Published By: Sreyanshi

How does 'sense of self' work? - Rubber hand illusion

What does the rubber hand illusion tell us about the sense of self?

This experiment is a curious one revealing how our brain processes our body consciousness. As it turns out, we can actually trick our brain into understanding our body differently using one simple trick that involves a prosthetic hand. Yes, just use a prosthetic hand, and you can actually trick your brain into thinking that it is your own hand. This experiment shows that our mind combines its information from all the different senses and finally creates a feeling of being inside one’s body.

This experiment conducted with the help of a fake body part exposes how the brain perceives our body and how we can confuse it. This illusion has been widely used as a party trick with a sassy nickname, the ‘rubber hand illusion’.

This trick was performed by researchers in Italy on a group of volunteers, and it revealed how the human mind combines information from five different senses and generates a feeling of being inside one's own body.

The idea is that people feel that the rubber hand which is placed on the table in front of their eyes are actually their own. It’s a very uncanny yet effective shift in one’s idea of body perception. This shift in body perception is accompanied by a certain sense of dissociating from one’s real hand.

This study was first launched after the scientists noticed a similar incident in the case of stroke patients. They experienced similar sensations in their paralysed limbs, to the extent that they would be certain their paralysed limb wasn’t part of their own body, and they’d even claim ownership over appendages that didn’t belong to their bodies.

To conduct the study, some of the healthy volunteers held their forearms out and rested upon a table, and their right hand was hidden inside a box. After that, a lifelike hand made out of rubber is placed in front of them, which is lined up from their shoulder. Now, all they needed to do was to cover the stump of the hand with a cloth, leaving the fingers visible. The illusion was activated after the researchers started stroking the middle finger of both the rubber and the real hands of the participant simultaneously.

Now the illusion comes to play. As the real and the fake hands are both stroked simultaneously for a couple of minutes, keeping the same pace and stroking, the mind combines the visual information with the sensation of touch, and the brain perceives the rubber hand as the real one.