The rubber-hand-illusion is a phenomenon through which a test person gets the feeling a fake hand is part of his own body. In this experiment a visible fake-hand is moved in exactly the same way as the real hand, which is invisible. As a result, the test person considers the fake-hand to be his real hand. This phenomenon is declared by the ability of the brain to make connections between different kinds of sensory perceptions (i.e., visual, tactile, and proprioceptive), based on a personal internal representation of someone's own body in the brain. This is what the video shows. Meanwhile, additional research has been conducted.

Instead of a fake hand, an image of a hand is shown on a monitor (in 2D, which works too). By varying the size of the fake-hand it was discovered that the illusion is still going for bigger hand sizes, but the illusion disappears when the fake-hand is smaller than the real hand. This can be declared by the real representation of our hand. When moved very close to our eyes, our hand is infinitely big. When moved away the maximum distance, on a stretched arm, it gets its minimum size. If the hand becomes even smaller, it can’t possibly be our hand any more. This experiment illustrates that.

This insight shows us how big an avator, or parts of that, can be in the virtual world, while we still have the feeling it is ours. And it thus feels more real.

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