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The projected hand illusion: component structure in a community sample and association with demographics, cognition, and psychotic-like experiences

Graham, Kyran T.; Martin-Iverson, Mathew T.; Holmes, Nicholas P.; Waters, Flavie A.


Kyran T. Graham

Mathew T. Martin-Iverson

Nicholas P. Holmes

Flavie A. Waters


The projected hand illusion (PHI) is a variant of the rubber hand illusion (RHI), and both are commonly used to study mechanisms of self-perception. A questionnaire was developed by Longo et al. (2008) to measure qualitative changes in the RHI. Such psychometric analyses have not yet been conducted on the questionnaire for the PHI. The present study is an attempt to validate minor modifications of the questionnaire of Longo et al. to assess the PHI in a community sample (n = 48) and to determine the association with selected demographic (age, sex, years of education), cognitive (Digit Span), and clinical (psychotic-like experiences) variables. Principal components analysis on the questionnaire data extracted four components: Embodiment of “Other” Hand, Disembodiment of Own Hand, Deafference, and Agency—in both synchronous and asynchronous PHI conditions. Questions assessing “Embodiment” and “Agency” loaded onto orthogonal components. Greater illusion ratings were positively associated with being female, being younger, and having higher scores on psychotic-like experiences. There was no association with cognitive performance. Overall, this study confirmed that self-perception as measured with PHI is a multicomponent construct, similar in many respects to the RHI. The main difference lies in the separation of Embodiment and Agency into separate constructs, and this likely reflects the fact that the “live” image of the PHI presents a more realistic picture of the hand and of the stroking movements of the experimenter compared with the RHI

Journal Article Type Article
Acceptance Date Aug 3, 2014
Online Publication Date Aug 14, 2014
Publication Date Jan 31, 2015
Deposit Date Jan 8, 2019
Journal Attention, Perception, & Psychophysics
Print ISSN 1943-3921
Electronic ISSN 1943-393X
Publisher Humana Press
Peer Reviewed Peer Reviewed
Volume 77
Issue 1
Pages 207-219
Public URL
Publisher URL

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