Date Published: March 11, 2014
Publisher: Public Library of Science
Author(s): Noah Carl, Francesco C. Billari, Jennifer Beam Dowd.
Generalized trust refers to trust in other members of society; it may be distinguished from particularized trust, which corresponds to trust in the family and close friends. An extensive empirical literature has established that generalized trust is an important aspect of civic culture. It has been linked to a variety of positive outcomes at the individual level, such as entrepreneurship, volunteering, self-rated health, and happiness. However, two recent studies have found that it is highly correlated with intelligence, which raises the possibility that the other relationships in which it has been implicated may be spurious. Here we replicate the association between intelligence and generalized trust in a large, nationally representative sample of U.S. adults. We also show that, after adjusting for intelligence, generalized trust continues to be strongly associated with both self-rated health and happiness. In the context of substantial variation across countries, these results bolster the view that generalized trust is a valuable social resource, not only for the individual but for the wider society as well.
The idea that trust in other members of society facilitates commerce and exchange goes back at least to Adam Smith , who noted that a merchant often prefers to trade within his own country because there “he can know better the character and situation of the persons whom he trusts.” Consistent with Smith’s intuition, an extensive empirical literature has established that generalized trust is an important aspect of civic culture–or social capital as it is also known –. Research has found, for example, that countries whose citizens place greater trust in one another have more efficient public institutions ,  and experience higher rates of economic growth , . In addition, research has found that individuals who place greater trust in their fellow citizens are more likely to start a business , perform voluntary work more often , report better physical health , and claim to be happier with their lives overall . The study of generalized trust therefore has profound implications for public policy, as well as being of inherent scientific interest .
Fig. 1 plots the relationship between generalized trust and verbal ability, conditional on socio-economic characteristics. The association between the two variables is strong and positive. An individual with the highest verbal ability is 34 percentage-points more likely to trust others than an individual with the lowest verbal ability. Fig. 2 plots the conditional relationship between generalized trust and question comprehension. Once again, the association is positive. An individual with a good understanding of the survey questions is 11 percentage-points more likely to trust others than an individual with a poor understanding of them. Both associations are robust to controlling for parents’ education, spouse’s education, and several indicators of socio-economic position at age 16 (Tables 2–3). Furthermore, the relationship holds among both men and women, among both blacks and whites, among the young, the middle-aged and the old, and in all five decades since the GSS began (Tables 4–11).
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 , . However, there are other possible explanations for the correlation, and further research is needed to gauge the relative importance of each one. The finding that generalized trust continues to be associated with self-rated health and happiness after adjusting for intelligence reinforces the view that generalized trust is a valuable social resource–one which governments, religious groups and civic organisations should strive to cultivate . Future research should focus on delineating the precise mechanisms by which generalised trust enhances people’s health and well-being.