The neural and behavioral correlates of target checking in prospective memory

Prospective memory represents the realization of a delayed intention at the appropriate time or in the appropriate environmental context. Strategic monitoring of the environment is one process believed to be important for successful prospective remembering. Guynn (2003) posited that strategic monitoring is comprised of retrieval mode and target checking. Ample evidence has supported the existence of retrieval mode but less is known about the nature of target checking. Using event related potentials (ERPs), this dissertation examined the neural correlates of target checking in a lexical decision task. Experiment 1 was designed to elucidate the physiological correlates of target checking. The physiological data revealed two ERP components that were associated with target checking: the posterior negativity (300-400ms) and the late positive component (600-1000ms). Both components were present during word and nonword trials, but there were differences in how participants engaged the neural processes associated with the posterior negativity and late positive component for the stimulus types. In Experiment 2, the late positive component was hypothesized to be associated with retrieval processes and this hypothesis was examined by varying the number of prospective memory cues. In Experiment 3, the posterior negativity was hypothesized to reflect neural processes associated with the underlying representation of a stimulus so the wordiness of the nonword stimuli was varied to create stimuli that could activate a lexical but not semantic representation. Based on the findings of the three experiments reported herein, target checking appears to involve an early process involving the representation of a stimulus and a late process involving retrieval of representations from memory.