Autism (research) as a disorder of prediction

In 2014, a paper by Pawan Sinha and colleagues claimed that autistic people have difficulties predicting what is coming next. As a result, things seem to happen to autistic people without a cause, so that they inhabit a supposedly ‘magical world’. While it’s a pretty huge jump to go from prediction difficulties to magic, I will put this aside for the moment and concentrate on the science.

One of the exciting things about this theory is that it has the potential to bring together seemingly different aspects of autism. An insistence on routines and repetitive behaviours could be a way of dealing with anxiety that arises because events tend to be unpredictable. Sensory sensitivities could come about because autistic individuals cannot predict and ‘get used’ to (or adapt to) sensory information, meaning that it quickly becomes overwhelming. Even social difficulties could be explained by prediction difficulties, which may affect the ability to understand the minds of others.

While an interesting idea, there is little direct evidence that prediction skills are impaired in autistic individuals. There are studies suggesting that predictive processes are atypical in some ways, but these studies are normally framed within a theory of how the brain works (predictive coding), rather than necessarily showing that prediction abilities are disrupted in everyday life. This is important, because evidence provided in support of atypical predictive coding – such as reduced adaptation to sensory stimulation – does not mean that autistic people cannot make predictions.

When theories are developed, they tend to explain previously collected data. But the real test of a theory is to generate new predictions that can be tested in future studies. Sinha and colleagues suggest some predictions, but these sometimes mix predictions with explanations of existing data. For example, one prediction is that autistic individuals should have atypical brain areas involved in prediction, but this is linked to already collected data suggesting that this is the case. Another prediction is that autistic individuals should have reduced appreciation of humour, which has already been shown in some studies. Moreover, these predictions are not necessarily specific to Sinha et al.’s theory, as brain atypicalities or reduced appreciation of humour could come about for reasons other than difficulties with prediction.

Furtuna Tewolde, Dorothy Bishop and I recently tested a prediction arising from Sinha et al.’s theory. We focused on how well autistic children can predict dynamic objects. This is a skill that Sinha and colleagues said should be impaired in autistic individuals, and we thought it made sense to start with a reasonably simple prediction task before testing more complex predictions. In one task, we showed autistic and typically developing children a cartoon car moving along a track, which vanished before reaching the end. The children were asked to press a button when they thought the invisible car would have reached the end of the track. We found that autistic children were just as good at making this prediction as the typically developing children – even when the task was made more challenging by hiding the car for a longer length of time. They were also just as good as children without autism in a different task that involved a grid filling up with lights.

So, we did not find evidence to support our prediction of impaired prediction in autism. Ironically, this suggests that the prediction deficit may lie with us autism researchers, rather than the autistic children themselves. Clearly, more studies like this are needed, but our results suggest that not all prediction abilities are disrupted in autistic individuals. Perhaps prediction difficulties would be found with a harder task (like those involved in social situations), or if we had seen different people with autism. However, the original theory was not restricted to any particular domain or subset of the autistic population, and it is important that theories remain falsifiable so that autism research doesn’t fall into its own prediction problem.