Social dysdecorum following severe traumatic brain injury: loss of implicit social knowledge or loss of control?

The purpose of the present study was to investigate two theoretical frameworks for understanding acquired deficits in social behavior in individuals with severe traumatic brain injury (TBI). Recent research has found that brain injury can lead to impairments in implicit processes including social cognition. Impairments in implicit social cognition have been recently advanced as an explanation for acquired social deficits, as implicit social cognition is hypothesized to mediate the processing and understanding of often subtle, nonverbal cues in social interactions. In contrast, the executive dysfunction account posits that deficits in higher order cognitive functions, such as attention, planning ability, and mental flexibility, are the locus for acquired deficits in social cognition and behavior. To test these two theories, 22 participants with severe TBI and 25 matched controls were administered a measure of implicit social cognition (Implicit Association Test, IAT), as well as two measure of explicit social attitudes and a range of executive functioning measures. The TBI participants were found to perform normally on the IAT and explicit measures of gender stereotyping but demonstrated executive deficits. Performance on the IAT and executive functions were correlated. Performance in general did not fit well with the implicit social cognition explanation for social dysdecorum following TBI. More evidence was found to support the executive account.