Local context influences memory for emotional stimuli but not electrophysiological markers of emotion-dependent attention.

Gemma E Barnacle,Alexandre Schaefer,Deborah Talmi,Dimitris Tsivilis

doi:10.1111/psyp.13014

Abstract

Emotional enhancement of free recall can be context dependent. It is readily observed when emotional and neutral scenes are encoded and recalled together in a “mixed” list, but diminishes when these scenes are encoded separately in “pure” lists. We examined the hypothesis that this effect is due to differences in allocation of attention to neutral stimuli according to whether they are presented in mixed or pure lists, especially when encoding is intentional. Using picture stimuli that were controlled for semantic relatedness, our results contradicted this hypothesis. The amplitude of well‐known electrophysiological markers of emotion‐related attention—the early posterior negativity (EPN), the late positive potential (LPP), and the slow wave (SW)—was higher for emotional stimuli. Crucially, the emotional modulation of these ERPs was insensitive to list context, observed equally in pure and mixed lists. Although list context did not modulate neural markers of emotion‐related attention, list context did modulate the effect of emotion on free recall. The apparent decoupling of the emotional effects on attention and memory, challenges existing hypotheses accounting for the emotional enhancement of memory. We close by discussing whether findings are more compatible with an alternative hypothesis, where the magnitude of emotional memory enhancement is, at least in part, a consequence of retrieval dynamics.

Highlights

This study tested the hypothesis that the effect of list context on behavioral emotional memory performance is caused by an enhancement of selective attention toward emotional stimuli only in mixed lists but not in pure lists
In contradiction with our hypothesis, whereas list context modulated the effects of emotion on behavioral memory performance, it did not modulate the effects of emotion on neural indicators of emotion-related attention at encoding
These results refute both the suggestion that attention is no longer preferentially allocated to emotional stimuli in pure lists, and the suggestion that attention to neutral stimuli in mixed lists is severely depleted compared to attention to the same pictures in pure lists

Summary

| INTRODUCTION

Thought to be adaptive, it is intriguing to observe that it can be context dependent. The dependence that Pastor et al (2008) observed did not comply with the logic of the hypothesis we propose to test here, that the emotional modulation of the relevant ERPs would be reduced in pure lists compared to mixed lists These studies used orienting tasks, such as passive viewing or emotionality ratings, which do not give participants reasons to pay special attention to neutral stimuli. We hypothesized, based on the previous work, that the emotional modulation of the LPP and the SW, which are thought to reflect the enhanced visual processing and sustained attention to emotional stimuli, would be heightened in mixed compared to pure lists, and perhaps even absent in pure lists, in close parallel with the free recall findings

| Participants

| Procedure

| RESULTS

| DISCUSSION

Findings

| Limitations