In the experiment conducted by Arvid Guterstam, Valeria I. Petkova and H. Henrik Ehrsson, participants were asked to put their right arm next to a prosthetic right arm. As you can see in the left half of the picture below, both hands were simultaneously stroked by a brush at similar points. You’d expect that a participant would only feel the brush on his real hand, but what happens is that their brain gets confused. The blanket hides the fact that only the real arm is connected to the participant, so his brain is comfortable enough with treating BOTH hands as part of the body. Most participants responded that they felt the brush on both hands. Awesome.

To further prove the illusion, the scientists then threatened the confused participants by holding a knife over the fake right arm and then doing the same to their actual arm. The stress response for both events were very similar, again proving that the participants thought that the prosthetic was also their arm. But our brains are not that dumb – when the scientists tried placing a prosthetic left arm or a rubber foot next to a participants’ real right arm, the experiment failed.

So what applications could this result have? Ehrsson says that maybe in the future, stroke patients and other people with paralyzed limbs will be able to use prosthetic arms, or even people who have functional arms but could use an extra limb to do their job more effectively. Check out the source links below for more details on the experiment.

[via PLoSone via PhysOrg]

The study, published in Psychology & Aging, reports that the test group who played the real-time-strategy title Rise of Nations, showed some cognitive improvement after time with the title. While the subjects — all of whom were 60 or older — did not improve in all categories, the gaming group showed increased reasoning ability and were better able to swap between tasks. Clearly, they are spreading the ADD to our parents and grandparents now, but if it gets them into multiplayer Civilization on Wednesday nights, is it worth a complaint?

Arthur Kramer, the man behind the study, cautioned that spending hours building a nation is certainly not the only thing older adults should do to help stave off loss of cognitive function, but he pointed out the connection between managing resources in a strategy game and managing one’s real-life finances. Anything that can help with that, and which also happens to be fun, can’t be a bad idea.

[PhysOrg via Wonderland]