Research integrating cultural and evolutionary psychological perspectives was the focus of the third and last day of the 2004 University of British Columbia Mind, Culture, and Evolution conference. Some of the complex human feats addressed were sharing, overeating, creating religion and breaking biology's mating rules.

  • To share is human? Hokkaido University psychologist Tatsuya Kameda, PhD, proposed that sharing might be humans' default setting when resources are uncertain. For example, both Americans and Japanese who were given an unexpected, uncertain reward in a laboratory study were much more likely to share their windfall than were people who were given an expected, certain reward. Using a computer simulation of evolution, Kameda and his colleagues found in 2003 that sharing was more profitable and stable than other ways of distributing resources. On the cultural side of things, Kameda showed that local cultures may amplify or dampen the will to share: In higher social class contexts, for instance, people are less likely to share unexpected gains, but in lower social class contexts, sharing windfalls is more common.

  • Eating habits. Much of human's evolved machinery is dedicated to identifying, procuring, ingesting, digesting and metabolizing food, said University of Pennsylvania psychologist Paul Rozin, PhD. At the same time, cultures shape which foods are cultivated, how they are prepared, and when, why, where, with whom and how they are eaten. These cultural practices, in turn, leave their marks on human bodies. For example, while Americans tend to value the speedy consumption of large quantities of comfort foods--and have the excess weight to prove it--the svelte French tend to value the languid consumption of moderate quantities of high-quality foods.

  • Making religion. University of British Columbia psychologist Ara Norenzayan, PhD, said that while religious practices and beliefs do not directly result from natural selection, they do exploit many evolved psychological tendencies. For example, our brains evolved to remember largely normal features that are combined with a few highly unusual details--something evident in many religions, Norenzayan said. Jesus Christ, for instance, is described as an ordinary carpenter who sometimes does extraordinary things, like walk on water. Likewise, Buddhism's Avalokiteshvara is depicted as having a mostly normal human body, except for an extra 998 arms. Religious beliefs also persevere, Norenzayan said, because of evolved features that make humans highly aware of time, self and death.

  • Breaking biology's rules, for a while. Evolutionary theory predicts, and most data support, that older men are usually attracted to younger women because they bear more and healthier offspring. Younger women, in contrast, prefer older men, because they have more resources and power to invest in their offspring. Yet in some groups, such as the Tiwi of Australia, young men routinely marry older women. Arizona State University psychologist Douglas Kenrick, PhD, explained why: Tiwi men are polygynous, and all of the women have to be married all of the time. The richest men marry the youngest women, leaving the widows to the poorer young men. Eventually, though, Tiwi men inherit their first wives' property and attain the wealth and status to marry younger, child-bearing brides.