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Tools as Body Parts

July 23, 2009

People perceive tools as extensions of their own bodies.


Body-extending tools. I’m Bob Hirshon and this is Science Update.

When you use a screwdriver to assemble a piece of furniture, your brain temporarily treats the tool as an extension of your body. This according to neuropsychologists Lucilla Cardinali and Alessandro Farné of the Institute of National Health and Medical Research in France. They asked volunteers to reach for an object, such as a cup of coffee. Then they had the volunteers repeat the same task using a mechanical grabber, which extended the length of the arm by 30 centimeters. Farné says after using the grabber, the volunteers temporarily perceived their arms as longer than they actually were.

By using a tool, we really modify the way in which the brain represents the body, itself so that people believe that their arm is longer.

He says this adaptability probably helped our ancestors be more effective tool-users. I’m Bob Hirshon, for AAAS, the science society.