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Processing affective images in the absence of visual awareness

Processing affective images in the absence of visual awareness
Processing affective images in the absence of visual awareness
Given capacity limits, the visual system must prioritize the processing of sensory inputs that are most critical to successful interactions with the environment. Neurocognitive theories suggest that humans have evolved mechanisms that operate without awareness that selectively prioritize threatening stimuli in subsequent allocation of processing resources and access to awareness. Evidence for this ‘standard hypothesis’comes from paradigms that dissociate visual input from awareness. This thesis combines a narrative review, a meta-analytic review and three empirical studies to examine the extent to which emotionally salient stimuli are prioritized in the absence of awareness.

A general introduction and review of the literature is provided in Chapter 1. The meta analysis of previous literature (Chapter 2) reveals that evidence for an unconscious processing bias for threat isundermined by insufficiently rigorous awareness measures and inadequate control of low-level confounds. Chapter 3 reveals that autonomic arousal and attentional orienting to visual threats are eliminated under conditions where observers are objectively unaware of stimuli. Chapter 4 reveals that prioritized processing of fearful faces is parsimoniously explained by effective contrast: the relationship betweentheir Fourier spectrum and the contrast sensitivity function. Importantly, this explanation does not require or involve unconscious processing mechanisms that are sensitive to threat. Chapter 5 reveals that prioritized processing of emotional face stimuli is restricted to conditions of awareness, and may be parsimoniously explained by simple low-level variability between emotional and neutral face stimuli.

Previous and present findings and analyses are considered together in the discussion (Chapter 6). It is concluded that evidence for emotion-sensitive visual processing that operates without awareness is weak and that uncritical acceptance of the standard hypothesis is premature.
Hedger, Nicholas
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Hedger, Nicholas
ad57df70-75e3-43f3-a56e-d7416e06f334
Adams, Wendy
25685aaa-fc54-4d25-8d65-f35f4c5ab688
Garner, Matthew
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Graf, Erich
1a5123e2-8f05-4084-a6e6-837dcfc66209
Gray, Katie
ac1f9467-033b-4423-91a0-414f3e06a593

(2016) Processing affective images in the absence of visual awareness. University of Southampton, School of Psychology, Doctoral Thesis, 232pp.

Record type: Thesis (Doctoral)

Abstract

Given capacity limits, the visual system must prioritize the processing of sensory inputs that are most critical to successful interactions with the environment. Neurocognitive theories suggest that humans have evolved mechanisms that operate without awareness that selectively prioritize threatening stimuli in subsequent allocation of processing resources and access to awareness. Evidence for this ‘standard hypothesis’comes from paradigms that dissociate visual input from awareness. This thesis combines a narrative review, a meta-analytic review and three empirical studies to examine the extent to which emotionally salient stimuli are prioritized in the absence of awareness.

A general introduction and review of the literature is provided in Chapter 1. The meta analysis of previous literature (Chapter 2) reveals that evidence for an unconscious processing bias for threat isundermined by insufficiently rigorous awareness measures and inadequate control of low-level confounds. Chapter 3 reveals that autonomic arousal and attentional orienting to visual threats are eliminated under conditions where observers are objectively unaware of stimuli. Chapter 4 reveals that prioritized processing of fearful faces is parsimoniously explained by effective contrast: the relationship betweentheir Fourier spectrum and the contrast sensitivity function. Importantly, this explanation does not require or involve unconscious processing mechanisms that are sensitive to threat. Chapter 5 reveals that prioritized processing of emotional face stimuli is restricted to conditions of awareness, and may be parsimoniously explained by simple low-level variability between emotional and neutral face stimuli.

Previous and present findings and analyses are considered together in the discussion (Chapter 6). It is concluded that evidence for emotion-sensitive visual processing that operates without awareness is weak and that uncritical acceptance of the standard hypothesis is premature.

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Nicholas Hedger Final THESIS.pdf - Other
Available under License University of Southampton Thesis Licence.
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More information

Published date: July 2016
Organisations: University of Southampton, Psychology

Identifiers

Local EPrints ID: 402691
URI: http://eprints.soton.ac.uk/id/eprint/402691
PURE UUID: f46404ed-2365-462b-9417-0fd24da64d21
ORCID for Wendy Adams: ORCID iD orcid.org/0000-0002-5832-1056
ORCID for Erich Graf: ORCID iD orcid.org/0000-0002-3162-4233

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Date deposited: 05 Dec 2016 10:06
Last modified: 06 Jun 2018 12:44

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