Relationships Between Personality Features and the Rubber Hand Illusion: An Exploratory Study.

Dalila Burin,Lorenzo Pia,Davide Ghirardello,Miriana Angilletta,Claudia Pignolo,Alessandro Zennaro,Laura Castellino,Luciano Giromini,Maria Pyasik,Francesca Ales

doi:10.3389/fpsyg.2019.02762

Dalila Burin, Lorenzo Pia + Show 8 more

Open Access

https://doi.org/10.3389/fpsyg.2019.02762

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Abstract

The rubber hand illusion paradigm allows investigating human body ownership by inducing an illusion of owning a life-sized fake hand. Despite the wide consensus on the fact that integration of multisensory signals is the main interpretative framework of the rubber hand illusion, increasing amount of data show that additional factors might contribute to the emergence of the illusion and, in turn, explain the strong inter-individual differences of the illusory patterns. Here, we explored whether and how personality features contribute to the emergence of the illusion by administering to healthy participants the rubber hand illusion paradigm along with two well-known personality tests, i.e., the Personality Assessment Inventory (PAI) and the Rorschach test. Results showed that two Rorschach domains (i.e., “Perception and Thinking Problems” and “Self and Other Representation”) were positively correlated with the illusory mislocalization of the own left hand toward the fake hand. Further analyses suggested that while the tendency to perceive unconventionally is related to mislocalizing the own hand toward the fake hand, the association of the RHI index and other personality features measured by the Rorschach remain uncertain. However, our findings in general suggest that personality features might have a role in the emergence of the rubber hand illusion. This, in turn, could explain the high inter-individual variability of the illusory effects.

Highlights

In psychological sciences, there is a wide consensus on the fact that human’s sense of self is strongly rooted in bodily related processes (Gallese and Sinigaglia, 2010)
Given that Personality Assessment Inventory (PAI) scale scores are expressed in T-scores, in a non-clinical sample one would expect to obtain a mean value of 50T and a standard deviation of 10T
Medium differences (i.e., Cohen’s d > 0.50) from the normative sample are observed for the Anxiety (ANX), Anxiety-Related Disorders (ARD), Mania (MAN), and Schizophrenia (SCZ) scales

Summary

Introduction

There is a wide consensus on the fact that human’s sense of self is strongly rooted in bodily related processes (Gallese and Sinigaglia, 2010). When a butterfly lands on our own arm, visual, tactile, and proprioceptive signals are matched in spatiotemporal terms This triggers the feeling that the unique source of these sensations is our own physical body. Such interpretation has been built up mainly through an experimental manipulation that alters this experience by creating a mismatch among some of these signals Such paradigm, known as the Rubber Hand Illusion (hereinafter RHI), shows that temporally synchronous (but not asynchronous) touches onto a visible fake hand and onto the hidden participant’s hand produces the compelling feeling of ownership of the fake hand (Botvinick and Cohen, 1998; Farnè et al, 2000; Ehrsson et al, 2004; Tsakiris and Haggard, 2005; Costantini and Haggard, 2007; Longo et al, 2008; Kammers et al, 2009; Tsakiris et al, 2011; Kalckert and Ehrsson, 2014; Burin et al, 2017a, 2018). Whenever the delivered stimuli are temporally and spatially synchronous (i.e., bottom–up signals), and whenever the fake hand is congruent with the preexisting representation of the body in terms of postures and identity (i.e., top–down signals), the conflict between somatosensory (i.e., touch and proprioception) representation of the own hand and vision of a fake hand is resolved by the incorporation of the fake hand within the participant’s own body (Costantini and Haggard, 2007; Makin et al, 2008; Tsakiris, 2010)

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