Chapter Six

Are Conservatives from the Amygdala?

Let’s begin with a tale of two brain regions. The first, the amygdala, is an almond-shaped bunch of neurons located in an evolutionarily older part of the brain, the limbic system. Among other functions, the amygdala has been shown to play a key role in our emotional responses to threats and stimuli that evoke fear.

The second region, the anterior cingulated cortex (ACC), is part of the frontal lobe and shares many links to the prefrontal cortex. It has been shown to be involved in detecting mistakes or errors that we make that require a corrective response—what is sometimes called “conflict monitoring.” This process, in turn, seems to be very important in what scientists refer to as “cognitive control”—switching from automatic responses to more measured, System 2 behaviors.

Now get this: A recent magnetic resonance imaging (MRI) study of 90 University College of London students found that on average, political conservatives had a larger right amygdala, while political liberals had more gray matter located in the ACC. The students’ political beliefs were identified in a fairly standard way: Based on their self-placement on a five point spectrum, which ranged from “very liberal” to “very conservative.” Then the study was repeated in another, smaller group of 28 student subjects. Once again, the finding held.

Before even beginning to tease out the implications of this study—they have probably leapt to mind already—let’s pause for a deep breath.

The study was commissioned by the (liberal) British actor Colin Firth, who did not hold back about his intentions. “I took this on as a fairly frivolous exercise,” Firth explained. “I just decided to find out what was biologically wrong with people who don’t agree with me and see what scientists had to say about it and they actually came up with something.”

Something, yes. But what exactly did they come up with, and prove? We must be careful in interpreting the results of this very new scientific field—often called neuropolitics or political neuroscience—where we find relatively few studies so far, and yet at the same time, mounting evidence that liberals and conservatives do indeed tend to have different brains.

Different brains: What does that mean? Probably not what most people think when they hear the phrase. So we need some background here. Asserting that liberal and conservative brains differ is meaningless unless we know how much human brains differ in general, from person to person.

The answer is quite a lot, and not just for reasons rooted in genetics. The brain is highly plastic; in the words of political scientist and neuropolitics researcher Darren Schreiber of the University of California-San Diego, we’re “hardwired not to be hardwired.” Each day, we change our brains through new experiences, which form new neural connections. Over a lifetime, then, we all develop different brains.

The brains of musicians, not surprisingly, are highly unique. The brain of someone who has learned to juggle is different from the brain of someone who has not learned to juggle. Surfers have gnarly brains, magicians have tricky brains—and most fascinating, once a person has changed his or her brain by mastering some skill, that brain then responds differently than an unskilled brain when observing someone else perform the activity. That’s why magicians can tell what another magician is up to. That’s why the magician and skeptic James the Amazing Randi is so adept at detecting frauds and tricksters—and why, before him, so was Harry Houdini.

Given that we can all change our brains by living life in a particular way or learning a new skill, it isn’t really too surprising to find that liberals and conservatives have some brain differences. “Being a liberal, and being a conservative, it’s almost a lifestyle, so I would be amazed if there aren’t differences in the brain that are associated with that,” says Marco Iacoboni, another neuropolitics researcher at the University of California-Los Angeles. Remember those liberal and conservative apartments and bedrooms? Remember conservatives liking order and keeping things on schedule? That’s what Iacoboni means by a “lifestyle.”

The real question is thus not whether liberals and conservatives have some brain differences—no big shocker there—but what those differences mean, and how they may influence political behavior and opinions. And here, it would be exceedingly rash to take a single brain imaging study and proclaim that it has forever uncovered the deep electricity behind our ideological divides.

Rather, the true state of political neuroscience is that researchers are finding some consistent results—especially regarding the amygdala and the ACC. But they’re also preaching caution. This is science, not phrenology, but there’s a lot of uncertainty. Still, the evidence so far is certainly consistent with theoretical expectations that are rooted in psychology.

After all, Colin Firth’s study isn’t the first to implicate the amygdala in conservatism, or the ACC in liberalism. And based on the research already discussed in the last three chapters, these are the kinds of brain areas where you might expect liberals and conservatives to differ—which is precisely why neuropolitics researchers have already homed in on them.

So let’s dig into the results further, looking first at conservatives and the amygdala.

In addition to Firth’s study, an intriguing bit of research by a team of scientists at the University of Nebraska at Lincoln and other institutions found that political conservatives—and more particularly, those whose hold tough-on-crime and pro-military views—have a more pronounced startle reflex, measured by eye-blink strength after hearing a sudden loud noise. Furthermore, when shown threatening images—maggots in an open wound, a large spider on a person’s face—these conservatives also showed greater “skin conductance.” Their sweat glands moistened more, making their skin more electrically conductive, an indication of sympathetic nervous system arousal.

These results, of course, are highly consistent with an “amygdala theory” of conservatism. “That’s obviously what’s in the back of people’s minds,” explains University of Nebraska political scientist John Hibbing, one of the study authors. In both tests, conservatives reacted, automatically, as if to defend life and limb from assault. Their ideology was reflected in their physiology. Every human being is built for such rapid-fire defensive reactions—we share our fear system with other animals—and liberals of course undergo the same core response. But in conservatives, it appeared to be stronger.

And still, we’re not finished with the evidence on conservatives and the amygdala. Yet another recent brain scan study, this time conducted by the aforementioned Darren Schreiber of the University of California-San Diego and his colleagues, once again documented this connection, through yet another type of neuroscience test.

In this case, study subjects were asked to perform a risky gambling task. As they watched a screen, it flashed three numbers (20, 40, and 80) for one second apiece in ascending order. Pressing a button while one of the numbers was onscreen meant winning the corresponding amount of money, in cents. But there was a risk: While 20 cents was always a gain, sometimes the numbers 40 and 80 flashed red, which meant losing 40 or 80 cents. Therefore, for each second you held out for more money in the test, you chanced greater rewards, but also greater losses.

Then the researchers simply looked at the study subjects’ voting records. Sure enough, Republicans who took a risk in this task (and won) showed much more amygdala activity—a finding that Schreiber interprets to mean that they were sensing a risk coming from outside of them, perhaps physical in nature. Meanwhile, gambling Democrats activated a region of the cortex called the insula, which suggests that they were monitoring internally how the risk felt. “It’s the difference between feeling your feelings, and reacting to the outside world,” says Schreiber.

All in all, that’s a fair bit of evidence connecting conservatism to the amygdala. Psychological theory, of course, also supports the connection: The whole point of the account of conservatism advanced by Jost and his colleagues is that the ideology appeals to the need to manage threat and uncertainty in our lives, with authoritarians presumably being the most strongly characterized by these needs.

So what’s the drawback?

There are a few qualifiers, at least. Perhaps the leading criticism of studies that link brain activity in a particular region with traits or behavior is the observation that brain regions do many things, not just one. That seriously complicates the notion of pinning any one trait or behavior on any one brain region or structure. Schreiber points out, for instance, that the amygdala does many things other than respond to threat and fear. “The amygdala also lights up for positive emotions, and lights up just as frequently,” he says.

Nevertheless, the amygdala is definitely a fear and threat center, and a central component of our evolutionarily older and emotion-centered brain. It has been called the “heart and soul of the fear system,” processing inputs from different brain regions to structure our life-preserving defensive responses. “If you want to make a really strong association between one emotion and one brain structure, that association between the amygdala and fear holds very well,” says Marco Iacoboni of UCLA. Iacoboni notes that neuroscientists have even been able to study rare cases of bilateral atrophy of the amygdala, and patients with this condition are unable to feel fear, or to recognize it in other people.

And then there are the liberals and the anterior cingulate cortex, or ACC. Its role in the brain is somewhat more complicated, but there is still general scientific consensus that it is involved in error detection and conflict monitoring, and ultimately cognitive control. And Colin Firth’s study isn’t the first to link it to liberalism.

Consider a 2007 work published in Nature Neuroscience, one of the earliest political neuroscience studies. The researchers—John Jost, New York University neuroscientist David Amodio, and several other scientists—hypothesized that liberals have more active ACCs, since after all, they are more flexible and intellectually innovative, and more tolerant of uncertainty. Then they proved as much by having liberals and conservatives perform a classic test for conflict monitoring, of the sort that this brain region is thought to govern.

It’s called a “Go-No Go” task: Study subjects are put in a situation where they are required to quickly tap a keyboard when they see “M” on the screen—and become habituated to doing so. But one fifth of the time, the screen instead flashes a “W,” and respondents have to quickly change their behavior and not tap the keyboard. Liberals performed better at the task—they were less likely to commit a “Doh!” and tap the keyboard at the wrong time—and they also showed more ACC activity when engaging in the corrective response. (This study was subsequently replicated by another research team, studying a Canadian sample, who also linked more brain firing in the task to egalitarianism, and less firing to right-wing authoritarianism.)

It isn’t hard to think of a way to interpret this finding—which, of course, is why the original hypothesis being tested had been generated to begin with. Liberals’ greater ACC activity may indicate their greater cognitive flexibility, and their being more willing to update and change their beliefs or responses based on changing cues or situations.

“Conservatives,” the authors concluded, with typical scientific understatement, “would presumably perform better on tasks in which a more fixed response style is optimal.”

Such is the political neuroscience evidence so far—and don’t be surprised if more of it rolls in soon. But no matter how much accumulates, or how consistent the results, a central issue will remain. It’s the classic “chicken and egg” problem.

Even if liberals have more gray matter in the ACC, or if this brain region is more active in them, that doesn’t tell us whether being a liberal leads to more growth and development of the ACC, or whether having a bigger or more active ACC makes one a liberal to begin with—or both. The same question goes for conservatives and the amygdala. Meanwhile, even if these brain regions do shape our politics—which seems likely—it’s doubtful they will turn out to be the only ones.

Nevertheless, right now the neuroscience evidence is lining up behind the psychology evidence in a way that makes a fair amount of sense. Remember, most of all, the evidence from the last chapter, showing that liberals who are made to feel fear behave more like conservatives—or, more like authoritarians. It is not exactly a radical stretch to suggest that the amygdala has something to do with this effect.

Everybody has the capacity to feel fear. But recent research suggests those who have greater fear “dispositions”—a trait that’s linked to much more distrust of outsiders, including immigrants and people of different races—tend to be politically conservative. So what if it’s the case that conservatives and authoritarians have a more active amydala in general, and go through life more sensitive to fear and threat? And what if, by contrast, liberals are more prone to “switch on” and “switch off” on this dimension, and only behave like conservative-authoritarians when they’re made afraid as they were after 9/11—when a whole breed of “liberal hawks” emerged who wanted to attack Iraq?

Neither group, in this interpretation, would feel there was anything wrong with their lives or experiences. Yet for each group, life would be lived just a little bit differently, on average—and one consequence of those differences might be our political divisions.

If that’s true, then Irving Kristol’s famous remark that a neoconservative is just “a liberal who has been mugged by reality” would take on quite a new meaning.

Even assuming that this seemingly “obvious” interpretation of the neuropolitics research is correct, it tells us nothing about what causes our brains to differ in ways that correspond to our politics.

As I’ve said already, your brain could cause you to have a particular political outlook, or your political outlook could cause you to have a particular brain. Or both. And indeed, “both” is very likely the reality of the situation.

We know the brain is highly plastic. So we know that our life experiences, including our political experiences, change it. That side of things is pretty well accounted for, even if we don’t always know which regions respond to which experiences, with which changes.

The thing is, we also know that political views are partly inherited, and explained by genetics. Not fully explained, of course, but the influence of genes on our politics is surprisingly powerful. There’s a persistent body of research suggesting that 40 percent or more of the variability in our political outlooks is ultimately attributable to genetic influences. And this evidence is hard to refute, because it is based on a classic research model for detecting the genetic heritability of traits: twin studies.

So-called “identical” twins share the same DNA, and grow up in the same family environment. Meanwhile, fraternal twins also grow up in the same environment but only share half of their DNA. This leads to the time-honored twin study design. Gather large numbers of identical and fraternal twin pairs, and measure how much members of the two different kinds of pairs diverge on some trait, and you’ll be measuring how strongly genes control it.

Inevitably, for any heritable trait—height, personality, and so on—identical twins have more in common than the fraternal twins. What’s amazing is that politics is such a trait. Indeed, as previously noted, twin studies suggest that genes explain 40 percent or more of the variability in the overall political attitudes we adopt. At the same time, genes seem to account for a much smaller percentage of the variability in one’s political party affiliation, but that’s not necessarily so surprising. Party affiliations shift with generations and time; left-right orientations, not as quickly.

Indeed, twin studies have also been used to show that genes explain a substantial percentage of the variability in personal religiosity or spirituality, church attendance, and especially conservative religiosity or being “born again.” But they don’t predict the specific religion we’ll adopt. Our parents control that: They bring us up “Baptist,” and they bring us up “Republican.”

As with the political neuroscience research, it is very easy to misinterpret the findings of political genetics. Nobody is saying, for instance, that there is an actual “conservative gene” or a “liberal gene,” any more than that there is a “God gene.” Rather, the idea seems to be that genes create basic dispositions or tendencies that in turn produce personalities—which, in turn, predispose us to political outlooks. It’s also possible that the same baseline set of genes may influence our personalities and our political outlooks separately, and these then wind up being aligned because both are influenced by the same genetic factors—kind of like two separate limbs of a puppet being pulled by the same puppeteer. In this view, Openness may not cause liberalism; rather, they would both be influenced by the same set of genes.

But either way, something is being passed on to us that winds up getting expressed as ideology. “It’s almost impossible to deny that there are these consistent pedigrees passed down through families,” says Peter Hatemi, a political scientist and microbiologist at Penn State University who has been at the center of research on the relationship between genetics and politics—a growing field. “The basic state of who we are, that’s inherited.”

It’s important to understand what a statement like this means—and doesn’t mean. Popular misconceptions notwithstanding, it is wrong to think of human traits as being either caused by genes or caused by the environment (upbringing, life experiences, and so on). Take height, for instance. Yes, it has a genetic basis and is strongly inherited. But if you’re malnourished, you’ll stunt your height no matter what kind of basketball star your genes might otherwise have been able to produce. “Nothing is all genes, or all environment,” Hatemi explains.

In fact, the very attempt to pit genes and environment in opposition to one another is nowadays a passé notion in science. We know that genes strongly influence us; we also know that environmental influences, aka our “experiences,” change us and change our brains. And get this: Environmental influences also change our genes, or at least how they are expressed by our bodies, via the production of proteins in individual cells (including individual brain cells). “Epigenetics” is the study of the many factors that modify the way our genes are expressed, even without any changes to the basic DNA code. It’s more about genes “switching off” and “switching on”—in different cells, in different phases of life, and even in response to our own choices and behaviors.

When it comes to political genetics, for instance, some research suggests that while we’re living at home with our parents and growing up, the family environment has a lot of influence on our ideologies—especially during our teenage years. But once we leave the nest, perhaps to attend college, it is suggested that then our genes kick in and start shaping us.

No wonder this area is complicated, and promises to fuel generations of ever-more-sophisticated research.

If genes are influencing our political views, you can rest assured their influence is not going to be manifested through our elbows. It’ll be manifested through our brains. One obvious area to examine will be how our genes influence neurotransmitters like dopamine, which carry chemical messages between our brain cells.

The question then becomes, which genes are involved, and what do they do?

It is very unlikely that we will find a few political genes that explain everything, or even that have very large effects. Rather, with a complicated social behavior like one’s political views, there are probably thousands of regions of the human genome involved, and these are affecting us in different ways—ways that are often triggered by the environment, and that vary over a lifetime.

At this very moment, the search for them is on. Scientists like Hatemi are conducting genome-wide studies to try to find what are called polymorphisms or markers—areas where the human genome varies from individual to individual—that are related to politics. This requires vast studies, with thousands of participants who get their genomes scanned and answer political questionnaires. Eventually, the hope is that markers will be identified that are statistically linked to political opinions—but it will probably turn out to be thousands of them, and it will be very hard to find all of them.

So far, there is at least one “liberal gene” claim. University of California-San Diego political scientist James Fowler and his colleagues have highlighted a gene called DRD4, which seems to be involved in novelty seeking. Technically, the gene codes for a protein receptor that is activated by dopamine, a chemical messenger in the brain. The idea seems to be that a particular variant of this gene (if you have it) plays a role in the trait Openness to Experience, and thus, in liberalism. But here again, there’s a gene-environment interaction: The gene’s contribution to Openness appears to depend on your social life and how many friends you had growing up.

That’s certainly intriguing, but again, we shouldn’t place too much weight on any one gene to explain why people vary in their political outlooks. Consider once again that steadfast analogy—the role of genes in height. Whereas genes appear to explain 40 percent or more of the variability in our ideologies, they explain 80 percent of the variability in height. However, scientists digging through the genome to try to find the “height” regions, over years and years, have only found about 20 percent of the specific DNA strips involved, according to Hatemi. That means sixty percent of the genetic regions involved in height remain unidentified, although we know they’re in the genome . . . somewhere.

Right now, Hatemi continues, less than one percent of politics can be similarly explained. He expects that to gradually change as researchers continue to comb through genomes—and then, the real fun begins. Once regions are identified that are involved in politics, the question will become how their activity affects us: Not just at one point in time, but over a lifetime, in interaction with the environment.

For many scientists, this itself portends a lifetime of exceedingly complicated research. But why do it?

The thrill is to be part of a dramatic new merger of political science, psychology, and biology that ultimately promises to uncover a “science of human nature”—sure to yield fruit, but not necessarily to produce full clarity any time soon. For now, you have to be patient, live in the uncertainty, and thrill in the search.

Any guesses about what personality types will want to be working in this area, or how they are likely to vote?

On this account of the origins of our politics, it would appear not only that political dispositions travel in families, but so do personalities—and these traits would presumably emerge when we’re quite young.

And, there’s suggestive evidence supporting this notion as well.

It is difficult and expensive to conduct a so-called longitudinal study that looks at the personalities and behaviors of young children, and then follows them until they are grown-ups to see how they identify politically. That kind of lifelong commitment to a scientific study is rare, and even heroic.

But in at least one case, it has been done. And the research, conducted at the University of California at Berkeley beginning in 1969, suggests that the children’s politics had already been set in motion at an early age. Note also that because this study was longitudinal, it is hard to imagine how the researchers could bias it: They didn’t know what was going to happen to the kids they observed. They couldn’t superimpose knowledge they would only gain later on what they saw as they watched three-year-olds play.

That’s what makes the results so stunning. As one part of the Berkeley study, preschoolers were first assessed at ages 3 and 4 for their personalities, and then were asked, much later at age 23, a battery of political questions. That’s how the researchers learned that children who later turned out to be conservatives had been observed as “uncomfortable with uncertainty, as susceptible to a sense of guilt, and as rigidifying when experiencing duress.” The later-life liberals, meanwhile, had been described as children as “autonomous, expressive, and self-reliant.” In other words, wrote the researchers, what centrally separated the future conservative children from the future liberal ones was that the former were seeking to “over-control” their environment, whereas the latter were seeking to “under-control” it.

Order and chaos, yin and yang—right there in the sandbox.

We’ve come a long way. Not only have we learned about the psychological underpinnings of political ideology—and seen how strong the evidence is that our political views are rooted, at least in part, in personality and psychological needs. We’ve also sought further confirmation of this insight in the 100 billion neurons of the brain (and the 100 trillion connections between them) and the more than 3 billion DNA base pairs that make up the human genome.

Not surprisingly, once you reach these realms, the search becomes vastly more difficult. These are the cutting edge areas of modern biological science, where real revolutions are expected to occur in the 21st century, as our powers of scientific computation steadily increase. No wonder we don’t have all the answers yet from political neuroscience or political genetics.

What’s surprising, in fact, is that we have such suggestive answers at all. “If you had called me four years ago and said, what is your view on whether Republicans and Democrats have different brains, I would have said no,” said the University of California-San Diego’s Darren Schreiber. Now, he sees it differently. It appears that people are partly making their political brains, and partly inheriting them, but the sum total of the process is measurable divergences in brain structure or in brain functioning. The result is that, in looking at those brains, we can already pinpoint consistent differences, between left and right, in key regions.

I’ve said plenty already about the high degree of scientific uncertainty that remains in this field, so I won’t further belabor it. The more I learn about the science—reading the studies and interviewing those who are designing them so I can understand what’s written between the lines of their research papers—the more I grow convinced that it all points in an obvious direction. But at the same time, I wouldn’t be a bit surprised if we don’t yet have the right overarching theory or organizing concept to unite all of the evidence—and if, in the next decade, much of this evidence winds up being reorganized into a different paradigm that nobody has thought up yet.

The evidence will still be there, of course. There’s just too much for it all to be wrong. How it’s all ultimately interpreted, though—that could certainly change. And that’s something that, as good liberals, we have to be ready for.

In closing this chapter, I think it is necessary to consider what it might mean, in an evolutionary sense, to find that people’s genes and brains vary in a way that leads to different tendencies in politics. If you find evidence that a human trait has a genetic basis, it is natural to inquire why that is—and whether evolution through the process of natural selection might have “put it there.”

Asking about whether evolution “intended” for us to be liberals and conservatives is a lot like asking whether it “intended” for us to be religious and irreligious. In evolutionary terms, what you are actually asking is whether politics (or religion) is an adaptation: a direct product of Darwinian natural selection, one that exists because it increased our ancestors’ chances of surviving until they reproduced. For any trait, there’s always another possibility as well: It could be a by-product, a feature that arose more accidentally, because of other adaptations.

For an example of a trait that is a by-product, consider the redness of our blood. As the renowned Harvard cognitive scientist Steven Pinker explains:

Is there some adaptive advantage to having red blood, maybe as camouflage against autumn leaves? Well, that’s unlikely, and we don’t need any other adaptive explanation, either. The explanation for why our blood is red is that it is adaptive to have a molecule that can carry oxygen, mainly hemoglobin. Hemoglobin happens to be red when it’s oxygenated, so the redness of our blood is a byproduct of the chemistry of carrying oxygen. The color per se was not selected for . . . Random stuff happens in evolution. Certain traits can become fixed through sheer luck of the draw.

When considered in this context, it seems exceedingly unlikely that the evolutionary process had Republicans and Democrats “in mind.” Nor were liberals and conservatives probably part of the endgame. As I’ve noted, the concept of a left-right divide originated in the French Revolution, not much more than 200 years ago. By contrast, Homo sapiens with complex tools, hunting styles, and symbolic art forms originated in Africa about 160,000 years ago.

Evolution did, however, build brains that were capable of intricate social interactions, ingenuity, and creativity—and of course, beliefs and opinions and group identification (including defending the in-group and attacking the out-group). And it did this in a context when life was certainly more difficult, often more brutal and violent, than it was today.

Our political beliefs and differences could thus be a by-product of these more core traits, varying within some natural range and interacting in different combinations in different people. A tendency to be distrustful of outsiders, say, or a tendency to want to try new things. Each, perhaps, comes in a variety of forms or degrees, and we all wind up somewhere on a spectrum—and these tendencies then predispose us to adopt certain political positions.

Political beliefs could also be partly influenced by physical traits that are far more basic to humans, and that were definitely acted on by natural selection.

As an example, consider male strength. In recent intriguing research by a group of evolutionary psychologists led by Aaron Sell of Griffith University, it was found that stronger men (as measured by bicep size, the amount of weigh they could lift at the gym in exercises like arm curls, and other measures) were more likely to show anger, had a greater history of getting into fights, and—politically—were more in favor of the death penalty, military spending, and the Iraq War. Male strength is surely an evolutionary adaptation. But these modern-day political offshoots of male strength would presumably be by-products, and more accidental. There was no such thing as modern large-scale war when we evolved, and there’s no way one man’s individual physical strength could determine the outcome in Iraq. Yet the stronger men in the study supported the Iraq invasion more.

According to Sell and his colleagues, here’s how such a result could come about. If you’re stronger, you “learn”—or at least, your brain calculates—that showing anger works as a negotiating technique (because you intimidate people), and that force works to resolve conflicts in your favor (because you beat up people). This then spills over into your view of the world, including your political views. “People have these intuitive gut feelings about whether or not force works,” says Sell, “and this stems from this evolutionary environment in which physical strength was a good predictor of your ability to survive and use aggression. So our modern minds are still designed that way.”

Not only does this suggest that conservatives could probably beat up liberals, if it ever came to that. It also implies, once again, that our political differences may be a by-product of actual evolutionary adaptations, and one consequence of plopping down evolved human beings in liberal democracies.

Yet despite the many reasons for thinking of politics as an evolutionary by-product, some thinkers—including Everett Young—suggest that evolution may have built us to vary in subtle but important ways because a society fares better when it has both “liberal” and also “conservative” tendencies in it. What would the core tendencies be? Something like maintaining order, versus generating innovation. Protecting and serving, versus creating and challenging. Once again, we’re back to the yin-and-yang view of our politics.

One difficulty with such an account, though, is that our differences today seem highly dysfunctional, rather than functional. And there’s an even deeper problem. This is a group selection theory, one that proposes that natural selection operated at the level of a group of individuals, to make it more fit to survive, rather than operating at the level of the individual or the gene. Such group selection theories have long been viewed skeptically in the field of evolutionary biology, although they have recently undergone a revival.

The truth is that very little is known about why political tendencies are so strongly influenced by our genes, and what evolution might have to say about that. It’s an area where, surely, there will be many insights in the coming years.

The last four chapters have made it very clear that liberals and conservatives are different, in ways that extend far beyond explicit ideology. And these differences are highly pertinent to my analysis of why it is that we have such a war over the facts in the U.S.—and why one side, the liberal side, is usually right.

But the background against which all of this plays out is hardly a static one, either in the United States or anywhere else in the world. American politics in particular have changed dramatically over the last 40 years, and it would be stunning if this had no impact on the dynamics that interest us. Parties have changed, and people have changed parties. New institutions have grown up and the media have been exploded and rebuilt.

These changes surely work in interaction with the basic tendencies I’ve been surveying—tendencies for people to rigorously defend their beliefs, for instance, and for liberals and conservatives to approach the world differently. In other words, if you want to understand why Tea Party followers don’t believe in global warming or the risks of breaching the debt ceiling, studying fundamental liberal-conservative differences will only get you so far. I contend that those differences are an essential part of the story—but still only part of the story.

In the next chapter, then, I will seek to interweave nature and nurture—or psychology and the environment—when it comes to the relationship between liberals, conservatives, science, and facts.

Notes

111 Let’s begin In preparing this chapter I have greatly benefited from many conversations and exchanges with Andrea Kuszewski. Her own take on the matter, “The Cognitive Neuroscience of Liberals and Conservatives,” can be found online at http://blogs.discovermagazine.com/intersection/2011/09/07/your-brain-on-politics-the-cognitive-neuroscience-of-liberals-and-conservatives/.

111 the amygdala Again, see Andrea Kuszewski, “The Cognitive Neuroscience of Liberals and Conservatives,” online at http://blogs.discovermagazine.com/intersection/2011/09/07/your-brain-on-politics-the-cognitive-neuroscience-of-liberals-and-conservatives/.

111 “conflict monitoring” Matthew M. Botvinik et al, “Conflict Monitoring and Cognitive Control,” Psychological Review, 2001, Vol. 108, No. 3, pp. 624–652. See also Matthew M. Botvinick et al, “Conflict Monitoring and Anterior Cingulate Cortex: An Update,” Trends in Cognitive Sciences, Volume 8, Issue 12, 539–546, 1 December 2004.

111 a recent magnetic resonance imaging (MRI) study Kanai et al, “Political Orientations are Correlated with Brain Structure in Young Adults,” Current Biology, 21, 1–4, April 26, 2011.

112 “I took this on as a fairly frivolous exercise” Quoted in Joe Churcher, “Brain shape ‘shows political allegiance,’” The Independent, December 28, 2010.

112 “hardwired not to be hardwired” Interview with Darren Schreiber, July 28, 2011.

112 brains of musicians Tom Jacobs, “The Musician’s Brain,” Miller-McCune, March 17, 2008. Available online at http://www.miller-mccune.com/science-environment/the-musician-s-brain-4698/.

112 that brain then responds differently than an unskilled brain See Darren Schreiber, “From SCAN to Neuropolitics,” in Man is By Nature a Political Animal, edited by P. K. Hatemi and R. McDermott. Chicago: University of Chicago Press, 2011. Also online at http://dmschreiber.ucsd.edu/Publications/FromSCANtoNeuropolitics.pdf.

113 “it’s almost a lifestyle” Interview with Marco Iacoboni, May 31, 2011.

113 a more pronounced startle reflex Douglas R. Oxley et al, “Political Attitudes Vary With Physiological Traits,” Science, September 19, 2008, Vol. 321, No. 5896, pp. 1667–1670.

114 “That’s obviously what’s in the back of people’s minds” Interview with John Hibbing, September 9, 2011.

114 a risky gambling task Darren Schreiber et al, “Red Brain, Blue Brain: Evaluative Processes Differ in Democrats and Republicans,” working paper available online at http://dmschreiber.ucsd.edu/Publications/RedBrainBlueBrain.pdf.

114 “reacting to the outside world” Interview with Darren Schreiber, July 28, 2011.

115 “the amygdala also lights up for positive emotions” Interview with Darren Schreiber, July 28, 2011.

115 definitely a fear and threat center As Joseph LeDoux puts it, “the amygdala seems to do the same thing—take care of fear responses—in all species that have an amygdala. This is not the only function of the amygdala, but it is certainly an important one. The function seems to have been established eons ago, probably at least since the dinosaurs ruled the earth, and to have been maintained through diverse branches of evolutionary development. Defense against danger is perhaps an organism’s number one priority and it appears that in the major groups of vertebrate animals that have been studied (reptiles, birds, and mammals), the brain performs this function using a common architectural plan . . . When it comes to detecting and responding to danger, the brain just hasn’t changed much. In some ways we are emotional lizards.” The Emotional Brain, New York: Simon & Schuster, 1996, p. 174.

115 “heart and soul of the fear system” LeDoux, The Emotional Brain, p. 172.

115 “that association between the amygdala and fear holds very well” Interview with Marco Iacoboni, May 31, 2011.

115 there is still general scientific consensus that it is involved in error detection and conflict monitoring Interview with Marco Iacoboni, May 31, 2011. See also Matthew M. Botvinik et al, “Conflict Monitoring and Cognitive Control,” Psychological Review, 2001, Vol. 108, No. 3, pp. 624–652.

115 a “Go-No Go” task David M. Amodio et al, “Neurocognitive correlates of liberalism and conservatism,” Nature Neuroscience, September 9, 2007.

116 This study was subsequently replicated David Amodio, email communication, November 8, 2011. The study in question appears to be only available online as a scientific poster. It is Meghan J. Weissflog et al, “Sociopolitical Ideology and Electrocortical Responses,” Poster presented at the 50th Annual Meeting for the Society for Psychophysiological Research, Portland, OR, September 2010. See: http://www.brocku.ca/psychology/people/Weissflog%20SPR%20poster%20Sept23%202010.pdf.

116 “fear dispositions” Peter K. Hatemi et al, “Fear Dispositions, Attachment, and Out-Group Political Preferences,” paper presented at the International Society of Political Psychology, Dublin, 2009.

117 ultimately attributable to genetic influences A number of scientific papers have now been published using twin studies to estimate the heritability of political ideology. And while they reach different estimates about the degree to which the variability in political outlooks can be explained by genes (in different populations), in all cases the estimate is substantial. For one classic paper, see Alford JR, Funk CL, Hibbing JR. 2005. “Are political orientations genetically transmitted?” American Political Science Review, Vol. 99, No. 2, May 2005:153–67. For further elaboration see John R. Alford et al, “Beyond Liberals and Conservatives to Political Genotypes and Phenotypes,” Perspectives on Politics, Volume 6, Issue 02, Jun 2008, pp. 321–328. I have also been influenced by a number of published and unpublished papers on the same subject by Peter K. Hatemi.

118 a much smaller percentage of the variability in one’s political party affiliation Peter K. Hatemi et al, “Is There a Party in Your Genes?” Political Research Quarterly, Vol. 62, No. 3, September 2009, p. 584–600.

118 being “born again” Matthew Bradshaw and Christopher G. Ellison, “Do Genetic Factors Influence Religious Life? Findings from a Behavior Genetic Analysis of Twin Studies,” Journal for the Scientific Study of Religion, 2008, Vol. 47, No. 4, pp. 529–544.

118 Openness may not cause liberalism Verhulst, B, Eaves, LJ, and PK Hatemi, “Causation or Correlation? The Relationship between Personality Traits and Political Ideologies,” American Journal of Political Science (forthcoming).

118 “The basic state of who we are, that’s inherited” Interview with Peter Hatemi, June 22, 2011. All quotes from Hatemi in this chapter are from the same interview.

119 once we leave the nest Peter K. Hatemi et al, “Genetic and Environmental Transmissions of Political Attitudes Over a Life Time,” The Journal of Politics, Vol. 71, No. 3, July 2009, pp. 1141–1156.

120 polymorphisms or markers . . . that are related to politics Peter K Hatemi et al, “A Genome-Wide Analysis of Liberal and Conservative Political Attitudes,” The Journal of Politics, Vol. 73, No. 1, January 2011, pp. 1–15.

120 DRD4 Jaime E. Settle et al, “Friendships Moderate an Association Between a Dopamine Gene Variant and Political Ideology,” Journal of Politics, Vol. 72, No. 4, October 2010, p. 1189–1198.

121 “science of human nature” See James H. Fowler and Darren Schreiber, “Biology, Politics, and the Emerging Science of Human Nature,” Science, Vol. 322, November 7, 2008.

121 what centrally separated the future conservative children from the future liberal ones Block, J., & Block, J. H., “Nursery school personality and political orientation two decades later,” Journal of Research in Personality, Vol 40(5), Oct 2006, 734–749. Available online at http://www.berkeley.edu/news/media/releases/2006/03/block.pdf.

122 100 trillion connections Carl Zimmer, “100 Trillion Connections: New Efforts to Probe and Map the Brain’s Detailed Architecture,” Scientific American, December 29, 2010.

122 “If you had called me four years ago” Interview with Darren Schreiber, July 28, 2011.

123 “Random stuff happens in evolution” Steven Pinker, “The Evolutionary Psychology of Religion,” lecture to the Freedom from Religion Foundation, October 29, 2004. Available online at http://www.ucs.louisiana.edu/~ras2777/relpol/pinker.htm.

124 Homo sapiens “Homo sapiens,” Institute on Human Origins, available online at http://www.becominghuman.org/node/homo-sapiens-0.

124 male strength Aaron Sell et al, “Formidability and the logic of human anger,” Proceedings of the National Academy of Sciences, September 1, 2009, Vol. 106, no. 35, 15073–15078.

125 “intuitive gut feelings about whether or not force works” Interview with Aaron Sell, August 12, 2011.

125 a society fares better when it has both “liberal” and “conservative” tendencies in it Everett Young, “Why We’re Liberal, Why We’re Conservative: A Cognitive Theory on the Origins of Ideological Thinking,” Ph.D. Dissertation, Stony Brook University, December 2009.

125 group selection David Sloan Wilson and Edward O. Wilson, “Evolution ‘for the Good of the Group,’” American Scientist, Vol. 96, September-October 2008, available online at http://evolution.binghamton.edu/dswilson/wp-content/uploads/2010/12/American-Scientist.pdf.