Effects of emotion and semantic relatedness on recognition memory: Behavioral and electrophysiological evidence

Abstract

Some aspects of our memory are enhanced by emotion, whereas others can be unaffected or even hindered. Previous studies reported impaired associative memory of emotional content, an effect termed associative "emotional interference". The current study used EEG and an associative recognition paradigm to investigate the cognitive and neural mechanisms associated with this effect. In two experiments, participants studied negative and neutral stimulus-pairs that were either semantically related or unrelated. In Experiment 1 emotions were relevant to the encoding task (valence judgment) whereas in Experiment 2 emotions were irrelevant (familiarity judgment). In a subsequent associative recognition test, EEG was recorded while participants discriminated between intact, rearranged, and new pairs. An associative emotional interference effect was observed in both experiments, but was attenuated for semantically related pairs in Experiment 1, where valence was relevant to the task. Moreover, a modulation of an early associative memory ERP component (300-550 ms) occurred for negative pairs when valence was task-relevant (Experiment 1), but for semantically related pairs when valence was irrelevant (Experiment 2). A later ERP component (550-800 ms) showed a more general pattern, and was observed in all experimental conditions. These results suggest that both valence and semantic relations can act as an organizing principle that promotes associative binding. Their ability to contribute to successful retrieval depends on specific task demands.

Keywords: EEG; ERPs; associative recognition; emotion; familiarity; old-new ERP effect; recollection; semantic relatedness; unitization; valence.

FIGURE 1

Example stimuli and experimental paradigm. (a) Example stimuli for each condition. Our factorial design included four types of picture pairs, varying in their semantic relatedness (related, unrelated) and valence (negative, neutral). (b) Schematic illustration of the experimental paradigm. At study, participants viewed picture‐pairs and indicated which item is more negative (Experiment 1) or more familiar (Experiment 2). At test, they discriminated between intact, rearranged, and new pairs.

FIGURE 2

ERP results for Experiment 1. (a) Grand average ERP waveforms for intact responses (black), rearranged responses (red), and new responses (blue) in the four experimental conditions (related\unrelated × negative\neutral) at three scalp locations (F3, Fz, F4 collapsed as the frontal site; C3, Cz, C4 as the central site; P3, Pz, P4 as the parietal site). Shaded areas indicate time‐windows used for the analyses of the early memory effects (300–550 ms, light gray) and the late memory effects (550–800 ms, dark gray). (b) Topographical maps of the associative memory effects (intact minus rearranged) in each time window.

FIGURE 3

ERP results for Experiment 2. (a) Grand average ERP waveforms for intact responses (black), rearranged responses (red), and new responses (blue) in the four conditions at three scalp locations. Shaded areas indicate time‐windows used for the analysis of the early and late memory effects. (b) Topographical maps of the associative memory effects in each time window.