Problem: Being too trusting is often associated with a sort of naïveté or foolishness—if you really understood the way the world works, you’d be looking out for number one. You don’t want to get played, be a sucker, fall prey to schemes or betrayal. None of the “smart” reality TV show contestants are here to make friends, right? Or at least, you know, the wily ones.

Science says trust is good for you, though, and it’s good for society. Previous research has shown that “generalized trust”—that is trusting other members of society generally, rather than trusting your friends or family specifically—is linked to better self-reported health and happiness. And “countries whose citizens place greater trust in one another have more efficient public institutions and experience higher rates of economic growth.” So notes a recent study published in PLOS One, which adds to the literature on the topic by looking at how generalized trust is related to intelligence.

Methodology: Noah Carl and Francesco C. Billari of the University of Oxford analyzed data from the General Social Survey, a nationally representative U.S. public opinion survey administered every one to two years. Generalized trust was measured by the question, “Generally speaking, would you say that most people can be trusted or that you can’t be too careful in dealing with people?” To measure intelligence, they looked at participants’ scores on a 10-question vocabulary quiz (“Despite its brevity, the test has a correlation of 0.71 with…an IQ exam developed by the U.S. Military,” the study notes), as well as the interviewer’s assessments of how well participants understood the survey questions.

Results: Both vocabulary and question comprehension were positively correlated with generalized trust. Those with the highest vocab scores were 34 percent more likely to trust others than those with the lowest scores, and someone who had a good perceived understanding of the survey questions was 11 percent more likely to trust others than someone with a perceived poor understanding. The correlation stayed strong even when researchers controlled for socio-economic class.


This study, too, found a correlation between trust and self-reported health and happiness. The trusting were 6 percent more likely to say they were “very happy,” and 7 percent more likely to report good or excellent health.

Implications: “The finding that generalized trust is highly correlated with intelligence, even after conditioning on socio-economic characteristics such as marital status, education, and income, supports the hypothesis that being able to evaluate someone’s quality as a trading partner is a distinct component of human intelligence, which evolved through natural selection,” the study reads.

The researchers posit that intelligent people might be better at correctly evaluating whether people are trustworthy, or whether a particular person is likely to act untrustworthily in a particular situation.

But despite the temptation to be on guard with others, knowing the benefits trust could have for yourself and for the community, it does seem like a pretty smart choice.

The study, "Generalized Trust and Intelligence in the United States," appeared in PLOS One