The hyper-rational and absolutely self-interested person — the Homo economicus — is used as model for behavior in certain schools of economic theory. But do people really consistently act in a rational and self-interested way? It turns out, a minority of people do, according to new research published in Psychological Science.
Japanese researchers found that a sample of 446 nonstudent adults living in the suburbs of Tokyo contained 31 people who met the behavioral definition of Homo economicus. An additional 39 people were classified as quasi–Homo economicus.
“Although they are a small minority in our sample of relatively wealthy Tokyo suburbanites, about 7% of our sample behaved in a manner consistent with Homo economicus,” Toshio Yamagishi and his colleagues wrote in the study. “These participants were less impulsive than even consistent cooperators, scored higher on intelligence than the other groups, and used longer-term strategies than did the other participants; these findings thus answer our second question about whether Homo economicus is a rational pursuer of self-interest.”
The researcher used a computerized dictator game and a prisoner’s dilemma game in their search for a real-life Homo economicus.
In the dictator game, one participant— the dictator — is given a fixed amount of money and asked to share that reward with another participant. The other participant in the game must passively accept whatever amount the dictator offers.
In prisoner’s dilemma game, the participants were given a set amount of money and the option to either defect against the other player and keep all their money, or cooperate with the other player and give them all their money. If the participant chose to cooperate with their partner, that partner received double the amount of money.
People were classified as Homo economicus if they decided to keep their money across all of the dictator games and prisoner’s dilemma games. Those who allocated no more than 15% of their money to their partner in the dictator games and cooperated no more than once in the prisoner’s dilemma games were classified as quasi–Homo economicus.
“These two groups of people exhibited similar behaviors in the experimental games. They both chose the option that gave them maximum benefits without considering their partner’s welfare, although the levels of self-regarding and other-disregarding tendencies were more extreme in the HE group than they were in the quasi-HE group,” Yamagishi and his colleagues explained.
Psychological, attitudinal, and demographic measures revealed that these Homo economicus had individualist values, a slightly higher than average IQ, manipulative personalities, and were socially and economically successful. Despite their manipulative personalities, they did not show other signs of psychopathy, such as impulsiveness.
“In the overall picture of Homo economicus, we see a person who is intelligent, driven to excel and to dominate other people, and capable of impulse control and of working toward long-term goals,” the researchers explained. “In other words, Homo economicus is the prototypical member of the social and economic elite. The traits of Homo economicus seem to lead to social and economic success, life satisfaction, and high self-esteem. Homo economicus is rational and a successful egoist. People who fit this model do not relinquish any money in anonymously played one-shot economic games with strangers, because keeping all the money is rational and necessary for achieving their goal of maximizing self-interests.”
