London, May 27 (IANS) Imagine shrinking to the size of a doll in your sleep. When you wake up, will you perceive yourself as tiny or the world as being populated by giants?

 
 Researchers at Karolinska Institutet in Sweden may have found the answer.
 
 According to textbooks, our perception of size and distance is a product of how the brain interprets different visual cues, such as the size of an object on the retina and its movement across the visual field.
 
 Some researchers have claimed that our bodies also influence our perception of the world, so that the taller you are, the shorter distances appear to be. However, there has been no way of testing this hypothesis experimentally -- until now.
 
 Henrik Ehrsson and his colleagues at Karolinska Institutet have already managed to create the illusion of body-swapping with other people or mannequins, reports the journal Public Library of Science ONE.
 
 Now they have used the same techniques to create the illusion of having a very small doll-sized body or a very large 13-foot-tall body, according to a Karolinska statement.
 
 Their results show for the first time that the size of our bodies has a profound effect on how we perceive the space around us. "Tiny bodies perceive the world as huge, and vice versa," says Ehrsson.
 
 One strategy that the brain uses to judge size is through comparison -- if a person stands beside a tree it computes the size of both.
 
 "Even though we know just how large people are, the illusion makes us perceive other people as giants; it's a very weird experience," says Ehrsson, who also tried the experiment on himself.
 
 The study also shows that it is perfectly possible to create an illusion of body-swapping with extremely small or large artificial bodies; an effect that Dr Ehrsson believes has considerable potential practical applications.