Can one gene make a difference?  Absolutely.  One case in point is Tay-Sachs Disease, a physical condition  where the central nervous system begins to degenerate in a four to six month old child who, until the onset of the disease, appeared normal.  Individuals with Tay-Sachs disease have two copies of a genetic mutation, one copy inherited from each parent.  In a carrier of Tay-Sachs, only one gene is different when compared to non-carriers. That’s how important one gene can be.   When we’re talking about complex behaviors, though, can the “cause” really boil down to one gene?  It’s unlikely.

I recently had the opportunity to attend several sessions of the “Future Directions in Genetic Studies” workshop at Washington University in St. Louis. On Friday, I attended a lively seminar led by Gar Allen, who teaches biology at Washington University. His talk was entitled “What’s Wrong with ‘The Gene for . . .’? Problems with Human Behavior Genetics and How to Combat Them.”

Allen opened his talk by asserting that claims about the genetic basis for complex human behaviors and traits are “notoriously difficult to investigate and replicate.” There is a long and troubled history of claims that genes are the cause of various conditions. For instance, in 1969, Arthur Jensen became the center of a storm when he wrote that Caucasians were more intelligent than African-Americans, suggesting that there was a genetic basis for this difference. Jensen’s position has been heavily criticized by numerous scientists on numerous grounds.

Jensen’s genetics-based pseudo-science was one of many such “scientific” conclusions, of course. Even prior to Jensen’s announcement, the eugenics movement of the early 20th century gave rise to numerous unsubstantiated genetic claims. Allen’s PowerPoint presentation illustrated the long history of dubious genetic claims. That history extends to the present. Allen illustrated the recent history of such claims with photos of the covers of at least a dozen popular magazines, each of them touting newly discovered genetic “causes” for complex medical conditions or complex social phenomena such as alcoholism and violence.

Genes are easy to blame for behaviors even when genes are incorrectly blamed. The media loves these stories that a gene is responsible for “causing” complex social phenomena. They are happy to bring fame to the scientists making such claims. Unfortunately, the media finds it much less newsworthy when other scientists to urge caution regarding such claims, even when caution is urgently needed. And if you’re looking for big headlines detailing methodological flaws in the studies on which gene-behavior claims are made, don’t hold your breath.

According to Allen, we should be suspicious of many claims that a gene “causes” a behavior. Genes are all too often put on thrones, resulting in reification and essentialism rather than true explanation. Genes are always situated in complex environments, and that it is a rare day when a single gene could be serve as “the” cause of a complex behavior. All careful scientists who study genes and behavior know that genes are always part of a complex cascade of causation. Nonetheless, all too many “Gene for X” stories start boldly with the (unsubstantiated) claim, ignoring or downplaying serious methodological concerns.

Further, it is common to hear gene jocks confusing correlation with causation. As Allen noted, responsibly testing the true role played by any particular genotype is made especially difficult due to problems with defining the relevant phenotypes and the difficulty of accurately choosing a population to study. Allen used Dean Hamer’s study regarding the alleged genetic basis for homosexuality.

Hamer’s study triggered widespread interest. If true, Hamer’s conclusion that homosexuality had a “genetic cause” would help gays defend themselves against claims that being gay was a mere lifestyle choice. On the other hand, there were numerous difficulties with Hamer’s study that didn’t make headlines. Compounding the problem, Hamer has a reputation as one who is reluctant to publicly engage with his critics.

One of the main problems with Hamer’s study is that it is extremely difficult to define homosexuality. Hamer asked his subjects rate themselves using Kinsley’s sexuality scale. It doesn’t take much to see the problem with this method. For instance, consider people like U.S. Senator Larry Craig (of airport restroom fame), who appears to have sex with men but nonetheless refuses to consider himself to be a homosexual. Consider, also, the numerous men with conscious or subconscious homosexual impulses who have not (yet) acted on those impulses.

Allen raised other serious concerns with Hamer’s study: Is all same-sex behavior to be treated the same, to be considered as having arisen from the same source or cause? If so, why? In Hamer’s homosexual group, seven out of 40 of the subjects lacked the “homosexual” marker.” Hamer concluded that perhaps there was a different genetic marker that also caused homosexuality. Allen suggested another possibility that Hamer ignored: “Maybe there is no genetic marker.” Allen also questioned why Hamer’s search was limited to markers on the X chromosome.

The types of problems one can see with Hamer’s study are common with many other studies announcing the discovery of “the gene for.” Studies seeking to find the genetic basis for human behaviors tend to be reductionistic. They tend to ignore gene-gene and the gene-environment interactions (Allen warns that it can be very difficult to pin down what constitutes the environment in many cases). Further, many genocentric studies fail to

A) consider alternative hypotheses;

B) appreciate plasticity of development;

C) take account of hierarchical systems and emergent properties; or

D) recognize the rampant nonlinearity of biological processes.

I would add that these bold stories announcing “The gene for X” also ignore the concerns recently expressed in this article urging a reworking of the modern synthesis.

Allen is concerned that we, as a society, are unduly obsessed with simplistic genetic causal stories. Our obsession with genetics causes us to ignore environmental factors that we might be better able to address and manipulate than genetic factors. For instance, there is much speculation about the alleged genetic basis for ADHD. Allen characterizes it as “criminal” that we are trying so hard to find a gene for ADHD, a move that conveniently serves to placate drug manufacturers (who, unsurprisingly, push genetic and biological explanations). Allen (who taught fourth grade for several years before becoming a biology professor) would focus more of our limited research dollars on exploring environmental factors such as classroom size, diet, pollution, and lack of physical activity.

Allen asks, “What else are we studying badly?” He suggests that many other illnesses and conditions might better be addressed environmentally. For instance, we should be more willing to consider the effect of pollution that occurs in workplaces rather than the “genes” for those “illnesses” that occur in workplaces. The environment would also appear be a better explanation than genes when studying alcoholism susceptibility. “Genocentrism is obliterating many other things we could and should be doing.” Allen laments that “It’s much cheaper to dispense Ritalin than to make classroom smaller.”

The media loves the genocentric view, however. When pressed to explain this obsession, media spokespersons claim that this over-emphasis is the public’s fault, because the public seeks simplistic (genetic) explanations. Or is it that the news media enjoys twisting the story to make the story simpler and thus more sellable? The genocentric story thus seems to be simply another variation on an old dispute: Does the media dumb down the news because readers demand it, or are the readers unable to digest nuanced stories because the media has dumbed them down for so long?

What can scientists do about the media’s love affair with over-simplistic genocentric explanations? Several people who commented at the seminar were concerned that the news media found genetic explanations to be more newsworthy, or at least more glitzy, than the nuanced versions of the stores told by scientists. The concern is that reporters without scientific training tend to tell cartoonish versions of the detailed accurate versions of the stories. Another concern expressed at the seminar is that the news media is all too willing to reward self-promoting entrepreneur scientists. For instance, the media has rewarded Hamer well, despite the big theoretical gaps in his homosexuality study methodology and the even bigger problems with his equally celebrated theory of the “God gene.”

If concerned scientists want to help get the scientific truth out, they probably need to try harder to take the time to spoon feed accurate versions of their stories to reporters. My experience as an attorney might apply here. When I don’t take lots of time making sure that the reporters get a deep understanding of a complicated lawsuit, I am to blame for the inevitable result. When I really want to make certain that the reporter understands the nuances of a case, I send the reporters a follow-up emails with some carefully-honed quotes.

There’s a lot of blame to go around for the ubiquity of the “Gene for X” stories. As much as I hate to admit it, I fear that the public really does demand simplistic stories. Why else are there so many popular newspapers and magazines that publish such short stores (a few hundred words) on such complicated topics? Too many American readers crave only the kinds of stories that they can recap in a phrase. And too many of us don’t have the stamina to thoroughly explore a topic.

And we insist on ONE cause. If it’s not one cause, it’s not much of a story. For instance, when the hometown baseball team trounces the visitors 10 to 4, we speak of the great hitting as the cause, even though it could equally be said that the visitor pitching was lacking. It doesn’t make catching headlines, though, to explain the outcome of the game as due to “some combination, as yet undetermined, of good hometown hitting and poor visitor team pitching.” Readers would rather hear that the home town batters walloped the other team. They want to know THE cause. And how else can we explain that so many people are convinced that the first cause argument proves the existence of God, when the conclusion violates the opening premise (that everything must have a cause)?

We do love simple stories and explanations. Need I say any more than “Disney?”

One final example I’d like to offer is the popular essentialist story of what it is to be an “American.” We all know the stereotype: Americans are supposedly independent, fearless, brash smart and innovative. We are a “special,” people, according to every politician who has publicly described Americans. We are told that the great things of America flow from the great people that we are. But how special are Americans, really? Immigrants assimilate quite well, thank you, and they often out-Americanize most Americans. The popular story continues to be, however, that each American is special and it is this special-ness of individual Americans that explains the special history of America. Using this same argument, swap genes for Americans and swap history of country for the phenotype of the organism and you can see that we excel at pouring huge explanatory burdens into single components of complex adaptive systems (e.g., both organisms and societies).

It feels good to have “the explanation.” It makes a person walk tall and feel smart. When we talk about the gene for courage or beauty or the gene for being “smart,” it’s a simple story that we feel that we understand and we like to believe. Too many of us don’t have time for nuances anymore. In modern day America, the quest for knowledge simply cannot be a painstaking interactive enterprise—our schedules simply won’t allow that. The quest for knowledge has become a treasure hunt where the winner is the person who makes up a story that lots of people want to believe.

Thus we love stories that someone has found “the gene for X,” whether or not it’s justified by evidence.