Autistic and non-autistic children’s perceptual decision-making in visual orientation and motion tasks and the effect of task instructions

Diffusion decision models (DDMs) offer the potential to go beyond standard accuracy and response time indices to better understand perceptual decision-making in autism. One unanswered question is whether autistic participants can flexibly adjust the speed and accuracy of their decision-making according to task demands. Across two pre-registered studies, 50 autistic and 50 non-autistic children aged 6-14 years completed a visual orientation task with no explicit instructions to be fast or accurate, and a visual motion task under both speed-emphasis and accuracy-emphasis instructions. These studies allowed us to investigate the influence of task, task instruction and modelling approach on group differences. We fit Bayesian hierarchical DDMs using a rigorous blind modelling approach, and follow-up two-step non-hierarchical analyses. For the first time, we showed that autistic children can flexibly adjust their decision-making strategies according to speed-accuracy instructions. Irrespective of task, instructions and modelling approach, we found no conclusive evidence of group differences in any DDM parameters, highlighting that autistic and non-autistic children were both able to modulate task performance according to instruction. These results show that cognitive flexibility is not uniformly reduced in autism. To better understand within-participants variability, we investigated relationships between decision-making parameters and ADHD-related traits, reading ability, sensory processing and coordination skills. We found task-specific evidence for relationships between DDM parameters and sensory under-responsivity, sight-word reading and hyperactivity/impulsivity. Resolving inconsistent results when applying DDMs to autism will require contrasting modelling approaches, clear reporting of task instructions, and considering dimensions that co-occur with autism.