9

RASH ACTIONS

THE LITTLE GIRL’S birthday was less than a week away. Through the haze of cheap booze, her father dreaded the day. For months Carlos had not had a steady job. Instead he had been out on the street corner in Gaithersburg, where the jobless men gathered at six o’clock every morning, waiting for the beaten up trucks to come by and pick up a few of them for the odd job. He was drinking almost every day, but these were the times when there was still a lot of construction going on in the Washington, D. C., suburbs. The builders were not too picky, and somehow he managed to get work often enough to pay the bills. Then he got lucky. The foreman at one of the construction sites somehow came to like him, and there was going to be steady work for weeks to come, maybe longer. It was a long trip, and he didn’t have a driver license or a car any more, but it was fine. He went first by bus, then by metro, then by another bus, relieved of the gnawing anxiety that there would not be any money that day. He still drank, but less now, and only in the evenings. And on the way home, as he stood up and held on to the handrail in the metro car, his lower back in pain after a long day of operating the cement mixer, he smiled. His daughter so badly wanted a new bike. She had outgrown the old one long ago and in the end had just stopped biking around with the other kids in the neighborhood, so that they would not tease her. Now, with the paycheck he was getting Friday, there was going to be enough to buy her a bike for her birthday. It wouldn’t be new or fancy, just a used one from the Salvation Army store. But his little girl was not picky; she’d never had a chance to be. She would be happy. And so would he.

The week went by, and Carlos was ever so slowly and subtly being transformed back into his old self. During breaks, when previously he had walked aside and smoked his cigarette in silence, holding on to it with a shaking hand, he now stood with a group of the other construction workers. First he just quietly listened to the conversation, sometimes in English, more often in Spanish, nodding now and again, a little noticed bystander. But as the days went by, he made the occasional comment, sometimes asked a question. Over time, unnoticed, he became one of the crew. The conversation wasn’t much: sports, money troubles, better jobs elsewhere, going back to a home that for almost all was somewhere else and seemed to be strangely transformed in memory with time, at once closer and farther away. He knew some of the men from other construction sites. They were all struggling, but most were good men. Most were married. What little money they made, they brought home, making sure their family made it through the day, week, or month, always hoping for the next day, week, or month to be better. Their wives worked long hours cleaning people’s homes, or, if they were lucky, at the cash register in a retail store. Afterward they came home and made the money last longer by slowly cooking simple meats into stews that tasted of home or mending torn clothes so that the family could proudly go to church on Sunday and look the way you should in God’s house. And then there were the children, most of whom spoke better English than their parents and struggled to understand whether their parents were there to take care of them or the other way around.

For Carlos, the mosaic of images from a life full of challenges had long been mercifully blurred by a cloud of drunkenness. Intoxication made everything vague and distant, softening the edges and soothing the unrest in his soul. Now, as he drank less and worked more, the clouds slowly started to part, and images broke through the haze. Some were so painful that he could not wait for them to fade away again: He is drunk. Marta yells at him, something about him being worthless and she would have been better off had she never married him. A rage beyond control rises up inside him, and he hits her, right in the face, with all his might. There is an awful thump, and before she falls, she goes completely silent, as if she were stunned by a Taser, unable to make a sound. And then, in his inner view, he turns around, and their little girl is curled up on the living room couch, as if she was trying to get as far away from them as possible, her eyes wide and black with terror, her mouth open, and tears forming in her eyes, before she screams out in desperation. But there are other images, too, some of which he tries to hold on to. Such as this one: It is a sunny Sunday in the fall, after church. They have borrowed Marta’s sister’s car to picnic at the lake. He and his daughter are throwing flat stones onto the lake. She is trying to make them bounce just the way he can, and this silly little skill for once makes him feel like she is looking up to him, the way a daughter should to a father. Meanwhile, Marta is putting food from the basket onto the picnic table and waving at them. These are the moments that make it all worthwhile.

When Friday comes, the paycheck is not quite as much as he had expected. Not much of a difference, but instead of satisfaction, there is a touch of disappointment. Something about new fees the county has put in place for the builders. The men are in no position to complain. And for Carlos, there is still enough to make this birthday celebration for his daughter count, maybe even make up for those birthdays he would rather forget. He has planned it all, with bike, cake, and balloons. But as he gets off the last bus and walks across the strip mall, music is streaming out of a bar. This is the place where he used to drink with his friends, long ago, before Marta, before their daughter, before the days of cheap wine or moonshine. He remembers sitting by the bar, being served rich, spicy food, watching a ballgame, downing beer and shots, dancing, and laughing so much that he could not understand how someone could have so much laughter inside him. Now, through the half-open door, someone calls out his name. It is a moment’s work, and then he is sitting by the bar again, with men who may or may not know him, but who laugh just like he used to, until he, too, does.

For a while he tries to hold on to the plans he has made, but in vain. In a moment the mission he has been on for quite a while flickers for his inner eye and then goes out like a candle. Before it does, he thinks, “It is going to be all right. I still have until Sunday to fix this. I’ll get the money somehow.”

He doesn’t.

What would you choose: a dollar today, or ten dollars a month from now? A hundred dollars today, or a thousand dollars a year from now? Easy, you may say, but there is in fact no answer that is always right. What is best depends on many factors. Some are of a universal nature—say, what a certain amount of money can buy. Others are unique to the individual making the choice. If you are terminally ill, receiving a thousand dollars a year from now may not be worth much. So it is clear that the utility, or “value,” of the same outcome can differ depending on both the individual making the choice and the context in which the choice is made.¹

There are other aspects, too, that complicate life. We may choose what seems to be “right” based on the expected value of an outcome, but what if it never materializes? It seems prudent to forsake a lower, immediate reward for one that is greater but will require us to wait. That is what we all try to teach our children. But when it comes to things that are more distant in the future, such as return on an investment with Lehman Brothers or payout from the GM retirement fund, there is clearly a risk that we will never get to enjoy the expected outcome. So in making their decisions, people also need to factor in risk and probabilities. If the person offering you money seems likely to skip town tomorrow, you are better off collecting what little you can up front instead of gambling on getting a higher return in an uncertain future. Whether we consciously identify them or not, we all struggle with these different factors that go into making reasonable decisions. What is most advantageous in each case depends on so many things: the effort required to achieve a desired outcome, its value, and the time and the many unknowns along the way to achieving it. To varying degrees, everyone will reduce, or “discount,” the value of an outcome that lies in the future. Given all this, a certain degree of “temporal discounting” like that is reasonable. Too much, though, and you will never get the really valuable things in life.

Now, how about a drink today or a happy child fifteen years into the future? Addicts, it is often said, make bad choices. And for choices, people are held accountable to a higher degree than for desires, fears, or passions. Shooting a wife’s lover is considered a crime of passion, widely viewed as an extenuating circumstance. Killing someone by driving drunk, in contrast, only aggravates culpability. This distinction contributes to the stigma of addiction and the often encountered view that an alcoholic with liver cirrhosis only has himself or herself to blame. Yet addicts are not alone in making choices with terrible consequences. Would I rather devour a steak for dinner and then crash on the couch in front of the TV, or eat broccoli and go out for a brisk walk? Go on vacation and pay for it with a credit card, or put more money into a retirement account? Drive an SUV today, or leave behind me a planet that is more livable for our children? Over the past decade or so, as both the importance and the complexity of people’s decision making have become better appreciated, a whole new research field has emerged. Often labeled “neuroeconomics,” this field has brought together an unusually diverse range of scientists, including economists, political scientists, neurobiologists, brain imagers, and addiction researchers. Plus, I suspect, a few people who would like to know how to set up a casino in the best way for people to lose money there. Decision making is key to whether people are able to cope with the ever-changing challenges of life and is at the core of the problem when they are unable to do so.

Interestingly, for most people, there is somehow a different flavor to the concept of decision making than to the idea of emotions. Decisions, perhaps in particular when made by the titans of Wall Street or investment bankers, somehow seem more cold-blooded and elevated, more “rational,” than the hot emotions of desire and aversion. We even tend to use a brain word, “cerebral,” to refer to this distinction. And yet from the perspective of brain science, it makes little if any sense to distinguish between processes that lead to plans and choices, on one hand, and those that produce desires and aversions, on the other. In fact these seemingly different processes are intimately linked. And all these functions must ultimately emanate from the activity of neuronal ensembles, firing away together at the right time and with the right pattern, be they distributed through one set of brain structures or another. Yet there has in our culture long been a history of what could be called a supremacism of rationality. As far back as Plato and Aristotle, hot emotions have somehow been thought to be of a more lowly and primitive nature than the refined domain of reason.

That is because, in a way, they are more primitive. To understand this, there is a complication we have to handle, and handle with care. Yes, humans are in many ways similar to other animals. It is an undisputable fact that the brain circuitry handling the simpler of our desires and fears developed early in our evolutionary history and has since remained much unchanged, or, as the evolutionary biologist would say, “conserved.” Because of that, the same brain areas—the nucleus accumbens, for instance—light up in a rat working for a tasty snack and in a human volunteer working for $5, or, for that matter, for a tasty snack.² The same goes for brain structures activated by anticipation of a modestly unpleasant electric shock, which will activate the amygdala and a network of structures connected to it in both cases. Yet it is equally true that we are also fundamentally different from other animals. Around the ancient machinery of motivation and emotion that we share with lower species, humans have wrapped a set of structures that have little or no precedent in evolution. Our frontal lobes are, relative to the size of our brains, larger than those of any other animal, except perhaps for the great apes. These frontal lobes are made up of characteristically human neocortex, which folds back on itself so that it can pack more nerve cells into the same space than would be possible had it been smooth like in other animals.

With the addition of these structures comes some unprecedented functionality. We no longer have to let our behavior be guided by decisions that are based on the value of immediate or near-immediate outcomes. Nor do we have to rely, for achieving longer-term objectives, on rigid behavioral programs that have proven beneficial through the evolutionary history of our species, the way a squirrel does when it collects nuts for the winter. We are the one species on the globe that has an ability to imagine a rather distant future, and ourselves in it. Because of that ability, we can flexibly plan for what may come. In fact, based on experience made during our own lifetime, or even that handed down to us from our ancestors in a book, we are able to imagine many alternative, hypothetical futures, assign value to them, and pursue complex behaviors that in the short term may require great effort for little reward but in the long term lead to an imagined future that seems to be a more desirable one. Because the world is a complex place, most of this has to happen quickly and intuitively, without reaching consciousness. An influential theory holds that imagining different “hypothetical futures” induces, in miniature, the body state we would experience if that particular outcome actually happened. That, in turn is monitored and evaluated by other parts of the frontal lobes, making us intuitively avoid a scenario associated with a body state, or “somatic marker,” that is unpleasant and pursue it if the marker feels good. This may well be the true meaning of the expression “gut feeling,” showing once again how much wisdom that can be embedded in language.³

To properly understand the relatively recently added functionality of being able to plan for the future, it is perhaps useful to remember that the evolutionary origin of our large frontal lobes is the part of the brain that moves our body, the motor cortex. This is the structure that forms a miniature human, or “homunculus,” a map of the body famously mapped out through electric brain stimulation in the operating room by the neurosurgeon Wilder Penfield, founder of the Montreal Neurological Institute. The basic wiring diagram through which the motor cortex gets things moving, running through the spinal cord and out to the muscles, is reasonably similar in humans and other animals. But in front of the motor cortex, humans have continued to build more and more sophisticated computational machinery. By now we have grown our frontal lobes beyond recognition, wrapping them around the frontal poles like no other animals. So it is easy to forget that the “prefrontal cortex” is an extension of the motor cortex. But it is, and it guides behavior, which in the end is nothing but movement.

The difference, of course, is that the various areas that make up the pre-frontal cortex do not move specific limbs. Instead they organize and guide all that movement, by doing many of the things needed for sensibly deciding on future objectives and planning for them. To get that job done, we need to represent in our minds future outcomes of behavior, assign value to them, and make decisions based on these assessments. We then need to monitor what actually happens, evaluate the difference between expected and actual outcomes, and update the valuation and decision functions once we have learned about those outcomes.⁴ Other parts of the prefrontal cortex help coordinate these sophisticated processes and harbor⁵ what is commonly referred to by the umbrella term “executive functions.” These parts are in intimate communication with the valuation and decision circuitry and supervise its workings, making sure that attention is on the right topic at the right time, that the right information gets put into working memory when needed,⁶ and that responses not aligned with longer-term objectives are properly inhibited.

Together, this is the machinery that makes it possible for some people to work hard on a meager stipend through years of graduate school, in the hope of one day becoming a well-regarded and perhaps even reasonably paid university professor. Or, more commonly, allows parents to give up on getting that fancy watch in order to buy their kids a present or put money into a college account. And it is this machinery that, had it functioned properly, would have helped Carlos make the decision to walk home after work instead of entering that bar, because the somatic marker associated with the latter scenario would have been unbearably repulsive. Except it didn’t. Like many patients I’ve met, Carlos did not feel that sinking feeling, could not maintain attention on it, or somehow was unable to take it into account. That does not mean he was less devastated the next day, when the hypothetical future rapidly became a real “now.” Neither does it mean he cared less about his daughter. It just meant that the machinery he would have needed to handle things was broken, through the double whammy of being born with ADHD that had never been treated and engaging in heavy alcohol use over many years.

A child is seated at a table on which a cake tin is placed. An experimenter removes the cake tin, which turns out to hide a pair of treats, for example, one marshmallow on one side and two on the other. The child is told that the experimenter will soon have to leave the room and come back after a while. To get the preferred treat, the child will have to wait until then. But the child is free to end the wait at any time simply by ringing a bell. In that case the experimenter will promptly return. The child will then get the less preferred treat at the expense of having to forgo the other one. So, in the most widely known version of this experiment, it is about choosing between getting one marshmallow now or two in fifteen minutes. Even in this simple task, where the value is clear, outcomes are certain, and the delay rather small, it takes some maturity to show the restraint needed to wait and earn the more desirable but delayed reward. In a series of classic experiments carried out at Stanford University in the early 1970s, Walter Mischel found that few preschool children were able to make it to ten minutes unless offered some distractions, and even then they didn’t last a whole lot longer.⁷

Most adults, of course, can wait longer than that. The ability to guide decisions by outcomes that are distant in time is an important reflection of the frontal lobes doing their job. This and other frontal lobe functions are among the last to mature in an individual’s development.⁸ Adults also discount the value of outcomes that are distant in time, but to a much lesser extent than do adolescents or children. People do not reach their adult performance levels in this respect until they are around twenty-five, when their frontal lobes, to all parents’ relief, finally achieve maturity. The same goes for other frontal lobe functions, such as a fully developed ability to suppress impulses or ability to avoid excessive risk.

Lack of maturity with regard to these functions can combine into a recipe for disastrously rash actions, in particular when highly attractive short-term rewards are present. Until such maturity is present, it takes quite a bit of adult supervision for those disasters to be avoided. As we know, because of poverty, broken-up families, parents who themselves are troubled, or just pure bad luck, that adult supervision is sometimes absent when it is most needed. That is when disasters often strike, in the form of fights, unprotected sex, teen pregnancy, drunk driving, drug use, or crime, in any combination. The actions involved often have terrible consequences not only for the individual carrying them out but also for others. Yet as a society we don’t hold juveniles accountable for their rash actions to the same extent we do with adults. Even the present Supreme Court of the United States, not exactly a group of bleeding-heart liberals, has agreed that sentencing juveniles as adults would amount to “cruel and unusual punishment” because these individuals have a diminished, not yet fully developed ability to appreciate future consequences of their actions.⁹

It turns out that the capacity for delaying gratification, as well as other aspects of appreciating future consequences of actions, varies greatly between adults, too. In fact, although we all hopefully get better at it between the age of four and adulthood, the relative ability to resist temptations that are near in time turns out to be a rather stable trait for an individual. When the children in Mischel’s studies were followed up, it turned out that their ability to delay gratification, as it had been determined at age four, predicted their ability to inhibit impulses later in life, both as adolescents and as adults. It also predicted their SAT scores, illustrating my father’s creed that academic achievement is as much about patience and tenacity as it is about smarts. Recently these subjects, now in their mid-forties, were tested again. The behavioral differences were still there. Then a group of them had their brains scanned while being tested for the ability to inhibit responding when presented with an attractive stimulus. People who had been “high delayers” as children were still good at withholding these responses. When they did so, they activated parts of their prefrontal cortex. In contrast, “low delayers” did not activate prefrontal areas. Instead they activated their ventral striatum, the key node of brain reward circuitry whose activity promotes approach behaviors.¹⁰

The reason all this is so important is that being impulsive, as measured by excessive delay discounting, inability to suppress responses, and other measures, is one of the strongest risk factors for developing an addictive disorder. Yes, it is quite possible to be impulsive and nevertheless avoid getting in trouble. Growing up in a well-structured, supportive, and nurturing environment, a person who tends to be uninhibited will perhaps have a successful career as an actor or a snowboarder. Or maybe that person will boldly go where no one else has gone before in science. But under less ideal environmental conditions, or when not combined with special talents, impulsivity will often set an individual on a path to many problems, including drug and alcohol use. After all, the more advanced society becomes, the greater is the need for being attentive, carefully planning, and reliably exerting self-control to achieve success in most normal walks of life. Impulsive personality traits clearly interact in major ways with the environment but are also quite heritable, so more on this topic will follow in the next chapter. For now let’s just say that, all else being equal, high impulsivity is associated with high addiction risk.¹¹

How strong is the association? Pretty strong. Here is one clinically important observation that illustrates it: impulsivity is one of the defining features of ADHD. Sadly, but precisely the way it would be expected from this discussion, children with ADHD have about twice the risk of developing addiction compared with those without the condition. There is good news too, however. The elevated risk is for kids who do not receive treatment. In contrast, contrary to common fears and beliefs, those whose ADHD is adequately treated with stimulant medications have their risk of addiction reduced by half, down to levels that no longer differ from those in the general population.¹² Reducing impulsivity and improving attention seems to help in the real world. There is another piece of good news, too. It does not necessarily take medications to improve functions that are impaired in ADHD. In some ways, brain functions are like muscles. Practice strengthens them and makes perfect. So it should come as little surprise that practicing attention, response inhibition, and delaying gratification can improve those functions. By now there are computer games that allow ADHD kids to do just that: practice these things while having fun and being engaged. This has been shown to help with the problems of ADHD.¹³ It remains to be shown if that kind of mental workout is also able to reduce addiction risk in these children when they grow up, but I would not be surprised if it does.

Clinicians have long known that patients with addictive disorders often seem to be more impulsive than people without them. But it has been hard to know what is causing what. Once someone has developed an addiction and seeks treatment, this becomes the proverbial chicken-and-egg problem. Most addictive drugs, including alcohol, increase impulsive behavior and risk taking by themselves, even when taken by healthy research volunteers in the laboratory. In addition, chronic drug use often results in damage to the frontal lobes, which in turn would be expected to further increase impulsivity.¹⁴ How, then, can we figure out if the relationship between impulsivity and addiction is really causal in nature? Perhaps impulsivity has nothing to do with the risk of developing addiction after all? Perhaps its role is simply that it makes people sample the forbidden fruit more easily, and after that the addictive properties of the drug are all that matters? Or maybe the connection is even less direct. Maybe impulsive people, because they don’t do as well in life as others, are more likely to become less well educated, poorer, and exposed to environments that are infested with drugs and crime? These issues have been much debated through the years. As is often the case, research in animal models can add a valuable perspective because it can distill complex questions like this and address them in less complex experimental models. Using that type of approach, research has provided support for the notion that impulsivity in itself is a major risk factor, not only for sampling addictive drugs but also for escalating drug use and transitioning from occasional drug use to addiction.

Almost twenty years ago, a team of researchers at the National Institutes of Health obtained some of the first animal data to support a link between impulsivity and addiction liability. Just like humans, our primate cousins the rhesus monkeys vary quite a bit in how much alcohol they will consume when given free access to an alcoholic drink. To people who work with them, they also seem to have very different personalities. Some are more aggressive, others less so. Some seem smarter than others. Could there also be consistent differences in impulsivity among them? To answer that question, one would have to come up with a method of measuring impulsivity in a way that makes sense for a monkey. In a series of experiments as brilliant as they were hilarious, that was just what Dee Higley, Markku Linnoila, and Steve Suomi did. Rhesus monkeys can all get around by jumping between trees, but different monkeys go about their transportation differently. Some play it safe, at the expense of not getting ahead very fast. Others take more risk and jump long distances. That allows them to move faster, but if they attempt jumps that are too long, there is a risk they will fall to the ground. That alone isn’t really a good measure of impulsivity and risk taking. If they only try long leaps close to ground level, the worst that can happen is that they will have to climb back up in the tree again. But if they try a long jump high up and fail, they could really get hurt. It turns out that “long” for a rhesus means greater than 3 meters, and “high up” means more than 7 meters up in the air. Now find out for each monkey the number of these dangerous long jumps, divide by the total to account for the fact that different monkeys get around more or less, and we have a good, ecologically meaningful measure of impulsive behavior. Using that measure, it turns out that the most impulsive individuals in the rhesus troop are also the ones that will escalate their alcohol intake to the highest levels.¹⁵

Those data, or course, were obtained in the early days, when scientists did not pay much attention to the distinction between simply high intake of a drug and patterns of use that might be more relevant for addiction in humans. In more recent years, several laboratories have been successful in modeling “compulsive” drug taking, meaning that drug use is continued with high motivation, and even when it leads to adverse consequences. Based on those characteristics, David Belin, a French researcher working at Cambridge University’s famous psychology department, assessed rats for individual differences in impulsivity and novelty seeking. These traits have both often been considered risk factors for addiction. Again, one has to ask, how could those behaviors be assessed in a way that makes sense for a rat? Novelty seeking is actually quite easy. This is all about how driven an individual is to explore a novel environment, so no matter what the species, it is probably enough if we can measure how vigorously that individual will explore novelty. But how about assessing impulsivity in a rat? Belin chose a test in which rats are trained to scan five holes and poke their nose into one of them when it is illuminated. If they do this, they get a food pellet. But after each time, they must hold back from responding for five seconds, until one of the holes is illuminated again. If the animal incorrectly pokes a hole that is not illuminated, it is punished by the reward being omitted, after which there will be a terribly frustrating five-second time-out. If the rat fails to wait for the light to come on and responds prematurely, it will be punished in the same manner. The premature responses provide a measure of impulsivity in the task. Using this model, Belin found that high novelty seekers among the rats initiated cocaine self-administration much faster than low novelty seekers. But once animals had initiated self-administration, the highly impulsive rats were the ones that made the transition to compulsive use.¹⁶

Interesting and elegant though this is, it still does not conclusively answer the question whether impulsivity is the cause rather than just a correlate of the addictive process. For all we know, both these behaviors could be independent consequences of some third, unknown factor. To conclusively determine causality, we would need some kind of intervention. Ideally, if impulsivity really causes addiction, we would like to see that suddenly losing key parts of the frontal lobes, together with the foresight they provide, should make a difference. Taking out the right parts of the frontal lobe should convert an individual previously not prone to addiction into one who does run a high risk of developing this condition. But this becomes a somewhat problematic proposition. I have discussed how key aspects of frontal lobe function are unique to humans, so animal experiments may have serious limitations. And an experiment that proposes to take out parts of the pre-frontal cortex in humans may face some challenges in recruiting volunteers.

The famous case of Phineas Gage, and less renowned patients with accidental damage to their prefrontal cortex, seem, however, to support the argument. Gage was the railroad construction worker who survived after his skull was pierced in 1848. A 3-centimeter-thick iron rod passed through it as a projectile, sent on its way by a controlled explosion gone wrong during the building of a Vermont railroad. In the textbook account, this led to profound changes in Gage’s behavior. A description of the consequences has made it into more than half of all undergraduate psychology textbooks. In this account, Gage turned from a responsible and trusted foreman at the railroad into a drifter showing a lack of foresight and judgment. What is less often discussed, but probably just as important, is that he also became, simply stated, a drunk.¹⁷ Gage’s case became a true celebrity in 1994. In a prequel to the CSI dramas of modern times, but in contrast to those carried out with an impeccable scientific quality, Gage’s skull was borrowed from the Warren Anatomical Medical Museum at Harvard University and analyzed by the neurologist Antonio Damasio and his team, then at University of Iowa. The team applied modern imaging techniques to the skull and reconstructed the trajectory the iron rod must have taken. This allowed them to identify what parts of the brain the projectile had damaged. Between an entry point below the mandibular bone and an exit hole at the top of the skull, the damage appeared to have been in regions on the underbelly and the inside of the frontal lobes. The textbook account of Gage and his case has recently been called in question,¹⁸ but the fact remains: in modern patients with brain lesions affecting the same areas as those the rod seems to have damaged in Gage, there is little impact on regular intellectual ability, such as that needed to solve math problems. Yet these individuals show a profound loss of judgment, foresight, and appropriate social behavior.

So the relationship between impulsivity and addiction is likely to go both ways. In the absence of protective family and societal factors, children who are impulsive run a much elevated risk for developing heavy drug use or addiction. Heavy chronic drug use, on the other hand, will make these individuals even more impulsive, in a truly vicious circle. By the time this dynamic has a person firmly in its grip, not even the happiness of a truly beloved child can successfully compete with the immediate attraction of a few drinks. This is not because the person is unable to do the math in theory. It is because when these real-life decisions are made, they are made in real time. And when that processing is carried out, the valuation, decision making, and behavioral inhibition machinery simply does not do the job it is supposed to do.

Decades of work in this field have convinced me that this is not a moral failing but rather a malfunction of sophisticated yet quite sensitive computational hardware. Some might disagree. Some might say, if all behavior can be reduced to the function or malfunction of brain machinery, then we are truly unable to make choices, there is no free will, and no one can be held accountable for their actions. And if that really is the case, then Adolf Hitler is no more culpable than the next person. I do not pretend to have an answer to this argument, and I agree that scientific understanding of how bad behavior happens should not be used to explain away individual responsibility. This dilemma has plagued philosophers for centuries. But I do know this: as he was admitted, after Marta had left him for their native Ecuador, taking their daughter with her, Carlos wished, at his core, that things had turned out different. After all these years working with patients who over and over fail to achieve what they seem to truly desire, I am convinced he wanted what most of us want. The difference is, the tools he had at his disposal let him down. Maybe if we can figure out how those tools work, we will be able to help people be touched by the better angels of their nature. That, I hope, is not too much to ask for.