How to Sense a "Force Field" Around Your Body

Swedish researchers have discovered a way to get people to sense a "force field" around their bodies. It must be noted that no actual force field was found to exist around anyone's body - this was an illusion at work.

The Huffington Post reports that the discovery was made by scientists at the Karolinska Institute in Stockholm. Their findings were presented last June 24th in an article, "The magnetic touch illusion," published in the journal Cognition.

The psychological illusion was accomplished using a setup inspired by the classic "rubber hand" illusion designed by a team of British psychologists in 2004. That study asked experiment volunteers to hide their right hand under a table while a rubber hand was put in front of them in a position that made it appear like the fake hand was attached to their body.

The visible fake hand and the unseen real hand were simultaneously stroked with a brush. Within a few seconds, volunteers would begin to experience the rubber hand as their own.

The Stockholm team recruited 101 adult volunteers for their study. Each volunteer was subjected to the rubber hand experiment, with a twist: the brushstrokes came close to but never made contact with the fake hand. The researchers only brushed the air above the rubber appendage. Meanwhile, the volunteer's hidden hand was feeling actual but unseen brushstrokes.

Many of the volunteers reported sensing a "magnetic force" or "force field" between the brush and the rubber hand that psychologically belonged to them. "We can elicit this bizarre sensation of there actually being something in mid-air between the brush and the rubber hand," notes the study's lead author Arvid Guterstam in New Scientist.

The illusion is a demonstration of the human sense of peripersonal space. This is the space that lies within the reach of the body's limbs.