In virtual reality (VR), “embodiment” is the illusion of being within another body: a life-size virtual body substitutes our own from first-person perspective. While the Pinocchio and the rubber hand illusions respectively allow you to experience your nose much longer and a rubber hand as your own, embodiment enables you to experience a (virtual) body as being yours.

This uncanny experience is accomplished through VR by incorporating some important technical procedures. First, having your body scanned in order to accurately reproduce an avatar (i.e. a virtual representation) of your actual (physical) body. Then, wearing a head-mounted display (HMD) that immerses you in a VR environment and having your body movements tracked in real-time by a motion capture system. While these procedures allow a persuasive interaction with the VR environment; the feeling of ownness over the avatar is still lacking. Before getting there, we need to take into account how the feeling of ownness is experienced or accomplished in normal life (outside of VR).


In everyday life, two powerful experiences implicitly lead to identify ourselves with our own physical bodies. The first one is the developmental stage of seeing a reflection of one’s body and recognizing it as one’s own — realizing that the image reflects our own body movements. The second is what we experience as first person bodily perspective, i.e. that I experience the movement of ‘my’ body as my own.

These two powerful experiences can be translated to VR by inserting a virtual mirror and having an avatar move according to the user’s movements. Yet, this is not necessarily enough to cause the illusion of being (within) the avatar. In daily life, we feel and recognize our body by the stimulation of our sensory systems and through sensorimotor integration. Examples are instinctive reflexes such as removing your hand when touching a hot surface or displacing your leg when feeling pain. So, how can we empower people to truly feel the avatar body as their own?

Synchronous multisensory correlations and sensorimotor stimulation are the technical terms encompassing the response to this question: a consistent (spatially and temporally) sensorimotor activity congruently occurring both with your own body (in the real world) and with your avatar (in VR). One example is continuously submitting the user, while immersed in the VR environment, to the sensation of impact from a virtual object. At the exact same moments and on the same spot of the physical body, similar sensations are reproduced in the real world (e.g. virtual balls repeatedly moving back and forth touch your legs and, synchronously, vibrators located in your physical legs are activated to reinforce embodiment). Devices reproducing sensory stimulation include haptic feedback suits, gloves or patches. This interaction enables you to feel the avatar as being your body. This results in illusory body ownership and agency with respect to the avatar (i.e. attributing actions of the avatar to oneself).



But it gets more interesting. What happens if  afterwards the characteristics of the avatar suddenly change? For example, by using the computer to manipulate or modify in real time features of the avatar such as skin color, eyes color, body shape, size, or facial expression of the avatar. Changing our avatars can change the perception of ourselves. Doing so, one could maintain embodiment by altering some features of our own avatar (e.g. changing skin color), or one can simply embody other virtual bodies. There are studies using embodiment for investigations on racial bias, gender harassment, pain reduction, domestic violence, fear of death and behavioral disorders. The opportunities are great and researchers are just starting to understand the potential of such technological capabilities. For example, one leading research group is using a particular manifestation of embodiment called “body swapping”, in which users have a conversation with themselves by changing from their own bodies to other people’s bodies, and back, and so on. Whereas swapping oneself to Sigmund Freud’s body showed to help in increasing self-awareness and providing self-advice when suffering from a personal/family problem, swapping oneself to Albert Einstein’s body can apparently make you feel smarter and even improve cognitive performance.

As part of Maastricht University, the Brightlands Institute for Smart Society (BISS) is a partner in a multicentric, collaborative project recently funded by the European Union and investigating the potential of VR embodiment to enhance lifestyle among people with obesity and binge eating habits. Additionally, BISS participated in a recent study combining functional magnetic resonance with VR showing that, by embodying human participants into a female avatar who was being verbally abused, embodiment can modulate the brain network responsible for the representation of the bodily self while increasing social empathy. The clinical implications of embodiment are vast. For instance, for sensorimotor rehabilitation (e.g. phantom limb pain), cognitive (e.g. anxiety) and behavioral treatments (e.g. empathy disorders), social aggression (e.g. bullying). There are also implications for business and entrepreneurial sectors. For example, for retirement planning (e.g. by embodiment of an older self) or for investments/savings (e.g. by embodiment of a richer or poorer person based on financial planning predictions). Embodiment comes with ethical and social challenges as well. A lot of personal information, sensitive health data and body characterization are in place during the incorporation of embodiment. Another potential risk is that VR embodiment could be used as a “persuasive technology” in manners that might undermine individual autonomy or be otherwise ethically questionable. A detailed, full explanation to each user for informed consent, a meticulous ethical analysis to safeguard human integrity, and a responsible data management plan are fundamental to keep your work socially responsible and respectful of the rights of each person. This applies to any type of application using embodiment.

In a time when digital technologies are becoming ubiquitous and VR is becoming more accessible and spreading across various societal levels, BISS envisions embodiment as a tool empowering individuals and organizations to transform our lives and society positively in a responsible manner. The journey of embodiment is warming up and looks fascinating.

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