UK: Seeing the body from within and without

A study led by Dr Manos Tsakiris from Royal Holloway, University of London, suggests the way we experience the internal state of our body may also influence how we perceive our body from the outside, as for example in the mirror.

Published in the Proceedings of the Royal Society B, a report of the study says the psychologists measured how good people were at feeling their body from within by asking them to count their heartbeats over a few minutes.

They then measured how good people are at perceiving their own body-image from the outside, by using a procedure that tricks them into feeling that a fake, rubber hand is their own hand.

Looking at a rubber hand being touched at the same time as one's own unseen hand creates the illusion the rubber hand is part of one's body. The less accurate people were in monitoring their heartbeat, the more they were influenced by the illusion.

The study showed for first time a strong link may exist between how we experience our body from within and how we perceive it from the outside.

Tsakiris says: "We perceive our own bodies in many different ways. We can look at our bodies, feel touch on our bodies, and also feel our body from within, as when we experience our hearts racing or butterflies in our stomachs.

"It seems that a stable perception of the body from the outside, what is known as 'body image', is partly based on our ability to accurately perceive our body from within, such as our heartbeat."

He says the study is important because it may shed new light into pathologies of body-perception. Exploring how certain people feel about or perceive the internal states of their body may help us understand why they perceive their body-image in distorted ways such as those who suffer from anorexia or body dysmorphia.

Or, as the psychologists described their conclusion in the journal: "The results suggest that interoceptive sensitivity predicts the malleability of body representations, that is, people with low interoceptive sensitivity experienced a stronger illusion of ownership in the RHI.

"Importantly, this effect was not simply due to a poor proprioceptive representation or differences in autonomic states of one's body prior to the multi-sensory stimulation, suggesting that interoceptive awareness modulates the online integration of multi-sensory body-percepts."

The study was funded by the Economic and Social Research Council, UK.