According to The New York Times, a federal appeals court in Manhattan recently overturned a six-and-a-half-year sentence in a child pornography case, saying the judge who imposed it improperly found that the defendant would return to viewing child pornography because of an as-of-yet undiscovered gene. The judge, Gary L. Sharpe of Federal District Court in Albany, was quoted as saying, “It is a gene you were born with. And it’s not a gene you can get rid of,” before he sentenced the defendant.
“You are what you’re born with,” the judge said, overlooking the small fact that such a gene has not—and probably will not—ever be found. “And that’s the only explanation for what I see here,” noted our profoundly ignorant jurist.
It is disturbing when I see my well-intentioned but sadly misinformed colleagues in the social sciences and humanities proclaim about the “irrelevance” of DNA and evolution to the behavior of Homo sapiens. But it is equally disquieting (maybe even more so, because of the potential for abuse, as exemplified by Judge Sharpe), when I witness the overzealous, equally unknowing, and perhaps even ill-intentioned tendency of others to see genes lurking behind every human act.
So let’s talk a bit about what evolutionary biologists mean when they refer to genes “for” a given behavior. We don’t mean that there is a likely one-to-one correspondence between gene and behavior; typically, there are multiple genes. Nor do we mean that behaviors (except for simple reflexes) are “determined” by DNA; rather, they are prone to being influenced. And we don’t mean that the behavior in question is irrevocably tied to genetics, in the manner of, say, blood type or eye color; rather, genes orchestrate a range of reactions, the details of which are nearly always a function of environmental circumstances.
There are only about 24,000 genes in the human genome, which have a lot on their hands: Not just behavior, but our anatomy, physiology, etc. And yet, the fact that there are immeasurably more behaviors than genes does not mean that genes aren’t relevant to many (perhaps most) of what we do. Its just that the connections are often more roundabout than most people realize.
For example, it turns out that there is a particular genetic factor that influences metabolism of the neurohormones dopamine and serotonin, thereby affecting people’s proclivity to be risk-takers, aka adrenaline junkies. Different people vary with respect to their genetic endowment in this regard. They also vary with respect to their fondness for, say, roller coasters. Now, I haven’t conducted the following research, but I’d bet that if someone did, she would find that the population that adores roller coasters differs statistically with regard to their genetic make-up from those who abhor them. If so, we could then talk about a gene “for” roller coasters, knowing full well that literally speaking, there is no such gene.
Similarly, I’d wager that one would find a roughly equal and opposite correlation between said alleles and admiration for sedate Volvo sedans … without there being a gene “for” sedate Volvo sedans.
By the same token, incidentally, when evolutionary biologists work on genes “for” altruism—a hot topic these days, and for good reason—for example, when it comes to alarm-calling among animals, we might actually be referring to genes “for” good eyesight, or a low anxiety threshold, both of which would result in a greater predisposition to give an alarm call after spotting a predator (and in the process, “altruistically” warn others while reducing the alarmist’s own fitness), without there necessarily being a gene “for” altruism as normally understood.
How about a law requiring that any judge who refers to “genes” or “evolution” as part of his or her sentencing statement to demonstrate having taken a bona fide course in, well, genes or evolution?
[DNA image from Wikimedia]
