What an illusion involving a fake hand can tell us about our mind–body connection

May 29, 2026 - 03:50

People who have a weaker sense of self are also more likely to have less bodily awareness, McGill researchers have found. The study supports the idea that people's perceptions of themselves and how they experience their physical body are deeply connected. To test this, scientists used a classic trick known as the rubber hand illusion.

In the experiment, a participant sits with one of their real hands hidden from view. A realistic fake hand is placed in front of them, and a researcher strokes both the fake hand and the hidden real hand at the same time. After a short while, many people start to feel as if the fake hand is actually their own. They can even feel a sense of touch where the fake hand is, rather than where their real hand is.

The McGill team wanted to see if this illusion worked differently depending on how strongly a person felt their own sense of self. They asked volunteers to fill out questionnaires about their identity and their awareness of their body. Those who reported a weaker sense of self were more easily fooled by the fake hand. They also showed less awareness of their own heartbeat and other internal body signals.

This suggests that the mental image we have of ourselves is not just a vague idea. It is tied to how we process physical sensations. When someone has a fuzzy sense of who they are, their brain may rely more on external cues, like the sight of a fake hand, rather than internal signals from their own body. The findings could help researchers understand conditions where people feel disconnected from themselves, such as depersonalization or certain eating disorders. The study adds a new layer to the old question of where the mind ends and the body begins.