frankie's via Shutterstock

Why do we trust, or not trust, strangers? The answer is based on those we've previously known

Research has revealed that strangers resembling past individuals known to be trustworthy are trusted more.

OUR TRUST IN strangers is dependent on their resemblance to others we’ve previously known, a new study has found.

The study has revealed that strangers resembling past individuals known to be trustworthy are trusted more, and by contrast, those similar to others known to be untrustworthy are trusted less.

“Our study reveals that strangers are disturbed even when they only minimally resemble someone previously associated with immoral behaviour,” lead author Oriel FeldmanHall, of New York University, said.

Senior author Elizabeth Phelps said: “We make decisions about a stranger’s reputation without any direct or explicit information about them based on their similarity to others we’ve encountered, even when we’re unaware of this resemblance.”

This shows our brains deploy a learning mechanism in which moral information encoded from past experiences guides future choices, according to Phelps.

Research method

Scientists have a decent grasp on how social decision-making unfolds in repeated one-on-one interactions. Less clear, however, is how our brain functions in making these same decisions when interacting with strangers.

To solve this, the researchers conducted a series of experiments centring around a trust game in which participants make a series of decisions about their partners’ trustworthiness – for example, deciding whether to entrust their money with three different players who were represented by facial images.

Here, the subjects knew that any money they invested would be multiplied four times and that the other player could them either share the money back with the subject (reciprocate) or keep the money for themselves (defect).

Each player was found to be highly trustworthy (reciprocated 93% of the time), somewhat trustworthy (reciprocated 60% of the time), or not at all trustworthy (reciprocated 7% of the time).

In a second task, the same subjects were asked to pick new partners for a new game. However, unbeknownst to the subjects, the face of each new partner was morphed, to varying degrees, with one of the three original players so the new partners bore some physical resemblance to the previous ones.

Although the subjects were not consciously aware that the strangers (ie. the new partners) resembled those they previously encountered, subjects consistently preferred to play with strangers who resembled the original player they previously learned was trustworthy and avoided playing with strangers resembling the earlier untrustworthy player.

In a striking result, trust steadily increased the more the stranger looked like the trustworthy partner from the previous experiment and steadily decreased the more the stranger looked like the untrustworthy one.

The findings point to the highly adaptive nature of the brain as it shows we make moral assessments of strangers drawn from previous learning experiences.

The research was published in the latest issue of the Proceedings of the National Academy of Sciences journal.

Read: Number of elderly people with four or more diseases to double by 2035

More: Researchers say new blood test for cancer could catch disease before it spreads

Your Voice
Readers Comments
This is YOUR comments community. Stay civil, stay constructive, stay on topic. Please familiarise yourself with our comments policy here before taking part.
Leave a Comment
    Submit a report
    Please help us understand how this comment violates our community guidelines.
    Thank you for the feedback
    Your feedback has been sent to our team for review.

    Leave a commentcancel