Putting things into perspective: Which visual cues facilitate automatic extraretinal symmetry representation?use asterix (*) to get italics

Elena Karakashevska, Marco Bertamini and Alexis D.J. Makin Please 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>Abstract</p> <p>Introduction: Objects often project different images when viewed from different locations. Our visual system can correct for perspective distortion and identify objects from different viewpoints that change the retinal image. This study attempted to determine the conditions under which the visual system spends computational resources to construct view-invariant, extraretinal representations. We focused on extraretinal representation of planar symmetry. Given a symmetrical pattern on a plane, symmetry in the retinal image is degraded by perspective. Visual symmetry activates the extrastriate visual cortex and generates an Event Related Potential (ERP) called Sustained Posterior Negativity (SPN), and previous studies have found that the SPN is reduced for perspective symmetry during secondary tasks. However, we hypothesised that this perspective cost might be reduced when additional visual cues support extraretinal representation. &nbsp;</p> <p>Method: 120 participants viewed symmetrical and asymmetrical stimuli presented in a frontoparallel or perspective view. The task did not involve symmetry, participants were instructed to discriminate the luminance of the patterns. &nbsp;Participants completed four blocks. In the Baseline block there were no cues supporting 3D interpretation. In the Monocular viewing block, participants viewed the same stimuli with one eye. In the Static frame block, additional pictorial depth cues were available - the elements appeared within a flat square surface with salient edges. In the Moving frame block, motion parallax was used to enhance 3D interpretation before stimulus onset.&nbsp;</p> <p>Results: We computed perspective cost as the difference between the frontoparallel SPN and the perspective SPN. Perspective cost was not significantly reduced in either of the three blocks compared to baseline.&nbsp;</p> <p>Discussion: We conclude that additional visual cues do not substantially reduce perspective cost and promote extraretinal symmetry representation. Our Stage 1 protocol and our predicted results can be found here https://osf.io/6uae2/.</p>

vision, perception, symmetry, EEG, sustained posterior negativity

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Life Sciences

2024-06-03 21:00:08

Grace Edwards