Researchers in Sweden have successfully created the illusion of people feeling sensations in three arms at the same time.
In five separate laboratory experiments, 154 volunteers were seated with their hands on a table and a rubber arm was placed next to their right arm. A sheet covered their shoulders and elbows, creating the illusion that the person had three arms. ( Source: Science Daily)
Researchers stroked the both the real and fake arms with a brush simultaneously until 7 out of 10 subjects reported feeling sensation in both limbs. They then threatened the fake arm with a knife and measured recognizable stress in heart rate that is normally associated with the threat of bodily harm.
The study could be helpful in helping amputees better accept prosthetics.