's especially easy to get turned around. To keep focused, remember that the conclusion of the argument is that the paintings were not based on the diet.

Let's evaluate the answer choices carefully:

(A) Once on these islands, the cave painters hunted and ate land animals.

This shows that the painters could have painted their current diet, but that diet just didn't consist of seafood. Therefore, it weakens the author's claim. Let's eliminate it.

(B) Parts of the cave paintings on the islands did not survive the centuries.

This shows that the evidence provided might be limited or unrepresentative, and therefore weakens the argument. Maybe they did paint sea animals, but those paintings have been lost. Let's eliminate it.

This answer seems less directly connected to the core than the first two. Let's leave it for now.

(D) Those who did the cave paintings that were discovered on the islands had unusually advanced techniques of preserving meats.

At first this seems out of scope, but (D) offers another explanation for how, perhaps, the food the painters were eating, and consequently painting, could have been something other than seafood. It calls into question the idea that the long journey required eating fish.

(E) The cave paintings on the islands were done by the original inhabitants of the islands who ate the meat of land animals.

If they were done by people who didn't need to travel to get to the island, one of the premises is made irrelevant. This answer presents the possibility that even though the painters didn't paint seafood they could have still painted the food they ate.

Once again, we're left with one answer that didn't get cut. Let's look at it one more time:

Does this prove that the premises don't connect to the conclusion? It could if you, as the reader, assume that the painters ate land animals. But it could also strengthen the conclusion if the painters did not eat the land animals (maybe the only land animals were ones that aren't nice to eat, or maybe the painters were vegans). Notice that, in order to determine whether this answer strengthens or weakens, we need a lot of conjecture. This is an answer that has an uncertain bearing on the conclusion, and it is therefore correct.

Conclusion

Strengthen and Weaken questions are still Assumption Family questions, and the skills you've developed for Assumption and Identify a Flaw questions should help you here. Here are some additional considerations specific to Strengthen and Weaken questions:

1. One extra layer. For Assumption and Identify a Flaw questions, we are expected to identify and assess the core. For Strengthen and Weaken questions, we also must address gaps in the core. The answers to Strengthen and Weaken questions may feel less directly connected to the argument than answers to Assumption and Identify a Flaw, and also less predictable.

2. Unique arguments. Strengthen and Weaken arguments have more of a tendency to vary from the norm than other Assumption Family questions. It's critical to be flexible. Beware of arguments without cores and of claims within premises.

3. The elimination process. Because the right answers are less predictable, your elimination process is crucial. Eliminate answers that don't relate to the core, have an indeterminate relationship to the core, or—and this one can be tricky to spot—play an opposite role.

4. EXCEPT questions. Make sure to change your process for EXCEPT questions. Eliminate the four answer choices that strengthen or weaken. The right answer will often relate to the elements in the argument, but have no clearly discernable bearing on the author's point.

DRILL IT: Strengthen and Weaken Questions

Give yourself no more than 20 minutes to complete the following problems.

1. PT29, S1, Q3

There should be a greater use of gasohol. Gasohol is a mixture of alcohol and gasoline, and has a higher octane rating and fewer carbon monoxide emissions than straight gasoline. Burning gasohol adds no more carbon dioxide to the atmosphere than plants remove by photosynthesis.

Each of the following, if true, strengthens the argument above EXCEPT:

(A) Cars run less well on gasoline than they do on gasohol.

(B) Since less gasoline is needed with the use of gasohol, an energy shortage is less likely.

(D) Gasohol is cheaper to produce and hence costs less at the pump than gasoline.

(E) Burning gasoline adds more carbon dioxide to the atmosphere than plants can remove.

2. PT29, S1, Q16

We can learn about the living conditions of a vanished culture by examining its language. Thus, it is likely that the people who spoke Proto-Indo-European, the language from which all Indo-European languages descended, lived in a cold climate, isolated from ocean or sea, because Proto-Indo-European lacks a word for “sea,” yet contains words for “winter,” “snow,” and “wolf.”

Which one of the following, if true, most seriously weakens the argument?

(A) A word meaning “fish” was used by the people who spoke Proto-Indo-European.

(B) Some languages lack words for prominent elements of the environments of their speakers.

(D) Proto-Indo-European possesses words for “heat.”

(E) The people who spoke Proto-Indo-European were nomadic.

3. PT29, S4, Q20

Amphibian populations are declining in numbers worldwide. Not coincidentally, the earth's ozone layer has been continuously depleted throughout the last 50 years. Atmospheric ozone blocks UV-B, a type of ultraviolet radiation that is continuously produced by the sun, and which can damage genes. Because amphibians lack hair, hide, or feathers to shield them, they are particularly vulnerable to UV-B radiation. In addition, their gelatinous eggs lack the protection of leathery or hard shells. Thus, the primary cause of the declining amphibian population is the depletion of the ozone layer.

Each of the following, if true, would strengthen the argument EXCEPT:

(A) Of the various types of radiation blocked by atmospheric ozone, UV-B is the only type that can damage genes.

(B) Amphibian populations are declining far more rapidly than are the populations of nonamphibian species whose tissues and eggs have more natural protection from UV-B.

(C) Atmospheric ozone has been significantly depleted above all the areas of the world in which amphibian populations are declining.

(D) The natural habitat of amphibians has not become smaller over the past century.

(E) Amphibian populations have declined continuously for the last 50 years.

4. PT30, S2, Q3

Opponents of peat harvesting in this country argue that it would alter the ecological balance of our peat-rich wetlands and that, as a direct consequence of this, much of the country's water supply would be threatened with contamination. But this cannot be true, for in Ireland, where peat has been harvested for centuries, the water supply is not contaminated. We can safely proceed with the harvesting of peat.

Which one of the following, if true, most strengthens the argument?

(A) Over hundreds of years, the ecological balance of all areas changes slowly but significantly, sometimes to the advantage of certain flora and fauna.

(B) The original ecology of the peat-harvesting areas of Ireland was virtually identical to that of the undisturbed wetlands of this country.

(C) The activities of other industries in coming years are likely to have adverse effects on the water supply of this country.

(D) The peat resources of this country are far larger than those of some countries that successfully harvest peat.

(E) The peat-harvesting industry of Ireland has been able to supply most of that country's fuel for generations.

5. PT30, S4, Q11

High school students who feel that they are not succeeding in school often drop out before graduating and go to work. Last year, however, the city's high school dropout rate was significantly lower than the previous year's rate. This is encouraging evidence that the program instituted two years ago to improve the morale of high school students has begun to take effect to reduce dropouts.

Which one of the following, if true about the last year, most seriously weakens the argument?

(A) There was a recession that caused a high level of unemployment in the city.

(B) The morale of students who dropped out of high school had been low even before they reached high school.

(D) High schools in the city established placement offices to assist their graduates in obtaining employment.

(E) The antidropout program was primarily aimed at improving students’ morale in those high schools with the highest dropout rates.

6. PT32, S1, Q20

Current maps showing the North American regions where different types of garden plants will flourish are based on weather data gathered 60 years ago from a few hundred primitive weather stations. New maps are now being compiled using computerized data from several thousand modern weather stations and input from home gardeners across North America. These maps will be far more useful.

Each of the following, if true, helps to support the claim that the new maps will be more useful EXCEPT:

(A) Home gardeners can provide information on plant flourishing not available from weather stations.

(B) Some of the weather stations currently in use are more than 60 years old.

(D) Weather conditions are the most important factor in determining where plants will grow.

(E) Weather patterns have changed in the past 60 years.

7. PT30, S4, Q12

The television show Henry was not widely watched until it was scheduled for Tuesday evenings immediately after That's Life, the most popular show on television. During the year after the move, Henry was consistently one of the ten most-watched shows on television. Since Henry's recent move to Wednesday evenings, however, it has been watched by far fewer people. We must conclude that Henry was widely watched before the move to Wednesday evenings because it followed That's Life and not because people especially liked it.

Which one of the following, if true, most strengthens the argument?

(A) Henry has been on the air for three years, but That's Life has been on the air for only two years.

(B) The show that replaced Henry on Tuesdays has persistently had a low number of viewers in the Tuesday time slot.

(D) After its recent move to Wednesday, Henry was aired at the same time as the second most popular show on television.

(E) That's Life was not widely watched during the first year it was aired.

8. PT32, S1, Q12

Navigation in animals is defined as the animal's ability to find its way from unfamiliar territory to points familiar to the animal but beyond the immediate range of the animal's senses. Some naturalists claim that polar bears can navigate over considerable distances. As evidence, they cite an instance of a polar bear that returned to its home territory after being released over 500 kilometers (300 miles) away.

Which one of the following, if true, casts the most doubt on the validity of the evidence offered in support of the naturalists’ claim?

(A) The polar bear stopped and changed course several times as it moved toward its home territory.

(B) The site at which the polar bear was released was on the bear's annual migration route.

(D) Polar bears are only one of many species of mammal whose members have been known to find their way home from considerable distances.

(E) Polar bears often rely on their extreme sensitivity to smell in order to scent out familiar territory.

9. PT32, S1, Q17

Detective: Because the embezzler must have had specialized knowledge and access to internal financial records, we can presume that the embezzler worked for XYZ Corporation as either an accountant or an actuary. But an accountant would probably not make the kind of mistakes in ledger entries that led to the discovery of the embezzlement. Thus it is likely that the embezzler is one of the actuaries.

Each of the following weakens the detective's argument EXCEPT:

(A) The actuaries’ activities while working for XYZ Corporation were more closely scrutinized by supervisors than were the activities of the accountants.

(B) There is evidence of breaches in computer security at the time of the embezzlement that could have given persons outside XYZ Corporation access to internal financial records.

(D) An independent report released before the crime took place concluded that XYZ Corporation was vulnerable to embezzlement.

(E) Certain security measures at XYZ Corporation made it more difficult for the actuaries to have access to internal financial records than for the accountants.

10. PT37, S4, Q2

The vomeronasal organ (VNO) is found inside the noses of various animals. While its structural development and function are clearer in other animals, most humans have a VNO that is detectable, though only microscopically. When researchers have been able to stimulate VNO cells in humans, the subjects have reported experiencing subtle smell sensations. It seems, then, that the VNO, though not completely understood, is a functioning sensory organ in most humans.

Which one of the following, if true, most weakens the argument?

(A) It is not known whether the researchers succeeded in stimulating only VNO cells in the human subjects’ noses.

(B) Relative to its occurrence in certain other animals, the human VNO appears to be anatomically rudimentary and underdeveloped.

(C) Certain chemicals that play a leading role in the way the VNO functions in animals in which it is highly developed do not appear to play a role in its functioning in humans.

(D) Secondary anatomical structures associated with the VNO in other animals seem to be absent in humans.

(E) For many animal species, the VNO is thought to subtly enhance the sense of smell.

Challenge Questions

11. PT29, S4, Q11

Sometimes when their trainer gives the hand signal for “Do something creative together,” two dolphins circle a pool in tandem and then leap through the air simultaneously. On other occasions the same signal elicits synchronized backward swims or tail-waving. These behaviors are not simply learned responses to a given stimulus. Rather, dolphins are capable of higher cognitive functions that may include the use of language and forethought.

Which one of the following, if true, most strengthens the argument?

(A) Mammals have some resemblance to one another with respect to bodily function and brain structure.

(B) The dolphins often exhibit complex new responses to the hand signal.

(D) Dolphins do not interact with humans the way they interact with one another.

(E) Some of the behaviors mentioned are exhibited by dolphins in their natural habitat.

12. PT30, S4, Q18

People who have political power tend to see new technologies as a means of extending or protecting their power, whereas they generally see new ethical arguments and ideas as a threat to it. Therefore, technical ingenuity usually brings benefits to those who have this ingenuity, whereas ethical inventiveness brings only pain to those who have this inventiveness.

Which one of the following statements, if true, most strengthens the argument?

(A) Those who offer new ways of justifying current political power often reap the benefits of their own innovations.

(B) Politically powerful people tend to reward those who they believe are useful to them and to punish those who they believe are a threat.

(D) New technologies are often used by people who strive to defeat those who currently have political power.

(E) Many people who possess ethical inventiveness conceal their novel ethical arguments for fear of retribution by the politically powerful.

13. PT30, S2, Q21

The new agriculture bill will almost surely fail to pass. The leaders of all major parties have stated that they oppose it.

Which one of the following, if true, adds the most support for the prediction that the agriculture bill will fail to pass?

(A) Most bills that have not been supported by even one leader of a major party have not been passed into law.

(B) Most bills that have not been passed into law were not supported by even one member of a major party.

(D) Most bills that have been passed into law were not unanimously supported by the leaders of all major parties.

(E) Most bills that have been passed into law were supported by at least one leader of a major party.

14. PT30, S4, Q20

Consumer advocate: The introduction of a new drug into the marketplace should be contingent upon our having a good understanding of its social impact. However, the social impact of the newly marketed antihistamine is far from clear. It is obvious, then, that there should be a general reduction in the pace of bringing to the marketplace new drugs that are now being tested.

Which one of the following, if true, most strengthens the argument?

(A) The social impact of the new antihistamine is much better understood than that of most new drugs being tested.

(B) The social impact of some of the new drugs being tested is poorly understood.

(D) The new antihistamine is chemically similar to some of the new drugs being tested.

(E) The new antihistamine should be on the market only if most new drugs being tested should be on the market also.

15. PT34, S2, Q12

The five senses have traditionally been viewed as distinct yet complementary. Each sense is thought to have its own range of stimuli that are incapable of stimulating the other senses. However, recent research has discovered that some people taste a banana and claim that they are tasting blue, or see a color and say that it has a specific smell. This shows that such people, called synesthesiacs, have senses that do not respect the usual boundaries between the five recognized senses.

Which one of the following statements, if true, most seriously weakens the argument?

(A) Synesthesiacs demonstrate a general, systematic impairment in their ability to use and understand words.

(B) Recent evidence strongly suggests that there are other senses besides sight, touch, smell, hearing, and taste.

(D) The synesthetic phenomenon has been described in the legends of various cultures.

(E) Synesthesiacs can be temporarily rid of their synesthetic experiences by the use of drugs.

SOLUTIONS: Strengthen and Weaken Questions

1. PT29, S1, Q3

Each of the following, if true, strengthens the argument above EXCEPT:

(A) Cars run less well on gasoline than they do on gasohol.

(B) Since less gasoline is needed with the use of gasohol, an energy shortage is less likely.

(D) Gasohol is cheaper to produce and hence costs less at the pump than gasoline.

(E) Burning gasoline adds more carbon dioxide to the atmosphere than plants can remove.

Answer choice (C) is correct.

Here, the author's conclusion is that there should be a greater use of gasohol. The support given is that gasohol is higher in octane and has fewer emissions than gasoline. Also, burning gasohol adds no more carbon to the atmosphere than plants remove.

This is a simple argument with a wide range of potential “strengtheners” (there might be a thousand additional reasons to use more gasohol), so we should keep our minds open and focus on eliminating choices that strengthen the conclusion.

(A) adds a reason that gasohol is superior to gasoline. This strengthens.

(B) tells us that gasohol use reduces the likelihood of an energy shortage. Since energy shortages are undesirable, this is a good thing for gasohol and therefore strengthens the argument.

(C) weakens the argument by saying that gasohol is a less efficient fuel than gasoline. This is definitely our answer, but let's rule out the other two just to be sure.

(D) says gasohol is cheaper. This strengthens.

(E) is a tempting choice. At first glance, it doesn't seem to say anything about gasohol. However, by stating that gasoline adds more carbon to the atmosphere than plants can remove, the case for using gasohol, which we know adds less carbon, is strengthened.

2. PT29, S1, Q16

Which one of the following, if true, most seriously weakens the argument?

(A) A word meaning “fish” was used by the people who spoke Proto-Indo-European.

(B) Some languages lack words for prominent elements of the environments of their speakers.

(D) Proto-Indo-European possesses words for “heat.”

(E) The people who spoke Proto-Indo-European were nomadic.

Answer choice (B) is correct.

The author's conclusion is that the people who spoke Proto-Indo-European lived in a cold climate, isolated from the ocean. The only reasons given are the presence of the words “winter,” “snow,” and “wolf” in that language, and the absence of the word “sea.”

The gap here is fairly clear: what exactly is the connection between the presence or absence of certain words in a language and the presence or absence of the features that those words represent? Since our task is to weaken the argument, we essentially want to select an answer choice that makes it possible for a culture to lack words for the environments in which they live.

Let's look at the choices:

(A) is a trap designed to make us associate “fish” with the “sea.” Fish can live in rivers, lakes, and ponds, however, and the Proto-Indo-Europeans might have had those words.

(B) weakens. If some languages lack words for prominent features of the speakers’ environment, then it is possible that the Proto-Indo-Europeans did live by the sea and yet did not have a word for it.

(D) has no bearing whatsoever.

(E) is a trap. Even if they were nomadic, they may still have lived in a cold climate isolated from the ocean. Therefore, this choice neither strengthens nor weakens.

3. PT29, S4, Q20

Each of the following, if true, would strengthen the argument EXCEPT:

(A) Of the various types of radiation blocked by atmospheric ozone, UV-B is the only type that can damage genes.

(B) Amphibian populations are declining far more rapidly than are the populations of nonamphibian species whose tissues and eggs have more natural protection from UV-B.

(C) Atmospheric ozone has been significantly depleted above all the areas of the world in which amphibian populations are declining.

(D) The natural habitat of amphibians has not become smaller over the past century.

(E) Amphibian populations have declined continuously for the last 50 years.

Answer choice (A) is correct.

“Primary” is a very important word on the LSAT, and one we should notice immediately. The author's conclusion is that the depletion of the ozone layer is the primary cause of the decline in amphibian populations. The reasons given are that (1) depleted atmosphere blocks less UV-B radiation, which is dangerous to amphibians, and (2) amphibian eggs have less protection than others.

We should focus on eliminating the four choices that strengthen the argument.

(A) does not seem to strengthen. Does it matter how many kinds of radiation damage genes? No! We know that UV-B does, and amphibians are vulnerable to it, and the atmosphere blocks it. To say that UV-B is the only kind of radiation that damages genes does not support that reasoning.

(B) strengthens the idea that UV-B is killing the amphibians. Eliminate it.

(D) strengthens by ruling out an alternative explanation. We should always be on the lookout for choices like this when we are working with causal arguments. As soon as we recognize an argument as causal (as in depletion of ozone had a direct impact on the decline of amphibians), we can anticipate potential strengthen and weaken answer choices. A weakening choice will suggest another cause, or an alternate mode of causation, while a strengthening choice will rule out other potential causes, or modes of causation.

In this argument, a decline in habitat size could very well be the primary cause for the demise of the amphibians. By ruling out that possibility, we strengthen the idea that depleted ozone is the cause. Eliminate it.

(E) strengthens by matching up the timelines of the ozone depletion and the amphibian decline. Eliminate it.

4. PT30, S2, Q3

Which one of the following, if true, most strengthens the argument?

(A) Over hundreds of years, the ecological balance of all areas changes slowly but significantly, sometimes to the advantage of certain flora and fauna.

(B) The original ecology of the peat-harvesting areas of Ireland was virtually identical to that of the undisturbed wetlands of this country.

(C) The activities of other industries in coming years are likely to have adverse effects on the water supply of this country.

(D) The peat resources of this country are far larger than those of some countries that successfully harvest peat.

(E) The peat-harvesting industry of Ireland has been able to supply most of that country's fuel for generations.

Answer choice (B) is correct.

The author concludes that opponents of peat harvesting are wrong and that it is in fact safe to proceed. The basis for the argument is a comparison to Ireland. This is another common argument type that we should recognize immediately! When an argument is made by analogy, as it is here, there is a simple way to weaken and a simple way to strengthen: to weaken, make the comparison less sound (apples to oranges); to strengthen, make the comparison more sound (apples to apples).

So here, we can anticipate that a good answer choice will make the comparison to Ireland stronger by relating Ireland to the country in question in some important way.

(A) has no bearing.

(B) strengthens. This is exactly what we anticipated. If Ireland's ecology was originally identical to this country's, then the argument is better because the comparison is well made. If Ireland's ecology was nothing at all like this country's, the argument would be severely weakened.

(D) is out of scope, though perhaps a bit tempting. First of all, we have no evidence that the size of the peat resources has anything to do with whether the peat can be harvested without contaminating the water. Another key is the word “some.” The fact that the resources here are larger than those in some countries does not say much. If other countries can successfully handle an equal or greater amount of resources, then this country should be able to as well.

(E) is out of scope. The amount of fuel produced has nothing to do with the question of water contamination or the comparison to Ireland.

5. PT30, S4, Q11

Which one of the following, if true about the last year, most seriously weakens the argument?

(A) There was a recession that caused a high level of unemployment in the city.

(B) The morale of students who dropped out of high school had been low even before they reached high school.

(D) High schools in the city established placement offices to assist their graduates in obtaining employment.

(E) The antidropout program was primarily aimed at improving students’ morale in those high schools with the highest dropout rates.

Answer choice (A) is correct.

Let's take a look at the core:

Some high school students drop out and go to work
+
last year the dropout rate was lower than the previous year

the morale program is reducing the number of dropouts.

There is definitely a “percentage vs. real numbers” flaw at work here, and we could go to the choices equipped with that perspective. What we find is that none of the choices address that issue. At that point, we might have to start over with (A) and reconsider things with an open mind. Another flaw to consider would be the causal nature of the program. What if something else was responsible for reducing the number of dropouts? That would be a clear way to weaken this argument.

(A) does exactly that. If unemployment was especially high, then students would not be able to drop out and find jobs. Therefore, they might be more likely to stay in school. This might explain the reduced number of dropouts.

(B) does not relate to the argument. Was the program effective at reducing dropouts or not?

(D) pretends to provide an incentive for the students to stay in school, which could potentially offer an alternative to the morale program. However, if most students who drop out do so to go to work, then we have no reason to believe that an employment program would be of any benefit to them.

(E) is irrelevant.

6. PT32, S1, Q20

Each of the following, if true, helps to support the claim that the new maps will be more useful EXCEPT:

(A) Home gardeners can provide information on plant flourishing not available from weather stations.

(B) Some of the weather stations currently in use are more than 60 years old.

(D) Weather conditions are the most important factor in determining where plants will grow.

(E) Weather patterns have changed in the past 60 years.

Answer choice (B) is correct.

Four of the answers will strengthen the claim that the new maps, drawn from information from modern weather stations and home gardeners, will be more useful than the old maps.

We want to eliminate the choices that strengthen:

(A) strengthens because the home gardeners are providing information for the new maps.

(B) definitely does not strengthen. It actually seems to weaken, though this is debatable. The pertinent issue regarding the weather stations is whether they are primitive or modern, which, as far as we know, may or may not have to do with their age. Just because the old maps were drawn over 60 years ago using primitive stations, this does not mean that all stations built more than 60 years ago were primitive. Perhaps the maps were drawn 60 years ago using the “primitive” stations built 200 years ago, and the new maps are being drawn using the “modern” stations built 70 years ago. So, at best, (B) does not affect the argument at all, and at worst, it weakens it. Let's leave it.

(C) definitely strengthens. Since the new maps utilize information from many more stations, and an additional source—home gardeners—we can infer that more information will be available.

(D) strengthens the “far more useful” part of our conclusion. Consider the opposite: if weather patterns are actually not important at all, then a weather map is useless, and a better weather map is equally useless.

(E) definitely strengthens. If the old maps are obsolete, the claim that the new maps will be more useful is supported.

Therefore, answer choice (B) is our answer.

7. PT30, S4, Q12

The television show Henry was not widely watched until it was scheduled for Tuesday evenings immediately after That's Life, the most popular show on television. During the year after the move, Henry was consistently one of the ten most-watched shows on television. Since Henry's recent move to Wednesday evenings, however, it has been watched by far fewer people. We must conclude that Henry was widely watched before the move to Wednesday evenings because it followed That's Life and not because people especially liked it.

Which one of the following, if true, most strengthens the argument?

(A) Henry has been on the air for three years, but That's Life has been on the air for only two years.

(B) The show that replaced Henry on Tuesdays has persistently had a low number of viewers in the Tuesday time slot.

(D) After its recent move to Wednesday, Henry was aired at the same time as the second most popular show on television.

(E) That's Life was not widely watched during the first year it was aired.

Answer choice (C) is correct.

We are asked to strengthen the conclusion that the show Henry was widely watched because it followed That's Life rather than because people liked it. The evidence is that when Henry followed That's Life, it was widely watched, and since it was moved, it is watched by far fewer people.

We should anticipate that a correct answer will most likely give us additional evidence that Henry's placement after That's Life was essential to its success. A correct answer might also give us reason to believe that Henry was not watched because people especially liked it.

(A) does not tell us anything about why the show was popular or why it declined in popularity.

(B) tells us that the show now occupying Henry's old slot is not popular. This hints at the fact that following That's Life does not guarantee success, and therefore does not strengthen the argument.

(C) adds direct support to our conclusion. If another show has doubled its audience since being placed after That's Life, we have an additional reason to believe that That's Life contributed to Henry's popularity as well.

(D) offers an alternate explanation of perhaps why fewer people watched Henry after its move. It does not offer support for the author's conclusion.

(E) gives us a bit more information about the premise, but does not impact reasoning issues in the core in any way.

8. PT32, S1, Q12

Which one of the following, if true, casts the most doubt on the validity of the evidence offered in support of the naturalists’ claim?

(A) The polar bear stopped and changed course several times as it moved toward its home territory.

(B) The site at which the polar bear was released was on the bear's annual migration route.

(D) Polar bears are only one of many species of mammal whose members have been known to find their way home from considerable distances.

(E) Polar bears often rely on their extreme sensitivity to smell in order to scent out familiar territory.

Answer choice (B) is correct.

This is a slightly different-flavored Weaken question. Our task is to challenge the validity of the evidence itself, so in this case, we will emphasize the evidence in our analysis.

First of all, to fit the definition of navigation, the animal must find its way from unfamiliar territory to familiar territory beyond the range of its senses. Next, a polar bear returned home after being released 300 miles away.

It is very difficult to anticipate or imagine potential answer choices here, so with the evidence firmly in mind, let's go to the choices.

(A) …so what? Nothing in the given definition of navigation says that changing direction is not allowed.

(B) weakens. If the place the bear was released was on its annual migration route, then that place is not unfamiliar. This is definitely our answer, but we'll check the others.

(D) says other species can find their way home. If anything, this strengthens the claim being used as evidence.

(E) …so what? In order for this to weaken, we would need to know that the bear actually used its sense of smell in this case. If this choice said something like “the bear could smell its home from where it was released,” it would be a good answer, because one of the conditions that must be met is “beyond the range of the senses.”

9. PT32, S1, Q17

Each of the following weakens the detective's argument EXCEPT:

(A) The actuaries’ activities while working for XYZ Corporation were more closely scrutinized by supervisors than were the activities of the accountants.

(B) There is evidence of breaches in computer security at the time of the embezzlement that could have given persons outside XYZ Corporation access to internal financial records.

(D) An independent report released before the crime took place concluded that XYZ Corporation was vulnerable to embezzlement.

(E) Certain security measures at XYZ Corporation made it more difficult for the actuaries to have access to internal financial records than for the accountants.

Answer choice (D) is correct.

In order to get this one right, we must stick to a disciplined process of elimination. Here's how that process might look:

First, the core:

The embezzler was either an actuary or an accountant
+
accountant would probably not make the kind of mistakes that were made

embezzler is likely an actuary.

Since this is an EXCEPT question, we should try to eliminate the answer choices that weaken.

(A) slightly weakens. If the actuaries were more closely scrutinized, it is reasonable to think that they are less likely to embezzle. Eliminate it.

(B) definitely weakens by suggesting that the embezzler may not have worked for the company at all. Eliminate it.

(D) does not weaken. Of course the company was vulnerable to embezzlement—embezzlement happened! The fact that a report was released does not weaken the idea that an actuary did the embezzling. Leave it for now.

(E) definitely weakens. Eliminate it.

Now, we're down to (C) and (D). It is unclear how (C) applies, and we know that (D) does not weaken. In a situation like this, which we will encounter many times in our LSAT adventures, we should choose (D) and move on.

To confidently eliminate (C), we must, as always, take another careful look at the wording of the argument's conclusion. It all comes down to simple math. If the embezzler is presumably either an accountant or an actuary, and there are eight accountants and only two actuaries, it seems to go against the idea that the embezzler was likely an actuary.

10. PT37, S4, Q2

Which one of the following, if true, most weakens the argument?

(A) It is not known whether the researchers succeeded in stimulating only VNO cells in the human subjects’ noses.

(B) Relative to its occurrence in certain other animals, the human VNO appears to be anatomically rudimentary and underdeveloped.

(C) Certain chemicals that play a leading role in the way the VNO functions in animals in which it is highly developed do not appear to play a role in its functioning in humans.

(D) Secondary anatomical structures associated with the VNO in other animals seem to be absent in humans.

(E) For many animal species, the VNO is thought to subtly enhance the sense of smell.

Answer choice (A) is correct.

Let's start with the core:

When researchers have stimulated the VNO in humans, those humans have reported smell sensations

the VNO is a functioning sensory organ in most humans.

The word “most” really jumps out of the conclusion, and as this question is very early in the section, we might expect the answer choice to relate to this “obvious” issue. Let's go to the choices and see.

(A) is a bit unclear. “Only” is certainly an important word on the LSAT, and this choice definitely relates to the argument's evidence. Let's leave it for now.

(B) does not directly relate to the conclusion. It doesn't matter if human VNOs are less developed than animal VNOs. We might say that human ears are less developed than the ears of deer, but human ears are still functioning organs! Eliminate it.

(C) makes the same “comparison” mistake that (B) makes. The question at hand is whether the human VNO functions at all—not whether it functions as well as an animal VNO. Eliminate it.

(D) says nothing about whether the human VNO functions. It is entirely possible that it functions without those secondary structures, as we have no evidence that those secondary structures are required for functioning.

(E), if anything, strengthens the argument by making clearer the connection between the VNO and smell, and thus, in a small way, validating the argument's evidence.

This leaves us with (A). Really? Absolutely. This is an example of a “claim in the premise” problem. Remember the “premature babies/adequate care” argument? While we must always accept the claims themselves as fact—the researchers definitely stimulated the VNO—we occasionally see a question that brings our attention to little assumptions hidden in those claims. Think about (A). What if the researchers did not stimulate only the VNO when they did their research? What if they also stimulated a part of the brain responsible for smell? Well, this would make us much less certain that the VNO was responsible for the smell sensations, and suddenly we have a bad experiment on our hands. Therefore, since (A) creates the possibility that the research was imperfect, and the research is the only leg the conclusion has to stand on, (A) weakens the conclusion.

Challenge questions

11. PT29, S4, Q11

Which one of the following, if true, most strengthens the argument?

(A) Mammals have some resemblance to one another with respect to bodily function and brain structure.

(B) The dolphins often exhibit complex new responses to the hand signal.

(D) Dolphins do not interact with humans the way they interact with one another.

(E) Some of the behaviors mentioned are exhibited by dolphins in their natural habitat.

Answer choice (B) is correct.

This is a tricky problem. The core looks something like this:

When given a signal, sometimes the dolphins do X, sometimes do Y

(these are not merely learned responses) dolphins are capable of higher cognitive functions.

Since our task is to strengthen the argument, we must focus on supporting the connection between the evidence and the conclusion. In other words, we should make it more likely that these two examples, X and Y, are not learned responses, but examples of higher cognitive function.

(A) is too vague to be relevant to the argument. A better, though not totally awesome, version of (A) might say something like, “the cognitive structures of dolphins are very similar to those of humans.”

(B) adds more evidence and therefore strengthens. If the dolphins always did either X or Y, then we might begin to think that these were merely automatic responses. However, if the dolphins often make new and complex responses, we have real evidence that they are doing more than merely responding to stimulus, which supports the idea that they are capable of higher cognitive function. This is probably our answer, but we should consider the other choices.

(C) is essentially irrelevant, though it seems to weaken. It is possible that the dolphins have higher cognitive capabilities and get food in their training. This choice does not significantly strengthen or weaken.

(D) is irrelevant.

(E) is a tempting choice. If we examine it closely, though, we'll see that even if the dolphins happen to do those things in nature, the tricks could still be mere responses to stimulus. Wild dogs sit all the time. Many dogs also sit as a simple response to stimulus. In addition, we can see that the fact that the dolphins do these things in nature is not good evidence that the dolphins have “higher cognitive function.”

12. PT30, S4, Q18

Which one of the following statements, if true, most strengthens the argument?

(A) Those who offer new ways of justifying current political power often reap the benefits of their own innovations.

(B) Politically powerful people tend to reward those who they believe are useful to them and to punish those who they believe are a threat.

(D) New technologies are often used by people who strive to defeat those who currently have political power.

(E) Many people who possess ethical inventiveness conceal their novel ethical arguments for fear of retribution by the politically powerful.

Answer choice (B) is correct.

Once again, we should consider the core as simply as possible before going to the choices:

The politically powerful see new tech as good and new ethics as threatening

new tech brings benefits to those who have it, and new ethics bring pain to those who have them.

The gaps in this argument are fairly clear—the author is assuming that the politically powerful are the primary determinants of benefit and pain. Furthermore, the author is assuming that the politically powerful will bring benefit to those they see as bringing good, and pain to those they see as threatening.

As we evaluate the answers, let's remember that our job is to strengthen the argument:

(A) sounds appealing, but actually does not apply to the case at hand. “New technology as means of extending or protecting” is not quite the same as “new ways of justifying.” And even if those terms were equivalent, the fact that this “often” benefits the creators does not add much support to the conclusion. How much is often? Ten percent of the time might be “often,” but not often enough to help this conclusion. This is a weak choice that we should eliminate.

(B) is a much better choice than (A). For one thing, “tend to” means “most of the time,” which is much stronger than “often.” Also, this choice has less language ambiguity than (A). It is totally reasonable to infer that people who invent new tech that can be used as a means to extend power are “useful” to those with power. And we can reasonably infer that “punishment” is roughly equivalent to “pain.” Let's leave (B) for now.

(C) is an interesting choice in some ways, but it does not directly affect the argument, so we can safely eliminate it. The fact that no individual possesses both traits does not support the idea that individuals with one trait are usually benefitted while individuals with the other get only pain.

(D) seems to weaken, but actually says nothing about the individuals who invent the new technology, which is who the argument concerns. Perhaps those who invent the new tech still receive benefits from the powerful, while other people use the new tech to defeat the powerful. These kinds of group/subgroup distinctions are important on the LSAT.

(E) does not provide evidence that those with ethical inventiveness actually receive pain or punishment, nor does it provide evidence that those with technical inventiveness receive benefits. Eliminate it.

In the end, we are left with only (B), which by no means makes the argument rock-solid. It does, however, strengthen the argument more than the other choices.

13. PT30, S2, Q21

The new agriculture bill will almost surely fail to pass. The leaders of all major parties have stated that they oppose it.

Which one of the following, if true, adds the most support for the prediction that the agriculture bill will fail to pass?

(A) Most bills that have not been supported by even one leader of a major party have not been passed into law.

(B) Most bills that have not been passed into law were not supported by even one member of a major party.

(D) Most bills that have been passed into law were not unanimously supported by the leaders of all major parties.

(E) Most bills that have been passed into law were supported by at least one leader of a major party.

Answer choice (A) is correct.

Here is the core of this (short) argument:

All major party leaders oppose the bill

therefore it will fail to pass.

The author is assuming that if all major party leaders oppose the bill, this is sufficient to ensure that the bill will fail to pass.

Our task is to strengthen this conclusion.

(A) matches the logic of the argument's particular case (the agriculture bill) with a general trend (“most unsupported bills have not passed”). In so doing, it adds validation to the underlying assumption, and therefore strengthens the argument.

(B) seems close, but uses the word “member,” while our argument is about “leaders.”

In order to firm up the argument, we need to know…

All major party leaders oppose the bill

therefore it will fail to pass.

This answer represents a negation of that…

All major leaders endorse

It will pass.

Therefore, it does not strengthen the argument.

(D) concerns subjects that are not directly related to the argument. The argument discusses a bill that is universally opposed, whereas (D) concerns bills that are opposed to some general level (not universally supported). These are two very different things. Furthermore, if we assumed (D) did relate to the argument, it would seem to weaken rather than strengthen it.

(E) is a very tempting choice, and at first glance may seem very similar to (A). However, the fact that most bills that pass are supported by at least one leader does not actually tell us anything about the odds of passing a bill that isn't supported by any leaders. It could be true that a very small percentage of all bills are not supported by any of the leaders, but that these all happen to get passed.

14. PT30, S4, Q20

Which one of the following, if true, most strengthens the argument?

(A) The social impact of the new antihistamine is much better understood than that of most new drugs being tested.

(B) The social impact of some of the new drugs being tested is poorly understood.

(D) The new antihistamine is chemically similar to some of the new drugs being tested.

(E) The new antihistamine should be on the market only if most new drugs being tested should be on the market also.

Answer choice (A) is correct.

Here's the core:

Introduction of drugs to marketplace should be contingent on understanding social impact
+
the social impact of a certain antihistamine (one already on the market) is unclear

there should be a general reduction in the pace of bringing to market new drugs now being tested.

The word “general” in the conclusion immediately jumps out. Our task is to strengthen, most likely by supporting the connection of this particular antihistamine to the other drugs.

(A) does exactly what we want. If the social impact of the other drugs is understood even less than the antihistamine, then according to the argument, these other drugs should certainly not soon be brought to market. This is a good choice, so let's keep it.

(B) does not impact the argument in a clear way. It does not relate the antihistamine to the more general conclusion. Furthermore, the word “some” has a weak impact. Without knowing how prevalent the “some” is, it's tough to prescribe a general slowdown.

(D) may seem to strengthen if we read too quickly, but chemical similarity may or may not have anything to do with social impact. Therefore, eliminate it.

(E) is an error of reversed logic.

15. PT34, S2, Q12

Which one of the following statements, if true, most seriously weakens the argument?

(A) Synesthesiacs demonstrate a general, systematic impairment in their ability to use and understand words.

(B) Recent evidence strongly suggests that there are other senses besides sight, touch, smell, hearing, and taste.

(D) The synesthetic phenomenon has been described in the legends of various cultures.

(E) Synesthesiacs can be temporarily rid of their synesthetic experiences by the use of drugs.

Answer choice (A) is correct.

This is a tough problem, mostly because the correct answer seems outlandish.

The conclusion of the argument is that the synesthesiacs have senses that do not respect normal boundaries. The evidence given is a study in which these people claimed they ate a banana and tasted blue or smelled colors.

We might first go through the choices anticipating an answer choice that simply made it more likely that the senses of these people did in fact respect normal boundaries.

(A) is actually kind of funny, isn't it? Imagine a bunch of nonsensical mumblers sitting in a research room claiming that they can smell red. Words don't have anything to do with the senses, so we might eliminate this one.

(B) is irrelevant. Do the senses of the synesthesiacs, no matter how many they have, respect boundaries or not? Eliminate it.

(C) sounds pretty good. But what if the definite pattern is one that violates the normal boundaries? That would actually strengthen. Therefore, eliminate.

(D) simply states that synesthesiacs have been described in the past. However, while this may support the claim that synesthesiacs exist, it does not support the claim that their senses do not respect normal boundaries. Always pay attention to the exact wording of the conclusion, especially on difficult questions!

(E) says nothing about whether their senses respect normal boundaries.

Now what? We've eliminated them all! Go back to the top, reconsider the argument core, and go back to the choices with a more open mind.

Aha! Take another look at answer (A). If the synesthesiacs cannot understand or use words, then what are we to make of the evidence used in the argument? Of what value is their claim that they taste blue when they eat bananas if they don't know what “blue” or “taste” means? This is our answer. If answer (A) is true, it puts the validity of the evidence in question, and therefore weakens the argument. The others are all wrong for the reasons previously stated.