Determined, page 63
*Note: “Everything in the brain” includes the frontal cortex; amid the drama of delayed maturation, a substantial percentage of its construction occurs during childhood.
*Naturally, there are problems with an overly literal reliance on stage thinking—the transitions from one stage to the next can be smooth continua, rather than crossings of distinctive borders; a child’s stage of, say, moral reasoning may differ with differing emotional states; insights have mostly come from studies of boys in Western cultures. Nonetheless, the basic idea is really useful.
*Whoa, different rat mothers mother differently? Sure, with variation as to how often they groom or licks their pups, respond to their vocalizations, and so on. This is landmark work pioneered by neuroscientist Michael Meaney of McGill University.
*The same effect holds for sports. Professional athletic teams are way disproportionately filled with players who were older than average in their childhood sports cohort.
*These effects on fetuses were first identified in humans in two horrifically unnatural “natural experiments of starvation”—the Dutch Hunger Winter of 1944, when Holland was starved by the occupying Nazis, and the Great Leap Forward famine in China in the late 1950s.
*For those with a background in this, it’s worth noting a few of the things that I ignored in this paragraph: the intronic/exonic structure of genes, gene splicing, multiple conformations in prion proteins, transposons, genes coding for small interfering RNA, and RNA enzymes . . .
*Things left out of this paragraph: transcription factors, signal transduction pathways, the fact that it is only steroid hormones, in contrast to peptidergic hormones, which directly regulate transcription . . .
*Some of the things left out here: promoters and other regulatory elements in DNA, transcriptional cofactors imparting tissue specificity of gene transcription, selfish DNA derived from self-replicating retroviruses . . .
*Things left out include how simplistic it is to focus on a single gene and its singular effect, even after accounting for environment. This is because of pleiotropic and polygenic genetic effects; startling evidence for the importance of the latter comes from genome-wide survey studies, indicating that even the most boringly straightforward human traits, such as height, are coded for by hundreds of different genes.
*Some of the things left out: homozygosity versus heterozygosity, dominant versus recessive traits . . .
*Aficionados: the genes coding for tryptophan hydroxylase and aromatic amino acid decarboxylase, the 5HTT serotonin transporter, monoamine oxidase-alpha, respectively.
*More details: the genes for tyrosine hydroxylase, the DAT dopamine transporter, catechol-O-methyltransferase.
*If each of those polymorphic spots comes in one of merely two possible versions, the number of different genetic makeups would be two to the four millionth power, a pretty good approximation of infinity—two to the mere fortieth power is something like a trillion.
*Just to reiterate a point about every fact in this chapter: These are broad populational differences that differ with statistical significance from chance, not reliable predictors of every individual’s behavior. Every statement is tacitly preceded by “on the average.”
*As an example that floored me, an irrigation system near Djiuangyan City in China irrigates five thousand square kilometers of rice fields and has been collectively used and maintained for two thousand years.
*To introduce a hot potato, are there genetic differences between individualist and collective cultures? Whatever there are can’t be too important; after a generation or two, descendants of Asian American immigrants are as individualistic as European Americans. Nonetheless, genetics differences have been found that are so interesting. Consider the gene DRD4, which codes for a dopamine receptor. You know, dopamine—that’s about motivation, anticipation, and reward. One DRD4 variant makes a receptor that is less responsive to dopamine and increases the likelihood of novelty seeking, extroversion, and impulsivity in people. Europeans and European Americans: a 23 percent incidence of that variant. East Asians: 1 percent, a difference way above chance, suggesting the variant being selected against in East Asia for thousands of years.
*Among the pastoralist Maasai I’ve lived near in Africa, group violence increasingly revolves around clashes with neighboring agricultural folks, Sharks-versus-Jets moments in market areas visited by both. But the historical enemies of my Maasai are the Kuria people of Tanzania, pastoralists prone to cattle rustling from Maasai at night; this leads to spear-laden retributive raids that can kill dozens. As a measure of the combativeness of the Kuria, after independence, Tanzania’s army was 50 percent Kuria, despite their being only 1 percent of the population.
*As a great experimental example, stage things so that your male subject is insulted by someone; if they come from the South, there is a huge increase in circulating cortisol and testosterone levels and an increased likelihood of advocating a violent response to a hypothetical honor violation (relative to uninsulted Southern subjects). Northerners? No such changes.
*The infectious-disease link may help explain the additional finding that cultures originating in the tropics tend toward more extreme in-group/out-group differentiation than cultures from regions farther from the equator. Temperate ecosystems make for cultures that are more temperate about outsiders.
*And as a possible neurobiological underpinning of this, consider people from cities, suburbs, and rural areas. The larger the population someone grew up in, the more reactive their amygdala is likely to be during stress. This has prompted various articles with titles revolving around “Stress and the City.”
*As a final vote for the power of ecological influences underlying many of these cultural patterns, humans and other animals living in the same ecosystem tend to share numerous traits. For example, high levels of biodiversity in a particular ecosystem predict high levels of linguistic diversity among the humans living there (and places where large numbers of species are in danger of extinction are also where languages and cultures are most at risk of extinction). A study of 339 hunter-gatherer cultures from around the world showed even more dramatic convergence between humans and other animals—human cultures with high degrees of polygamy tend (at higher-than-chance level) to be surrounded by other animals with high rates of the same. There is also human/animal covariance in likelihood of males helping to take care of kids, of storing food, and of subsisting predominantly on a fish diet. And statistically, the human/animal resemblances are explained by ecological features like latitude, altitude, rainfall, and extreme versus temperate weather. Once again, we’re just another animal, if a weird one.
*It’s worth noting that similar, if not identical, types of turtles all the way down also explain why, say, some chimp is the most gifted member of her generation at making tools: good social and observational skills allowing her to hang out closely and learn the trade from an older master, impulse control allowing patience with trial and error, attention to detail, the combination of innovativeness and the confidence to ignore how the cool kids are doing it—all arising from events one minute before, one hour before, and so on. Not a smidgen of “when the going gets tough, tough chimps choose to get going.”
*This approach is implicit in the thinking of Cornell philosopher Derk Pereboom; he posits four scenarios: you do something awful because (1) scientists manipulated your brain a second ago; (2) they manipulated your childhood experiences; (3) they manipulated the culture you were raised in; (4) they manipulated the physical nature of the universe. These are ultimately equally deterministic scenarios, though most people’s intuitions solidly view the first as far more so than the other three, because of its close proximity to the behavior itself.
*Mind you, the compatibilist Tse isn’t pleased with this, writing somewhere between how this regress can’t exist and how it shouldn’t exist—a contrast that anchors parts of chapter 15.
*As a small clarification, Levy doesn’t necessarily believe that we have no control over our actions, just that we have no relevant control.
*Levy has an interesting analysis that focuses on a file-this-away-for-future-use word, akrasia, which is when an agent acts against her expressed judgment. When certain akrasias become common enough, we have seemingly insoluble inconsistencies . . . until we generate a view of ourselves that consistently accommodates the akrasia. “I’m normally a very self-disciplined person . . . except when it comes to chocolate.”
*“Forever” may not really be the case because, at some point in this regression, you get to the big bang and whatever came before that, about which I understand precisely zero. Regardless of whether things go back infinitely, as a key point, the further back you go, the smaller the influence is likely to be—how you respond to this stranger who may have just insulted you is more influenced by your circulating stress hormone levels at the time than by the infectious-disease load experienced by your distant ancestors. When trying to explain our behavior, I’m perfectly happy to call a time-out on “what came before that” when it’s going far enough back to explain, say, why we’re a carbon-based rather than silicon-based life form. But we have ample evidence for the relevance of what-came-befores that people used to feel justified in ignoring—the trauma that occurred a few months before a person behaved as they did, the ideal level of stimulation experienced in their childhood, the alcohol levels their fetal brain was pickled in . . .
*I’ve testified saying something like this paragraph to about a dozen juries as a teaching witness, in case after case where someone with that sort of life story had a few seconds to make a similar decision and went back to the prone assailant and stabbed him an additional sixty-two times. So far, with one exception that I now view as a fluke, the juries have decided that it’s premeditated murder and convicted on all charges.
*To my surprise, some studies have shown that high-IQ kids are more prone than average toward illegal drug use and alcohol abuse in adulthood.
*Perfect pitch is actually a classic example of genes being about potential, not certainty. Research suggests that you probably need to have inherited the potential for perfect pitch; however, it is not expressed in someone unless they were exposed to a fair amount of music early in life.
*Neuroanatomists will turn over in their graves, but from here on out, I’m going to refer to the entire frontal cortex as the PFC, for simplicity’s sake.
*Which tells you something very important about primate dominance. For example, for a male baboon, attaining high rank is all about muscles, sharp canines, and winning the right fight. But maintaining high rank is about avoiding fights, having the self-control to ignore provocations, avoiding fighting by being psychologically intimidating, being a sufficiently self-disciplined, stable coalition partner (unlike Finn) to always have someone watching your back. An alpha male who is constantly fighting won’t be in the corner office long; successful alphaship is a minimalist art of nonwar.
*There’s a world of complexity to this. It depends on whom the picture is of—strapping young guy, and the amygdala roars into activity; frail, grandmotherly type, not so much. More for a stranger than for an other-race beloved celebrity—that person counts as an honorary Us. What about the 25 percent of people who don’t have the amygdala response? They were typically raised in multiracial communities, have had intimate relationships with people of that other race, or have been psychologically primed before the experiment to process each face as an individual. In other words, the implicit racism coded in the amygdala is not remotely inevitable.
*These studies have produced another distressing finding. When we look at faces, there is activation of a very primate part of the cortex called the fusiform face area. And in most subjects, the face of an other-race Them activates the fusiform less than usual. Their face doesn’t count as being much of a face.
*Studies like this include a key control, showing that it is social anxiety that is being generated: the other two stop tossing the ball to the subject, who is told that it’s because of some problem with the computer. If it’s that, rather than social ostracism, there’s no equivalent brain response.
*Depressing finding: Instead of conditioning subjects to a neutral, innocuous object, condition them to a picture of an out-group Them. People learn to associate that with a shock faster than if it were an in-group member.
*Is the PFC causing the amygdala to forget that bells are scary? No—the insight is still there but is just being suppressed by frontal cortex. How can you tell this? On day three of the study, go back to the sight of that arbitrary object being followed by a shock. The person relearns the association faster than they learned it in the first place—the amygdala remembers.
*Here are some factoids that emphasize the extent to which social demands sculpt the evolution of the PFC. The PFC contains a neuron type not found elsewhere in the brain. To add to its coolness, for a while people thought that these “von Economo neurons,” introduced in the footnote on page 61, occurred only in humans. But as something even cooler, the neurons also occur in the most socially complex species out there—other apes, elephants, cetaceans. A neurological disease called behavioral frontotemporal dementia demonstrates that PFC damage causes inappropriate social behavior. What are the first neurons that die in that disease? The von Economo neurons. So whatever they do (which isn’t at all clear), it has “doing the harder thing” written all over it. (Brief screed of interest to only a few readers—despite quasi–New Age neuroscientific claims, von Economo neurons are not mirror neurons responsible for empathy. These aren’t mirror neurons. And mirror neurons don’t do empathy. Don’t get me started.)
*Such as the hippocampus, septum, habenula, hypothalamus, mammillary bodies, and nucleus accumbens.
*And of considerable importance, we’ll be getting to circumstances where the limbic system convinces the PFC to rubber-stamp strongly emotional decisions.
*Heads up, running-dog capitalists: one study has used TMS to manipulate the projection from the dlPFC to dopaminergic reward pathways in the striatum, thereby transiently changing people’s music tastes—enhancing the subjective appreciation of a piece of music and the physiological response to it . . . as well as boosting the monetary value subjects assign to the music.
*Starting in the 1960s, the esteemed neuroanatomist Walle Nauta of MIT nearly ruined his career by stating that the vmPFC should be viewed as part of the limbic system. Horror—the cortex is about solving Fermat’s theorem, not getting all weepy when Mimi is dying in Roger’s arms. And it took years for everyone else to see that the vmPFC is the limbic system’s portal to the PFC.
*Cash = ATP, aka adenosine triphosphate, just to tap into the recesses of your memory, dredging up a factoid from ninth-grade biology.
*Similar concepts that are invoked include “ego depletion” and “decision fatigue.” See notes for how the core concepts of cognitive reserve and ego depletion have been heavily criticized in recent years.
*The finding was challenged by some critics who suggested that it was a statistical artifact of the way parole hearings were carried out; the authors reanalyzed their data to control for these possibilities, convincingly showing that the effect was still there. An additional study showed the identical pattern: subjects read job applicant profiles from out-group minority members; the longer it had been since a meal, the less time was spent on each application.
*“My god, this guy is such a bleeding-heart liberal.” Nah. Way beyond that—you’ll see.
*In the same vein, credit loan officers become more likely to turn down loan applications as the day progresses. Similarly, savvy actors know not to pick the time slot just before lunch or at the end of the day for auditioning.
*How was this learned? The hard way. Parkinson’s disease, a movement disorder where initiating voluntary movements becomes difficult, is caused by a dearth of dopamine in an unrelated part of the brain. Well, let’s treat that by raising the person’s dopamine levels (done using a drug called L-DOPA; long story). You’re not going to drill a hole in the person’s head and infuse L-DOPA directly into that part of the brain. Instead, the person swallows an L-DOPA pill, resulting in more dopamine in that diseased part of the brain . . . as well as in the rest of the brain, including the PFC. Result? A side effect of high-dose L-DOPA regimes can be behaviors like compulsive gambling.
