Theory of mind broad and narrow: Reasoning about social exchange engages ToM areas, precautionary reasoning does not

Abstract

Baron-Cohen (1995) proposed that the theory of mind (ToM) inference system evolved to promote strategic social interaction. Social exchange—a form of co-operation for mutual benefit—involves strategic social interaction and requires ToM inferences about the contents of other individuals’ mental states, especially their desires, goals, and intentions. There are behavioral and neuropsychological dissociations between reasoning about social exchange and reasoning about equivalent problems tapping other, more general content domains. It has therefore been proposed that social exchange behavior is regulated by social contract algorithms: a domain-specific inference system that is functionally specialized for reasoning about social exchange. We report an fMRI study using the Wason selection task that provides further support for this hypothesis. Precautionary rules share so many properties with social exchange rules—they are conditional, deontic, and involve subjective utilities—that most reasoning theories claim they are processed by the same neurocomputational machinery. Nevertheless, neuroimaging shows that reasoning about social exchange activates brain areas not activated by reasoning about precautionary rules, and vice versa. As predicted, neural correlates of ToM (anterior and posterior temporal cortex) were activated when subjects interpreted social exchange rules, but not precautionary rules (where ToM inferences are unnecessary). We argue that the interaction between ToM and social contract algorithms can be reciprocal: social contract algorithms requires ToM inferences, but their functional logic also allows ToM inferences to be made. By considering interactions between ToM in the narrower sense (belief–desire reasoning) and all the social inference systems that create the logic of human social interaction—ones that enable as well as use inferences about the content of mental states—a broader conception of ToM may emerge: a computational model embodying a Theory of Human Nature (ToHN).

Acknowledgments

This research was supported by a grant from the UCSB/Dartmouth Brain Imaging Program and an NIH Director's Pioneer Award to Leda Cosmides.

We thank David Turk for indispensable technical assistance and Tammy Laroche and Amy Rosenblum for recruiting subjects and running the scanner. We thank Howard Waldow and Mike Gazzaniga for making this project possible.

Notes

¹We tried to avoid creating rules that can be interpreted as both a social contract and a precaution: e.g., drinkers would view “If you drink beer, you must be over 21 years old” as a social contract (it involves access to a benefit), whereas those making the rule view it as precautionary (drinking can lead to hazardous behavior); “If you play outside, you must wear your coat” is precautionary for the mother making the rule, but a social contract for the child who wants to play outside. To avoid such hybrid rules, we tried to make precautions in which the action in the antecedent was hazardous but not something people enjoy doing, and social contracts in which the consequent was not obviously precautionary.

²Excluding the single social contract outlier gives Mann − Whitney U=7, p=.007, consistent with the striking separation between problem sets one sees.