We don’t trust extraverts more than introverts

When you think of an extravert, what personality traits come to mind? Sociability? Fun? While we often make positive judgments about extraversion, the picture is more complex, with negative traits also projected onto extraverts. Some research suggests that extraverts are seen as poorer listeners, for example.

A new study, published in Personality and Social Psychology Bulletin, looks specifically at how much people trust those who are extraverted. The team finds that agreeableness, not extraversion, is the key to gaining trust in social situations.

In the first study, participants were told they would be matched with another participant (who in reality did not exist) to play a trust game, in which decisions they made would affect both their payoffs and the payoffs of the other participant. All participants were given the role of the "trustor", while their apparent partner played the "trustee". They started with £1. If they chose to keep the money, this did not increase, but if they transferred it to their partner it was tripled. The partner could then choose how much of the £3 to transfer back to the participant.

After being given the £1, participants were told that their partner was either agreeable or disagreeable, and extraverted or introverted. They were then asked to indicate whether they would transfer the money or not.

The results showed that participants were more likely to trust agreeable than disagreeable partners: participants were four times more likely to transfer the £1 to agreeable trustees than disagreeable ones. Extraversion, however, was not significantly related to trust. This finding was replicated in a second study.

A third study found that even without explicitly knowing a person's personality, it still seems to affect our judgement of their trustworthiness. Participants first rated their own personalities. Then, 1 to 2 weeks later, they completed an in-person lab session in groups  of three to six people, most of whom did not know each other. Participants were told they would solve tasks as a group: three riddles, and two "unusual uses" tasks, which involve thinking of as many uses as possible for an object. They then took part in a similar trust game to the first studies.

Results again showed that people who had rated themselves as higher in agreeableness were more likely to be trusted by the other members of their group. No other Big Five trait, including extraversion, was related to trust. So it seemed that participants made judgements of others' personalities based on their behaviour, and trusted those who they judged as agreeable.         

In the final study, the team found that we seem to instinctively know that agreeable people are more likely to be trusted. Participants were told they would interact with another participant and were given details of the trust game. However, this time, they were all assigned as the trustee, not the trustor. They then rated themselves on extraversion and agreeableness. In one condition, participants were told their answers would be shown to their partner; in another, they were told the answers would remain private and they should answer as accurately as possible.

Participants in the public condition reported being more agreeable than those in the private condition: in other words, they presented themselves as more agreeable when they thought someone was judging them on how trustworthy they were. This was not the case with extraversion, however: participants did not report being more extraverted in the public condition compared to the private one.

Overall, the results from the four studies suggest that we don't place any more trust in people with higher levels of extraversion. Agreeableness, however, is a trait that not only seems to facilitate trust but that we also want to emphasise when we ourselves want to be trusted.

Future research could explore exactly what it is about agreeableness that makes us trust people who embody it: non-verbal behaviour such as smiles or body language, types of verbal expression, or particular traits such as honesty or altruism.

Further reading

– The Effects of Partner Extraversion and Agreeableness on Trust

About the author

Emily Reynolds is a staff writer at BPS Research Digest