Emotion Based Attentional Priority for Storage in Visual Short-Term Memory

Luca Simione,Frances A Maratos,Marta Olivetti Belardinelli,Antonino Raffone,Lucia Calabrese,Francesco S Marucci,Silvana Allodi

doi:10.1371/journal.pone.0095261

Abstract

A plethora of research demonstrates that the processing of emotional faces is prioritised over non-emotive stimuli when cognitive resources are limited (this is known as ‘emotional superiority’). However, there is debate as to whether competition for processing resources results in emotional superiority per se, or more specifically, threat superiority. Therefore, to investigate prioritisation of emotional stimuli for storage in visual short-term memory (VSTM), we devised an original VSTM report procedure using schematic (angry, happy, neutral) faces in which processing competition was manipulated. In Experiment 1, display exposure time was manipulated to create competition between stimuli. Participants (n = 20) had to recall a probed stimulus from a set size of four under high (150 ms array exposure duration) and low (400 ms array exposure duration) perceptual processing competition. For the high competition condition (i.e. 150 ms exposure), results revealed an emotional superiority effect per se. In Experiment 2 (n = 20), we increased competition by manipulating set size (three versus five stimuli), whilst maintaining a constrained array exposure duration of 150 ms. Here, for the five-stimulus set size (i.e. maximal competition) only threat superiority emerged. These findings demonstrate attentional prioritisation for storage in VSTM for emotional faces. We argue that task demands modulated the availability of processing resources and consequently the relative magnitude of the emotional/threat superiority effect, with only threatening stimuli prioritised for storage in VSTM under more demanding processing conditions. Our results are discussed in light of models and theories of visual selection, and not only combine the two strands of research (i.e. visual selection and emotion), but highlight a critical factor in the processing of emotional stimuli is availability of processing resources, which is further constrained by task demands.

Highlights

An extensive body of literature suggests that emotional stimuli are more effective in their capture of attention than non-emotive stimuli [1]
Consistent with this, we found: i) an overall selection and encoding superiority effect for the emotional compared with neutral faces; and ii) greater storage of the threatening and happy, compared with neutral, schematic faces at the short exposure time
To expand, when increasing task demands by decreasing exposure time from 400 to 150 ms, our planned comparisons revealed that both the angry and happy faces were prioritised for storage

Summary

Introduction

An extensive body of literature suggests that emotional stimuli are more effective in their capture of attention than non-emotive stimuli [1]. Data from behavioural paradigms utilizing visual search, visual probe and rapid serial visual presentation (RSVP) reliably demonstrate that when there is competition for cognitive resources, emotional information, and especially that which is threatening, is typically processed more quickly and with greater accuracy than non-emotive stimuli. This is evidenced by reduced reaction times and increased accuracy of responses to such stimuli compared with non-emotive stimuli across paradigms (see [2] for a review), and suggests that emotional stimuli receive prioritised processing. Shapiro, Caldwell & Sorensen [6] found that the AB was abolished when the second target stimulus in an RSVP stream was the participant’s own name

Methods

Results

Conclusion