Free Will and Genetics

               

Free Will and Genetics

by : Aria Ratmandanu

                 From an evolutionary perspective, our parents have been very carefully selected for us—by natural selection. But we are also the products of our parental upbringing, family dynamics, peer groups, community values, teachers and education, preachers, culture and politics, and much more. The science of assigning some portion of our lives to genetics and the remaining portion to the environment has a long and controversial history. The process strikes me as an exercise in futility because of the interactive nature of genes and memes, evolutionary history and cultural history. Such binary thinking, particularly since the completion of the mapping of the human genome, for example, has led to oversimplified claims for a “math gene,” a “risk-taking gene,” a “promiscuity gene,” or a “smoking gene.

              In reality, the story is much more complex, and claims for genetic determinism are greatly exaggerated. Consider as one example among many a gene called D4DR, located on the short arm of the eleventh chromosome. D4DR codes for dopamine receptors, a neurotransmitter released by neurons that, when received by other neurons receptive to its chemical makeup, sets up dopamine pathways throughout the brain that stimulate the organism to be active (or not, if a shortage exists). A complete lack of dopamine, for example, causes patients (or rats) to slip into a virtual catatonic state. High levels of dopamine turn humans schizophrenic and rats frenetic. Dopamine stimulation, in fact, is the basis of the famous experiment where rats pressed a bar to stimulate their so-called pleasure center, which they did until collapsing in exhaustion. This is the fascinating work of geneticist Dean Hamer who, in his quest to find genes for smoking and homosexuality, discovered the gene (or, more precisely, the gene-complex) for a thrill-seeking personality. It turns out that the D4DR gene sequence repeats on chromosome eleven, and while most of us have four to seven copies, some people have two or three, and others have eight, nine, ten, or eleven copies.

            More copies of D4DR sequence means lower levels of dopamine, which translates into higher novelty-seeking behavior that artificially produces more dopamine (jumping off buildings and out of planes will do the trick). Hamer took 124 people who scored high on a survey that measured their desire to seek novelty and thrills (bungee jumpers and sky divers knock the roof off these tests), then looked at their DNA—specifically, chromosome eleven. He found that people who like to jump off buildings and out of planes had more copies of D4DR sequence than those who prefer knitting and watching grass grow. When Hamer’s research was picked up in the media, headlines declared that scientists had discovered the novelty-seeking gene, implying that perhaps all of our personality traits are genetically coded at a single point on a single chromosome arm. Alas, if only it were that simple—whenever you get that urge to jump off the top of Yosemite’s Half Dome, just take a dopamine tablet and you’ll prefer to stay on the marked trails. But there is another side to this story. When you actually read the original research, it turns out that Hamer claims to explain no more than 4 percent of novelty-seeking behavior by D4DR sequences. That is, if we say that humans vary by 100 percent in their novelty-seeking behavior—catatonics on one end and X-Game skateboarders careening down hills at 50 mph two inches off the ground on the other—only 4 percent of that variance can be accounted for by D4DR. That’s it! As the science writer Matt Ridley explains in his analysis of the research”

         Do you see now how unthreatening it is to talk of genetic influences over behaviour? How ridiculous to get carried away by one “personality gene” among 500 ? How absurd to think that, even in a future brave new world, somebody might abort a foetus because one of its personality genes is not up to scratch—and take the risk that on the next conception she would produce a foetus in which two or three other genes were a kind she does not desire? Do you see now how futile it would be to practise eugenic selection for certain genetic personalities, even if somebody had the power to do so? You would have to check each of 500 genes one by one, deciding in each case to reject those with the “wrong” gene. At the end you would be left with nobody, not even if you started with a million candidates. We are all of us mutants. The best defence against designer babies is to find more genes and swamp people in too much knowledge. 

         Nature is so intertwined with nurture that to say that a complex human characteristic like personality or intelligence or—to the point of this article—morality is, say, 40 percent genetics and 60 percent environment (to arbitrarily pick two figures) misses “something very important: inheritability of talent does not mean inevitability of success, and vice versa. We are free to select the optimal environmental conditions that will allow us to rise to the height of our biological potentials. In this sense, athletic success, like any other type of success, may be measured not just against others’ performances, but also against the upper ceiling of our own ability. To succeed is to have done one’s absolute best. To win is not just to have crossed the finish line first, but also to cross the finish line in the fastest time possible within one’s own limits. The closer one comes to reaching the personal upper limit of potential, the greater the achievement, as depicted in the Genetic Range of Potential model in . Individual “A” may have more absolute talent potential than individual “B,” but this does not guarantee relative success. If “B” prepares to the height of his or her upper limit of potential, but “A” slacks off below that mark, inherited talent becomes meaningless. There is not much we can do about selecting our parents, but we can select our environmental conditions to push us to the top of “our range of potential.”