Another intriguing experiment by Mel Slater‘s group from Barcelona[1], this one sure to get a good whack of popular media coverage. 24 (supposedly normal) healthy blokes put on virtual reality goggles and were ‘transported’ into a scene that contained two virtual women. They then induced the illusion of body transfer, which has been shown before by Henrik Ehrsson[2,3] and others[4], into the body of one of the women. They used a questionnaire and the heart-rate response to seeing their ‘avatar’ hit, both of which have been used before, to assess the strength of the illusion. In short, it worked – the male participants felt a sense of ownership and agency over the female body.
I think the clever bit of this study is the untangling of what aspects of the illusory devices contributed most to its effect. The winner by far was first person versus third person – the other woman stroked the shoulder of the avatar and, simultaneously, the participant felt a stroke on their own shoulder. If they simultaneously saw the other woman stroking from the perspective of the avatar, the illusion was far stronger than if they saw both virtual women from a third person perspective. If you don’t get this, have a look at the figures in their paper. The synchronicity of the felt and seen touch, and the synchronocity of the participant’s head movements with those of the avatar, had an effect, albeit smaller than the perspective thing.
So, Mel Slater has now given some men the feeling of having a woman’s body, but as the woman next to me on the bus yesterday said as we struck up a conversation, first about the stupendous gaff made by our leader of the opposition but then about the experiment in question – “To feel like you have a woman’s body is one thing and not much chop if the woman was me for example, but to know what it is like to be a woman – that glorious state of enlightenment will, I am afraid, be something men will never get.” She then stared wistfully at the beads of Sydney rain – thick and boisterous – race down the window.
References
[1] Slater, M., Spanlang, B., Sanchez-Vives, M., & Blanke, O. (2010). First Person Experience of Body Transfer in Virtual Reality PLoS ONE, 5 (5) DOI: 10.1371/journal.pone.0010564
[2] Petkova, V., & Ehrsson, H. (2008). If I Were You: Perceptual Illusion of Body Swapping PLoS ONE, 3 (12) DOI: 10.1371/journal.pone.0003832
[3] Ehrsson, H. (2007). The Experimental Induction of Out-of-Body Experiences Science, 317 (5841), 1048-1048 DOI: 10.1126/science.1142175
[4] Lenggenhager B, Tadi T, Metzinger T, & Blanke O (2007). Video ergo sum: manipulating bodily self-consciousness. Science (New York, N.Y.), 317 (5841), 1096-9 PMID: 17717189