Casual Discussion Science Forum @scivillage

Full Version: Did humans tame themselves? (self-design)
You're currently viewing a stripped down version of our content. View the full version with proper formatting.

EXCERPT: . . . [Richard] Wrangham showed just how common chimp brutality is. Goodall had acknowledged with frank regret that her beloved chimpanzees could be quite violent. One mother and daughter killed the infants of other females in their group. Males often coerced and beat females, and would sometimes gang up and attack a chimp from another group.

At Kibale, large groups of chimps range together, and aggression escalates accordingly. Wrangham observed as these bigger parties of males got excited and went out on “patrol” in what looked like an organized way: They walked along their territorial border, attacking lone chimps from neighboring communities when they came across them en route. In his 1996 book, Demonic Males, co-authored with Dale Peterson, Wrangham recapped this and other evidence to draw a dire portrait of humanity (the male version) as inherently violent by evolutionary legacy. Here was vivid support for a Hobbesian view of human nature, rooted in genetics.

[...] In his new book (The Goodness Paradox), Wrangham grapples fully for the first time with the paradox of the title. Over the decades during which he has focused mostly on the dark side of human nature, evidence has steadily accumulated that humans, from early on in their development, are the most cooperative species in the primate world. [...] Wrangham draws on this trove of material as he pursues yet another ambitious hypothesis: “Reduced reactive aggression must feature alongside intelligence, cooperation, and social learning as a key contributor to the emergence and success of our species.” (By reactive aggression, he means attacking when another individual gets too close, as opposed to tolerating contact long enough to allow for a possible friendly interaction.) He also applies his evolutionary logic to studies of a wider array of animals. He dwells in particular on some marvelous experiments that explore the taming of wild foxes, minks, and other species by human-directed artificial selection over many generations.

Such breeding efforts, Wrangham notes, have produced “the domestication syndrome”: a change in a suite of traits, not just the low reactive aggression that breeders have deliberately singled out. For instance, in a fox study begun in Russia in the early 1950s, the pups in each litter least likely to bite when approached by humans were bred forward. Yet a variety of other features appeared in tandem with docility, among them a smaller face with a shortened snout and more frequent (less seasonally circumscribed) fertile periods, as in some other similarly domesticated species.

[...] In fact, Wrangham’s notion of human evolution powered by self-domestication has an ancient lineage: The basic idea was first proposed by a disciple of Aristotle’s named Theophrastus and has been debated several times since the 18th century. This latest version, too, is bound to provoke controversy, but that’s what bold theorizing is supposed to do. And Wrangham is nothing if not bold as he puts the paradox in his title to use. In his telling, the dark side of protohuman nature was enlisted in the evolution of communal harmony.

Central to his argument is the idea that cooperative killing of incurably violent individuals played a central role in our self-domestication. Much as the Russian scientists eliminated the fierce fox pups from the breeding pool, our ancestors killed men who were guilty of repeated acts of violence. Certainly all-male raiding parties have operated in some groups of humans, seeking out and killing victims in neighboring villages (which recalls the patrolling chimps that Wrangham reported on earlier in his career). The twist in his current theory is that such ambushes are turned inward, to protect the group from one of its own: They serve as a form of capital punishment. Wrangham cites a number of examples of anthropologists witnessing a group of men collaborating to kill a violent man in their midst.

The idea is intriguing, and it is indeed true that human hunter-gatherers, whose societies exist without governments, sometimes collectively eliminate bad actors. But such actions are rare, as the Canadian anthropologist Richard Lee emphasized in his extensive studies of the !Kung, which include the report of an unusual case: After a certain man killed at least two people, several other men ambushed and killed him. My own two years with the !Kung point to a more robust possible selection process for winnowing out aggression: female choice. Women in most hunter-gatherer groups, as I learned in the course of my experience in the field, are closer to equality with men than are women in many other societies. Evolutionary logic suggests that young women and their parents, in choosing less violent mates through the generations, could provide steady selection pressure toward lower reactive aggression—steadier pressure than infrequent dramas of capital punishment could. (Female bonobo coalitions would seem primed to serve a similar taming function.)

Although he downplays such a comparatively domestic story of self-domestication, Wrangham has nonetheless highlighted a puzzle at the core of human evolution, and delivered a reminder of the double-edged nature of our virtues and vices...

No post.