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A new study published in PNAS by University of Pittsburgh School of Medicine researchers describes how two personality traits, callousness and exploitativeness, are related to the way humans learn to cooperate in interpersonal relationships, and how this learning unfolds in the brain. The study represents an important step toward understanding whether differences in the way we learn from others impact the types of problems we have in relationships.

“The motivation for this work was the idea that getting along with others requires us to learn from them, and adjust our own behavior based on that experience. We wanted to understand how this learning happens in the brain and also how it relates to common interpersonal problems we see in clinic, like callousness, aggression, and exploitativeness,” said Timothy Allen, PhD (Assistant Professor of Psychiatry) lead author of the study.

To answer this question, Dr. Allen and his colleagues examined how people make decisions in a variant of a classic economic exchange paradigm known as the trust game, in which participants make a series of decisions with a social partner and have decide how to best split a monetary investment. While playing, participants underwent functional magnetic resonance imaging to record their neural activity. 

Dr. Allen and his colleagues found that during the game, players used the outcome of past interactions with their partner to dynamically adjust their strategy. Neural activity in the default network, a network of the brain that has greatly expanded as humans have become more social, was correlated with how well participants learned on the task. Intriguingly, more compassionate (i.e., less callous and aggressive) and exploitative participants both showed greater default network neural activity, and were more responsive to their co-player. 

“It is fascinating that exploitative people not only cooperate with others selectively when it is to their own advantage, but also display superior learning in the brain’s default network,” said senior author Alex Dombrovski, MD (Pittsburgh Foundation Professor of Brain and Mind Research and Professor of Psychiatry). 

Results from the study suggest that the default network plays a critical role in monitoring our social experience and helping us to adjust our strategy toward others. In some cases, this may help individuals to be more empathic or compassionate to others, but in other cases, it may enable exploitation. 

“The human transition to sociality, which involved the emergence of sophisticated social-cognitive abilities, seems to have given rise to both ‘light’ and ‘dark’ sides of human personality,” said Dr. Allen. “In other words, social learning in this context enables us to better connect with others, but also to be more successful in exploiting them.” 

In future work, Dr. Allen hopes to address the cognitive and neural dynamics that promote learning to empathize with others vs. learning to exploit them. He also plans to examine how the behavioral and neural markers identified in this study relate to daily and long-term interpersonal outcomes. 

Callousness, Exploitativeness, and Tracking of Cooperation Incentives in the Human Default Network
Allen TA, Hallquist MN, Dombrovski AY
Proceedings of the National Academy of Sciences Vol. 121, No. 29, July 16, 2024 PubMed: 38980906