EVENT-RELATED POTENTIAL CORRELATES OF CONTROLLED AND AUTOMATIC PROCESSING (P300, SLOW WAVE)

The neural processes underlying the selective apportionment of attentional resources to the environment have been studied extensively with Event-Related Potential (ERP) methodology. This has done little to improve the understanding of the psychological or physiological mechanisms, in part because the paradigms used to define cognitive processes are too narrow to encompass both instances of severe limitations and great efficiency evident in human information processing. Typically, the experimental paradigms are particularly weak in accounting for the role of learning in the development of highly facilitated processing.;The present study employs the paradigm described by Schneider and Shiffrin (1977) to contrast highly facillitated automatic processing with slower, more effortful controlled processing as they develop with practice. Concurrent with the visual presentation of task stimuli, ERPs were recorded at three points in training under conditions known to produce highly facilitated automatic processing or more inefficient controlled processing.;Contrary to expectations, there were no effects attributable to automaticity per se. Rather, changes to P2, the Late Positive Complex, and Slow Wave accompanied the performance of controlled processing. The early effects were interpreted in terms of the rehearsal strategies used in controlled processing. A Principal Components Analysis revealed that a Late Positive Component at about 630 ms was sensitive to the relevance of the stimulus and electrode site, while a longer latency positive Slow Wave at about 920 ms increased with practice in controlled processing but not automatic processing. These results were interpreted in terms of the effort directed at reducing uncertainty (equivocation) by subjects forced to employ controlled processing.