16 October 2008
People with autism make more rational decisions
People with autism-related disorders are less likely to make irrational decisions and are less influenced by gut instincts, according to research funded by the Wellcome Trust. The study adds to the growing body of research implicating altered emotional processing in autism.
Decision-making is a complex process, involving both intuition and analysis: analysis involves computation and more ‘rational’ thought, but is slower; intuition, by contrast, is much faster, but less accurate, relying on heuristics, or ‘gut instincts’.
Previous studies have shown that our response to a problem depends on how the problem is posed – the so called ‘framing effect’. A surgeon who tells a patient that there is an 80 per cent chance of surviving an operation is more likely to gain consent than one who tells the patient there is a 20 per cent chance of dying, even though statistically these mean the same thing.
Now, in a study published today in the ‘Journal of Neuroscience’, researchers in Professor Ray Dolan‘s group at the Wellcome Trust Centre for Neuroimaging at University College London (UCL) have used the framing effect to study decision making in people with autism spectrum disorders (ASD).
According to the National Autistic Society, these disorders affect up to one in a hundred people in the UK. They range from mild conditions, such as Asperger’s syndrome, through to highly disabling conditions, such as Rett syndrome. Symptoms – which vary widely in severity – include language problems, poor social interaction and rigid patterns of behaviour and thinking.
Participants in the study performed a task involving deciding whether or not to gamble with a sum of money. For example, they would be given £50 and be presented with two options: option A was to keep £20 and option B was to gamble, with a 40 per cent chance of keeping the full £50 and a 60 per cent chance of losing everything. This version was known as the ‘gain frame’.
At other times, the participants would be presented with the ‘loss frame’, the only difference being that option A was phrased in terms of losing money. In other words, when given £50, option A was to lose £30 of their initial amount and option B was the same as above.
Despite option A being essentially the same in both gain and loss frames, the researchers found that the ‘control’ participants – those without ASD – were more likely to gamble if the first option was to ‘lose’ rather than ‘keep’ money. For participants with ASD, this effect was much smaller, suggesting that this latter group was less susceptible to the framing effect ‘ in other words, they were less likely to be guided by their emotions into making inconsistent or irrational choices.
“People with autism tended to be more consistent in their pattern of choices, their greater attention to detail perhaps helping them avoid being swayed by their emotions,” says Dr Neil Harrison.
Although this attention to detail and a reduced influence of emotion during decision making is beneficial in some situations, it may be a handicap in daily life, explains Dr Benedetto De Martino.
“During social interactions a lot of information must be processed simultaneously, making this a very complicated computational task for the brain,” he says.
“To solve these complex problems we rely on simplifying heuristics – gut instincts – rather than extensive logical reasoning. However, the price that we seem to pay for this ability is that sometimes irrelevant contextual information leads us to make inconsistent or illogical choices.
“Less reliance on gut instincts by people with autism may underlie their difficulties in social situations, but also enable them to avoid potentially irrelevant emotional information and make more consistent choices.”
The study reinforces previous research suggesting that the key difference in how people with ASD make decisions may lie in the amygdala, an area of the brain critically involved in processing emotions. In a 2006 study published in the journal ‘Science’, Dr De Martino and colleagues showed that decision making involves activity in the amygdala. In people with ASD, the amygdala has been shown to differ from that in the majority of people – not in size, but in the density of nerve cells.
Dr Harrison believes their research may play an important role in highlighting the strengths of people with ASD, rather that focusing on negative aspects of the disorder.
“Our research shows a positive strength in people with autism, more research focusing on abilities as well as disabilities of people with autism will enable us to gain a clearer understanding of this condition while simultaneously assisting people with autism in living rich and full lives.”
Notes for editors
1. De Martino B, Harrison NA et al. Explaining enhanced logical consistency during decision making in autism. J Neurosci 2008.
2. The Wellcome Trust is the largest charity in the UK. It funds innovative biomedical research, in the UK and internationally, spending over £600 million each year to support the brightest scientists with the best ideas. The Wellcome Trust supports public debate about biomedical research and its impact on health and wellbeing.
3. Founded in 1826, UCL was the first English university established after Oxford and Cambridge, the first to admit students regardless of race, class, religion or gender, and the first to provide systematic teaching of law, architecture and medicine. In the Government’s most recent research assessment exercise, 59 UCL departments achieved top ratings of 5* and 5, indicating research quality of international excellence.
UCL is in the top ten world universities in the 2007 THES-QS World University Rankings, and is the third-ranked UK university in the 2007 league table of the top 500 world universities produced by the Shanghai Jiao Tong University. UCL alumni include Marie Stopes, Jonathan Dimbleby, Lord Woolf, Alexander Graham Bell and members of the band Coldplay.