Category prototypicality judgments in adults and children: Behavioral and electrophysiological correlates

Event‐related potentials (ERPs) and reaction time were used to examine the categorization of prototypical and non‐prototypical items. Adults and 6‐year‐old children were presented with pictures of prototypical and non‐prototypical dogs and cats and instructed to press a button for members of one of the categories. Behavioral data indicated that adults responded more rapidly than children and that both adults and children responded more rapidly to prototypes than to non‐prototypes. ERPs manifested a P300 and a N400 apparent at midline (Pz, Cz, and Fz) leads. For adults, P300 amplitudes were greater to target events than to non‐target events at Pz, whereas N400 amplitudes were greater to non‐target than to target events at all leads. For children, P300 peak amplitudes were greater to target than to non‐target events at Pz and Cz. Additionally, for children, N400 latency‐to‐peak amplitudes were shorter to target than to non‐target events. P300 peak amplitudes and latencies also distinguished between prototypical and non‐prototypical category items. For children, peak amplitudes were greater to prototypes than to non‐prototypes. For adults, latency‐to‐peak was shorter to prototypes than to non‐prototypes. These data underscore the importance of prototypicality in categorization and indicate age differences in the electrophysiological correlates of this process.