Brownian trends

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I'm not sure whether David Brooks has changed his mind about nature and nurture, or just has a short attention span. It wasn't long ago that he told us ("David Brooks, Neuroendocrinologist", 9/17/2006) that

Once radicals dreamed of new ways of living, but now happiness seems to consist of living in harmony with the patterns that nature and evolution laid down long, long ago.

But in his most recent column (David Brooks, "The Luxurious Growth", 7/15/2008), he's singing a different song:

It wasn’t long ago that headlines were blaring about the discovery of an aggression gene, a happiness gene or a depression gene. The implication was obvious: We’re beginning to understand the wellsprings of human behavior, and it won’t be long before we can begin to intervene to enhance or transform human life.

Few talk that way now. There seems to be a general feeling, as a Hastings Center working group put it, that “behavioral genetics will never explain as much of human behavior as was once promised.”

Studies designed to link specific genes to behavior have failed to find anything larger than very small associations. It’s now clear that one gene almost never leads to one trait. Instead, a specific trait may be the result of the interplay of hundreds of different genes interacting with an infinitude of environmental factors.

[The Hastings Center publication in question appears to be Erik Parens et al., "Wrestling with Behavioral Genetics: Science, Ethics, and Public Conversation", JHU Press, 2006 -- Brooks' quotation is on p. xxii of the introduction, written by Nancy Press, Audrey Chapman, and Erik Parens.]

I guess it's possible to believe that gender stereotypes are genetically determined, while aggression, happiness and depression involve complex gene-environment interactions. Or maybe the point is that behavioral dispositions are either genetic and therefore immutable, or else determined by interactions so complex as to preclude rational intervention. Or perhaps Brooks just saw the opportunity to identify an intellectual trend — one of his characteristic moves — and doesn't care that it's in some sense the opposite of a trend that he identified a couple of years ago.

But skepticism about "the gene for X" has been around for just as long as enthusiasm for the same idea. And the "gene for X" enthusiasts have by no means folded their tents and moved on — a quick Google News search for {"genetic basis"} turns up (among many others):

"Genetics Behind Male Homosexuality Could Be Explained By Sexually Antagonistic Selection", 6/19/2008; "Genes explain why Chihuahuas are so high-strung", 6/20/2008; "Psychiatric genetics: progress amid controversy", 6/24/2008; "Dog genome provides clues to breeds' personalities", 6/25/2008; "Migraine Mutations Reveal Clues to Biological Basis Of Disorder", 7/1/2008; "That cig in your mouth may be linked to what's in your genes", 7/11/2008; "Autism Genes are Linked to Early Learning", 7/12/2008; "Gene Produces Hormones That Lead To Obesity", 7/14/2008, "Taking a Cue From Ants on Evolution of Humans", NYT, 7/15/2008.

A search for {"gene for"} yields similarly high-grade ore.

I suspect that the powerful attraction of genome-wide association studies will continue to produce increasing numbers of such headlines, so that my call for "Two simple numbers" will remain relevant.



  1. Stumblng Tumblr said,

    July 16, 2008 @ 5:19 am

    This is so unfair. No one's expected actually to remember afterwards what these blowhards say.

  2. Doctor Deaf said,

    July 16, 2008 @ 7:00 am

    @Stumblng Tumblr:
    That's a very attractive website you've got. (Sorry, Arnold Zwicky).

  3. windy said,

    July 17, 2008 @ 7:35 pm

    Perhaps you didn't mean to imply it, but not everyone who uses "a gene for…" is necessarily an enthusiast for a particular naive view of how genetics influence human traits.

    Richard Dawkins makes a good case for a legitimate use of "a gene for X" in the second chapter of The Extended Phenotype, summarized here by Cosma Shalizi. The evolutionary perspective is very different from the popular misconception of 'one gene leading to one trait'.

    Most of the top hits for "gene for" in your Google News search are talking about genes coding for particular receptors or enzymes, and in that context "gene for" is rather uncontroversial: what makes them "high-grade ore"?

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