Determined: A Science of Life without Free Will

by Robert M. Sapolsky

Peer socialization, with different peers modeling different behaviors with varying allure. The importance of peers has often been underappreciated by developmental psychologists but is no surprise to any primatologists. Humans invented a novel way to transmit information across generations, where an adult expert intentionally directs information at young’uns—i.e., a teacher. In contrast, the usual among primates is kids learning by watching their somewhat older peers.[35] Environmental influences. Is the neighborhood park safe? Are there more bookstores or liquor stores? Is it easy to buy healthy food? What’s the crime rate? All the usual. Cultural beliefs and values, which influence these other categories. As we’ll see, culture dramatically influences parenting style, the behaviors modeled by peers, the sorts of physical and social communities that are constructed. Cultural variability in overt and covert rites of passage, the brands of places of worship, whether kids aspire to earn lots of merit badges versus getting skilled at harassing out-group members.

a study examining more than a million people across China and the U.S. showed the effects of growing up in clement weather (i.e., mild fluctuations around an average of seventy degrees). Such individuals are, on the average, more individualistic, extroverted, and open to novel experience. Likely explanation: the world is a safer, easier place to explore growing up when you don’t have to spend significant chunks of each year worrying about dying of hypothermia and/or heatstroke when you go outside, where average income is higher and food stability greater. And the magnitude of the effect isn’t trivial, being equal to or greater than that of age, gender, the country’s GDP, population density, and means of production.[36]

For example, lots of childhood stress, by way of glucocorticoids, impairs construction of the frontal cortex, producing an adult less adept at helpful things like impulse control. Lots of exposure to testosterone early in life makes for the construction of a highly reactive amygdala, producing an adult more likely to respond aggressively to provocation. The nuts and bolts of how this happens revolves around the massively trendy field of “epigenetics,” revealing how early life experience causes long-lasting changes in gene expression in particular brain regions.

Where do differences in rodential mothering style come from? Obviously, from one second, one minute, one hour, before in that rat mom’s biological history. Knowledge about epigenetic bases of this has grown at breakneck speed, showing, for example, how some epigenetic changes in the brain can have multigenerational consequences (e.g., helping to explain why being a rat, monkey, or human abused in childhood increases the odds of being an abusive parent). Just to show the scale of epigenetic complexity, differences in mothering styles in monkeys cause epigenetic changes in more than a thousand genes expressed in the offspring’s frontal cortex.[38]

How does a gene “decide” when to initiate the construction of the protein it codes for, and whether there will be one or ten thousand copies made? Implicit in this question is the popular view of genes as the be-all and end-all, the code of codes in regulating what goes on in your body. As it turns out, genes decide nothing, are out at sea. Saying that a gene decides when to generate its associated protein is like saying that the recipe decides when to bake the cake that it codes for. Instead, genes are turned on and off by environment. What is meant here by environment? It can be the environment within a single cell—a cell is running low on energy, which generates a messenger molecule that activates the genes that code for proteins that boost energy production. Environment can encompass the entire body—a hormone is secreted and is carried in the circulation to target cells at the other end of the body, where it binds to its distinctive receptors; as a result, particular genes are turned on or off. Or environment can take the form of our everyday usage, namely events happening in the world around us. These different versions of environment are linked. For example, living in a stressful, dangerous city will produce chronically elevated levels of glucocorticoids secreted by your adrenal glands, which will activate particular genes in neurons in the amygdala, making those cells more excitable.[*]

Does behavior genetics disprove free will? Not on its own—as a familiar theme, genes are about potentials and vulnerabilities, not inevitabilities, and the effects of most of these genes on behavior are relatively mild. Nonetheless, all these effects on behavior arise from genes you didn’t choose, interacting with a childhood you didn’t choose.[48]

Where do these differences come from? The standard explanations for American individualism include (a) not only are we a nation of immigrants (as of 2017, ~37 percent immigrants or children of), but it’s not random who emigrates; instead, immigrating is a filtering process selecting for people willing to leave their world and culture behind, sustain an arduous journey to a place with barriers impeding their entry, and labor at the most shit jobs when granted admission; and (b) most of American history has been spent with an expanding western border settled by similarly tough, individualist pioneers. Meanwhile, the standard explanation for East Asian collectivism is ecology dictating the means of production—ten millennia of rice farming, which demands massive amounts of collective labor to turn mountains into terraced rice paddies, collective planting and harvesting of each person’s crops in sequence, collective construction and maintenance of massive and ancient irrigation systems.[*],[51] A fascinating exception that proves the rule concerns parts of northern China where the ecosystem precludes rice growing, producing millennia of the much more individualistic process of wheat farming. Farmers from this region, and even their university student grandchildren, are as individualistic as Westerners.

varmint

This pastoralist vulnerability has generated “cultures of honor” with the following features: (a) extreme but temporary hospitality to the stranger passing through—after all, most pastoralists are wanderers themselves with their animals at some point; (b) adherence to strict codes of behavior, where norm violations are typically interpreted as insulting someone; (c) such insults demanding retributive violence—the world of feuds and vendettas lasting generations; (d) the existence of warrior classes and values where valor in battle produces high status and a glorious afterlife. Much has been made of the hospitality, conservatism (as in strictly conserving cultural norms), and violence of the traditional culture of honor of the American South. The pattern of violence tells a ton: murders in the South, which typically has the highest rates in the country, are not about stickups gone wrong in a city; they’re about murdering someone who has seriously tarnished your honor (by conspicuously bad-mouthing you, failing to repay a debt, coming on to your significant other . . .), particularly if living in a rural area.

For various reasons, humans were sculpted by evolution over millions of years to be, on the average, more aggressive than bonobos but less so than chimps, more social than orangutans but less so than baboons, more monogamous than mouse lemurs but more polygamous than marmosets. ’Nuff said.[57]

This seamless stream shows why bad luck doesn’t get evened out, why it amplifies instead. Have some particular unlucky gene variant, and you’ll be unluckily sensitive to the effects of adversity during childhood. Suffering from early-life adversity is a predictor that you’ll be spending the rest of your life in environments that present you with fewer opportunities than most, and that enhanced developmental sensitivity will unluckily make you less able to benefit from those rare opportunities—you may not understand them, may not recognize them as opportunities, may not have the tools to make use of them or to keep you from impulsively blowing the opportunity. Fewer of those benefits make for a more stressful adult life, which will change your brain into one that is unluckily bad at resilience, emotional control, reflection, cognition . . . Bad luck doesn’t get evened out by good. It is usually amplified until you’re not even on the playing field that needs to be leveled.

“it is not ontology that rules out free will, it is luck (his emphasis).”[*]

Why did that moment just occur? “Because of what came before it.” Then why did that moment just occur? “Because of what came before that,” forever,[*] isn’t absurd and is, instead, how the universe works.

Agents are not responsible as soon as they acquire a set of active dispositions and values; instead, they become responsible by taking responsibility for their dispositions and values. Manipulated agents are not immediately responsible for their actions, because it is only after they have had sufficient time to reflect upon and experience the effects of their new dispositions that they qualify as fully responsible agents. The passing of time (under normal conditions) offers opportunities for deliberation and reflection, thereby enabling agents to become responsible for who they are. Agents become responsible for their dispositions and values in the course of normal life, even when these dispositions and values are the product of awful constitutive luck. At some point bad constitutive luck ceases to excuse, because agents have had time to take responsibility for it.[1]

A similar view comes from the distinguished philosopher Robert Kane, of the University of Texas: “Free will in my view involves more than merely free of action. It concerns self-formation. The relevant question for free will is this: How did you get to be the kind of person you now are?” Roskies and Shadlen write, “It is plausible to think that agents might be held morally responsible even for decisions that are not conscious, if those decisions are due to policy settings which are expressions of the agent [in other words, acts of free will in the past].”[3]

Some baboons are just that way. They’re full of potential—big, muscular, with sharp canines—but go nowhere in the hierarchy because they never miss an opportunity to miss an opportunity. They break up their coalition with an impulsive act, like Finn did. They can’t keep themselves from challenging the alpha male for a female, and get pummeled.

As noted in the last chapter, it’s the last part of the brain to fully mature, not being fully constructed until your midtwenties; this is outrageously delayed, given that most of the brain is up and running within a few years of birth.

the prefrontal cortex (PFC)—is proportionately even larger than the rest of the frontal cortex, and more recently evolved.[*],[10]

What the PFC is most about is making tough decisions in the face of temptation—gratification postponement, long-term planning, impulse control, emotional regulation. The PFC is essential for getting you to do the right thing when it is the harder thing to do. Which is so pertinent to that false dichotomy between what attributes fate hands you and what you do with them.

“Doing the right thing” requires two different skills from the PFC. There’s sending the decisive “do this” signal along the path from the PFC to the frontal cortex to the supplementary motor area (the SMA of chapter 2) to the motor cortex. But even more important, there is the “and don’t do that, even if that’s the usual” signal.

Tell subjects there’s been a computer glitch so that they can’t enter their guess; that’s okay, they’re told, we’ll show you the answer and you can just tell us whether you were right. In other words, an opportunity to cheat. Throw in enough of those there-goes-that-computer-glitch-again opportunities, and you can tell if someone starts cheating—their success rate averages above 50 percent. What happens in the brains of cheaters when temptation arises? Massive activation of the PFC, the neural equivalent of the person wrestling with whether to cheat.[16] And then for the profound additional finding. What about the people who never cheated—how do they do it? Maybe their astonishingly strong PFC pins Satan to the mat each time. Major willpower. But that’s not what happens. In those folks, the PFC doesn’t stir. At some point after “don’t pee in your pants” no longer required the PFC to flex its muscles, an equivalent happened in such individuals, generating an automatic “I don’t cheat.” As framed by Greene, rather than withstanding the siren call of sin thanks to “will,” this instead represents a state of “grace.” Doing the right thing isn’t the harder thing.

As it turns out, a substantial percentage of people incarcerated for violent crime have a history of concussive head trauma to the PFC.[18]

Thus, the frontal cortex isn’t just this cerebral, eggheady brain region weighing the pluses and minuses of each decision, sending nice rational Libetian commands to the motor cortex—i.e., an excitatory role. It’s also an inhibitory, rule-bound goody-goody telling more emotional parts of the brain not to do something because they’re going to regret it. And basically, those other brain regions think of the PFC as this moralizing pain with a stick up its butt, especially when it turns out to be right.

minutiae,

Then there are people who have sustained selective damage to their dlPFC. The outcome is just what you’d expect—impaired planning or gratification postponement, perseveration on strategies that offer immediate reward, plus poor executive control over socially inappropriate behavior. A brain with no voice saying, “I wouldn’t do that if I were you.”

You can demonstrate this with brain-imaging techniques, showing how a working PFC consumes tons of glucose and oxygen from the bloodstream, or by measuring how much biochemical cash is available in each neuron at any given time.[*] Which leads to the main point of this section—when the PFC doesn’t have enough energy on board, it doesn’t work well.

What best predicted whether a judge granted someone parole versus more jail time? How long it had been since they had eaten a meal. Appear before the judge soon after she’s had a meal, and there was a roughly 65 percent chance of parole; appear a few hours after a meal, and there was close to a 0 percent chance.[*],[28]

Chapter 3 covered how over this time span, the structure and function of the brain can change dramatically. Recall how years of depression can cause the hippocampus to atrophy, how the sort of trauma that produces PTSD can enlarge the amygdala. Naturally, neuroplasticity in response to experience occurs in the PFC as well.

Extensive damage to the PFC increases the likelihood long after of disinhibited behavior, antisocial tendencies, and violence, a phenomenon that has been called “acquired sociopathy”[*]—remarkably, such individuals can tell you that, say, murder is wrong; they know, but they just can’t regulate their impulses.

Conversely, an enriched, stimulating environment during adolescence has great effects on the resulting adult PFC and can reverse some of the effects of childhood adversity.

Miseries like childhood poverty and childhood abuse are incorporated in someone’s Adverse Childhood Experiences (ACE) score. As we saw in the last chapter, it queries whether someone experienced or witnessed physical, emotional, or sexual childhood abuse, physical or emotional neglect, or household dysfunction, including divorce, spousal abuse, or a family member mentally ill, incarcerated, or struggling with substance abuse. With each increase in someone’s ACE score, there’s an increased likelihood of a hyperreactive amygdala that has expanded in size and a sluggish PFC that never fully developed.[49]

Let’s frame this sort of difference more mechanically. Suppose you have an electrical cord that plugs into a socket; when it’s plugged in, you don’t steal. The socket is made of an imaginary protein that comes in two variants, which determine how wide the slots are that the plug plugs into. In a silent, hermetically sealed room, a plug remains in the socket, regardless of variant. But if a group of taunting, peer-pressuring elephants thunders past, the plug is ten times more likely to vibrate out of the loose-slot socket than the tight one.

Here’s one you couldn’t make up—in Westerners, the vmPFC activates in response to seeing a picture of your own face but not your mother’s; in East Asians, the vmPFC activates equally for both; these differences become even more extreme if you prime subjects beforehand to think about their cultural values. Study bicultural individuals (i.e., with one collectivist culture parent, one individualist); prime them to think about one culture or the other, and they then show that culture’s typical profile of vmPFC activation.[55]

Where do these differences come from on a big-picture level?[*] As discussed in the last chapter, East Asian collectivism is generally thought to arise from the communal work demands of floodplain rice farming. Recent Chinese immigrants to the United States already show the Western distinction between activating your vmPFC when thinking about yourself and activating it when thinking about your mother. This suggests that people back home who were more individualistic were the ones more likely to choose to emigrate, a mechanism of self-selection for these traits.[57]

This relationship between starting states and mature states helped give rise to what has been the central concept of science for centuries. This is reductionism, the idea that to understand something complicated, break it down into its component parts, study them, add your insights about each component part together, and you will understand the complicated whole. And if one of those component parts is itself too complicated to understand, study its eensy subcomponent parts and understand them.

antediluvian

Imagine a universe that consists of just two variables, the Earth and the Moon, exerting their gravitational forces on each other. In this linear, additive world, it is possible to infer precisely where they were at any point in the past and predict precisely where each will be at any point in the future;[*] if an approximation was accidentally introduced, the same magnitude of approximation would continue forever. But now add the Sun into the mix, and the nonlinearity happens. This is because the Earth influences the Moon, which means that the Earth influences how the Moon influences the Sun, which means that the Earth influences how the Moon influences the Sun’s influence on the Earth. . . . And don’t forget the other direction, Earth to Sun to Moon. The interactions among the three variables make linear predictability impossible. Once you’ve entered the realm of what is known as the “three-body problem,” with three or more variables interacting, things have inevitably become unpredictable.

So a tiny difference in a starting state can magnify unpredictably over time. Lorenz took to summarizing this idea with a metaphor about seagulls. A friend suggested something more picturesque, and by 1972 this was formalized into the title of a talk given by Lorenz. Here’s another holy relic of the field (see figure on the next page). Thus was born the symbol of the chaos theory revolution, the butterfly effect.[*],[4]

highfalutin

The system is deterministic, but you can’t say what it’s going to do next.”[6]

brouhaha

To say that chaotic systems are unpredictable is not to say that science cannot explain them.”

Similarly, consider a group of soldiers lining up in a firing squad to kill someone. No matter how much one is pulling a trigger in glorious obedience to God and country, there’s often some ambivalence, perhaps some guilt about mowing down someone or worry that fortunes will shift and you’ll wind up in front of a firing squad. And for centuries, this gave rise to a cognitive manipulation—one soldier at random was given a blank rather than a real bullet. No one knew who had it, and thus every shooter knew that they might have gotten the blank and thus weren’t actually a killer.

—“Break it down to its component parts” reductionism doesn’t work for understanding some vastly interesting things about us. Instead, in such chaotic systems, minuscule differences in starting states amplify enormously in their consequences. —This nonlinearity makes for fundamental unpredictability, suggesting to many that there is an essentialism that defies reductive determinism, meaning that the “there can’t be free will because the world is deterministic” stance goes down the drain. —Nope. Unpredictable is not the same thing as undetermined; reductive determinism is not the only kind of determinism; chaotic systems are purely deterministic, shutting down that particular angle of proclaiming the existence of free will.

put enough of the same simple elements together, and they spontaneously self-assemble into something flabbergastingly complex, ornate, adaptive, functional, and cool. With enough quantity, extraordinary quality just . . . emerges, often even unpredictably.[*],[1]

Let’s start with what wouldn’t count as emergent complexity. Put a beefy guy in a faux military uniform carrying a sousaphone in the middle of a field. His behavior is simple—he can walk forward, to the left, or to the right, and does so randomly. Scatter a bunch of other instrumentalists there, and the same thing happens, all randomly moving, collectively making no sense. But toss three hundred of them onto the field and out of that emerges a giant Michael Jackson moonwalking past the fifty-yard line during the halftime performance.[*] There are all these interchangeable, fungible marching band marchers with the same minuscule repertoire of movements. Why doesn’t this count as emergence?

Here’s real emergent complexity: Start with one ant. It wanders aimlessly on the field. As do ten of them. A hundred interact with vague hints of patterns. But put thousands of them together and they form a society with job specialization, construct bridges or rafts out of their bodies that float for weeks, build flood-proof underground nests with passageways paved with leaves, leading to specialized chambers with their own microclimates, some suited for farming fungi and others for brood rearing. A society that even alters its functions in response to changing environmental demands. No blueprint, no blueprint maker.[2] What makes for emergent complexity? —There is a huge number of ant-like elements, all identical or coming in just a few different types. —The “ant” has a very small repertoire of things it can do. —There are a few simple rules based on chance interactions with immediate neighbors (e.g., “walk with this pebble in your little ant mandibles until you bump into another ant holding a pebble, in which case, drop yours”). No ant knows more than these few rules, and each acts as an autonomous agent. —Out of the hugely complicated phenomena this can produce emerge irreducible properties that exist only on the collective level (e.g., a single molecule of water cannot be wet; “wetness” emerges only from the collectivity of water molecules, and studying single water molecules can’t predict much about wetness) and that are self-contained at their level of complexity (i....

Here’s a more complex example: An ant forages for food, checking eight different places. Little ant legs get tired, and ideally the ant visits each site only once, and in the shortest possible path of the 5,040 possible ones (i.e., seven factorial). This is a version of the famed “traveling salesman problem,” which has kept mathematicians busy for centuries, fruitlessly searching for a general solution. One strategy for solving the problem is with brute force—examine every possible route, compare them all, and pick the best one. This takes a ton of work and computational power—by the time you’re up to ten places to visit, there are more than 360,000 possible ways to do it, more than 80 billion with fifteen places to visit. Impossible. But take the roughly ten thousand ants in a typical colony, set them loose on the eight-feeding-site version, and they’ll come up with something close to the optimal solution out of the 5,040 possibilities in a fraction of the time it would take you to brute-force it, with no ant knowing anything more than the path that it took plus two rules (which we’ll get to). This works so well that computer scientists can solve problems like this with “virtual ants,” making use of what is now known as swarm intelligence.[*],[7]

And the intensely cool thing is that these very different physiological systems—neurons, blood vessels, the pulmonary system, and lymph nodes—use some of the same genes, coding for the same proteins in the construction process (a menagerie of proteins such as VEGF, ephrins, netrins, and semaphorins). These are not genes used for, say, generating the circulatory system. These are genes for generating bifurcating systems, applicable to one single neuron and to vascular and pulmonary systems using billions of cells.[24] Aficionados will recognize that these bifurcating systems all form fractals, where the relative degree of complexity is constant, no matter at what scale of magnification you are considering the system (with the recognition that unlike the fractals of mathematics, fractals in the body don’t bifurcate forever—physical reality asserts itself at some point). We’re now in very strange terrain, having to consider the molecules of the sort mentioned in the previous paragraph being coded for by “fractal genes.” Which means that there must be fractal mutations, disrupting normal branching in everything from single neurons to entire organ systems; there are some hints of these out there.[25] These principles apply to nonbiological complexity as well—for example, why rivers emptying into the sea bifurcate into river deltas. And it even applies to cultures. Let’s consider one last emergent bifurcating tree, one that shows either the deeply abstract ubiquity of the phenom...

No committee, no planning, no experts, no choices freely taken. Just the same pattern as for the planned town, emerging from some simple rules: —Each neuron that has been thrown randomly into the soup secretes a chemoattractant signal; they’re all trying to get the others to migrate to them. Two neurons happen to be closer than average to each other by chance, and they wind up being the first pair to be clumped together in their neighborhood. This doubles the power of the attractant signal emanating from there, making it more likely that they’ll attract a third neuron, then a fourth . . . Thus, through a rich-get-richer scenario, this forms a nidus, the starting point of a local cluster growing outward. Growing aggregates like these are scattered throughout the neighborhood. —Each clump of neurons reaches a certain size, at which point the chemoattractant stops working. How would that work? Here’s one mechanism—as a ball of clumping neurons gets bigger, the ones in the center are getting less oxygen, triggering them to start secreting a molecule that inactivates chemoattractant molecules. —All along, neurons have been secreting a second type of attractant signal in minuscule amounts. It’s only when enough neurons have migrated into an optimally sized cluster that there is collectively enough of the stuff to prompt the neurons in the cluster to start forming dendrites, axons, and synapses with each other. —Once this local network is wired up (detectable by, say, a certain d...