The effect of covert visual attention on pupil size during perceptual fadinguse asterix (*) to get italics

Ana Vilotijević, Sebastiaan MathôtPlease use the format "First name initials family name" as in "Marie S. Curie, Niels H. D. Bohr, Albert Einstein, John R. R. Tolkien, Donna T. Strickland"

2024

<p>Pupil size is modulated by various cognitive factors such as attention, working memory, mental imagery, and subjective perception. Previous studies examining cognitive effects on pupil size mainly focused on inducing or enhancing a subjective experience of brightness or darkness (for example by asking participants to attend to/ memorize a bright or dark stimulus), and then showing that this affects pupil size. Surprisingly, the inverse has never been done; that is, it is still unknown what happens when a subjective experience of brightness or darkness is eliminated or strongly reduced even though bright or dark stimuli are physically present. Here, we aim to answer this question by using perceptual fading, a phenomenon where a visual stimulus gradually fades from visual awareness despite its continuous presentation. The study will contain two blocks: Fading and Non-Fading. In the Fading block, participants will be presented with black and white patches with a fuzzy outline that are presented at the same location throughout the block, thus inducing strong perceptual fading. In contrast, in the Non-Fading block, the patches will switch sides on each trial, thus preventing perceptual fading. Participants will covertly attend to one of the two patches, indicated by a cue, and report the offset of one of a set of circles that are displayed on top. We hypothesize that pupil size will be modulated by covert visual attention in the Non-Fading block, such that the pupil will be larger when attending to the dark as compared to the bright patch, but that this effect will not (or to a lesser extent) arise in the Fading block. This would imply that cognitive modulations of pupil size (gradually) disappear along with the subjective experience of brightness or darkness; in turn, this would suggest that cognitive modulations of pupil size reflect, at least in part, a high level of visual processing.&nbsp;</p>

pupil size, covert attention, adaptation, perceptual fading

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Social sciences

Sander Nieuwenhuis suggested: Paola Binda, https://www.unipi.it/index.php/research/item/20802-paola-binda, Yaffa Yeshurun [yeshurun@research.haifa.ac.il] suggested: Paola Binda, paola1binda@gmail.com , Yaffa Yeshurun [yeshurun@research.haifa.ac.il] suggested: Rachel Denison, rdenison@bu.edu

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2024-01-18 13:28:02

D. Samuel Schwarzkopf

Martin Rolfs