Symmetry Perception and Psychedelic Experience

Makin, Alexis DJ ORCID: 0000-0002-4490-7400, Roccato, Marco, Karakashevska, Elena, Tyson-Carr, John ORCID: 0000-0003-3364-2184 and Bertamini, Marco ORCID: 0000-0001-8617-6864 (2023) Symmetry Perception and Psychedelic Experience Symmetry, 15 (7). p. 1340. ISSN 2073-8994, 2073-8994

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Abstract

This review of symmetry perception has six parts. Psychophysical studies have investigated symmetry perception for over 100 years (part 1). Neuroscientific studies on symmetry perception have accumulated in the last 20 years. Functional MRI and EEG experiments have conclusively shown that regular visual arrangements, such as reflectional symmetry, Glass patterns, and the 17 wallpaper groups all activate the extrastriate visual cortex. This activation generates an event-related potential (ERP) called sustained posterior negativity (SPN). SPN amplitude scales with the degree of regularity in the display, and the SPN is generated whether participants attend to symmetry or not (part 2). It is likely that some forms of symmetry are detected automatically, unconsciously, and pre-attentively (part 3). It might be that the brain is hardwired to detect reflectional symmetry (part 4), and this could contribute to its aesthetic appeal (part 5). Visual symmetry and fractal geometry are prominent in hallucinations induced by the psychedelic drug N,N-dimethyltryptamine (DMT), and visual flicker (part 6). Integrating what we know about symmetry processing with features of induced hallucinations is a new frontier in neuroscience. We propose that the extrastriate cortex can generate aesthetically fascinating symmetrical representations spontaneously, in the absence of external symmetrical stimuli.

Item Type:	Article
Uncontrolled Keywords:	Psychophysics, Neuroscience, Aesthetics, Nature-Nurture, DMT, Flicker-induced hallucinations, Comparative Neuroscience
Divisions:	Faculty of Health & Life Sciences Faculty of Health & Life Sciences > Inst. Population Health
Depositing User:	Symplectic Admin
Date Deposited:	27 Sep 2023 08:52
Last Modified:	16 Jun 2026 11:29
DOI:	10.3390/sym15071340
Open Access URL:	https://doi.org/10.3390/sym15071340
Related Websites:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3173100
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