Electrophysiological evidence for task effects on semantic priming in auditory word processing.

Event-related brain potentials (ERPs) associated with semantic relatedness were recorded in two auditory word recognition tasks. In the Memorize task, subjects listened to a list of words in anticipation of a subsequent recognition test. In the Count Nonwords task, subjects silently counted the number of nonwords occurring within a list of words. Within each list, target words were either semantically related or unrelated to the immediately preceding word. As in comparable visual tasks, the amplitude of a negative ERP component (N400) was significantly attenuated when targets were preceded by semantically related primes. This attenuation was greater in the Memorize than in the Count Nonwords task. These data are consistent with the view that the sensitivity of N400 amplitude to semantic relatedness is modulated by task variables that manipulate depth of processing.