Diamonds are said to be a girl’s best friend, but a new study suggests that the people who can afford diamonds may have trouble making friends in the first place. In the December issue of Proceedings of the Royal Society B, psychologists at the University of Waterloo write that being of a higher social class is linked to a lower ability to deal with interpersonal conflicts. While wealthier people may have the educational benefits that come with cash, this study suggests that they are more likely to lack the wisdom it takes to make smart decisions about relationships.

The paper contradicts “a long line of research suggesting that higher social class is aligned with superior cognition,” the researchers point out, noting that, while previous research linking intelligence and social class focused on data from IQ tests, they focused on the wisdom-related pragmatic reasoning of their participants. This sort of wisdom includes a person’s capacity to recognize that the world is in flux and constantly changing, the ability to take different perspectives into account besides one’s own, and level of intellectual humility.

The psychologists write:

“While higher-class individuals may enjoy the cognitive benefits of status (e.g. environments that foster development in such areas as fluid cognition), those same environments may constrain their ability or motivation to reason wisely (e.g. acknowledge change, uncertainty, and the limits of their knowledge). Conversely, limited resources and other threats associated with lower class environments may promote wise reasoning about interpersonal affairs, enabling greater vigilance and management of uncertainty associated with such environments.”

Psychologists found that higher social status is connected with limited wisdom on interpersonal relationships.

To come to this conclusion, psychologists Justin Brienza, Ph.D., and Igor Grossman, Ph.D., evaluated the results of two studies. In the first study, 2,145 people from different socio-economic backgrounds recruited through Amazon’s Mechanical Turk program were asked to recall recent conflicts they had with a friend or in the workplace, then judge whether or not they engaged in one of the five aspects of what the authors describe as the “wise reasoning style.” For example, if a study participant said that they recognized where the other person was coming from ad looked for a compromise, then they were deemed to have acted wisely.

In the second study, Brienza and Grossman evaluated the responses of 299 people from Michigan who either came from working or middle-class backgrounds. These people were asked to go over the problems described in “Dear Abby” letters and asked what how they thought the situation developed after the letter was sent, why that happened, and what they think the people looking for advice should do. Those responses were then evaluated for whether or not they displayed wise reasoning and matched to the participant’s socio-demographic information.

Across both studies, people from higher classes were consistently evaluated as being worse at wisdom reasoning than people from the working class. Grossman told Time in an article on Tuesday that this lessened ability likely stems from “social structure and lack of social mobility” rather than “their ability to reason about interpersonal affairs.” Rich people surrounded by rich people aren’t often in a position where their success hinges on collaborating and cooperating — meaning that when conflict enters a relationship, they are more likely to misstep when searching for a resolution.