Knowing who to trust is part and parcel of everyday life. Instinctively we may trust one person but not fully understand why. Researchers have puzzled over this question for decades, trying to piece together what makes a person trustworthy or not.
“Trustworthiness is essentially being a prosocial person,” says Sebastian Siuda, a psychologist who researches the dynamics of trust. “If somebody opens up to you and makes [themselves] vulnerable to you, you don’t use that act for your own good, but you repay that vulnerability.”
How Scientists Evaluate and Define Trustworthiness
To understand and attempt to gauge elements of trustworthiness, psychologists and researchers use economic games. Variations exist, but essentially, they involve one person who receives money with the opportunity to either pass it on to another person, or keep it.
Such studies have indicated that certain personality traits mean some people may trend towards trustworthiness. “What a few studies found was that people who are more agreeable tend to be a little bit more trustworthy,” Siuda says, adding that research indicates those who score higher on honesty-humility tests are similar.
Siuda and his team conducted a review of studies, published in the International Review of Social Psychology in 2022, that focused on trustworthiness detection – or how good people are at knowing who to trust. The researchers concluded that factors like prior interaction and face-to-face contact are important in evaluating others.
This holds true for trust in general, according to other psychologists. “Generally, trust decreases when the social distance between the trustor and the trustee increases," says Siuda. "People are more likely to trust others when they perceive them as familiar and socially similar.”
Predicting Symptoms of Trustworthiness
Research also suggests that a tendency to feel guilt may be one of the strongest predictors of trustworthiness. “People who are high in guilt-proneness are more likely to be trustworthy than are individuals who are low in guilt-proneness,” scientists wrote in a 2018 paper. In essence, those who fear feeling guilty in the future will try to avoid any action that causes this to occur.
But personality traits are likely only part of the question as each person’s own experiences, history, and social interactions also impact who we decide to trust. Such building blocks of each individual’s self – known as schemas – differ from person to person and are often developed during childhood.
Other researchers have explored trustworthiness based on split second judgements, whether someone appears trustworthy or not. One paper published in the journal Psychological Science suggests there is a tendency to deem others to be trustworthy when they appear similar to ourselves.
Similarly, in a 2008 study, a team from Princeton modeled trustworthy and untrustworthy faces; the results suggested that such judgements about a variety of features also play a role in our propensity to trust in another person. Whether they seem angry, threatening or otherwise can all play some part in how trustworthy we deem them. Other elements such as body language play a role, as well.
So What Makes a Person Trustworthy?
What makes a person trustworthy, then, is a complex and mixed bag. Some traits and indicators may make them slightly more trustworthy, but whether they appear so is also in the eye of the beholder, something which is likely based on our own experiences.
For Siuda, when it comes down to it in the real world outside of the lab, these split-second judgements are going to come into play.
“If you're in the driving seat, and you approach another person directly and you want to trust them, the probability is pretty high that the person is going to be trustworthy,” Siuda says. “But that doesn't mean that if you're just sitting there and somebody approaches you, that person is trustworthy, because you have the self-selection effect.”