The P300 (P3) is an endogenous event-related potential (ERP) that occurs between 300 and 400ms post-stimulus and has traditionally been associated with the detection of stimulus novelty. Research by Barcelo, Perianex and Knight (2002), through experimentation using the Wisconsin card sorting test (WCST; Heaton, Chelune, et al., 1993), has provided evidence to suggest that the P3a may provide a general measure of cognitive flexibility in both stimulus and task novelty. The WCST is a test of prefrontal function where a card is presented and the participant is required to match it to one of four key cards according to a previously specified stimulus dimension (either colour, shape, or number of items in the card). The dimension on which the cards are to be matched (the task rule) is systematically varied, and the ability of the participant to successfully adjust to the changes in task rules provides a measure of cognitive flexibility, presumed to be controlled by the prefrontal cortex. Barcelo et al. (2002) found frontally distributed P3a activity to be elicited by feedback cues signalling a change in task rules. In contrast, feedback cues signalling that the task rules were to remain the same elicited a comparatively sharp reduction in P3a amplitude. These results suggested that the P3a reflected the switching of task sets in working memory. The ability to switch task sets in problem solving has been implicated by Russ (1993) as an important aspect of creativity.
The P300 is a measure that can also be used to gauge the use of working memory (WM) during the completion of a task (Donchin & Coles, 1988). Lavric, Forstmeier and Rippon (2000), analysed differences in P300 amplitude between analytical and creative tasks, in order to determine whether there were differences in the use of WM between these tasks. The analytical task was a well-defined deductive reasoning task while the creative task involved the novel use of information in order to arrive at a successful solution. In order to gauge the use of WM during the completion of the tasks, a concurrent WM task (CWMT) was administered in addition to the analytical or creative task. The CWMT consisted of counting auditory stimuli presented at pseudorandom intervals. P3a amplitudes were found to be higher in the frontal region in response to counting tones during analytical problem solving as compared to creative problem solving. Further, the later P3b amplitudes were found to be higher across all regions with a left laterality in frontal, central-parietal and temporal regions in analytical compared to creative problem solving. In relation to the higher frontal amplitudes observed in the P3a during the analytical task, Lavric et al. (2000) suggested that this was due to a stronger involvement of WM in this task in comparison to the creative task (i.e. greater competition for attentional resources between the analytical task and the CWMT). These findings suggest that working memory is not as crucial to creative problem solving as to the successful solution of analytical tasks.
Future research concerning differences in P300 amplitudes between individuals rated high on creativity compared to those rated low on creativity could be used to identify stable individual differences in brain function (if any) between these individuals. An intriguing aspect to the literature on P300 is that a growing body of evidence from pharmacological studies now implicate neurotransmitter systems in the modulation of P300 amplitude. Two neurotransmitters that have been found to modulate the expression of the P300 are dopamine (Klorman & Brumaghim, 1991; Callaway, 1991; Hansenne et al., 1995) and serotonin (Hansenne, Pitchot, Papart, & Ansseau, 1998). It is possible that differences in the amplitude of the P300 in creative problem solving may in part reflect a different mode of operation in the brain as compared to analytical problem solving, mediated by different patterns of dopaminergic and serotonergic transmission. However, caution is needed in interpreting the meaning of increased P300 amplitudes as the P300 has also been found to be sensitive to motivation and vigilance factors (Johnson, 1993; Hansenne, 1999).
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