Oxytocin – the “love” hormone produced by the body to encourage bonding – may also help us to lie to the benefit of our group, according to new research published in the Proceedings of the National Academy of Science.

Produced in the hypothalamus region of the brain, oxytocin is a peptide of nine amino acids that functions as both a hormone and a neurotransmitter. It has been demonstrated in research as promoting bonding in couples and between mothers and babies, and is also thought to drive people’s impulse to be sociable.

Generally, the higher levels of oxytocin a person has, the more empathy and trust they will have, as well as lower social anxiety and fear response.

Oxytocin can also stimulate aggression, if it is required for reasons of defense.

The work of researchers from the Ben-Gurion University (BGU) of the Negev in Israel and the University of Amsterdam in the Netherlands focuses on ethical decision making. When it comes to explaining the biological foundations of lying, however, there is very little scientific knowledge.

The researchers therefore designed an experiment to investigate this. A group of 60 male participants either received a dose of oxytocin or a placebo, and were then split into teams of three.

The teams were asked to predict the results of 10 coin tosses. If a participant correctly guessed coin tosses then this would earn his team more money, to be divided among the members.

Rather than the participants’ predictions being measured objectively, however, they were asked to toss the coin and self-report whether their prediction was correct or not.

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The statistical probability of someone correctly guessing the results of nine or 10 coin tosses is about 1%. In the oxytocin group, 53% of the subjects claimed to have guessed this many coin tosses.

The coin toss results reported by participants who had taken oxytocin and those who had received the placebo were very different. Among the control subjects, 23% claimed to have guessed the results of nine or 10 of the coin tosses.

But in the oxytocin group, 53% of the participants claimed to have correctly guessed this many coin tosses.

“The statistical probability of someone correctly guessing the results of nine or 10 coin tosses is about 1%,” says Dr. Shaul Shalvi, director of BGU’s Center for Decision Making and Economic Psychology. “Yet, 53% of those who were given oxytocin claimed to have correctly predicted that many coin tosses, which is extremely unlikely.”

So it seems fair to assume that the majority of the subjects who claimed 90% or 100% success rates were lying, but it shows that the oxytocin group were more than twice as likely to lie than the placebo group.

Oxytocin promotes group bonding, so were the subjects who received the oxytocin lying in order to benefit their group?

“Our results suggest people are willing to bend ethical rules to help the people close to us, like our team or family,” says Dr. Shalvi. “This raises an interesting, although perhaps more philosophical, question: are all lies immoral?”

Dr. Shalvi considers the experiment to provide “insight into when and why collaboration turns into corruption.” He goes on to describe how the results highlight the role of bonding and cooperation in shaping dishonesty:

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.”

Oxytocin has been the subject of several recent studies reported by Medical News Today. Researchers have found that poor oxytocin development could be to blame for drug and alcohol addiction, and that high oxytocin levels can trigger emotional oversensitivity.

Researchers from Yale University have also investigated using oxytocin as a means of boosting empathy and social interaction in children with autism.