PERSONAL experience plays a bigger part in deciding who we trust, rather than nature, scientists have discovered.

Researchers from the universities of Aberdeen and Western Australia, in Perth, studied more than 1200 twins to ascertain whether differences in trust were based on genetic, shared or personal environments. They showed the twins images of faces and asked them to rate how trustworthy, attractive and dominant each was.

Their results, published in the journal Proceedings of the National Academy of Sciences of the United States of America journal (PNAS), showed the twins’ ratings were not the same, which ruled out any overarching effect of genetics and implied a key effect of personal experience on these trait perceptions.

This meant that who we individually trust is mostly a product of our individual life experience, rather than either nature or nurture.

However, the researchers said there can be extreme consequences of our impressions of trustworthiness.

These included decisions about financial lending and partner selection, and scientists said it is important to understand how they come about and what influences our perceptions of trust.

Dr Clare Sutherland, a psychology lecturer at Aberdeen, who led the research while at the University of Western Australia, said: “We think that as we go about our lives we learn who looks trustworthy to us based on specific social interactions we have with others.

“So, for example, if I experience particularly trustworthy interactions with people with green eyes, whereas you experience particularly trustworthy interactions with people with feminine features, then I might learn to specifically trust people with green eyes and you might learn to specifically trust feminine features. This finding is new. Most research on first impressions of trust focuses on what we have in common, not why we disagree.”

Dr Jemma Collova, a postdoctoral researcher who worked on the project at Western University, added: “Our study offers a new perspective on the origins of trust and on our capacity to change whom we trust, for good or for ill.

“As the information we access online becomes increasingly individual, especially in these strange times, our findings also suggest that disagreements about whom we trust are also likely to increase.”