The effects of multiple forms of disgust exposure on the processing of emotional photographic images

• Main Author: Hartigan, Alex
• Published: Birkbeck (University of London) 2017
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.731795

Exposure to disgust has been found to influence both short term attentional processes and decision making. This thesis proposed to investigate the extent to which disgust exposure can also influence emotion processing and evaluation – specifically of real world photographic images. To this end, both behavioural and event related potential (ERP) paradigms were utilised. Disgust was induced in multiple ways – through videos, written scenarios and briefly presented prime images. After exposure to disgusting prime images, participants high in disgust propensity were quicker to respond to disgust targets (a congruence effect that was not obtained for fear targets preceded by fear primes). After reading disgusting sentences, participants who were high in disgust propensity were more likely to judge pleasant food images (as well as disgusting images) as unpleasant (but not other pleasant images) thus reconfirming the relationship between disgust and digestion. ERP data revealed that individuals high in attentional shifting ability had a suppressed Late Positive Potential (LPP) to both disgusting and threatening images but that this effect was washed out through reading disgusting scenarios. After exposure to disgusting videos, attentional focus was associated with an increased LPP response to disgust (but not fear) images. There was a strong occipital LPP enhancement for disgust (over both fear and neutral) that was independent of disgust exposure and could represent an electrophysiological marker of disgust processing. The results demonstrate that both the processing of disgusting images, as well as the processing of emotional images of a variety of content (both positive and negative), can be affected by disgust exposure. These effects can be seen early in processing and also influence later emotional assessments, and are strongly dependent on individual differences in disgust propensity and attentional control. The results highlight the extent to which disgust can influence multiple short-term emotion processing mechanisms.