Cultureplaces

As modern humans moved north into environments with longer winters, women were less able to feed themselves and their children through food gathering. They thus became more dependent on food from their male partners. For men, this greatly increased the cost of having a wife and children, thus making polygyny prohibitively expensive for all but the ablest hunters. Initially, this situation came about by men and women pushing their respective envelopes of behavioral plasticity. It may not have been the happiest of situations, but circumstances left no other choice.Over time, however, natural selection should have improved things by favoring men who were less predisposed to polygyny and more predisposed to provide for their wives and children. How? Apparently, by lowering testosterone levels in men once they've entered a pair bond. This has been shown by findings recently presented at this year's annual meeting of the American Association of Physical Anthropologists. According to

By Michael Medved http://townhall.com/Columnists/MichaelMedved/2008/05/14/respecting_-_and_recognizing_-_american_dna ...[T]wo respected professors of psychiatry have recently come out with challenging books that contend that those who chose to settle this country in every generation possessed crucial common traits that they passed on to their descendents. In “American Mania,” Peter C. Whybrow of U.C.L.A. argues that even in grim epochs of starvation and persecution, only a small minority ever chooses to abandon its native land and to venture across forbidding oceans to pursue the elusive dream of a better life. The tiny percentage making that choice (perhaps only 2%, even in most periods of mass immigration) represents the very essence of a self-selecting group. Compared to the Irish or Germans or Italians or Chinese or Mexicans who remained behind in the “Old Country,” the newcomers to America would naturally display a propensity for risk-taking, for restlessness, for exuberance and