Social cognition after head injury: sarcasm and theory of mind.

Closed head injury (CHI) is associated with communication difficulties in everyday social interactions. Previous work has reported impaired comprehension of sarcasm, using sarcastic remarks where the intended meaning is the opposite of the sincere or literal meaning. Participants with CHI in the present study were assessed using two types of sarcastic items, those with a directly opposite meaning and those with an indirect, non-literal but not directly opposite meaning. The CHI group was differentially poorer at comprehending sarcastic versus sincere remarks, although type of sarcastic materials did not influence performance. Errors involved not only literal interpretations, but also incorrect non-literal interpretations. Theory of mind (mentalising) was also assessed by comparing comprehension of human actions with control physical events. The CHI group was selectively impaired on the mentalising component of this task, and mentalising scores correlated with sarcasm comprehension. The implications of the findings for our understanding of impaired sarcastic comprehension after acquired brain injury are discussed.