Electrocortical Signs of Levels of Processing: Perceptual Analysis and Recognition Memory

Abstract
The electrocortical manifestations of levels of perceptual processing and memory performance were investigated by recording event related potentials (ERPs) during a verbal comparison task and a subsequent test of recognition memory. Two words were judged, on each trial, to be the same or different according to an orthographic, phonemic, or semantic criterion. Orthographic processing of words led to poor performance on a test of recognition memory whereas phonemic and semantic processing led to increasingly better performance. “Same” judgments led to better memory performance for phonemically and semantically processed items. The ERP waveforms included a late positive component (LPC) and a slow wave, both of which were responsive to the comparison criterion and the type of judgment. Further, the LPC appeared to index recognition accuracy in the memory test. The ERP data are interpreted as reflecting associative activation in the human memory system.