Darwin errou feio sobre a seleção sexual como mecanismo evolucionário!!!

segunda-feira, janeiro 14, 2013

Darwin Was Wrong About Dating

Published: January 12, 2013 

A COUPLE of evolutionary psychologists recently published a book about human sexual behavior in prehistory called “Sex at Dawn.” Upon hearing of the project, one colleague, dubious that a modern scholar could hope to know anything about that period, asked them, “So what do you do, close your eyes and dream?”

Actually, it’s a little more involved. Evolutionary psychologists who study mating behavior often begin with a hypothesis about how modern humans mate: say, that men think about sex more than women do. Then they gather evidence — from studies, statistics and surveys — to support that assumption. Finally, and here’s where the leap occurs, they construct an evolutionary theory to explain why men think about sex more than women, where that gender difference came from, what adaptive purpose it served in antiquity, and why we’re stuck with the consequences today.

Lately, however, a new cohort of scientists have been challenging the very existence of the gender differences in sexual behavior that Darwinians have spent the past 40 years trying to explain and justify on evolutionary grounds.

Of course, no fossilized record can really tell us how people behaved or thought back then, much less why they behaved or thought as they did. Nonetheless, something funny happens when social scientists claim that a behavior is rooted in our evolutionary past. Assumptions about that behavior take on the immutability of a physical trait — they come to seem as biologically rooted as opposable thumbs or ejaculation.

Using evolutionary psychology to back up these assumptions about men and women is nothing new. In “The Descent of Man, and Selection in Relation to Sex,” Charles Darwin gathered evidence for the notion that, through competition for mates and sustenance, natural selection had encouraged man’s “more inventive genius” while nurturing woman’s “greater tenderness.” In this way, he suggested that the gender differences he saw around him — men sought power and made money; women stayed at home — weren’t simply the way things were in Victorian England. They were the way things had always been.

A century later, a new batch of scientists began applying Darwinian doctrine to the conduct of mating, and specifically to three assumptions that endure to this day: men are less selective about whom they’ll sleep with; men like casual sex more than women; and men have more sexual partners over a lifetime.

In 1972, Robert L. Trivers, a graduate student at Harvard, addressed that first assumption in one of evolutionary psychology’s landmark studies, “Parental Investment and Sexual Selection.” He argued that women are more selective about whom they mate with because they’re biologically obliged to invest more in offspring. Given the relative paucity of ova and plenitude of sperm, as well as the unequal feeding duties that fall to women, men invest less in children. Therefore, men should be expected to be less discriminating and more aggressive in competing for females.

It was an elegant, powerful application of evolutionary theory to the mating game. The evolutionary psychologists of the 1980s and ’90s built on Mr. Trivers’s theory to explain a wide array of stereotypical gender differences in mating.

In 1993, David M. Buss and David P. Schmitt used parental investment theory to explain why men should be expected to “devote a larger proportion of their total mating effort to short-term mating.” Because men invested less time and effort in their offspring, they evolved toward promiscuity, while women evolved away from it. Promiscuity, the researchers hypothesized, would have been more damaging to the female reputation than to the male reputation. If a man mated with a promiscuous woman, he would never be able to ensure his paternity. Men, on the other hand, could potentially enhance their status by pursuing a short-term mating strategy. (Think Kennedy, Clinton, Spitzer, Letterman and so forth. My space is limited.)

One of the earliest critics of this kind of thinking was Stephen Jay Gould. He wrote in 1997 that parental investment theory “will not explain the full panoply of supposed sexual differences so dear to pop psychology.” Mr. Gould felt that the field had become overrun with “ultra-Darwinians,” and that evolutionary psychology would be a more fruitful science if it didn’t limit itself “to the blinkered view” that evolutionary explanations accounted for every difference.

BUT if evolution didn’t determine human behavior, what did? The most common explanation is the effect of cultural norms. That, for instance, society tends to view promiscuous men as normal and promiscuous women as troubled outliers, or that our “social script” requires men to approach women while the pickier women do the selecting. Over the past decade, sociocultural explanations have gained steam.

Take the question of promiscuity. Everyone has always assumed — and early research had shown — that women desired fewer sexual partners over a lifetime than men. But in 2003, two behavioral psychologists, Michele G. Alexander and Terri D. Fisher, published the results of a study that used a “bogus pipeline” — a fake lie detector. When asked about actual sexual partners, rather than just theoretical desires, the participants who were not attached to the fake lie detector displayed typical gender differences. Men reported having had more sexual partners than women. But when participants believed that lies about their sexual history would be revealed by the fake lie detector, gender differences in reported sexual partners vanished. In fact, women reported slightly more sexual partners (a mean of 4.4) than did men (a mean of 4.0).

In 2009, another long-assumed gender difference in mating — that women are choosier than men — also came under siege. In speed dating, as in life, the social norm instructs women to sit in one place, waiting to be approached, while the men rotate tables. But in one study of speed-dating behavior, the evolutionary psychologists Eli J. Finkel and Paul W. Eastwick switched the “rotator” role. The men remained seated and the women rotated. By manipulating this component of the gender script, the researchers discovered that women became less selective — they behaved more like stereotypical men — while men were more selective and behaved more like stereotypical women. The mere act of physically approaching a potential romantic partner, they argued, engendered more favorable assessments of that person.

Read more here/Leia mais aqui: The New York Times