Showing posts with label evolutionary psychology. Show all posts
Showing posts with label evolutionary psychology. Show all posts

Thursday, March 2, 2017

Lethal aggression in pan troglodyte, or, Killer Chimps!

Image result for lethal aggression in pan
In homo sapiens, males account for 90% of the perpetrators of homicide, and 77% of victims (FBI data). The percentages for chimpanzees/bonobos are 92% and 73%. Maybe that Darwin fellow was onto something.



Lethal aggression in Pan is better explained by adaptive strategies than human impacts

Nature
 
513,
 
414–417
 
 
doi:10.1038/nature13727
Received
 
Accepted
 
Published online
 

Thursday, January 14, 2016

Robert Trivers profile in Psychology Today


Psychology Today

"[Evolutionary biologist Robert] Trivers’ first paper, on the evolution of reciprocal altruism, described a theoretical model showing how altruism among strangers could naturally develop—people cooperate with the expectation of similar treatment from others. This model explained a wide variety of feelings and behaviors, from friendship to moralistic aggression. The emotion of gratitude, for instance, evolved to motivate us to return favors, encouraging cooperationGuilt motivates us to repair relationships we’ve harmed. Anger makes us avoid or punish those who have harmed us. And gossip makes us mindful of our reputations. Trivers suggested that complex strategies of cheating, detecting cheating, and the false accusation of cheating (itself a form of cheating) pushed the development of intelligence and helped increase the size of the human brain.
Next, in Trivers’ second paper, he hypothesized that a single factor drives sex differences across all species. He argued that differences in parental investment—the energy and resources invested in an offspring—lead the sex that invests more (females, in most species) to focus on mate quality and the sex that invests less (males) to seek quantity. So in humans we expect choosiness in females and aggression between males as they vie for females. The theory has tremendous explanatory power, from justifying the brightly colored feathers of male birds to illuminating why sexual jealousy is a leading (and, until recently, legally defensible) cause of homicide—men prize their mate’s fidelity above all.
In another paper, Trivers conceptualized offspring not as passive recipients of parental investment, but as independent actors, generating the theory of parent-offspring conflict. A child wants disproportionate attention and resources for him- or herself, but a parent wants to spread the goods equally between all offspring. And so we have kids who bawl until they get what they want, siblings who maintain lifelong rivalries, and parents who try to instill equality no matter how selfish the kids’ tendencies. It was for these three papers, plus another two, on insect colonies and on parents’ ability to vary the sex ratio of their offspring, that he won the Crafoord.
...
After writing papers addressing how we treat strangers, friends, lovers, parents, and children, Trivers offered a no-less-powerful theory on how we deal with ourselves. In a sentence in the foreword to Dawkins’ book, he proposed that self-deception evolved to facilitate the deception of others. Trivers says he’d planned to flesh out the theory but didn’t get around to it because he was “smoking too much strong herb.”"

Tuesday, December 31, 2013

America's Polygamous Future

Wall Street Journal

When the Supreme Court paved the way for universal recognition of same-sex marriage last June, opponents predicted that polygamy would be next. They didn't realize how quickly this would happen.
Less than six months after the high court issued a pair of decisions expanding access to gay marriage and its benefits, a federal judge in Utah has ruled unconstitutional key parts of a Utah bigamy law that makes polygamous cohabitation a crime. The law had been challenged by 44-year-old Kody Brown and his four wives, who, together with their 17 children, star in the reality-TV show "Sister Wives." The Browns, who used to live in Lehi, Utah (they have since moved to Las Vegas), belong to one of several breakaway Mormon sects that practice plural marriage. (The mainstream Church of the Latter-day Saints formally abandoned polygamy in 1890, shortly before Utah became a state). An estimated 40,000 residents of Utah live in polygamous households.
To be sure, the court ruling, by U.S. District Judge Clark Waddoups, does not legalize polygamous marriage or even invalidate Utah's bigamy law in its entirety. All 50 states have antibigamy laws on their books. But Utah's law, apparently uniquely, forbids plural marriages entered into via multiple marriage licenses and also applies to a married person who "cohabits with another person."
The typical practice for breakaway Mormon men, including Kody Brown, is to enter into only one legally recognized marriage but to take on additional "sister wives" in "spiritual" unions sanctified by religious ceremonies. Such unions are technically adulterous, but since the state of Utah does not prosecute adultery, Judge Waddoups said there was no "rational basis" for Utah's criminal law to distinguish between plain old adulterous cohabitation and informal polygamy entered into for religious reasons.
His ruling thus affects only so-called "fundamentalist" Mormons. However, the decision becomes precedent elsewhere, then it may apply to an estimated 50,000 to 100,000 Muslims in the U.S. who are in similar polygamous arrangements that they believe are permitted by the Quran.
...
"Polyandry"—one woman with multiple husbands—is extremely rare. It seems to exist only among isolated Amazonian hunter-gatherer tribes and in parts of rural Tibet...
Polygamy invariably favors "alpha" males who can beat down the competition for available women and maintain a lock on the affections of the women themselves. The women also have to be willing to sacrifice being the only object of attention of their spouse or lover for the glory of being an object of his attention at all.
The evolutionary psychologist Geoffrey Miller, in his 2000 book "The Mating Mind," described polygyny as a kind of default setting for human societies, and indeed primate societies as well. "[M]ating in our species has always been moderately polygynous," Mr. Miller wrote. He pointed out that women crave powerful, charismatic, often sexually promiscuous men—the most successful hunters and herdsmen, conqueror-kings such as Charlemagne and Genghis Khan, politicians, rock stars, and even sociopaths such as Charles Manson —because women instinctively reach out to men strong enough to protect them and the vulnerable offspring they bear.
And, as those evolutionary psychologists say, it is more advantageous for a woman to have half, a third, or even a fourth of a prime male specimen, than 100% of a loser. She wants her offspring to inherit those alpha male traits and thereby have enhanced chances for survival and reproduction.

And, by the way, we already have polygamy in the United States. What do you call a man who sires three sets of children by three different women? Well, the biologists would call him polygamous, but we just call him a twice-divorced guy with child support and alimony payments.