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Modulation of the initial light reflex during affective picture viewing
Author(s) -
Henderson Robert R.,
Bradley Margaret M.,
Lang Peter J.
Publication year - 2014
Publication title -
psychophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.661
H-Index - 156
eISSN - 1469-8986
pISSN - 0048-5772
DOI - 10.1111/psyp.12236
Subject(s) - psychology , reflex , brightness , pupil , orienting response , context (archaeology) , pupillary response , audiology , habituation , neuroscience , optics , physics , medicine , paleontology , biology
An initial reflexive constriction of the pupil to stimulation—the light reflex—is primarily modulated by brightness, but is attenuated when participants are under threat of shock (i.e., fear‐inhibited light reflex). The present study assessed whether the light reflex is similarly attenuated when viewing emotional pictures. Pupil diameter was recorded while participants viewed erotic, violent, and neutral scenes that were matched in brightness; scrambled versions identical in brightness were also presented as an additional control. Compared to viewing neutral scenes, the light reflex was reliably modulated by hedonic content, with significant attenuation both when viewing unpleasant as well as pleasant pictures. No differences in the light reflex were found among scrambled versions. Thus, emotional modulation of the initial light reflex is not confined to a context of fear and is not indicative of brightness differences when viewing pictures of natural scenes.