ARTICLE UPDATE - How emotional arousal and valence influence access to awareness.

Sheth BR, Pham T.

Vision Research, in press


Volume 8, Number 6, Abstract 248, Page 248a doi:10.1167/8.6.248 http://journalofvision.org/8/6/248/ ISSN 1534-7362
How emotional arousal and affect influence access to visual awareness
Bruno Breitmeyer

Department of Psychology, University of Houston, and Center for NeuroEngineering and Cognitive Science, University of Houston

[e-mail]
Thuan Pham

University of Houston

Bhavin Sheth

Department of Electrical and Computer Engineering, University of Houston, and Center for NeuroEngineering and Cognitive Science, University of Houston

Abstract

Emotional stimuli attract attention and potentiate the effect of attention on contrast sensitivity, a feature of early vision. The amygdala, a key structure in emotional processing, responds to emotional content prior to awareness and projects to visual cortex. In light of evidence that the primary visual cortex does not have direct access to awareness, we hypothesize that emotion can affect the processing of a visual stimulus even before awareness. Moreover, emotion varies along at least two dimensions: arousal and affect (valence). Dissociating their effects is important to understanding the link between emotion and perception. We examined these effects in binocular rivalry. Pairs of images (54 total) were selected from a known database of natural images (IAPS). Pictures of a pair differed significantly along only one emotional dimension, creating two types – iso-valence and iso-arousal pairs. Pictures of a given pair were presented side by side in a rivalry setup for trials lasting 1 min. each. The duration for which each eye's image was dominant in a trial (dominant phase duration) was obtained from 12 observers. Our results showed: –A main effect of arousal: The dominant phase durations for more arousing pictures of the iso-valence pairs were significantly longer than those for the less arousing pictures. –No main effect of affect: The dominant phase durations of pleasant and unpleasant pictures of iso-arousal pairs did not differ significantly. –An interaction between arousal and affect: For low arousal-level stimuli, the more pleasant image of the pair dominated significantly. In contrast, for high arousal-level stimuli, the more unpleasant image dominated significantly. Our findings suggest that the limbic system acts on visual signals early in processing. While emotional arousal and valence interactively affect access to visual awareness, only arousal exerts an independent control of such access.