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»  June 6, 2005


The Murderous Gene. And Bob, Joe, and Albert.

It's a shame that more people online don't see her work, because Sharon Begley, the "Science Journal" columnist at the Wall Street Journal gets off the occasional slam at wacko theories. I was catching up on some copies of the hard edition of WSJ the other day and ran across "Theory Men Are Wired To Kill Straying Mates Is Offensive and Wrong" (and unlike some other folks, I know that you can occasionally do a Google search to find WSJ articles without registration).

In her May 20 column, Begley discusses a theory put forth in a new book on the origins of homicide by David Buss, a psychology professor at the University of Texas, Austin, entitled The Murderer Next Door: Why the Mind Is Designed to Kill. The column opens with a "Just So" story of why men "evolved" to kill mates who stray, then continues (emphasis added):

Killing, according to his [Buss'] Kipling-esque reasoning, offered so many "advantages to our early ancestors in the competition for survival and reproduction" that, today, "all men have an evolved psychology of mate killing that lies latent in their brains." Men with the genetically based mental circuit for uxoricide had such an edge over their pacifist peers, in other words, that all men living today -- their descendants -- have this murder circuit, too.

For proof, Prof. Buss cites homicide statistics showing that more men than women kill, that over a five-year period in Dayton, Ohio, 52% of the women murdered were killed by a husband, lover or ex, and that women age 15 to 24 are killed by their mates or ex-mates more than over-the-reproductive-hill women are. His explanation: Only the former have evolutionary value, so men are wired to kill them if they stray but not to bother with unfaithful old bags. Also, unemployed men are more likely to kill women who dump them than are gainfully-employed men. Such low-status men, explains Prof. Buss, have the toughest time replacing their lost access to a uterus, so they're wired to raise their attractiveness to women ("you're so strong and powerful!") by murdering a cheating mate.

As evolutionary theory, this is ludicrous. Killing the owner of the uterus that is your only current chance to get your genes into the next generation (the evolutionary imperative), especially if she is caring for your current children and has a father or brothers who take exception to your uxoricide, is an excellent way to a dead end personally and genealogically. Being the target of angry in-laws, not to mention life imprisonment or lethal injection, tends to limit one's reproductive opportunities.

As a parsimonious explanation of data, the "evolution made me do it" explanation pales beside alternatives. Yes, murdered women skew young. But twenty-something men are more impulsive than fifty-something men and more likely to have a 23-year-old than a 57-year-old as a mate. And yes, unemployed men are more likely to kill or try to kill when dumped. But traits that make getting a job tough (being poorly educated, stupid, impulsive, psychotic ...) can also incline a man to murder.

Keep in mind that Buss is a psychologist bending evolutionary theory to his own uses (which, presumably, could include future court testimony to support a defense of "my genes made me do it"), not a biologist explaining an adaptation. Begley goes on to make a couple of other points against Buss' thesis, and she deserves credit for her exposure of this incredibly stupid conjecture. However, there is one argument against the evolution of the mate-killing trait that she misses.

Successful evolutionary adaptations are usually shared by the majority of a species. Eyes, for instance, can be considered a successful trait in humans, as they are in most complex animals on earth. Most humans have eyes when they are born; those who do not or whose eyes are non-functional have difficulty leading an unassisted life. Opposable thumbs are a successful trait. Most people are born with them; some, myself included, have one or more missing or malformed thumbs. I can tell you, having two thumbs would be handy sometimes (sorry, I couldn't resist).

Eyes and thumbs are dominant traits in humans, murder of a mate is not. That's not to say it doesn't happen, but genetic defects occur all the time and they're not treated by biologists as the norm. Buss' treatment of evolution in this thesis is almost as confused as that of the intelligent design crowd. Rather than looking at humans in general and hypothesizing a process of evolution that reaches that point, he chooses an outlier subset of men and draws his conclusions about all men from that small sample.

Most humans will never kill another human. Most men will not kill their mates, no matter what the circumstances. Those who do are not considered acceptable to society at large in most cultures.

As Begley points out, some of the traits that make men unemployable are also linked to murderous urges. Certainly, many people are stupid, many are impulsive, many are psychotic, but even the average person fitting each of those descriptions is unlikely to commit murder. My wife's family once had a (non-feral) cat that would lash out at anyone but my mother-in-law unprovoked, scaring another male cat of theirs twice his size, until the day he slashed my sister-in-law's wrist so badly the tendon was exposed and they finally, tearfully, decided to put him down. That was a maladapted cat.

If evolutionary psychology wants to end up with more credibility than, say, phrenology, it must accept the same logical constrains as biological evolution. There's no doubt that inherited physical differences in the brain can affect behavior. In all likelihood, some of the internal forces that would lead a man to murder his mate are related to differences in the makeup of his brain. That's not the same thing as saying that mate-murder is an evolutionary adaptation of male humans in general, particularly since the act is statistically uncommon.

Perhaps Buss intends us to view those with a predilection to murder as a further evolution of the human species, like the X-Men. But it would seem to me that the numbers lie with the mass of non-murderous humanity, and that those of us who make it through our three score and ten without taking another's life (and here I make exceptions for self-defense, public safety, combat, etc.) can consider murderers as lacking something that's supposed to be there but isn't quite right -- sort of like my left thumb.

Mon Jun 06, 2005 08:47 -0700