A study by a University of Georgia researcher shows that how much individuals trust others is associated with brain structure, which could potentially determine how successful relationships are.

Using a questionnaire, cognitive tests and an MRI scan, researcher Brian Haas, assistant professor of the behavioral and brain sciences program, found that study participants who were more trusting of others had a bigger volume in one part of their brain than those who were less trusting of others.

“The ventral medial prefrontal cortex is used to process things like “Is it worth me trusting this person? Is it dangerous for me to trust this person?” Haas said.

Another part of the brain researchers looked at was the amygdala, which Haas found to be greater in volume in people who tend to be more trusting of others- and also more distrustful of others. Haas said the amygdala is important in emotional processing.

“Both of those poles — being more trustful and being more distrustful — are more emotional decisions as opposed to saying “I don’t really care one way or another,” Haas said. “The amygdala guides the way we remember emotional decisions, so it makes sense that this part of the brain was greater in people making these more emotional decisions.”

Brain structure can alter all the time, Haas said, so if these regions of your brain are larger at one point in time, they can become smaller, or vice versa, related to events that would cause you to trust or distrust others. Research of PTSD, an extreme example, shows there is a lot of evidence of structural and functional abnormalities in the brain of people who have PTSD, Haas said.

The brain structures Haas observed in his study could be the result of nature or nurture, but it is difficult to distinguish the two.

“We don’t know if people were born with this anatomy and thats why they are more trusting of others or if they were raised with a particular social environment that allowed them to be more trusting of others, so their brain structure reflects that,” Haas said. “That’s something we’ve yet to explore.”

Haas’ study did not address relationships, but he said he would predict that “people who have a mutually trusting relationship would probably exhibit a similar pattern of behavior and have a similar pattern of brain anatomy.”

In a successful relationship, Haas said, the two people would equally trust one another.

According to Justin Lavner, assistant professor in the clinical psychology department, trust is an important foundation for many different types of relationships.

“Trust is a sense of security in a relationship,” said Lavner. “Its important that people feel they can connect with that other person, that the other person is reliable, whether that is with friendships, relationships with roommates, romantic relationships, relatives as well as coworkers.”

The way relationships are harmed by lack of trust depends on the reason you don’t trust the other person, Lavner said.

“Sometimes the other person does things that can make us not trust them, and it becomes difficult to repair that relationship because you’re always worried about what they might be doing,” Lavner said.

Lack of trust can be either related to specific events that make a person distrustful of another, or it can come from what is called “attachment styles”, which make it harder or easier for certain people to trust others.

“An attachment can develop based on experiences we have throughout our lives that make it so that in general we approach relationships in either a more trusting way or a less trusting way,” Lavner said.

There are ways to work on trusting others so that relationships can be more successful. Lavner said that not shutting down and being aware of the problem is one critical way.

“Its a process of working together to rebuild trust, so that it becomes something both people work on and acknowledge,” he said. “If someone feels it is difficult for them to trust others, as part of a bigger issue, they can always talk with a therapist.”