Event-related potentials during encoding coincide with subsequent forced-choice mnemonic discrimination.

Computational models and eye-tracking research suggest that encoding variability accounts for the reduced recognition of targets (A) when paired with non-corresponding lures (B') relative to corresponding lures (A'). The current study examined whether neural activity during learning coincided with subsequent performance on the forced-choice Mnemonic Similarity Task (MST). Event-related potential responses were collected during encoding while young adults completed A-B' and A-A' trials of the forced-choice MST. Consistent with previous research, performance was lower on A-B' trials than A-A' trials. The subsequent memory effect was not significant for the A-A' test format. However, for A-B' trials, we observed a significant Accuracy × Stimulus interaction 1000-1200 ms poststimulus onset across frontal and fronto-central electrodes. As hypothesized, subsequently correct A-B' trials were associated with a larger amplitude response at encoding to the target (A) than the original version of the non-corresponding lure (B). However, subsequently incorrect trials were associated with a larger amplitude response to the non-corresponding lure (B) than the target stimulus (A). These findings provide additional support for the effect of encoding variability on mnemonic discrimination.