The over-sampling of American college students may be skewing our understanding of human behavior, finds an analysis by researchers from the University of British Columbia. In a forthcoming issue of Brain and Behavioral Sciences, anthropologist Joe Henrich, PhD, and psychologists Steven Heine, PhD, and Ara Norenzayan, PhD, review the available database of comparative social and behavioral science studies. They found that people from Western, educated, industrialized, rich and democratic (WEIRD) societies — who represent as much as 80 percent of study participants, but only 12 percent of the world’s population — are not only unrepresentative of humans as a species, but on many measures they’re outliers.

In one illustrative study from the 1966 book “The Influence of Culture on Visual Perception,” researchers found that U.S. college students perceive some visual illusions to a much greater degree than people from many other cultures, including the San foragers of the Kalahari. In fact, people from some cultures were completely unaffected by certain illusions. If such seemingly basic processes as visual perception can differ across cultures, says Henrich, it makes sense that others do, too.

He and his colleagues use many examples to demonstrate that studies that rely on a narrow swath of the world’s population need to be careful in assuming, as many do, that their results are universally applicable to the human species.

 “We hope that researchers will come to realize just how precarious a position we’re in when we’re trying to construct universal theories from a narrow, and unusual, slice of the population,” says Heine.

To address the problem, Heine and his colleagues suggest that journal editors and funding agencies encourage researchers to discuss the limitations of their samples and seek more representative study participants.

Not all researchers agree with Heine. In a commentary that will accompany the article, University of Tennessee at Knoxville psychologist Lowell Gaertner, PhD, and his colleagues argue that simply looking at surface differences among cultures — what they call the phenotype — does little to advance the understanding of universal human behavior or genotype.

— B. Azar