People with Autism spectrum disorder (ASD) face difficulties in social interaction and communication. ASD is complex and the underlying causes of the developmental disorder are still under investigation. The inability to recognize faces, prevalent in people with ASD, is speculated to be one underlying cause.
It was believed that abnormally rapid dissipation of memory trace is responsible for this deficiency. In other words, the failure is due to faulty short-term memory and not due to the perception of faces per se. This would mean that people with ASD process faces they see like everyone else, but fare worse in remembering or discriminating faces (Weigelt et al. 2012).
A meta-analysis by Jason Griffith et al. analyzed 112 studies involving face recognition in people with ASD (N=2612). The meta-analysis found that individuals with ASD performed worse in face-recognition tasks consistently and across the board. The deficit was large irrespective of age, sex, IQ, task paradigm, and design of experiment.
The researchers compared studies involving face identity recognition tasks with those involving identity discrimination tasks, to see if deficits were restricted to memory. Contrary to expectations, participants showed comparable deficits in face perception. The authors concluded (laying to rest previous theories) that difficulty for ASD individuals in face-recognition has to do with deficits in processing information both at the representational level (memory) as well as the perceptual level.
Read more about the study here.