Podium: Autism - a different way of thinking

Francesca Happe From the Spearman Medal Lecture given to the British Psychological Society by the

psychiatric researcher

AUTISM IS a devastating disorder of social and communicative development, affecting at least one in a thousand children and adults.

In recent years, there have been considerable advances in understanding the nature of these social difficulties, which appear to spring from a failure to represent thoughts and feelings - sometimes called "mind-blindness". What "mind- blindness", and indeed all deficit accounts of autism, fails to explain is why people with autism are often so unusually good at certain things. Take, for example, the young man with autism who draws like a master although unable to fasten his coat or add five and five. Or the girl with autism who has perfect pitch and can play any tune by ear after only one hearing. Or the boy with autism who can tell you, within seconds, what day of the week any past or future date will fall upon. Or, less spectacularly but more commonly, the child who can construct jigsaw puzzles at lightening speed, even picture-side down, or the adult who, despite generally low ability, recalls the exact date and time of your last visit, perhaps 20 years ago. How can we explain these abilities?

There are at least two possible interpretations of such superior performance. The first is that these individuals are actually of high intelligence, and that these "islets of ability" actually reflect the true intelligence level - which must be underestimated, in that case, by standard assessments. It is possible that children with autism score so poorly on standard IQ assessments because social insight is crucial both developmentally and online in IQ tests. In other words, we acquire knowledge and skills primarily through interaction with other people - and even IQ assessments involve some degree of "mind-reading".

Alternatively, the surprising skills in individuals with autism may reflect the workings of a very different sort of mind - a different information- processing style. Take, for example, the finding that perfect pitch is very common in even musically naive children with autism.

It has been suggested that perfect pitch is relatively easy for normal children to acquire before the age of six years or so, when a shift occurs from processing features (notes) to processing relations among features (melody). Might people with autism retain a feature-based, rather than global, processing style throughout their lives?

There is now good evidence for a detail-focused processing style in autism. This has been referred to as "weak central coherence'. Central coherence is the term for the normal tendency to process information in context for meaning, to integrate information to get the "big picture", usually at the expense of the parts. For example, after hearing this you will hopefully remember the gist but will probably forget the actual words. People with autism often do the opposite - recall the exact words but fail to get the meaning!

Children and adults with autism show weak central coherence, or detail- focused processing, at a number of different levels. At the perceptual level, for example, people with autism (even of low IQ) are very accurate in judging visual illusions - where surrounding context induces misperception in ordinary people. At the visual-spatial level, people with autism excel at finding small shapes hidden in bigger designs with consummate ease. On verbal tasks, too, people with autism process parts rather than wholes - so they may finish a sentence like "The sea tastes of salt and..." with "pepper" or "You can you hunting with a knife and... fork"

This type of detail-focused processing, or weak coherence, appears to be a cognitive style not a deficit, associated with advantages as well as disadvantages.

This is reinforced by findings from an ongoing study of the relatives of children with autism. Autism has a strong genetic component, but it is not as yet clear which genes are involved, nor what traits they might affect in non-autistic individuals who carry them. Our study focuses on skills and assets that might characterise the relatives of those with autism. In particular, it seems that many fathers of boys with autism also show weak central coherence, mirroring their sons' performance assets and deficits despite high IQ and achievement. Many of these fathers excel in professions where the ability to focus on details helps, such as science, engineering or computing.

The challenge for the future is to uncover the cognitive and brain mechanism of coherence to better understand autism. In the meantime, recognition of the many things that people with autism are good at will be a very positive step.