Acquired theory of mind impairments in individuals with bilateral amygdala lesions.

Studies in humans suggest that the amygdala plays a role in processing social information. A key component of social information processing is what developmental psychologists call "theory of mind": the ability to infer others' mental states. Recent studies have raised the possibility that the amygdala is involved in theory of mind, showing amygdala activation during a theory of mind task, or showing impairment on theory of mind tasks in a patient with amygdala damage acquired in childhood. Here, we present the first evidence of theory of mind deficits following amygdala damage acquired in adulthood. Two participants, D.R. and S.E., with acquired bilateral amygdala damage showed difficulties with two theory of mind tasks, "Recognition of Faux Pas" (for D.R., z=-5.17; for S.E., z=-1.83) and "Reading the Mind in the Eyes" (for S.E., z=-1.91; for D.R., z=-1.4). The items on which D.R. and S.E. made errors on these tasks were uncorrelated with the items that control participants found most difficult, indicating that these deficits cannot be attributed solely to the cognitive difficulty of the tasks. These results indicate that the amygdala's critical role in theory of mind may not be just in development, but also in "on-line" theory of mind processing in the adult brain.