Automatic activation of positive but not negative attitudes after traumatic brain injury

This study investigated social judgment problems of an individual (AM) with bilateral frontal and temporal lobe damage including damage to the amygdal a. We hypothesized that AM could automatically process positive, but not ne gative evaluative information and could process both types of evaluative in formation using controlled processing. In Phase 1 of Experiment 1 AM and co ntrols were shown a series of words one at a time and were required to make good/bad judgments as quickly as possible. Results showed that AM was more likely than controls to rate words as good, and was significantly slower t o make good/bad judgments of negatively, but not positively, evaluated word s. In Phase 2 AM was shown a prime (positive or negative) then target (posi tive or negative) and instructed to evaluate whether the target word was go od or bad. Results showed that AM responded more quickly when prime and tar get were both positive: but not when prime and target were both negative, w hereas controls showed both types of priming. Experiment 2 determined wheth er AM's impaired processing of negative evaluative information could be abo lished under controlled processing. AM was explicitly instructed to generat e positive and negative connotations of a series of single words and given essentially unlimited time. Under these conditions, AM and controls did not differ significantly in their ability to generate positive versus negative connotations of words. In Experiment 3 AM and controls both showed normal semantic priming effects. The results are interpreted within the component process model of memory. (C) 2000 Elsevier Science Ltd. All rights reserved .