Wednesday, September 14, 2011

The sense of body ownership

Today I've been preparing the poster that I'm going to present at the Japanese Psychological Association in a few days. My idea is about the recognition of one's own body, especially the sense of body ownership.

Recognizing the given body as "mine" or as "one's own" is not so trivial as it seems. For example, there are two contrasting, anomalous cases of body experience. One is the rubber hand illusion (RHI), the other is the case of depersonalization. I already wrote here on both cases. Please see;

rubber hand illusion


In RHI experiments, the participants feels touch on the rubber hand and also feels as if the rubber hand is the real one. In this case, "my body" includes the rubber hand, which is originally an external object.

On the contrary, the patients with depersonalization feel as if they were disembodied. They are difficult to have the sense of body ownership on their own bodies. There is almost nothing that can be felt as "my body", as the very sense of self is alienated from the body.

The sense of body ownership probably derives from the fact that one's own body is ambiguous as Merleau-Ponty described. On the one hand, body is the subject, which I live from within. I am the body and I perceive the world and act in the world as the body. On the other hand, the body appears as an object to me. I can see it in front of my eyes, I touch it with my hands.

Neurologically speaking, the subject side of the body appears as proprioceptive sensation and the object side of the body appears as visual or tactile sensation. Then, the multimordal or cross-modal integration of these sensations create the sense of body ownership in the brain.