Apr 16, 2011 10:54 GMT  ·  By

According to the conclusions of a new scientific investigation, it would appear that the concentrations of a specific neurotransmitter in the brain play a determining factor in the way we perceive intimacy in a couple we are observing at that point.

Experts have determined that the way we view others' intimate relationships is linked to the actions of serotonin, a brain transmitter that is usually involved in promoting feelings of well-being.

The reason why this chemical is so heavily investigated is because studies have demonstrated that it plays a role in depression, as well as other forms of psychiatric activity, PsychCentral reports.

In humans, the neurotransmitter determines the way we view interpersonal relationships, both our own and those of others. Maintaining positive personal relationships is also largely controlled by serotonin.

Now, a neuropsychologist at the Oxford University details the mechanisms through which the chemical acts to produce its effects. “Serotonin is important in social behavior, and also plays a significant role in psychological disorders such as depression,” says Robert Rogers, PhD.

The Oxford expert was the leader of the new research. “We wanted to see whether serotonin activity influences the judgments we make about peoples’ close personal relationships,” he explains.

In the new experiments, test participants were divided into two groups. Each of them was given a drink. People in the first group had the amino-acid tryptophan mixed in their beverages, whereas members of the second group did not receive the chemical.

Tryptophan plays a vital role in the synthesis of serotonin in the brain. By administering it, experts increased the level of serotonin in participants' bloodstream. Both groups were then asked to watch photos of romantic couples.

People in the photographs were consistently rated as being less “intimate and romantic” by those who did not receive the amino-acid. Those who did were most likely to view the couples as being more intimate.

“Although this is only a small study, the same patterns may well extend to the way we perceive our own relationships,” Rogers explains. Details of the work appeared in the latest issue of the journal Biological Psychiatry.

“The ability to chemically influence the capacity for intimacy could be very important. Reduced capacity for intimacy can be a vexing symptom of many psychiatric disorders and an important target for treatment,” says Dr. John Krystal.

“Drugs that ameliorate the impact of serotonin deficits might play a role in the treatment of this symptom,” adds the expert, who is the editor of Biological Psychiatry.