Brain potentials associated with perceptual priming vs explicit remembering during the repetition of visual word-form.

Priming of visual word-form was studied using a reading manipulation in which some words appeared in a backward format (e.g., d-r-o-w) instead of the usual forward format. In Experiment 1, subjects discriminated occasional targets (common first names) from other words with a speeded response. Reaction time was faster for words that had also appeared earlier in the forward format compared to the backward format. Event-related potentials (ERPs) recorded in response to word presentations showed a corresponding difference, a positive offset present during the time interval beginning about 300 ms after word onset from electrodes over occipital and parietal cortex. In Experiment 2, the task was changed to a recognition test, and a later and more widespread ERP response was observed, thus confirming the association between the ERP difference in Experiment 1 and priming rather than explicit remembering. ERP measures were presumably sensitive to neural events underlying the specific influence of recent reading experiences on the processing of visual word-form, thus providing real-time evidence on the neural mechanisms of priming.