Cambridge Encyclopaedia of Child Development

Acknowledgments: The author was supported by the MRC during the period of this work. Portions of this article also appeared in Encarta (2004). 2 2 Introduction Autism, a condition of neurodevelopment, is more common in males, with onset typically in infancy. It is diagnosed when a child or adult has abnormalities in a 'triad' of behavioral domains: social development, communication, and repetitive behaviour/obsessive interests. People with autism typically may appear to be self-absorbed, or 'in a different world', due to their lack of responsiveness to those around them. It can occur at any point on the IQ continuum, and IQ is a strong predictor of outcome. Autism is also invariably accompanied by language delay (e.g., no single words before 2 years old). Asperger Syndrome (AS) is a subgroup on the autistic spectrum. Those with AS share many of the same features as are seen in autism, but with no history of language delay and where IQ is in the average range or above. Typically, classic autism is identified before age 3, and can be diagnosed as early as 18 months. AS is typically identified later than this, usually around age 6 years-old. Early estimates of the prevalence of autism suggested this was quite rare (4 in 10,000 children), but over the 1990s a series of reports suggested that it was far more common than this. The highest estimate is that autism spectrum conditions (i.e,, autism and AS) occur at a rate of 1 child in every 166. This massive change in reported figures has been interpreted by some to indicate that there is some new environmental cause (e.g., vaccine damage), but critics of this view argue that the 3 3 increase can be explained more simply as the result of widening the diagnostic category (e.g., previously AS was not included); improved awareness among clinicians and the general public (previously there was no special training or media coverage of autism); and the existence of many services for autism (which hitherto simply did not exist). It is widely recognized that people with autism spectrum conditions process information differently to other people. Information processing in the mind is referred to as cognition. The main cognitive theories of autism are summarized below. Mindblindness theory The mindblindness theory proposed that in autism spectrum conditions there are deficits in the normal process of empathizing, relative to mental age (Baron-Cohen, 1995). These deficits can occur by degrees. …