17 March 2015 10:45

Everyone suffers from massive distortions in the relative perception of their own body according to research led by Lancaster University.

Previously, it had been assumed that a distorted body perception only applied to clinical disorders including neglect, paralysis and eating disorders.

But a study found that everyone has a distorted view of the relative size of their body parts like hand, arm, leg and torso.

Lead researcher Dr Sally Linkenauger said the research showed “large systematic distortions in individuals’ perceptions of their relative bodily proportions, something that had previously been assumed to be accurate”.

The research published in the Journal of Experimental Psychology: General is by an international team led by Dr Linkenauger and including Dr Kathleen McCulloch from Lancaster University.

The first experiment asked people to estimate the length of various body parts like leg, head and foot by using either their hand or a wooden stick.

The length of the torso was overestimated the most, the foot was the most underestimated part of the body while the length of the arm was more overestimated than the leg.

The experiment was repeated, but this time with the participants being asked to make the estimates while looking at their own reflection in a full-length mirror.

Dr Linkenauger said: “We quantified a very distorted body representation that persists even when viewing one’s body in a mirror, and the distortions across different body parts appear to vary with respect to physical size and tactile sensitivity.

“These distortions were primarily apparent when comparing relative body parts than when comparing a body part to another object.”

The pattern of distortions is  inversely related to Weber’s illusion in that less sensitive parts of the body are overestimated more than more sensitive parts.

“These experiments reveal large and systematic distortions in the relative size of perceived overall body proportions when viewing one’s own body. Not only do these distortions appear when assessing one’s body from a first-person perspective, they also persist when viewing one’s body from a third-person perspective.

“In terms of perceiving relative body proportions, it seems that individuals appear to err drastically in a manner that i consistently differs across different body parts.”