Psychophysiological correlates of levels and stages of cognitive processing

The psychophysiological manifestations of levels of cognitive processing were investigated. Words were processed at three cognitive levels (phonetic, low semantic, high semantic), and physiological recordings were made during cue, covert processing and verbalization stages. Differentiation of physiological reactivity across processing levels depending on stage of processing was found, with greater activation and incidental recall for the more complex semantic tasks. Heart rate and skin conductance showed greatest increases on trials that were later recalled. Results were interpreted as demonstrating a differentiation of the arousal of task expectancy from cognitive effort associated with processing level.