| It is known that individuals who rate high on the impulsivity personality characteristic commit more behavioral errors than those who rate low. It is important to treatment implications to understand the association between impulsivity and the efficiency of neural processes involved in error detection. It is unknown whether the level of awareness of having committed an error covaries with impulsivity. The amplitude of an event-related potential (ERP) called the error-related negativity (ERN) is an indicator of the neural involvement associated with error detection. Utilizing Gehring et al.'s (1993) model of the etiology of the ERN, it was predicted that the amplitude of the ERN would be related to that of the P300, an ERP that is an indicator of information processing, such that small P300s would be associated with small ERNs. ERNs and P300s were recorded from 20 subjects, who were divided into high and low impulsivity groups (HI group and LI group) by a median split of the total score of the Barratt Impulsivity Questionnaire (BIS-11). The task used to elicit the ERPs, the Eriksen Flanker Task, was administered under both moderate (400 ms response window) and severe (350 ms response window) TP conditions. It was hypothesized that the ERN recorded from the HI group would be smaller than that recorded from the LI group. Further, due to reports indicating that high impulsivity subjects possess an enhanced cognitive tempo, it was hypothesized that the amplitude difference between groups would be greater in the severe than the moderate TP condition, thus demonstrating that the HI group possess a sensitivity to enhanced TP.; In addition to committing more errors, the HI group exhibited a significantly smaller P300 than did the LI group. However, the amplitude of the ERN for both groups did not significantly differ. Rather, it was found that the HI group exhibited a significantly later ERN than did the LI group. Further, this latency difference, although present in both conditions, was greater in the severe condition. These results support the hypothesis that high impulsivity subjects have less efficient error detection processes that may be due to the presence of an enhanced cognitive tempo. |
