behavioral genetics is pseudo-science

ScientificAmerican | Last spring, I kicked up a kerfuffle by proposing that research on race and intelligence, given its potential for exacerbating discrimination, should be banned. Now Nature has expanded this debate with “Taboo Genetics.” The article “looks at four controversial areas of behavioral genetics”—intelligence, race, violence and sexuality—”to find out why each field has been a flashpoint, and whether there are sound scientific reasons for pursuing such studies.”

The essay provides a solid overview, including input from both defenders of behavioral genetics and critics. The author, Erika Check Hayden, quotes me saying that research on race and intelligence too often bolsters “racist ideas about the inferiority of certain groups, which plays into racist policies.”

I only wish that Hayden had repeated my broader complaint against behavioral genetics, which attempts to explain human behavior in genetic terms. The field, which I’ve been following since the late 1980s, has a horrendous track record. My concerns about the potential for abuse of behavioral genetics are directly related to its history of widely publicized, erroneous claims.

I like to call behavioral genetics “gene whiz science,” because “advances” so often conform to the same pattern. Researchers, or gene-whizzers, announce: There’s a gene that makes you gay! That makes you super-smart! That makes you believe in God! That makes you vote for Barney Frank! The media and the public collectively exclaim, “Gee whiz!”

Follow-up studies that fail to corroborate the initial claim receive little or no attention, leaving the public with the mistaken impression that the initial report was accurate—and, more broadly, that genes determine who we are.

Over the past 25 years or so, gene-whizzers have discovered “genes for” high IQ, gambling, attention-deficit disorder, obsessive-compulsive disorder, bipolar disorder, schizophrenia, autism, dyslexia, alcoholism, heroin addiction, extroversion, introversion, anxiety, anorexia nervosa, seasonal affective disorder, violent aggression—and so on. So far, not one of these claims has been consistently confirmed by follow-up studies.

These failures should not be surprising, because all these complex traits and disorders are almost certainly caused by many different genes interacting with many different environmental factors. Moreover, the methodology of behavioral geneticists is highly susceptible to false positives. Researchers select a group of people who share a trait and then start searching for a gene that occurs not universally and exclusively but simply more often in this group than in a control group. If you look at enough genes, you will almost inevitably find one that meets these criteria simply through chance. Those who insist that these random correlations are significant have succumbed to the Texas Sharpshooter Fallacy.

To get a sense of just how shoddy behavioral genetics is, check out my posts on the “liberal gene,” “gay gene” and God gene” (the latter two “discovered” by Dean Hamer, whose record as a gene-whizzer is especially abysmal); and on the MAOA-L gene, also known as the “warrior gene.” Also see this post, where I challenge defenders of behavioral genetics to cite a single example of a solid, replicated finding.

Ever since I first hammered behavioral genetics in my 1993 Scientific American article “Eugenics Revisited,” critics have faulted me for treating the field so harshly. But over the last 20 years, the field has performed even more poorly than I expected. At this point, I don’t know why anyone takes gene-whiz science seriously.