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some of the wind out of genetic determinists’ sails. Marcy and Melissa are, genetically speaking, identical to one another. And though they were reared apart, they did spend the first eight and a half months of their existences (they were premature, remember) in an identical environment. During that time, they coexisted within a single uterus, absorbing the same nutrients and chemicals, reacting to the same stimuli, breathing in the same amniotic fluid. Sure, from that point on their paths diverged dramatically — Marcy was ushered into a life of privilege and intense intellectual nourishment, while Melissa remained in a home that was financially struggling and structurally laissez-faire — but neither were subjected to heinous abuse or dire poverty. Melissa had fewer advantages, but she never wanted for food, clothing, or shelter, and though she would probably scoff at the suggestion, she was loved.
Is it that simple, then? Do well-meaning but inattentive parents doom their children to a life of alcoholism and drug abuse? Hardly. Even within our brief example, we have David, who turned out well despite growing up in suboptimal early rearing conditions. We’ve already put forth one hypothesis for this discrepancy: David is a low-reactive child, while Melissa is high-reactive. Does this mean that Marcy, somehow, inherited a low-reactive gene not imbued to her sister?
Not necessarily. In fact, according to the theory of Biological Sensitivity to Context, it is probable that Marcy, like her sister, possesses high-reactive genes.
Biological Sensitivity to Context
When differences in reactivity among children first came to the attention of the scientific community, the predominant assumption was that high reactivity was a maladaptive trait — a genetic mutation that made those carrying it less likely to survive into adulthood than their unaffected peers. On first blush, high-reactive genes do appear to be something of a burden to those who possess them, a ball and chain shackled to their chromosomes, leaving their unfortunate heirs prey to whatever trauma the surrounding environment may decide to throw at them. We’ve presented this viewpoint once already, and explained its overarching flaw: these traits are old. In the face of hundreds of millions of years of evolutionary scrutiny, the 7-repeat DRD4 allele and its histrionic brethren should have been selected out eons ago, replaced by their staunch, stable, and unwavering counterparts. The fact that they haven’t suffered such an ignoble fate strongly suggests that they may provide some benefit to offset their potential costs, and a researcher named W. Thomas Boyce has compiled substantial evidence as to what that benefit might be.
Boyce is a professor of pediatrics at the University of British Columbia. In 2005, he released a paper explaining his theory of Biological Sensitivity to Context. Boyce was understandably skeptical of the notion that some genes were “worse” than others yet had somehow remained floating in the global gene pool all this time. He posited that high reactivity may be a double-edged sword, but can nevertheless be wielded effectively in the right circumstances. Increased sensitivity to one’s environment is not the same as increased sensitivity to pathogens, or exceptionally brittle bones, or haemophilia, or any other conditions that leave one in a vulnerable state without providing any tangible benefit. Rather, it is a difference in malleability. The behaviours of more reactive children — who, in Boyce’s theory, would be considered to have high Biological Sensitivity to Context (BSC) — are more easily sculpted by the surrounding environment than those of low-reactive children — those with low BSC. For Melissa, this meant succumbing to the more unfortunate aspects of her upbringing, and acting out against them in a short-sighted, self-destructive way. David, a low BSC child if ever there was one, took his home life in stride. Between the two of them, David seems to have the evolutionary edge.
But then there’s Marcy. Raised by exhaustingly attentive parents, ensconced in wealth and privilege, provided with every learning resource imaginable, she excelled at everything she put her mind to. For her, high BSC was a tremendous advantage, as it allowed her to make the most of the resources her privileged upbringing afforded her.
Boyce divides children into two poetically named categories: orchids and dandelions. Drawn from an old Swedish aphorism, the term “dandelion children” refers to hardy, rugged individuals with low BSC. Like the plants they are named for, they seem to thrive equally well in manicured lawns and cracks in the sidewalk. Orchid children, on the other hand, have high BSC. Like orchids, they flounder in substandard environments. But if the soil is pH balanced and nutrient rich, and the sun is shining just right, and the rain falls gentle but often, they grow into flowers of exceptional beauty.
Think back to some of the studies discussed in the previous chapter, namely those dealing with the DRD4 7-repeat allele. As you may recall, those with the 7-repeat allele — the “high-reactive” version of the gene — responded much more poorly to hardship than children with different, less reactive alleles. The precise nature of the response (depression, aggression, ADHD, etc.) and hardship (poverty, etc.) varied between studies, but the results were markedly similar.
The severity of these results swept aside a second finding. High-reactive children struggled in adverse living conditions while low-reactive children soldiered on; but in supportive conditions, where low-reactive children achieved about the same as their peers in “high risk” environments, high-reactive children thrived.
Monkey Business
Thirty miles from Washington, D.C., away from the crowds and the noise and the politics, the National Institute of Health’s Laboratory of Comparative Ethnology nestles into the bucolic Maryland countryside. Its location is well-chosen, for the LCE is not the stereotypical lab bedecked with stainless steel counters and finicky instruments awash in harsh fluorescent light. Most of the lab is outdoors, comprised of a swath of Appalachia demarcated by twin bands of electrified chain-link fence. Inside the fence live a colony of rhesus macaques, a primate not quite as closely related to us as chimpanzees or bonobos but that nevertheless shares about 95 percent of our DNA. The LCE is run by Dr. Stephen Suomi, a distinguished psychologist with a long history of working with macaques. Compared to some of his earlier studies, his present work is largely hands off. Much (but not all) of the research done at LCE is observational; aside from having food provided for them — in the form of a delightfully named substance called “monkey chow” — and living within borders defined by a two-tiered cyclone fence, the macaques at Suomi’s lab exist very much as they would in the wild. They feast and fight and fornicate, form alliances, and make power plays, all the while observing a strict and complex social hierarchy.
Macaque troops are matrilineal, stabilizing around a dominant and typically elderly female in groups of between 30 and 300 macaques, called troops. Females born into a troop stay there for life, their position rising and falling within the confines of that matrilineal line, until they themselves are, potentially, among the elder alpha females. Males, by contrast, exist on the fringes of macaque society. At adolescence (which, in macaques, occurs when the male is roughly four years old) they leave the clan of their birth — be it voluntarily or by force — and join roving gangs of similarly disenfranchised males. Life in a gang is a turbulent time for macaques, a Darwinian trial by fire where only the strongest, swiftest, and smartest escape the flames. Mortality rates in these gangs are exponentially higher than in any other facet of macaque society, and males are understandably eager to leave their shiftless existence and rejoin a troop in order to engage in the far more enjoyable pursuit of siring offspring.
Life among the macaques is relentlessly social. Size and strength undeniably help determine a macaque’s place in the hierarchy, but the truest predictor of success is a macaque’s ability to understand and interact with other macaques. In humans, we might call this emotional intelligence. A successful macaque knows exactly where she stands in the hierarchy. She knows which matriarch is the quickest to anger, and which is showing signs of weakness. She can recall without hesitation which macaques have her back in a fight, and which would just as soon bash her brains in with a rock. Macaque society thrums with political intrigue; to thrive, social graces are essential.
Sadly, when it comes to social graces, not all macaques are born equal. Over years of careful observation, Suomi noticed two recurring deviations in macaque behaviour. Macaques of the first deviation have what Suomi deemed to be neurotic personalities, and comprise roughly 20 percent of the total population. These macaques are reluctant to leave their mothers’ sides, and remain anxious and withdrawn well into adulthood.