How We Perceive Intimacy Is Correlated with Serotonin Levels

Experts say that the amount of serotonin we have in the brain at any given time plays an important role in dictating the way we view other people's relationships. This has implications for how we perceive other couples we see, in images, on TV, or on the street, the team behind the work says.

The entire way we perceive intimacy may therefore be linked to serotonin concentrations in the cortex. This chemical is a neurotransmitter, which means it contributes to facilitating the transfer of impulses between neurons in specific manners.

In the new research, healthy adult volunteers recruited by experts at the University of Oxford were made to watch photos of couples, and rate how “intimate” or “romantic” they perceived them to be.

When levels of the hormone, which is also associated with mood, were lower, the participants were adamant that the couples they were looking at were less intimate and romantic. Test subjects with normal serotonin levels were more likely to see the couples with kinder eyes.

One of the most interesting implications of the new work is that the differences in perceiving personal relationships that characterize conditions such as depression, may in fact be a result of low hormone levels in the brain, PsychCentral reports.

“Serotonin is important in social behavior, and also plays a significant role in psychological disorders such as depression,” Oxford University Department of Psychiatry professor Robert Rogers explains.

“We wanted to see whether serotonin activity influences the judgments we make about peoples’ close personal relationships,” adds the expert, who was also the leader of the research. The work is published in the latest issue of the journal Biological Psychiatry.

“Although this is only a small study, the same patterns may well extend to the way we perceive our own relationships. Serotonin activity may affect people’s ability in depression to maintain positive or intimate personal relationships,” Rogers goes on to say.

This investigation, conducted with funds from the UK Medical Research Council, also included experts from the University of Liverpool and King’s College London. Of the 41 volunteers, 22 were given a substance without tryptophan, whereas 19 got the chemical.

This substance is an amino-acid from which serotonin can be produced in the brain, the experts say. The 22 participants who did not get the active chemical received a placebo instead.