'Love' hormone promotes group lying: Study

Researchers have said that oxytocin - a hormone the body naturally produces to stimulate bonding - caused participants to lie more to benefit their groups, and to do so more quickly and without expectation of reciprocal dishonesty from their group.

In the experiment designed by Dr. Shaul Shalvi of Ben-Gurion University of the Negev's Department of Psychology and director of BGU's Center for Decision Making and Economic Psychology, and fellow researcher Carsten K. W. De Dreu of the University of Amsterdam's Department of Psychology, 60 male participants received an intranasal dose of either oxytocin or placebo. They were then split into teams of three and asked to predict the results of 10 coin tosses.

Participants were asked to toss the coin, see the outcome and report whether their prediction was correct. They knew that for each correct prediction, they could lie and earn more money to split between their group members, who were engaging in the same task.

"The statistical probability of someone correctly guessing the results of nine or 10 coin tosses is about one percent," says Shalvi. "Yet, 53 percent of those who were given oxytocin claimed to have correctly predicted that many coin tosses, which is extremely unlikely."

Only 23 percent of the participants who received the placebo reported the same results, reflecting a high likelihood that they were also lying, but to a lesser extent compared to those receiving oxytocin.

The research has been published in the Proceedings of the National Academy of Science (PNAS).