A popular theory states that the difficulty in facial recognition starts from childhood.
Children with autism are likely to avoid encountering different faces during childhood, which harms the development of the brain area for processing faces.
Darren Hedley, a PhD graduate from Flinders University proposes another theory that could explain this situation.
According to Hedley, people with autism might have an early or unconscious memory of faces and the problem is the way they process the information in their later years.
"People with autism have difficulty recognising peoples' faces and that's believed to contribute to social impairments such as understanding emotion and the thoughts and feelings of others, which is a characteristic of autism," Hedley said.
"But we think that part of the facial recognition deficit in autism may be because of difficulties with complex information processing, which may affect the person's ability to combine and process all that incoming sensory information and to then make an accurate response," he said.
During his doctoral studies, Hedley performed a series of "eye-tracking" tests on adults with autism to determine their conscious and subconscious reaction to new and familiar faces.
Hedley said the findings indicated that people with autism may have "dissociation between implicit processing and explicit face recognition", as opposed to an early memory deficit.
"It's not so much the face isn't recognised by the brain but there's a problem in them being able to then use that information to say 'I recognise this person'."
In addition to his PhD research, Hedley has been involved in a cross-cultural partnership to evaluate the effectiveness of an early detection tool for children with autism that was developed at Flinders University and tried out in Mexico from 2004 to 2008.
A paper on the Autism Detection in Early Childhood assessment tool was recently selected as a winner of Flinders inaugural Best Student Paper Award, which aims to recognise excellence in student research across the University.