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

Abstract

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.