With the number of rubber body(part) studies that have been done, each showing that if it looks to be a body part, and feels like a body part, the brain accepts it as a body part, this research should also hold no surprises. We finally have direct proof of the concept that, when we utilise any tool, even for a scant few minutes, our brains integrate that tool into our self-body-image.

This of course can be seen every day, if you drive a car. Sit in the car, and within moments you are thinking of yourself in terms of the dimensions of that vehicle. Whilst perhaps obvious, it offers a new, and slightly different tack to the rubber body studies, offering direct correlating evidence that the brain is plastique enough to adapt its body schema on a whim. This when applied to a VR setting, serves as proof that the avatar's form, however weird and wonderful, is likely going to be adapted to by the brain, in short order.

It also serves to show how people adapt so swiftly to a prosthetic exoskeleton or similar device. The brain is literally converting the person's new dimensions into the body schema.

In the study itself, performed by Alessandro Farnc, Lucilla Cardinali, and colleagues of the French organisation Institut national de la santé et de la recherche médicale, or INSERM, the reserarchers directed their attentions towards the hypothesis that his or her subsequent bodily movements should differ when compared to those performed before the tool was used.

This is of course, exactly what occurred. After using a mechanical grabber that extended their reach, people behaved as though their arm really was longer, they found. In addition, when the participants were touched on theirt elbow, then on their middle fingertip (out of their visual sight), on both the tool using arm and the non tool using arm, universally the participants reported that the touches were further apart on the tool using arm. In other words, reinforcing the longer arm theory.

"Since the origin of the concept of body schema, the idea of its functional plasticity has always been taken for granted, even if no direct evidence has been provided until now," said Alessandro Farnc. "Our series of experiments provides the first, definitive demonstration that this century-old intuition is true."

"We believe this ability of our body representation to functionally adapt to incorporate tools is the fundamental basis of skillful tool use," Cardinali said. "Once the tool is incorporated in the body schema, it can be manoeuvred and controlled as if it were a body part itself."

References

Tool-use induces morphological updating of the body schema

INSERM

Resource List: Virtual Limbs