Asperger syndrome impedes action anticipation
Researchers in Denmark and the UK have found that in a non-verbal test, adults with Asperger syndrome (an autism-spectrum disorder) do not spontaneously anticipate others' actions as do typical adults and two-year-old children. Their findings, published in the journal Science, contrast sharply with the observation that these individuals pass similar tests in a verbal form and suggest that people with Asperger syndrome can develop workarounds for certain neurological limitations. Many adults diagnosed with Asperger syndrome are highly intelligent but have difficulties in day-to-day social interactions. Part of this difficulty stems from their seeming inability to predict what another person might say or do based solely on their knowledge of the other person's mental state (i.e. their knowledge and beliefs). An example of this anticipation is highlighted in the 'Sally-Ann' False Belief Task (FBT): Sally leaves a marble in a basket and leaves the room, Ann moves the marble into a box, and Sally returns and looks for the marble where she left it. When asked where Sally will look for the marble, a child who understands that Sally's actions will be based on what she believes to be true will answer that she'll look for it in the basket. Children with Asperger syndrome often answer incorrectly; however, affected individuals with a particularly high verbal ability often pass the test. This challenges the hypothesis that the problems people with autism disorders have with 'reciprocal social interaction' can be put down to a neurological failure that impairs their capacity to attribute mental states to self and others. In the current study, a team of researchers from Aarhus University Hospital in Denmark and the University of London in the UK used a modified version of the Sally-Ann FBT to find evidence that high-ability individuals with Asperger syndrome have learned to reason through the task to come up with the right answer, despite still having difficulties with spontaneous mental-states attribution. The researchers applied a non-verbal Sally-Ann FBT to 19 adults with Asperger syndrome and 17 'neurotypical' adults. Instead of prompting for a verbal answer, the researchers looked at the subjects' eye movements during the task. 'Children with autism are more likely to give a correct verbal answer than a correct anticipatory look,' they explain. The team observed that adults with Asperger syndrome tended to look equally at the basket and the box, rather than looking consistently at the box mistakenly chosen by the actor. This suggests that affected individuals do not spontaneously attribute mental states to others but can compute and deduce the mental states of others when asked to do so. However, while slow and deliberate thinking about other people's thoughts can indeed lead to the right answer, it is not the same as the spontaneous and automatic ability to attribute inner thoughts. 'The contrast with neurotypical two-year-olds who show spontaneous looking to the correct location on the same task is striking,' the study reads. 'It is unlikely that differences in motivation are to blame, since neurotypical adults showed the same bias as typically developing children, and the Asperger group exhibited correct anticipatory looking on familiarisation trials when no belief reasoning was required.' The researchers conclude that developing the ability to 'mentalise' (understand the desires and beliefs of others) early is not a prerequisite for developing the ability to anticipate the actions of others later in life. 'We suggest that compensatory learning can circumvent neurophysiological limitations, even without removing the original cause of the limitation,' the study concludes. 'Such compensatory learning might explain the apparent paradox between success on explicit FBTs and continued difficulty in everyday social interaction in individuals with Asperger syndrome.'
Countries
Denmark, United Kingdom