The influence of skin colour on the experience of ownership in the rubber hand illusion

Marilia Lira,Óscar F Gonçalves,Paulo S Boggio,Patricia A Dall’Agnol,David M Amodio,Julia H Egito

doi:10.1038/s41598-017-16137-3

Abstract

Racial prejudice is associated with a fundamental distinction between “us” and “them”—a distinction linked to the perceived overlap between representations of the self and others. Implicit prejudice has been shown to reduce the intensity of White individuals’ hand ownership sensation as induced by the Rubber Hand Illusion (RHI) with dark rubber hands. However, evidence for this link to implicit prejudice comes from self-report questionnaire data regarding the RHI. As an alternative, we assessed the onset time of the RHI. We hypothesized that onset time of the RHI would be higher for the black compared to the white RH, acting as the mediator between implicit prejudice and magnitude of the RH illusion and proprioceptive drift. As expected, participants took longer to incorporate the black RH and presented lower RH illusion magnitude and a smaller proprioceptive drift for the black RH. Mediation analysis revealed a significant indirect effect of implicit racial bias on proprioceptive drift and magnitude of illusion through onset time to illusion only for the black RH. These findings further illuminate the connection between implicit prejudice and embodied perception, suggesting new perspectives on how implicit biases operate.

Highlights

Racial prejudice is associated with a fundamental distinction between “us” and “them”—a distinction that has been linked to the degree of perceived overlap between cognitive representations of the self and others1,2
The authors found a negative correlation between illusion intensity and participants’ implicit racial bias assessed after the Rubber Hand visual-tactile illusion6 (RHI), suggesting that a stronger experience of the rubber hand (RH) illusion across color conditions was associated with lower implicit prejudice
The aim of the present study was to investigate the effect of the skin color on the onset of the RHI in White participants by testing whether the onset time was related to the intensity of the illusion (Rubber Hand Illusion Questionnaire and Proprioceptive Drift Test), and whether these effects are predicted by implicit racial bias (Implicit Association Test)

Summary

Introduction

Racial prejudice is associated with a fundamental distinction between “us” and “them”—a distinction that has been linked to the degree of perceived overlap between cognitive representations of the self and others. RHI is a multisensory experience that simultaneously integrates visual and tactile stimuli to induce a sense of ownership of a realistic looking rubber hand (RH) In this illusion, the RH is located inside the peripersonal space in a position congruent with the participant’s hand. Maister et al. reported that the ownership experience of a dark RH in white participants altered the implicit racial bias; i.e. greater subjective experience of hand ownership resulted in lower implicit bias. This pattern is consistent with the findings of Peck et al., in which the perceptual appropriation of a dark body avatar was associated with a decrease in White participant’s implicit racial bias scores. As timing is an important component in multisensory integration, measuring the onset time to illusion might reveal previously-obscured phenomena that link racial bias and body ownership

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