actually predict the future just yet, that he merely had the germ of an idea about how to do so if the mathematics could be properly developed. Seldon, in fact, was skeptical that he would ever succeed.
“In studying society, we put human beings in the place of subatomic particles, but now there is the added factor of the human mind,” Seldon explained. “To take into account the various attitudes and impulses of mind adds so much complexity that there lacks time to take care of all of it.”7
In fact, Seldon pointed out, an effective psychohistory capable of predicting the galactic future would have to account for the interacting human variables on 25 million planets, each containing more than a billion free-thinking minds. “However theoretically possible a psychohistorical analysis may be, it is not likely that it can be done in any practical sense,” he admitted.8
By displeasing the emperor with such pessimism, Seldon soon found himself a fugitive, roaming from one sector to another on the planet Trantor—the urban sector of the Imperial capital, a university town, a farming region, an impoverished mining center. By the end of the book Seldon realized that Trantor was a microcosm of the galaxy, home to hundreds of societies each with their own mores and customs. That was his solution to achieving a science of psychohistory! He didn’t have to analyze 25 million worlds; he could understand the variations in human behavior by using Trantor itself as a laboratory.
Toward the end of the 20th century, Earth-bound anthropologists independently arrived at a similar scheme for analyzing human social behavior. By playing the ultimatum game (and some variants) in small, isolated societies around the planet, those scientists have found that human nature isn’t so universal after all. College students in postindustrial society, it turns out, are not perfectly representative of the entire human race.
This worldwide game-playing project began after anthropologist Joe Henrich, then a graduate student at UCLA, tried out the ultimatum game with the Machiguenga farmers of eastern Peru in 1996. The rules were the same as with college students: One player