According to researchers at Durham University, difficulties with identifying the body language of others presents day-to-day difficulties with social interaction for autism sufferers.
The study showed that adults with autism spectrum disorder (ASD) found it difficult to identify emotions, such as anger or happiness, from short video clips of body movements without seeing faces or hearing sound.
Those adults who struggled most with this task also performed poorly when asked to detect the direction in which a group of dots moved coherently on a screen, thought to be due to visual processing problems.
People with autism often have difficulty in attributing mental states to others and this is thought to be one of the main causes of their struggle to know how other people feel.
The study suggests that visual processing problems may also be a contributing factor.
The findings of the study indicate that one of these visual processing problems is a difficulty in perceiving certain sorts of motion, particularly the movement of spatially separate elements spread over a relatively wide area that nevertheless move in the same direction, which is consistent with most previous findings.
Dr. Anthony Atkinson from Durham University's Psychology Department and lead author of the study said that the strong link between performances on the tests within the study suggests people with autism have trouble reading body movements because they process some basic visual information differently.
The typically developing adults, those without autism, in the study generally performed well in both tests.
Atkinson says his findings help to further understand the underlying causes of social interaction problems experienced by people with autism.
"The way people move their bodies tells us a lot about their feelings or intentions, and we use this information on a daily basis to communicate with each other. We use others' body movements and postures, as well as people's faces and voices, to gauge their feelings. People with autism are less able to use these cues to make accurate judgements about how others are feeling. Our research attempts to find out why," Atkinson said.
"Our findings point to a difficulty in perceiving or attending to motion as a contributor to the problem of gauging people's emotions. We now need to look further to see how exactly this happens and how this may combine with potential difficulties in attention," Atkinson added.
The study has been published in the academic journal Neuropsychologia.