Separate thinking skills underlie autism, attention deficit

For more than 30 years, scientists have debated which of two cognitive abilities, theory of mind and executive function, is more closely related to autism.

Difficulty with theory of mind — the ability to infer other people’s mental states — can complicate social behavior and communication¹.

Trouble with flexible thinking, working memory and self-control — the core executive functions — can impair the ability to adapt to changing situations, understand new concepts, set goals and keep calm².

Until now, research into which of the two abilities relates more to core autism traits has been inconsistent. My team has new findings suggesting that theory of mind is the more important contributor to autism and that problems with executive function are more often associated with attention deficit hyperactive disorder (ADHD). The latter often accompanies autism.

Understanding how these core cognitive skills relate to behavior in real-world social situations has implications for treatments. Improving theory of mind skills might help teenagers with autism navigate their complex social world — to understand their peers’ behavior and respond appropriately. Boosting cognitive control might help them focus and control their impulses, which can improve social relationships as well as academic performance.

This treatment could be effective as late as in adolescence, because we know that cognitive abilities are related to success and independence in adulthood.

Statistical tricks:

A decade ago, my colleagues and I gave 100 adolescents with autism a battery of cognitive tasks³. These included the ‘reading the mind in the eyes’ test, in which people guess the emotions portrayed in pictures of eyes. We also examined executive function with a card-sorting task that measures the ability to adapt to new rules, and a test of working memory that taps the capacity to recall strings of digits.

We characterized the adolescents’ behavior using a range of measures of autism traits, including the Social Responsiveness Scale and the Autism Diagnostic Observation Schedule, along with two assessments of ADHD traits.

We looked at the association between theory of mind and executive function and two core autism features: social communication and rigid and repetitive behaviors. We used a statistical approach that allowed us to look at the strength and significance of individual associations when a large number of variables are likely to be interrelated.

The more difficulties the adolescents in our study had with theory of mind tasks, the higher their levels of repetitive behaviors and social communication difficulties, we found. Problems with executive function tasks, however, are not related to either trait.

We do not know why theory of mind skills influence repetitive behavior and rigid thinking. It is possible that the connection is indirect: Having trouble deciphering others’ behavior might cause anxiety, which could lead to unusual behavior and thought patterns⁴.

Attention focus:

Last year, we explored how ADHD relates to executive function and theory of mind⁵. We found the opposite pattern from the one we had found in autism: Executive function difficulties, but not theory of mind, are associated with ADHD traits such as inattention and impulsivity.

This pattern is consistent with the idea that the features of autism and ADHD are dissociable.

As much as 40 percent of young people with autism meet diagnostic criteria for ADHD. And individuals who have both conditions may have difficulties with both theory of mind and aspects of executive function — a phenomenon sometimes referred to as the ‘double hit.’ But each condition also has its hallmark traits.

Because we studied adolescents, our results do not necessarily inform how autism unfolds during development. However, the associations that we have identified have implications for autism treatment.

For instance, teenagers who have both autism and ADHD might benefit most from therapies that improve both theory of mind and cognitive control. Our findings may also help clinicians match therapies to individual young people with autism so as to maximally improve their everyday functioning.

Tony Charman is chair of clinical child psychology at the Institute of Psychiatry, Psychology and Neuroscience at King’s College London.