26 August 2009

Autism and extraordinary ability

Genius locus
Apr 16th 2009
From The Economist print edition

There is strong evidence for a link between genius and autism. In the first of three articles about the brain this week, we ask how that link works, and whether “neurotypicals” can benefit from the knowledge

THAT genius is unusual goes without saying. But is it so unusual that it requires the brains of those that possess it to be unusual in others ways, too? A link between artistic genius on the one hand and schizophrenia and manic-depression on the other, is widely debated. However another link, between savant syndrome and autism, is well established. It is, for example, the subject of films such as “Rain Man”, illustrated above.

A study published this week by Patricia Howlin of King’s College, London, reinforces this point. It suggests that as many as 30% of autistic people have some sort of savant-like capability in areas such as calculation or music. Moreover, it is widely acknowledged that some of the symptoms associated with autism, including poor communication skills and an obsession with detail, are also exhibited by many creative types, particularly in the fields of science, engineering, music, drawing and painting. Indeed, there is now a cottage industry in re-interpreting the lives of geniuses in the context of suggestions that they might belong, or have belonged, on the “autistic spectrum”, as the range of syndromes that include autistic symptoms is now dubbed.

So what is the link? And can an understanding of it be used to release flashes of genius in those whose brains are, in the delightfully condescending term used by researchers in the area, “neurotypical”? Those were the questions addressed by papers (one of them Dr Howlin’s) published this week in the Philosophical Transactions of the Royal Society. The society, Britain’s premier scientific club and the oldest scientific body in the world, produces such transactions from time to time, to allow investigators in particular fields to chew over the state of the art. The latest edition is the outcome of a conference held jointly with the British Academy (a similar, though younger, organisation for the humanities and social sciences) last September.

A spectrum of belief
A standard diagnosis of autism requires three things to be present in an individual. Two of these three, impairments in social interaction and in communication with other people, are the results of autists lacking empathy or, in technical jargon, a “theory of mind”. In other words they cannot, as even fairly young neurotypicals can, put themselves in the position of another being and ask themselves what that other is thinking. The third criterion, however, is that a person has what are known as restrictive and repetitive behaviours and interests, or RRBI, in the jargon.

Until recently, the feeling among many researchers was that the first two features were crucial to someone becoming a savant. The idea was that mental resources which would have been used for interaction and communication could be redeployed to develop expertise in some arbitrary task. Now, though, that consensus is shifting. Several of the volume’s authors argue that it is the third feature, RRBI, that permits people to become savants.

Francesca Happé of King’s College, London, is one of them. As she observes, obsessional interests and repetitive behaviours would allow someone to practice, albeit inadvertently, whichever skill they were obsessed by. Malcolm Gladwell, in a book called “Outliers” which collated research done on outstanding people, suggested that anyone could become an expert in anything by practising for 10,000 hours. It would not be hard for an autistic individual to clock up that level of practice for the sort of skills, such as mathematical puzzles, that many neurotypicals would rapidly give up on.

Many, but not all. Dr Happé has drawn on a study of almost 13,000 individual twins to show that childhood talent in fields such as music and art is often associated with RRBIs, even in those who are not diagnosed as classically autistic. She speculates that the abilities of savants in areas that neurotypicals tend to find pointless or boring may result from an ability to see differences where a neurotypical would see only similarities. As she puts it, “the child with autism who would happily spend hours spinning coins, or watching drops of water fall from his fingers, might be considered a connoisseur, seeing minute differences between events that others regard as pure repetition.”

Simon Baron-Cohen, a doyen of the field who works at Cambridge University, draws similar conclusions. He suggests the secret of becoming a savant is “hyper-systematising and hyper-attention to detail”. But he adds sensory hypersensitivity to the list. His team have shown one example of this using what is known as the Freiburg visual acuity and contrast test, which asks people to identify the gap in a letter “c” presented in four different orientations. Those on the autistic spectrum do significantly better at this than do neurotypicals. That might help explain Dr Happé’s observations about coins and raindrops.

Insight, too, is given by autists themselves. Temple Grandin is a professor of animal science at Colorado State University. She also writes about her experience of being autistic. As she describes in the volume, one of the differences she perceives between her experience and that of most neurotypicals is that she thinks in images. She says her mind is like an internet search engine that searches for photographs. To form concepts, she sorts these pictures into categories. She does not, however, claim that all autistic people think like this. To the contrary, she describes two other sorts: pattern thinkers who excel at maths and music, and verbal specialists who are good at talking and writing, but lack visual skills. The latter might not qualify as autistic under a traditional diagnosis, but slip into the broader autistic spectrum.

The question of how the autistic brain differs physically from that of neurotypicals was addressed by Manuel Casanova of the University of Louisville, in Kentucky. Dr Casanova has spent many years dissecting both. His conclusion is that the main difference is in the structure of the small columns of nerve cells that are packed together to form the cerebral cortex. The cortical columns of those on the autistic spectrum are narrower than those of neurotypicals, and their cells are organised differently.

The upshot of these differences is that the columns in an autistic brain seem to be more connected than normal with their close neighbours, and less connected with their distant ones. Though it is an interpretative stretch, that pattern of connection might reduce a person’s ability to generalise (since disparate data are less easily integrated) and increase his ability to concentrate (by drawing together similar inputs).

Rain and sunshine
Given such anatomical differences, then, what hope is there for the neurotypical who would like to be a savant? Some, possibly. There are examples of people suddenly developing extraordinary skills in painting and music in adult life as a result of brain damage caused by accidents or strokes. That, perhaps, is too high a price to pay. But Allan Snyder of the University of Sydney has been able to induce what looks like a temporary version of this phenomenon using magnetism.

Dr Snyder argues that savant skills are latent in everyone, but that access to them is inhibited in non-savants by other neurological processes. He is able to remove this inhibition using a technique called repetitive transcranial magnetic stimulation.

Applying a magnetic field to part of the brain disrupts the electrical activity of the nerve cells for a few seconds. Applying such a field repeatedly can have effects that last for an hour or so. The technique has been approved for the treatment of depression, and is being tested against several other conditions, including Parkinson’s disease and migraines. Dr Snyder, however, has found that stimulating an area called the left anterior temporal lobe improves people’s ability to draw things like animals and faces from memory. It helps them, too, with other tasks savants do famously well—proofreading, for example, and estimating the number of objects in a large group, such as a pile of match sticks. It also reduces “false” memories (savants tend to remember things literally, rather than constructing a mnemonic narrative and remembering that).

There are, however, examples of people who seem very neurotypical indeed achieving savant-like skills through sheer diligence. Probably the most famous is that of London taxi drivers, who must master the Knowledge—ie, the location of 25,000 streets, and the quickest ways between them—to qualify for a licence.

The expert here is Eleanor Maguire of University College, London, who famously showed a few years ago that the shape of the hippocampus, a part of the brain involved in long-term learning, changes in London cabbies. Dr Maguire and her team have now turned their attention to how cabbies learn the Knowledge.

The prodigious geographical knowledge of the average cabbie is, indeed, savant-like. But Dr Maguire recently found that it comes at a cost. Cabbies, on average, are worse than random control subjects and—horror—also worse than bus drivers, at memory tests such as word-pairing. Surprisingly, that is also true of their general spatial memory. Nothing comes for nothing, it seems, and genius has its price.

Savant syndrome, then, is a case where the politically correct euphemism “differently abled” has real meaning. The conclusion that should be drawn, perhaps, is not that neurotypicals should attempt to ape savants, but that savants—even those who are not geniuses—should be welcomed for what they are, and found a more honoured place in society.

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