Oxytocin is thought to be released in the body during hugging, breastfeeding, sex, and even social bonding. Recent research investigating this hormone (that doubles as a neurotransmitter in the brain) highlights some surprising results. Two scientists have discovered that intranasal oxytocin given to healthy males increased their lying to benefit the financial interests of their group. Yet, strangely enough, the researchers discovered no increase in lying for purely selfish motives. “These findings highlight the role of bonding and cooperation in shaping dishonesty, providing insight into when and why collaboration turns into corruption,” wrote the authors in their new study published this month in the Proceedings of the National Academy of Sciences.

Oxytocin, a hormone produced mainly in the hypothalamus, is released into the blood via the pituitary gland. Yet at other times it works as a neurotransmitter in parts of the brain, where it influences physiology and also behavior. The earliest research on oxytocin celebrated its effects on maternal behavior, lactation, and sexual pleasure. “We had a series of studies published in PNAS and Science showing that oxytocin makes people more caring about their own group,” Dr. Shaul Shavi of Ben-Gurion University and Dr. Carsten K. W. De Dreu of University of Amsterdam, told Medical Daily in an email. Yet more recent investigations have cast shadows on this hormone, showing how levels may increase during stressful conditions, including unhappy relationships and social isolation. Shavi and De Dreu decided to pursue other possible connections between oxytocin and behavior.

“Shaul's dissertation research revealed that people are more likely to cheat when justifications can be generated,” De Dreu told Medical Daily. “Lying for one's group is a good justification and we thus hypothesized that oxytocin should increase group-serving dishonesty.” To investigate this theory, the authors designed an experiment where participants could lie privately and anonymously during a simple coin-toss prediction task. The researchers gave half of the 60 participants, all healthy males, intranasal oxytocin while the other half received a placebo. (During the test itself, neither researchers nor participants knew which participants had received the oxytocin.) By dishonestly reporting their individual performance on the coin-toss prediction task, participants understood they could benefit their group’s total outcome.

What did the researchers discover? They found that the participants who received oxytocin lied more to benefit their group, and did so faster, than did the participants who received only a placebo. Apparently, those lying did not do so because they expected reciprocal dishonesty from their fellow group members. “One core message from our work is that lying and dishonesty may often be motivated by concerns for others, fellow group members included,” the authors told Medical Daily. Interestingly, the oxytocin effects only emerged when lying had financial consequences and money could be gained. When losses alone were at stake, the participants, whether they had received a placebo or oxytocin, lied to similar degrees. Finally, the researchers discovered that when dishonesty benefited just the participants themselves and did not benefit their fellow group members, oxytocin had no influence on lying.

“This has implications for several economic theories on human decision making,” the authors said. Yet one question remained: If Oxytocin is stimulated during sex, does that mean love makes us bigger liars, especially when money is involved? “That would be an unwarranted stretch,” the authors told Medical Daily. “[We’re] unaware of studies showing that highly sexed people have higher levels of brain oxytocin. To be sure, oxytocin is much more than an 'orgasm hormone.'”

Source: Shalvi S, De Dreu CKW. Oxytocin promotes group-serving dishonesty. PNAS. 2014.