This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Homosexuality is a lifestyle choice. Or so religious conservatives would have us believe. But liberalism is in our genes. Or so researchers at the University of California, San Diego, and Harvard University would have us believe.
Yes, the inevitable has happened. Just before Election Day—surely not a coincidence—scientists report an association between liberal political views and DRD4, a gene that produces a receptor for the neurotransmitter dopamine. The study in The Journal of Politics, published by Cambridge University Press, examined 2,000 subjects and found a DRD4–liberalism correlation in those who had lots of friends in adolescence.
The lead investigator, U.C. San Diego's James Fowler, focused on DRD4 because it had previously been linked to "novelty-seeking". According to a San Diego press release, Fowler reasoned that "people with the novelty-seeking gene variant would be more interested in learning about their friends' points of views. As a consequence, people with this genetic predisposition who have a greater-than-average number of friends would be exposed to wider variety of social norms and lifestyles, which might make them more liberal than average."
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The U.C. San Diego–Harvard team brags that it is the first to link a specific gene to a specific political outlook. Actually, if the team's claim holds up, it will be the first confirmed linkage of a specific gene to any complex behavioral trait.
The "liberal gene" is just the latest in a long string of dramatic claims from behavioral genetics—or "gene-whiz science," my preferred term. Behavioral genetics, which traces behavioral differences among individuals and groups to genetic variance, receives an inordinate amount of attention, especially considering that its findings so rarely hold up to scrutiny.
Researchers, or gene-whizzers, typically make a surprising announcement: There's a gene that makes you gay! That makes you supersmart! 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 much less 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 two decades, gene-whizzers have discovered "genes for" high IQ, male homosexuality, religious belief, gambling, attention-deficit disorder, obsessive-compulsive disorder, bipolar disorder, schizophrenia, autism, dyslexia, alcoholism, heroin addiction, sadness, extroversion, introversion, anxiety, anorexia nervosa, seasonal affective disorder, violent aggression—you get the picture. 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.
The most prominent of all gene-whizzers is the geneticist Dean Hamer of the National Cancer Institute. He first attained fame and fortune in 1993 by "discovering" a gene linked to male homosexuality. After his initial report in Science, Hamer and a journalist quickly co-wrote a book, The Science of Desire The Search for the Gay Gene and the Biology of Behavior (Simon and Schuster, 1994), which The New York Times named a "notable book." Meanwhile follow-up studies found no evidence for the gay gene.
In his 2004 book, The God Gene: How Faith Is Hardwired into Our Genes (Doubleday), Hamer claimed to have found a gene linked to religious belief or spirituality. TIME devoted a cover story to Hamer's claim, but in a review for Scientific American, journalist Carl Zimmer quipped that Hamer should have titled his book "A Gene That Accounts for Less Than One Percent of the Variance Found in Scores on Psychological Questionnaires Designed to Measure a Factor called Self-Transcendence, Which Can Signify Everything from Belonging to the Green Party to Believing in ESP, According to One Unpublished, Unreplicated Study."
Hamer also led the group that in 1996 first linked the DRD4 gene to "novelty-seeking". Lots of other groups have sought to replicate Hamer's finding, but according to a 2008 review "the strength of evidence for this association remains uncertain." Meanwhile, DRD4 has also been tied to schizophrenia, Parkinson's disease, bipolar disorder, sex addiction, anorexia nervosa, binge eating and, now, liberalism, according to Wikipedia.
I hope the liberal-gene finding—unlike all previous gene-whiz claims—holds up, because then we can create a utopia by genetically engineering liberal designer babies. We could even pay for it with Obama's health care plan! But alas, this vision—like the liberal gene itself—is just a fantasy.
I'll describe Margaret Mead's theory of war in my next post.
Image: Does a gene make Barney Frank liberal?
Credit: Wiki Commons