Visual processing and decision-making in children with autism and dyslexia: Insights from cross-syndrome approaches

Atypical visual processing has been reported in a range of developmental conditions, including autism and dyslexia. One explanation for this is that certain neural processes are vulnerable to atypical development, leading to shared effects across developmental conditions. However, few studies make direct comparisons between developmental conditions, or use sensitive-enough methods, to conclude whether visual processing is affected differently in these conditions, or whether they are affected similarly, therefore reflecting a more general marker of atypical development. After evaluating the current state of the science, I will present findings from two sets of studies that apply computational modelling approaches (equivalent noise modelling and diffusion modelling) and measure EEG data in matched groups of autistic, dyslexic and typically developing children aged 6 to 14 years (n = ~50 per group). These methods help pinpoint the component processes involved in processing visual information and making decisions about it, while linking brain and behaviour. The results identify both areas of convergence and divergence in autistic and dyslexic children’s visual processing and decision-making. For example, both autistic and dyslexic children show differences in late stimulus-locked EEG activity in response to coherent motion stimuli, which may reflect reduced segregation of signal-from-noise. However only dyslexic children (and not autistic children) show a reduced accumulation of sensory evidence which is reflected in a shallower build-up of activity in a centro-parietal EEG component. Therefore, while there may be some shared effects across conditions, there are also condition-specific effects, which will require refined theories.