Abstract: The relationship between memory encoding and stimulus distinctiveness detection was examined by means of event-related potentials (ERP) in a single-trial word list learning paradigm with recognition following distraction. To manipulate primary and secondary distinctiveness, encoding of deep vs. shallow processing was contrasted, and encoding of high vs. low frequency words was contrasted. The major results were: (1) According to behavioral results, low-frequency words had more accurate recognition than high-frequency ones; deep processing had more accurate recognition than shallow processing; and there was a significant main effect of word frequency in deep processing whereas no significant difference in shallow processing. (2) Amplitudes of late positive component (LPC) were larger for low- than for high-frequency words; for low-frequency words, ERPs were more positive for the subsequently recognized than for the unrecognized words. Therefore, encoding success was dependent on indirect processing and word frequency.

Key words: event-related potentials, distinctiveness, encoding, Dm effect, word frequency