Episodic memory encoding and distinctiveness detection
were examined using event-related potentials (ERP) in a
single-trial word list learning paradigm with free recall
following distraction. To manipulate distinctiveness, encoding
of high- and very low-frequency words was contrasted. Amplitudes
of the N400 and late positive component (LPC) were larger
for low- than for high-frequency words, and ERPs were more
positive for subsequently recalled than not recalled words.
This subsequent memory effect was dissociated from the
correlates of distinctiveness by polarity for the N400
and by time course for the LPC and dissociable into two
effects. The data suggest that the first subsequent memory
effect, which occurred for both word categories, is more
directly related to episodic memory formation, whereas
the second effect, which occurred for high-frequency words
only, is related to processes influencing episodic encoding
success indirectly.
