#251: Research into the Virtual Body Ownership Illusion

Domna-BanakouDomna Banakou is a Ph.D. student studying with Mel Slater at the Event Lab in Barcelona, Spain. She’s been researching different aspects of the virtual body ownership illusion in order to investigate the short-term and long-term impacts of embodying virtual avatars which have different qualities than your physical body. Specifically, she found that embodying the avatar with childlike proportions can result in an overestimation of the sizes of virtual objects. She also has found that it’s possible to create the illusion of attributing things that appear to be coming from your avatar, but that you hadn’t actually said. There are a number of potential implications for how the virtual body ownership illusion through VR can alter our sense of self and identity, and Mel Slater’s Event Lab is on the forefront of investigating these questions.


The virtual body ownership illusion occurs can be induced when the limb tracking within a virtual reality experience is accurate enough. Mel Slater has said that for most people who haven’t experience virtual reality, 100% of the time that when we’ve looked down to see our body, then it’s been our body. So it’s surprisingly easy to trick or fool the mind into believing that a virtual avatar is your body.

Domna Banakou has been researching some of the psychological implications of virtual body ownership, and found that embodying a child avatar changes our perception of sizes and can have an implicit impact on our attitudes. Here’s the abstract from here paper titled “Illusory ownership of a virtual child body causes overestimation of object sizes and implicit attitude changes:”

An illusory sensation of ownership over a surrogate limb or whole body can be induced through specific forms of multisensory stimulation, such as synchronous visuotactile tapping on the hidden real and visible rubber hand in the rubber hand illusion. Such methods have been used to induce ownership over a manikin and a virtual body that substitute the real body, as seen from first-person perspective, through a head-mounted display. However, the perceptual and behavioral consequences of such transformed body ownership have hardly been explored. In experiment 1, immersive virtual reality was used to embody 30 adults as a 4-y-old child (condition C), and as an adult body scaled to the same height as the child (condition A), experienced from the first-person perspective, and with virtual and real body movements synchronized. The result was a strong body-ownership illusion equally for C and A. Moreover there was an overestimation of the sizes of objects compared with a nonembodied baseline, which was significantly greater for C compared with A. An implicit association test showed that C resulted in significantly faster reaction times for the classification of self with child-like compared with adult-like attributes. Experiment 2 with an additional 16 participants extinguished the ownership illusion by using visuomotor asynchrony, with all else equal. The size-estimation and implicit association test differences between C and A were also extinguished. We conclude that there are perceptual and probably behavioral correlates of body-ownership illusions that occur as a function of the type of body in which embodiment occurs.

Donna has also found that it’s possible to trick your mind into believing that you’re saying something, when it’s actually your avatar doing the speaking. After inducing the virtual body ownership illusion through accurate limb tracking, Domna describes an experiment where they had participants watch their movements in a mirror and provided haptic feedback called “synchronous vibrotactile stimulation on the thyroid cartilage” while asynchronously moving the avatar’s lips. It was possible to cause the participants to misattribute that they had actually said these things by both explicit surveys and implicit measurements that showed their fundamental speaking frequency had shifted.

Here’s the abstract from that paper titled “Body ownership causes illusory self-attribution of speaking and influences subsequent real speaking:”

When we carry out an act we typically attribute the action to ourselves, the sense of agency. Explanations for agency include conscious prior intention to act followed by observation of the sensory consequences, brain activity that involves feed-forward prediction of the consequences combined with rapid inverse motor prediction to fine-tune the action in realtime, priming where there is e.g. a prior command to perform the act, cause (the intention to act) preceding effect (the results of the action), and with the common-sense rules of attribution of physical causality satisfied. We describe an experiment where participants falsely attributed an act to themselves under conditions that apparently cannot be explained by these theories. A life-sized virtual body (VB), seen from first person perspective in 3D stereo, as if substituting the real body, was used to induce the illusion of ownership over the VB. Half of the 44 experimental participants experienced VB movements that were synchronous with their own movements (Sync), and the other half asynchronous. The VB, seen in a mirror, spoke with corresponding lip movements, and for half this was accompanied by synchronous vibrotactile stimulation on the thyroid cartilage (Von), and the other half not. Participants experiencing Sync misattributed the speaking to themselves and also shifted the fundamental frequency of their later utterances towards the stimulus voice. Von also contributed to these results. We show that these findings can be explained by current theories of agency provided that the critical role of ownership over the VB is taken into account.

Here’s a summary of other experiments into how VR can impact the implicit attitudes, behaviors, and brings up a lot of philosophical questions about the sense of self:

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