Increased influence of prior choices on perceptual decisions in autism

  1. Helen Feigin
  2. Shir Shalom-Sperber
  3. Ditza A. Zachor
  4. Adam Zaidel

  • Curated by eLife

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    Summary: The study addresses a timely and important question of the role of prior choices on perceptual decisions in individuals diagnosed with autism; 17 high functioning (but not mild cases) children and teenagers (8-17 years) with ASD. The experiments are well motivated and thoughtfully designed. Using a model to dissociate the contribution of prior stimuli and choices, the authors found a strong effect of prior choices not stimuli, which is stronger in ASD than controls. Similar results from another data set are also reported.

    Overall, this is a strong study with a sophisticated protocol, elaborate data analysis, ASD participants who were tested on a large battery, in-depth analysis of the literature with interesting insights, interesting results and a well written manuscript.

    The first two experiments provided compelling evidence that prior choices affect perceptual decision making in ASD, but the outcome of the response invariant condition suggests that the authors' interpretation goes beyond the data. This has serious implications for the interpretations of the findings. Also, the bias interpretation should be informed by measures of performance.

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Abstract

Autism spectrum disorder (ASD) manifests sensory and perceptual atypicalities. Recent theories suggest that these may reflect a reduced influence of prior information in ASD. Some studies have found reduced adaptation to recent sensory stimuli in ASD. However, the effects of prior stimuli and prior perceptual choices can counteract one-another. Here, we investigated this using two different tasks (in two different cohorts): (i) visual location discrimination, and (ii) multisensory (visual-vestibular) heading discrimination. We fit the data using a logistic regression model to dissociate the specific effects of prior stimuli and prior choices. In both tasks perceptual decisions were biased toward recent choices. Notably, the ‘attractive’ effect of prior choices was significantly larger in ASD (in both tasks and cohorts), while there was no difference in the influence of prior stimuli. These results challenge theories of reduced priors in ASD, and rather suggest an increased consistency bias for perceptual decisions in ASD.

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  1. eLife

    Reviewer #3:

    General assessment:

    This paper applies a sophisticated psychophysical paradigm to assess the effect of prior choices on perceptual decisions in a group of 17 high functioning (but not mild cases) children and teenagers (8-17 years) with ASD. Using a model that is assumed to dissociate the contribution of prior stimuli and choices, the study found a strong effect of prior choices not stimuli, which is stronger in ASD than controls. Similar results from another data set are also reported. There was no convincing evidence found for a correlation between the effect of the priors and the ASD severity.

    Overall, this is an impressive study with a sophisticated paradigm, elaborate data analysis, ASD participants who were tested on a large battery, in-depth analysis of the literature with interesting insights, convincing results (but see below) and a well written manuscript.

    Major issues:

    1. The finding from the model that the prior stimuli did not have a positive impact (and even negative) on the decision bias is counter-intuitive and needs explanation (I apologize if there is one and I missed it). There were typically 5 prior trials, ~4 of them on one side, e.g. right, resulting in a higher rate of right presses on the test (because the test was unbiased, and the results showed a bias). Assuming the prior trials were mostly replied correctly, there should be a correlation between the stimuli and the choices. I see 2 possible reasons why the model produced negative weights - one is that indeed the choices were different from the stimuli, in which case we need to know the performance of the participants on the prior trials (which would be useful anyway). The other possibility is that the choices for the model were binary and the stimuli were continuous. If the stimuli had been coded as binary, it would have been difficult to dissociate between the stimuli and the choices. In this case, the conclusion should be that the prior stimulus laterality could have impacted the test choices, but not their magnitude. This issue should be explained in the text.

    2. The performance on the test trials staircase procedure is not reported, only the PSE difference. It would be useful to know if the groups differed on this, as the example psychometric curves shown seem shallower in ASD. Biases are likely to push the staircase procedure to higher laterality discrimination thresholds. I suspect (but without proof) that worse performance (more errors) on the staircase procedure may amplify (but not create) the bias. It would be useful to show the performance data and discuss this issue.

    3. The paradigm used is quite complex and complex paradigms are more difficult to fully understand, so I wonder about the justification for it. Why is it better or different from testing SDT shift of criterion by change in target probability? For example, in a Yes/No experiment for contrast detection set around 70% correct, the criterion may shift when there are more Yes or No trials. What would the authors expect in such an experiment? It would be useful to discuss this for the wondering reader.

    4. About the interpretation: the word "perseveration", i.e. a tendency to repeat the last key or recent keys is not mentioned. The authors conducted a "response invariant" experiment which showed significant but much smaller biases (Figure 7). Are these significantly smaller than the 1st experiment (as seems from the plots)? If so, one cannot rule out a major contribution of repeating the recent keys, i.e. perseveration. It would be useful to see the raw data in this case, e.g. what is the %trials of pressing right when the priors were biased to the right. My understanding is that it must be high given that the staircase was symmetric (50/50 trials on left and right) and that a bias emerged from the data.

    5. I wonder if the data could be analyzed to reveal the different contribution of preceding trials, i.e. the details of the serial dependency. Currently, all previous trials are treated equal in the model, but their contribution is not necessarily equal.

  2. eLife

    Reviewer #2:

    General assessment and major comments:

    The study addresses a timely and important question of the role of potential modulations in perceptual decision-making in the atypicalities observed in perceptual processing of individuals diagnosed with autism. The manuscript is important, and the methods used are sound.

    There are however some issues to consider:

    Thresholds, or other indications of sensitivity and precision of performance in the task are not detailed (although judging by the individual psychometric functions presented in the figures, slopes seem less steep in ASD). Was sensitivity considered in any way in the analysis? wondering how the model fitting would look like and how it would interact with the biases. Bias magnitude could vary as a factor of noise or sensitivity.

    Also, could larger consistency bias in the ASD group result from weaker performance, more lapses of attention etc.?

    Age range is quite large. Did you check for age-related differences? I understand the sample size is not big enough to analyze data across different age groups but maybe as a covariate? (there is also the problematic issue of determining sample size of children based on the study in young adults).

    Not sure why the effects of prior stimuli are considered adaptation effects, particularly in the first experiment where stimuli were briefly presented. Also, regarding the argument in the Introduction about Bayesian priors producing positive effects -- there are other prior effects that may cause 'negative effects' in relation to prior expectations (for example, in perceptual illusions such as the weight-brightness illusion).

    Can you think of a reason why controls did not show significant consistency bias in their responses in the heading discrimination?

    There is some wording in the reports of the statistics such as 'more significant' or 'more marginally' that needs to be rephrased.

    Were the analyses corrected for multiple comparisons?

    Usually RTs in this sort of perceptual task are longer in ASD. Wonder how this is not the case here, although instructions for the subjects emphasize speed and accuracy.

    I agree with the authors. It is interesting to look at correlations between the effects of prior choices and clinical scores of repetitiveness and flexibility in ASD. Did you look at the correlation between the effects of prior choices and SCQ scores across the two groups? Previous work documenting correlation between autistic traits (AQ) and modulated perception provided important information about the generalization of the findings to the broader spectrum of autism in the wider, nonclinical population (see Lawson, Mathys, & Rees, 2017; Hadad, Scwartz, & Binur, 2019).

  3. eLife

    Reviewer #1:

    General Assessment:

    I found the studies to be well motivated and thoughtfully designed to disentangle competing interpretations in the extant literature on visual perception in ASD. The first two experiments provided compelling evidence that prior choices affect perceptual decision making in ASD, but the outcome of the response invariant condition suggests that the authors' interpretation goes beyond the data.

    Substantive Concerns:

    "In summary, we found here that individuals with ASD demonstrated an increased influence of recent prior choices on perceptual decisions (vs. controls),..." is the major finding in the paper, quoted here in the concluding paragraph. It seems, however that the data support a narrower (and potentially less interesting) conclusion that individuals with ASD demonstrated an increased influence of recent button presses/motor responses, as the finding which forms the basis of the summary went away when different keys were used to report prior vs. test responses (i.e., in the response invariant condition). I understand that the authors present these data as challenges to theories of attenuated priors in ASD, but they seem to sidestep the issue that these data make their general conclusion more complicated.

    For completeness, it would be helpful to present some information on the stimulus values for the test stimuli, as these were set individually using a staircase. Where did these staircases converge? Were there group differences?

  4. eLife

    Summary: The study addresses a timely and important question of the role of prior choices on perceptual decisions in individuals diagnosed with autism; 17 high functioning (but not mild cases) children and teenagers (8-17 years) with ASD. The experiments are well motivated and thoughtfully designed. Using a model to dissociate the contribution of prior stimuli and choices, the authors found a strong effect of prior choices not stimuli, which is stronger in ASD than controls. Similar results from another data set are also reported.

    Overall, this is a strong study with a sophisticated protocol, elaborate data analysis, ASD participants who were tested on a large battery, in-depth analysis of the literature with interesting insights, interesting results and a well written manuscript.

    The first two experiments provided compelling evidence that prior choices affect perceptual decision making in ASD, but the outcome of the response invariant condition suggests that the authors' interpretation goes beyond the data. This has serious implications for the interpretations of the findings. Also, the bias interpretation should be informed by measures of performance.

  5. Version published to 10.1101/2020.07.28.224808 on bioRxiv