Farmer, H., Tajadura-Jiménez, A., Tsakiris, M. (2012). Beyond the colour of my skin: How skin colour affects the sense of body-ownership. Consciousness and Cognition, 21(3):1242-1256 Details
In 1998 psychologists from Pennsylvania showed that people may become convinced that a rubber hand was their own by placing it on a table and stroking it while simultaneously stroking their real (but unseen) hand.
The so-called “rubber hand illusion” develops through synchronized visuo-tactile stimulation provided that the rubber hand is anatomically and posturally congruent with the subject’s real hand. In theory, because the brain normally processes different sensory streams in a way that links them into a unified experience, neural representations in sensory areas of the brain can link to other senses by association – and this can be exploited to create a perceptual illusion.
There are limits of course: discrepancies in the visual form or position of the alien hand can diminish or even abolish the rubber hand illusion. However, it has been unknown until now whether hand skin colour might be important, and what role ethnic distinctions may play in body-ownership.
This question was addressed by a group of psychologists at the University of London. Test participants received visuo-tactile stimulation while looking at either a white or black rubber hand, with their real hand hidden. To quantify the degree of body ownership, three measurements were taken. A 7-pt Likert scale assessed participants’ subjective experience. ‘Proprioceptive drift’ – the perceived shift in location of the real hand – was taken as a behavioural measure. Skin conductance responses (SCR) measured using a GSR Amp (ADInstruments) in response to perceived pain stimulation of the rubber hand provided a physiological measure.
Subjective reports indicated that skin colour influenced feelings of body-ownership. However, participants showed the same amount of proprioceptive drift regardless of skin colour, and SCR responses to perceived pain were similar overall between white and black hands. These results suggest that body-ownership may override ethnic and racial distinctions.