Under normal circumstances, we experience that our center of awareness is located behind our eyes and inside our own body. To learn more about the perceptual processes that underlie this tight coupling between the spatial dimensions of our consciously perceived self and our physical body, we conducted a series of experiments using an ‘out-of-body illusion’. In this illusion, the conscious sense of self is displaced in the testing room by experimental manipulation of the congruency of visual and tactile information and (...) a change in the visual perspective. We demonstrate that when healthy individuals experience that they are located in a different place from their real body, they disown this body and no longer perceive it as part of themselves. Our findings are important because they reveal a relationship between the representation of self-location in the local environment and the multisensory representation of one’s own body. (shrink)

Although it has been shown that immersive virtual reality can be used to induce illusions of ownership over a virtual body , information on whether this changes implicit interpersonal attitudes is meager. Here we demonstrate that embodiment of light-skinned participants in a dark-skinned VB significantly reduced implicit racial bias against dark-skinned people, in contrast to embodiment in light-skinned, purple-skinned or with no VB. 60 females participated in this between-groups experiment, with a VB substituting their own, with full-body visuomotor synchrony, reflected (...) also in a virtual mirror. A racial Implicit Association Test was administered at least three days prior to the experiment, and immediately after the IVR exposure. The change from pre- to post-experience IAT scores suggests that the dark-skinned embodied condition decreased implicit racial bias more than the other conditions. Thus, embodiment may change negative interpersonal attitudes and thus represent a powerful tool for exploring such fundamental psychological and societal phenomena. (shrink)

In this article, we explore the effect of a modification of one aspect of body awareness, the so-called sense of body-ownership, on pain perception. In order to do so, we modify body-ownership in healthy participants by using a visuo-tactile illusion called the 'rubber hand illusion'.We combine the classical experimental paradigm of the RHI with a method to induce pain by thermal stimulation. We present and discuss two experiments that show interesting but conflicting results. In the first experiment our results show (...) the RHI has the effect of decreasing pain estimations, whereas in the second experiment the RHI has the effect of increasing pain estimations. We discuss the different factors that could be involved in this difference, and suggest that different types of changes in participants' body schema might have been involved in the two experiments. We propose that an approach that considers participants' subjective experience of the illusion will help us to solve this puzzle. (shrink)

Genes adjacent to species-specific loci are 6.2% older than genes adjacent to other dynamic loci (P < 10−2 by randomization; gray bars in Fig. 3); thus, species-specific genes are not randomly distributed but are found preferentially in the older regions, indicating that the incipient Escherichia and Salmonella lineages continued to participate in recombination at loci unlinked to lineage-specific genes.

Previous studies on body ownership illusions have shown that under certain multimodal conditions, healthy people can experience artificial body-parts as if they were part of their own body, with direct physiological consequences for the real limb that gets ‘substituted’. In this study we wanted to assess (a) whether healthy people can experience ‘missing’ a body-part through illusory ownership of an amputated virtual body, and (b) whether this would cause corticospinal excitability changes in muscles associated with the ‘missing’ body-part. Forty right-handed (...) participants saw a virtual body from a first person perspective but for half of them the virtual body was missing a part of its right arm. Single pulse transcranial magnetic stimulation was applied before and after the experiment to left and right motor cortices. Motor evoked potentials (MEPs) were recorded from the first dorsal interosseous (FDI) and the extensor digitorum communis (EDC) of each hand. We found that the stronger the illusion of amputation and arm ownership, the more the reduction of MEP amplitudes of the EDC muscle for the contralateral sensorimotor cortex. In contrast, no association was found for the EDC amplitudes in the ipsilateral cortex and for the FDI amplitudes in both contralateral and ipsilateral cortices. Our study provides evidence that a short-term illusory perception of missing a body-part can trigger inhibitory effects on corticospinal pathways and importantly in the absence of any limb deafferentation or disuse. (shrink)

Here, we assess the usefulness of first-person methods for the study of embodiment during the rubber hand illusion (RHI). Participants observed a rubber hand being stroked synchronously and asynchronously with their concealed hand after which they made proprioceptive judgments about the location of their hand and completed a self-report questionnaire. A randomly selected cohort was further interviewed during the illusion and their transcripts analyzed using interpretative phenomenological analysis (IPA). Results showed that the IPA group experienced a more intense embodied experience (...) during the RHI, measured by proprioceptive distortion and self-report. IPA revealed four main themes of embodied experience: recalibration of the body schema; violation of the body schema; multisensory integration; and illusory experience over time. The report of agency was a significant predictor of proprioceptive distortion. This study shows how first-person methodologies can be empirically rigorous and how the introspective interview provides a rich, detailed account of embodied experience. (shrink)