Most of the time, our brains are very good at combining information from all our senses into a seamless, unified conscious experience of “my body.” When this process of integrating different sensory signals goes wrong, according to a theoryThis can give a person an inaccurate and distressing perception of their body, called “body image disturbance.”
There are many types of body image disorders, including dissatisfaction with our bodies or a misperception of our bodies. We don’t know much about how many people have a misperception of their bodies, but we do know that body dissatisfaction is very common. investigation A study last year of more than 1,600 Australians aged 12 to 18 found that almost half were unhappy with their appearance.
Body image disorders are strongly linked to eating disorders And body dysmorphic disorder (which involves perceived defects in a person’s appearance). Existing treatments for these disorders have high relapse rates.
In our latest articleMy colleagues and I reviewed the evidence that a surprising approach might help address the root cause of these disorders and potentially improve symptoms: “embodiment illusions,” which use virtual reality or other methods to trick the mind into feeling like it is inhabiting a different body or body part.
Malleable body image
Perhaps the best-known embodiment illusion is the “rubber hand.” If you show a person a rubber hand being stroked while simultaneously stroking their hand (which they cannot see), the combined visual and tactile sensations usually make the person feel as if they “own” the rubber hand.
Thanks to virtual reality, this illusion can also be extended to other parts of the body, or even to an entire body.
In our systematic review of 32 previous studiesWe found compelling evidence that people with higher levels of body image disturbance tend to be more susceptible to such embodiment illusions compared to others.
Their greater malleability in body image reconfiguration is consistent with theories suggesting that body image disturbances involve impaired multisensory integration.
For example, relying on sight over touch may lead a person to value seeing a thin reflection in the mirror more than feeling their own ribs sticking out. This may be combined with expectations (such as “my body should be thinner”) that override specific sensory information.
Positive effects
We also found that most studies showed that tricking the brain into experiencing these illusions had positive effects. Participants improved their perceptual distortions and distressing thoughts and emotions about their body size and shape.
The idea is to experience an artificial body as if it were one’s own, especially if that body appears to be a desirable shape or size. This can “update” an individual’s persistent, distorted mental representation of their actual physical appearance.
A study The study involved women with anorexia nervosa who used a virtual reality avatar of healthy weight. Afterward, they overestimated their own (real) body size less than before the experiment.
Another study Healthy women have been reported to feel thinner and less dissatisfied with their bodies after identifying with a thin virtual body.
New treatments needed
Treating body image disorders, such as eating disorders and body dysmorphic disorder, can be very difficult. Recovery can take a long time.
The first line of treatment for many such disorders is cognitive behavioral therapywhich primarily targets negative body-related thoughts, emotions and behaviors. However, relapse rates are high.
This is one reason why we need to look for new complementary treatments that directly address the body’s misperception. This is where embodiment illusions that can alter distorted perceptions can be helpful.
Many questions remain
There is still much we don’t know about how embodiment illusions may affect people with body image distortions, such as how long potential treatments last or how long their effects last. We also need better methods to measure body image disturbances. Another limitation of existing research is the bias toward participants from Western cultures.
Future research could also focus on “appearance illusions,” which induce a sense of belonging to another face. This research could help us understand and improve facial misperception, particularly in people with body dysmorphic disorder.
Altering a person’s perception of their body is inherently risky. Research is also needed into the potential negative effects of these illusions, such as increase in a misperception of body size or shape.
There are also ethical concerns. Could having a “healthy” body reduce an anorexic person’s motivation to gain weight, even if they are dangerously thin?
Despite these issues, the use of immersive illusions to temporarily reshape body image appears promising. It could offer an innovative complementary approach to understanding and treating distressing body image distortions, complementing current treatments.
The author would like to thank his supervisors, Associate Professor Isabel Krug of the University of Melbourne and Dr David Butler of the Cairnmillar Institute.