How brain structure alters in reference to trust

Researchers have found differences in brain structure after analysing how trusting people are of others.

The research may have implications for future treatments of psychological conditions such as autism.

"There are conditions like autism that are characterised by deficits in being able to process the world socially, one of which is the ability to trust people," said the study's lead author Brian Haas from the University of Georgia in the US.

Here we have converging evidence that these brain regions are important for trust.

"If we can understand how these differences relate to specific social processes, then we may be able to develop more targeted treatment techniques for people who have deficits in social cognition," Haas added.

Haas and his team of researchers used two measures to determine the trust levels of 82 study participants.

Participants filled out a self-reported questionnaire about their tendency to trust others.

They also were shown pictures of faces with neutral facial expressions and asked to evaluate how trustworthy they found each person in the picture.

This gave researchers a metric, on a spectrum, of how trusting each participant was of others.

Researchers then took MRI (magnetic resonance imaging) scans of the participants' brains to determine how brain structure is associated with the tendency to be more trusting of others.

The researchers found differences in two areas of the brain.

"The most important finding was that the grey matter volume was greater in the ventral medial prefrontal cortex - the brain region that evaluates social rewards - in people that tended to be more trusting of others," he said.

"Another finding that we observed was for a brain region called the amygdala. The volume of this area of the brain - which codes for emotional saliency - was greater in those that were both most trusting and least trusting of others."

"If something is emotionally important to us, the amygdala helps us code and remember it," the researcher said.

Future studies may focus on how, and if, trust can be improved and whether the brain is malleable according to the type of communication someone has with another, he said.