The Hormone that can Make you More Dishonest


Everyone likes to think of themselves as honest. But sometimes honesty is not the best policy.

In a recent study, the hormone oxytocin caused people to lie more for the benefit of their friends. They were also dishonest more quickly and without expectation of reciprocal dishonesty from their group.

“Our results suggest people are willing to bend ethical rules to help the people close to us, like our team or family,” said Dr. Shaul Shalvi of Ben-Gurion University of the Negev and lead author of the paper. “This raises an interesting, although perhaps more philosophical, question: Are all lies immoral?”

Oxytocin is a hormone naturally produced in the body which is involved in stimulating bonding.

The Biology of Ethical Decision-making

The research done by Dr. Shalvi focuses on ethical decision-making and what justifications people use to do wrong and still feel moral. He particularly looks at what determines how much people lie and which settings increase people’s honesty.

About the biological foundations of immoral behavior, very little is known.

“Together, these findings fit a functional perspective on morality revealing dishonesty to be plastic and rooted in evolved neurobiological circuitries, and align with work showing that oxytocin shifts the decision-maker’s focus from self to group interests,” Shalvi says. “The results highlight the role of bonding and cooperation in shaping dishonesty, providing insight into when and why collaboration turns into corruption.”


Oxytocin is a peptide of nine amino acids produced in the brain’s hypothalamus. It is unique in that it functions as both a hormone and neurotransmitter.

Research has shown that in addition to its bonding effect in couples and between mothers and babies, oxytocin also stimulates one’s social approach.

Higher levels of oxytocin are correlated with:

  • Greater empathy
  • Lower social anxiety
  • More pro-social choice in anonymous games
  • Reduction in fear response
  • Greater trust in interpersonal exchange.

But oxytocin also stimulates defense-related aggression, which could help explain why having empathy can make you more aggressive.

Coin Toss Prediction Task

In the study, 60 male volunteers got an intranasal dose of either oxytocin or a 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 say if their prediction was correct or not.

For each correct prediction, the instructions were, they could lie and earn more money to split between their group members, who were doing 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.”

By comparison, just 23 percent of the men who got the placebo reported the same results, which indicates that they were probably also lying, but to a lesser extent than those receiving the oxytocin.

  1. S. Shalvi, C. K. W. De Dreu. Oxytocin promotes group-serving dishonesty. Proceedings of the National Academy of Sciences, 2014; DOI:10.1073/pnas.1400724111
  2. Mazar N, Amir O, Ariely D. The dishonesty of honest people: A theory of self-concept maintenance. J Mark Res 45:633–644. (2008)

Last Updated on October 24, 2023