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Flicker-light induced visual phenomena: Frequency dependence and specificity of whole percepts and percept features

Allefeld, C. ORCID: 0000-0002-1037-2735, Puetz, P., Kastner, K. & Wackermann, J. (2011). Flicker-light induced visual phenomena: Frequency dependence and specificity of whole percepts and percept features. Consciousness and Cognition, 20(4), pp. 1344-1362. doi: 10.1016/j.concog.2010.10.026


Flickering light induces visual hallucinations in human observers. Despite a long history of the phenomenon, little is known about the dependence of flicker-induced subjective impressions on the flicker frequency. We investigate this question using Ganzfeld stimulation and an experimental paradigm combining a continuous frequency scan (1–50 Hz) with a focus on re-occurring, whole percepts. On the single-subject level, we find a high degree of frequency stability of percepts. To generalize across subjects, we apply two rating systems, (1) a set of complex percept classes derived from subjects’ reports and (2) an enumeration of elementary percept features, and determine distributions of occurrences over flicker frequency. We observe a stronger frequency specificity for complex percept classes than elementary percept features. Comparing the similarity relations among percept categories to those among frequency profiles, we observe that though percepts are preferentially induced by particular frequencies, the frequency does not unambiguously determine the experienced percept.

Publication Type: Article
Additional Information: © Elsevier 2011. This manuscript version is made available under the CC-BY-NC-ND 4.0 license
Publisher Keywords: Flicker light, Ganzfeld, Visual hallucinations, Stroboscopic patterns, Frequency dependence, Frequency specificity, Phenomenology
Subjects: B Philosophy. Psychology. Religion > BF Psychology
R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
Departments: School of Arts & Social Sciences > Psychology
Text - Accepted Version
Available under License Creative Commons Attribution Non-commercial No Derivatives.

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