Studies and illusions

Sharon Begley is one of the country's most popular science writers, in part because she seems to have an uncanny ability to zoom in on what the educated public is wondering about. (Begley, if memory serves, was lured away from the Wall Street Journal by Newsweek around the time some strange, ominous force took over ownership of the Journal.)

Anyway, this week she zoomed in on something I've often wondered about - what does the pervasive use of U.S. college undergraduates in psychological studies really tell us about humanity as a whole?

According to Begley's reporting of current research, not so much.

For instance, she says, a recent paper by Joseph Henrich at the University of British Columbia and colleagues considered the well-know optical illusion involving two vertical lines, each the same length. One (A) has arrows at each end pointing out, the other (B) has arrows at each end pointing in. To most U.S. college kids (and me!), (B) looks longer by 20 percent. But the illusion doesn't fool African hunter-gatherers known as the San of the Kalahari. Begley suggests American college kids are fooled because they grew up in urban areas filled with right angles - so a universal trait of the human mind it isn't.

Likewise, consider the well-known "fairness" game in which scientists give money to one player, who decides how to split it with another player. If the second play doesn't like the split, neither gets anything. Say the first player gets $10. If he offers the second player anything less than $4, the second player will say "stick it in your ear," and both walk away with nothing. That's so among American undergrads, anyway. But to people from some nonindustral societies, an offer of about $2.50 will be accepted.

Even within the U.S., these kinds of studies can be misleading. For instance, sexual differences in spatial ability found among middle-class kids don't appear among poor kids.

Next time I attend college, and am approached by its psychology department to volunteer for an experiment, I just might have to decline.