Determined, page 8
What might gene/environment interactions look like? Suppose someone has a gene variant related to aggression; depending on the environment, that can result in an increased likelihood of street brawling or of playing chess really aggressively. Or a gene related to risk-taking that, depending on environment, will influence whether you rob a store or gamble on founding a start-up. Or a gene related to addiction that, depending on environment, produces a Brahmin drinking too much Scotch in his club or someone desperately stealing to get money for heroin.[*]
Final bit of the primer. Most genes come in more than one flavor, with people inheriting their particular variants from their parents. Such gene variants code for slightly different versions of their protein, with some being better at their job than others.[*]
Where have we gotten? People differing in the flavors of genes they possess, those genes being regulated differently in different environments, producing proteins whose effects vary in different environments. We now consider how genes relate to this free-will obsession of ours.
It’s button time; how will your brain be influenced in that moment by the flavors of particular genes you inherited? Consider the neurotransmitter serotonin—differing profiles of serotonin signaling among people help explain individual differences related to mood, levels of arousal, tendency toward compulsive behavior, ruminative thoughts, and reactive aggression. And how can individual differences in gene variants contribute to differences in serotonin signaling? Easily—different flavors exist for the genes coding for the proteins that synthesize serotonin, that remove it from the synapse, and that degrade it,[*] plus variants in the genes that code more than a dozen different types of serotonin receptors.[44]
Same story with the neurotransmitter dopamine. To barely scratch the surface, individual differences in dopamine signaling are relevant to reward, anticipation, motivation, addiction, gratification postponement, long-term planning, risk-taking, novelty seeking, salience of cues, and ability to focus—you know, things pertinent to our judging, say, whether someone could have transcended their dire circumstances if only they could have shown some self-discipline. And the genetic sources of dopaminergic differences among people? Genetic variants related to dopamine’s synthesis, degradation, and removal from the synapse,[*] as well as in the various dopamine receptors.[45]
We could go on now to the neurotransmitter norepinephrine. Or enzymes that synthesize and degrade various hormones and hormone receptors. Or pretty much anything pertinent to brain function. There’s usually extensive individual variation in every relevant gene, and you weren’t consulted as to which you’d choose to inherit.
What about the flip side—a bunch of people all have the identical gene variant but live in different environments? You get precisely what was discussed above, namely dramatically different effects of the gene variant depending on environment. For example, one variant of the gene whose protein breaks down serotonin will increase your risk of antisocial behavior . . . but only if you were severely abused during childhood. A variant of a dopamine receptor gene makes you either more or less likely to be generous, depending on whether you grew up with or without secure parental attachment. That same variant is associated with poor gratification postponement . . . if you were raised in poverty. One variant of the gene that directs dopamine synthesis is associated with anger . . . but only if you were sexually abused as a kid. One version of the gene for the oxytocin receptor is associated with less sensitive parenting . . . but only when coupled with childhood abuse. On and on (and with many of the same relationships being seen in other primate species as well).[46]
Dang, how can environment cause genes to work so differently, even in diametrically opposite ways? Just to start to put all the pieces together, because different environments will cause different sorts of epigenetic changes in the same gene or genetic switch.
Thus, people have all these different versions of all of these, and these different versions work differently, depending on childhood environment. Just to put some numbers to it, humans have roughly twenty thousand genes in our genome; of those, approximately 80 percent are active in the brain—sixteen thousand. Of those genes, nearly all come in more than one flavor (are “polymorphic”). Does this mean that in each of those genes, the polymorphism consists of one spot in that gene’s DNA sequence that can differ among individuals? No—there are actually an average of 250 spots in the DNA sequence of each gene . . . which adds up to there being individual variability in approximately four million spots in the sequence of DNA that codes for genes active in the brain.[*],[47]
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]
Back Centuries: The Sort of People You Come From
The Libetian buttons beckon. What does your culture have to do with the intent you will act upon? Tons. Because from your moment of birth, you were subject to a universal, which is that every culture’s values include ways to make their inheritors recapitulate those values, to become “the sort of people you come from.” As a result, your brain reflects who your ancestors were and what historical and ecological circumstances led them to invent those values surrounding you. If a fairly tunnel-visioned neurobiologist became dictator of the world, anthropology would be defined as “the study of the ways that different groups of people attempt to shape brain construction in their children.”
Cultures produce dramatically different behaviors with consistent patterns. One of the most studied contrasts concerns “individualist” versus “collectivist” cultures. The former emphasize autonomy, personal achievement, uniqueness, and the needs and rights of the individual; it’s looking out for number one, where your actions are “yours.” Collectivist cultures, in contrast, espouse harmony, interdependence, and conformity, where the needs of the community guide behavior; the priority is that your actions make the community proud, because you are “theirs.” Most studies of these contrasts compare individuals from the poster child of individualist cultures, the United States, with those from the textbook collectivist cultures of East Asia. The differences make sense. People from the U.S. are more likely to use first-person-singular pronouns, to define themselves in personal rather than relational terms (“I’m a lawyer” versus “I’m a parent”), to organize memory around events rather than social relations (“the summer I learned to swim” versus “the summer we became friends”). Ask subjects to draw a sociogram—a diagram with circles representing themselves and the people who matter in their lives, connected by lines—Americans typically place themselves in the biggest circle, in the center. Meanwhile, an East Asian’s circle typically is no bigger than the others, and is not front and center. The American goal is to distinguish yourself by getting ahead of everyone else; the East Asian is to avoid being distinguishable.[*] And from these differences come major differences as to what count as norm violations and what you do about them.[49]
Naturally, this reflects different workings of the brain and body. On average, in East Asian individuals, the dopamine “reward” system activates more when looking at a calm versus excited facial expression; for Americans, it’s the opposite. Show subjects a picture of a complex scene. Within milliseconds, East Asians typically scan the entire scene as a whole, remembering it; Americans focus on the person in the center of the picture. Force an American to tell you about times that other people influenced them, and they secrete glucocorticoids; someone East Asian will secrete the stress hormone when forced to tell you about times they influenced other people.[50]
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. As one finding that is beyond cool, Chinese from rice regions accommodate and avoid obstacles (in this case, walking around two chairs experimentally placed to block the way in Starbucks); people from wheat regions remove obstacles (i.e., moving the chairs apart).[52]
Thus, cultural differences arising centuries, millennia, ago, influence behaviors from the most subtle and minuscule to dramatic.[*] Another literature compares cultures of rain forest versus desert dwellers, where the former tend toward inventing polytheistic religions, the latter, monotheistic ones. This probably reflects ecological influences as well—life in the desert is a furnace-blasted, desiccated singular struggle for survival; rain forests teem with a multitude of species, biasing toward the invention of a multitude of gods. Moreover, monotheistic desert dwellers are more warlike and more effective conquerors than rain forest polytheists, explaining why roughly 55 percent of humans proclaim religions invented by Middle Eastern monotheistic shepherds.[53]
Shepherding raises another cultural difference. Traditionally, humans make livings as agriculturalists, hunter-gatherers, or pastoralists. The last are folks in deserts, grasslands, or plains of tundra, with their herds of goats, camels, sheep, cows, llamas, yaks, or reindeer. Such pastoralists are uniquely vulnerable. It’s hard to sneak in at night and steal someone’s rice field or rain forest. But you can be a sneaky varmint and rustle someone’s herd, stealing the milk and meat they survive on.[*] 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.[*] Where does the Southern culture of honor come from? A widely accepted theory among historians makes this paragraph’s point perfectly—while colonial New England filled with Pilgrims, and the mid-Atlantic with mercantile folks like Quakers, the South was disproportionately peopled by wild-assed pastoralists from northern England, Scotland, and Ireland.[54]
One last cultural comparison, between “tight” cultures (with numerous and strictly enforced norms of behavior) and “loose” ones. What are some predictors of a society being tight? A history of lots of cultural crises, droughts, famines, and earthquakes, and high rates of infectious diseases.[*] And I mean it with “history”—in one study of thirty-three countries, tightness was more likely in cultures that had high population densities back in 1500.[*],[55]
Five hundred years ago!? How can that be? Because generation after generation, ancestral culture influenced the likes of how much physical contact mothers had with their children; whether kids were subject to scarification, genital mutilation, and life-threatening rites of passage; whether myths and songs were about vengeance or turning the other cheek.
Does the influence of culture disprove free will? Obviously not. As usual, these are tendencies, amid lots of individual variation. Just consider Gandhi, Anwar Sadat, Yitzhak Rabin, and Michael Collins, atypically inclined toward peacemaking, assassinated by coreligionists atypically inclined toward extremism and violence.[*],[56]
Oh, Why Not? Evolution
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]
Seamless
Where does intent come from? What makes us who we are at any given minute? What came before.[*] This raises an immensely important point first brought up in chapter 1, which is that the biology/environment interactions of, say, a minute ago and a decade ago are not separate entities. Suppose we are considering the genes someone inherited, back when they were a fertilized egg, and what those genes have to do with that person’s behavior. Well then, we are being geneticists thinking about genetics. We could even make our club more exclusive and be “behavior geneticists,” publishing our research only in a journal called, well, Behavior Genetics. But if we are talking about the genes inherited that are relevant to the person’s behavior, we’re automatically also talking about how the person’s brain was constructed—because brain construction is primarily carried out by the proteins coded for by “genes implicated in neurodevelopment.” Similarly, if we are studying the effects of childhood adversity on adult behavior, often best understood on the psychological or sociological level, we’re implicitly also considering how the molecular biology of childhood epigenetics helps explain adult personality and temperament. If we are evolutionary biologists thinking about human behavior, by definition we’re also being behavior geneticists, developmental neurobiologists, and neuroplasticians (spell-check just went crazy). This is because evolving means changes in what variants of genes you find in organisms and thus the ways in which they shape brain construction. Study hormones and behavior, and we’re also studying what fetal life had to do with the development of the glands that secrete those hormones. So on and so on. Each moment flowing from all that came before. And whether it’s the smell of a room, what happened to you when you were a fetus, or what was up with your ancestors in the year 1500, all are things that you couldn’t control.[*] A seamless stream of influences that, as said at the beginning, precludes being able to shoehorn in this thing called free will that is supposedly in the brain but not of it. In the words of legal scholar Pete Alces, there is “no remaining gap between nature and nurture for moral responsibility to fill.” Philosopher Peter Tse hits the nail on the head when referring to the biological turtles all the way down as a “responsibility destroying regress.”[*],[58]
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.
This is the view forcefully argued by philosopher Neil Levy in his 2011 book, Hard Luck: How Luck Undermines Free Will and Moral Responsibility (Oxford University Press). He focuses on two categories of luck. One, present luck, examines its role in the difference between driving while so drunk that, when coupled with events in the seconds to minutes before, you would have killed someone if they had happened to be crossing the street, and the bad luck of being in that state and actually killing someone. As we saw, whether this distinction is meaningful is often the domain of legal scholars. More meaningful to Levy is what he calls constitutive luck, the fortune, good or bad, that sculpted you up to this moment. In other words, our world of one second before, one minute before . . . (although he only passingly frames the idea biologically). And when you recognize that that is all there is to explain who we are, he concludes, “it is not ontology that rules out free will, it is luck (his emphasis).”[*] In his view, not only does it make no sense to hold us responsible for our actions; we also had no control over the formation of our beliefs about the rightness and consequences of that action or about the availability of alternatives. You can’t successfully believe something different from what you believe.[*]
In the first chapter, I wrote about what is needed to prove free will, and this chapter has added details to that demand: show me that the thing a neuron just did in someone’s brain was unaffected by any of these preceding factors—by the goings-on in the eighty billion neurons surrounding it, by any of the infinite number of combinations of hormone levels percolated that morning, by any of the countless types of childhoods and fetal environments were experienced, by any of the two to the four millionth power different genomes that neuron contains, multiplied by the nearly as large range of epigenetic orchestrations possible. Et cetera. All out of your control.
