Abstract
Background Autism Spectrum Disorder (ASD) is a class of neurodevelopmental disorders that affect social interaction, communication, sensory processing, and other aspects of cognition and behavior. Although ASD research has traditionally focused on social cognition, alterations to sensory processing are increasingly recognized as a core phenotype. Perceptual decision-making lies at this interface, and influential theories propose a Bayesian decision-theoretic framework for understanding processing alterations in ASD. Yet perceptual decision making has received scant direct investigation. Objectives Here we ask two questions about Bayesian decision making in ASD. First, to what extent does perceptual decision making in ASD incorporate prior knowledge, sensory uncertainty, and reward? Second, to what extent does higher-level metacognitive decision making in ASD incorporate these three components? Method Two groups of participants, ASD and typically developed (NT), performed an orientation categorization task. We manipulated priors, cost function, and likelihood by varying category probability, reward, and stimulus contrast, respectively. Participants simultaneously reported stimulus category (perceptual decision) and decision confidence (metacognitive decision) by pressing a key. Before each experiment, we trained participants with categorical and confidence reports. To validate the Baysian component manipulations, participants explicitly reported category probability and category reward on random trials. Results Both groups shifted criteria to favor the category with higher probability or reward and relied more on priors or rewards when contrast (sensory evidence) was low. Furthermore, ASD and NT were suboptimal to the same extent. Finally, the ASD group showed typical abilities in metacognitively assessing their perceptual performance. Conclusion Contrary to recent views, when making a categorical judgment, individuals with ASD rely on Bayesian inference to the same degree as NT. Our study suggests that neither alterations in perceptual decision-making nor differences in the integration of explicit priors with low-level sensory information can explain findings of atypical perception in ASD.