TUESDAY, Aug. 13, 2002 (HealthDayNews) -- Cheating and being cheated are integral, if unfortunate, aspects of human interaction.
However, people seem to have evolved with the ability to recognize when others haven't lived up to their end of the social bargain, new research has found.
Two studies in this week's Proceedings of the National Academy of Sciences describe how the sense of reciprocity is preserved vastly different cultures, and what happens to a person when this skill is missing.
"It actually works better to reciprocate," says Valerie E. Stone, a cognitive neuroscientist at the University of Denver and a co-author of one of the papers. "Nice guys do finish first, and cheaters never prosper long-term because they get a reputation as a cheater."
Stone and her colleagues have been studying a man who at the age of 26 suffered a serious bicycle accident that left his brain damaged. The injuries didn't affect his ability to think, perform calculations and carry out other basic mental functions. However, they did deprive him of the impulse to become outraged when deceived -- a fact his family learned only after he was repeatedly bilked out of money.
"He did not seem to be good at detecting cheating, and he didn't seem to have that reaction of outrage," Stone says. "He essentially had to have his family take care of his personal affairs and finances."
The man's deficit implies the presence of a dedicated cheater detection module, possibly located in the orbitofrontal cortex or the amygdala of the brain. These two areas, which have been linked to emotion and judgment, were damaged in the bike wreck.
The second study, which included some of the same researchers, shows how even hunter-gatherers with relatively simple social structures are as adept at identifying cheaters who violate the social compact as are residents of industrialized countries.
Indeed, the scientists found the Shiwiar people of the rain forests of Ecuador were as proficient at detecting deception as were the students of Harvard Yard.
"It appears that very few animals can actually engage in [social] exchange, and this is one necessary component for doing it," says Lawrence Sugiyama, an anthropologist at the University of Oregon and a co-author of the study.
Although the Shiwiar do display culturally specific differences in reasoning, these weren't related to cheating.
For example, Sugiyama says, "They had an interest in who was giving away stuff to other people without taking anything in return. That makes perfect sense, because they spend a lot of time trying to figure out who's on their side in coalitions."
All this raises the obvious question: What good is a cheating alert that only kicks in after a deception has occurred?
"The hypothetical function of the module is to keep you from engaging in future exchanges with people who don't fulfill their end of the deal," Sugiyama says.
Of course, humans being humans, the tenets of reciprocity are broken all the time. To be sure, Stone admits, many people are habitual suckers and some scammers succeed even over the span of their lifetime.
However, she points out, the social centers of the human brain evolved when our circles were much smaller, consisting of tribes of fewer than about 150 members. As a result, word of a cheat got around much quicker, making it harder for one to succeed more than once.
What To Do
For more on these findings, try the University of California, Santa Barbara. For more on game theory, try this site at the University of California, Los Angeles.
