Tuesday, June 9, 2009

More about the evolution of human behavior: warfare and the rise of altruism

Hey all,

Here is another recent study from Science magazine looking at the evolution of human behavior, this time looking at warfare and the resulting group selection as a possible mechanism for the rise of the uniquely human trait of altruism. Darwin himself remarked on warfare's role in the evolution of human behavior; in The Descent of Man, he remarks that "a greater number of courageous, sympathetic and faithful members, who were always ready to warn each other of danger, to aid and defend each other...would spread and be victorious over other tribes." (156) It seems that Darwin saw in warfare a way to select for altruistic traits like compassion and self-sacrifice, an implication that is at the heart of this study.

Samuel Bowles, a researcher at the Santa Fe Institute in New Mexico, wanted to see if frequent warfare could drive group selection for altruistic traits in human behavior. Despite the controversy surrounding the archaeological and ethnographic evidence regarding intergroup conflict between hunter-gather groups and their implications, he decided to use the information available and mathematically model the relationship between warfare and selective pressures targeting altruistic behavior. He plugged in data derived from ethnographic and archaeological evidence regarding warfare between different groups of hunter-gatherers into mathematical models of human evolution and competition. Such a method basically is looking at the survival probability of a gene promoting self-sacrifice in future generations. The results seems to suggest that warfare can allow for the passing on of genes with a higher self-sacrificial cost (about 10 percent more) compared to an analogous situation without warfare. According to Boyle, this is more than enough to influence the evolution of human behavior, allowing for the advent of altruistic traits not possible otherwise.

The Economist posted an informal assessment of both Bowles' study and the cultural sophistication study I posted last week. The article brings up a number of concepts related to Bowles' work, including the outdatedness of group selection/'good-of-the-group' mentalities and the the rise of alternative explanations regarding gene versus gene selection. Gene versus gene selection basically focuses on the interests of particular genes rather than groups; a major example is Richard Dawkins' "selfish gene" theory that stands at odds with group selection.

Again, such studies on the origins of human behavior are very speculative at best, as they are reliant on incomplete data and mathematical models. Regardless, Bowles presents an interesting theory on the evolution of human behavior that raises pertainent questions regarding whether or not social interaction in general has an effect in promoting human behavior evolution and (if so) if forms of social interaction less extreme than warfare can affect evolution of behavior.

Link to Economist article: http://www.economist.com/science/displaystory.cfm?story_id=13776964
click for direct study link

-Andrew Plan

1 comment:

Rob Willox said...

The gene selection theory as outlined in Dawkins' The Selfish Gene and in subsequent works can and does explain how altruism could arise in groups through kinship bonds and further between individuals within groups.

As Dawkins himself has made the point that the book may have been better named The Co-operative Gene.

The very name change casts a completely different perspective on what has become a misunderstood idea in that of selfishness rather than co-operation towards a common goal of survival.

Without gene group co-operation the individual genes themselves have little chance of reproduction and transfer into their next vehicle for co-operative evolution.