Priors Bias Perceptual Decisions in Autism, But Are Less Flexibly Adjusted to the Context

Abstract

According to the predictive coding framework, percepts emerge from combinations of sensory input and prior knowledge, whose relative contributions depend on their reliability. Recent predictive coding theories suggest that Autism Spectrum Disorder (ASD) could be characterized by an atypical weighting of priors. Here, we assessed whether individuals with ASD can flexibly adjust the weight (precision) of the prior to the context. Thirty‐one neurotypical adults (NT) and 26 adults with ASD participated in a visual discrimination task designed to elicit a time‐order effect (TOE). The TOE reflects the integration of priors with sensory estimates. We used two experimental contexts: a narrow stimulus range (Narrow condition) and a broader range (Broad condition) in order to induce a prior with a higher and lower precision, respectively. Both groups learned a prior that biased their perception, as shown with the TOE. As expected, the NT group had a larger TOE in the Narrow condition than in the Broad condition, revealing a contextual adjustment of the prior precision. In contrast, ASD participants were more inflexible: the extent of the TOE was not modulated by the context. In addition, the accuracy increased when the stimulus range decreased in both group, which may be interpreted as a contextual adjustment of the sensory precision. To conclude, adults with and without ASD implicitly learned a prior mean, but ASD participants failed to flexibly adjust the prior precision to the context. This increased inflexibility in ASD could account for many symptoms, such as their intolerance of uncertainty. Lay Summary Based on our experience, we have expectations about our environment. Theories suggest that the symptoms encountered in autism could be due to atypical expectations, leading to an impression of an unpredictable world. Using a visual discrimination task, we showed that adults with and without autism were biased by their expectations. Yet, the extent to which expectations biased perception did not depend on the context in autism. This higher inflexibility found in autism may explain symptoms such as resistance to change.

Prediction learning in adults with autism and its molecular correlates

“…priors learned over shorter time scales) gave more heterogeneous results in ASD. For instance, low-level perceptual tasks in autistic adults showed slower prior learning in ASD [ 21 ] or more inflexible priors [ 22 ]. Results of associative learning tasks in ASD often depend on context.…”

Disentangling “Bayesian brain” theories of autism spectrum disorder

“…This possibility was suggested by previous concepts and studies. 11,19,31,36 Because inflexibility has been defined inconsistently in the context of Bayesian perception, the findings might also be explained by other causes, 36,37 as discussed by some authors. 19…”

“…(i) many studies did not compare the relative plausibility of the different hypotheses but tested a single one, (ii) some studies did not examine individuals with a clinical diagnosis of ASD, but autistic traits in the general population, 26,29,31 and when diagnosed individuals were investigated, (iii) sample sizes were mostly small, ranging from N=14 to N=26 in most studies, 19,22,24,25,28,[31][32][33]36,37,44 with few exceptions. 23,27,34 In the current study, we tried to address these issues and designed a set of experiments to systematically test the different hypotheses in a larger clinical sample (47 adults diagnosed with ASD and 50 matched controls).…”

“…These hypotheses have been tested in previous studies, 19,22–25,27–29,31,32,43,44 however, with conflicting results. At least the three aforementioned reasons may explain this inconsistency: (i) many studies did not compare the relative plausibility of the different hypotheses but tested a single one, (ii) some studies did not examine individuals with a clinical diagnosis of ASD, but autistic traits in the general population, 26,29,31 and when diagnosed individuals were investigated, (iii) sample sizes were mostly small, ranging from N =14 to N =26 in most studies, 19,22,24,25,28,31–33,36,37,44 with few exceptions. 23,27,34…”

Flexibility in autism during unpredictable shifts of socio-emotional stimuli. Investigation of group and sex differences.

“…An imbalance in the weight attributed to sensory input and predictions in autism (Brock, 2012;Pellicano & Burr, 2012) could lead to high precision of prediction errors (Van de Cruys et al, 2014), meaning that predictions would not be flexibly adjusted according to the context (Sapey-Triomphe et al, 2021;Van de Cruys et al, 2014). In line with this hypothesis, Sapey-Triomphe et al (2021) found that autistic adults , unlike TD participants, constructed priors but did not flexibly modulate them according to the context during a low-level discrimination task. These findings might generalize to different tasks or situations requiring flexibility and could partly explain flexibility difficulties in autism and why these difficulties appear in unpredictable situations.…”