Time course of processes underlying picture and word evaluation: an event-related potential approach.

A substantial body of research suggests that the cognitive mechanisms for picture and word processes are functionally and anatomically distinct. In spite of significant advancements in the understanding of pictures and words, the electrophysiological activities mediating these processes are not well known. To address this issue, we examined event-related brain potentials (ERPs) to pictures and their printed names in a modified dual-target oddball task. ERPs were recorded while participants classified schematic pictures and their corresponding names into target and nontarget categories. Results showed that pictures and words were associated with electrophysiological responses that differed temporally and topographically. In comparison to words, P300s to pictures were characterized by shorter latency and larger amplitude at parietal electrodes. In contrast, words produced greater P200 amplitude at frontal areas. The results are consistent with the view that categorization of pictures is faster than words. Findings are discussed in relation to stimulus evaluation and the time course for picture and word classification.