Predictive Coding Theories of Autism

Predictive coding is a theoretical framework that posits the brain as a hierarchical prediction machine. According to this framework, the brain continuously generates models or predictions about incoming sensory information and updates these models based on the actual sensory input. This process involves minimizing prediction errors—the differences between expected and actual sensory input—through a dynamic interaction between higher-level predictions and lower-level sensory data. In the context of autism, predictive coding theories attempt to explain some of the characteristic features of autism, such as sensory sensitivities, repetitive behaviors, and difficulties with social interactions.


Slow-Updating Theories

These theories propose that autistics update their predictive models more slowly than NTs. This means that their brain's predictions about sensory input do not adjust as quickly to new or changing information.


Implications:

  • Repetitive Behaviors: Slow updating might lead to reliance on repetitive behaviors and routines as a way to manage the uncertainty caused by slow adaptation to new information.
  • Sensory Sensitivities: May contribute to heightened sensory sensitivities because unexpected sensory input can be more overwhelming when predictive models are not quickly adjusted.
  • Social Difficulties: Slow updating can impact social interactions, as the ability to predict and respond to social cues in real-time is crucial for effective communication.


Slow-Updating Theories


1. Predictive Coding Deficit Theory: Autistics may have deficits in predictive coding mechanism that updates internal models based on new sensory information. This leads to slower adaptation to changes in the environment.

Implications: Difficulty in adjusting to new stimuli, preference for routine and sameness, and challenges in dynamic social interactions.


2. Reduced Sensory Prediction Error Theory: There is a reduction in the ability to generate prediction errors (the difference between expected and actual sensory input). This slow error signaling results in slower updating of sensory predictions.

Implications: Persistent sensory sensitivities and difficulties in habituating to repetitive sensory inputs.


High-Precision or Hypoprior Theories

These theories suggest that autistics assign too much precision or certainty to sensory input (the "priors" in predictive coding). This means they place a high degree of confidence in their sensory experiences and are less influenced by prior expectations or context.


Implications:
  • Sensory Overload: High-precision predictions can lead to sensory overload because every sensory detail is given significant weight, making it harder to filter out irrelevant information.
  • Literal Interpretation: In social contexts, this might result in a literal interpretation of language and difficulty understanding nuances or implied meanings, as context is given less weight.
  • Detail-Oriented Processing: This theory aligns with the idea of weak central coherence, where individuals focus on specific details rather than integrating information into a broader context.


High-Precision Theories


1. Aberrant Precision of Prediction Errors: Autistics assign abnormally high precision to sensory prediction errors. This means they give excessive weight to the actual sensory input, leading to overreaction to sensory stimuli.

Implications: Sensory overload, heightened sensory sensitivities, and detail-oriented processing.


2. Increased Sensory Precision Theory: There is an overall increase in the precision of sensory predictions, meaning the brain treats all sensory input as highly reliable. This high precision can overshadow prior knowledge and context.

Implications: Literal interpretation of sensory information, difficulty filtering out irrelevant stimuli, and challenges in contextual integration.


3. Attenuated Priors Hypothesis: In this theory, individuals with autism have attenuated (weakened) priors, meaning their prior beliefs or expectations about sensory input are less influential. This leads to a reliance on current sensory input with high precision.

Implications: Difficulty with abstract thinking and integrating broader context, leading to a focus on immediate and concrete details.


Additional Predictive Coding Theories in Autism


1. Aberrant Salience Theory: This theory suggests that autistics assign aberrant salience to sensory stimuli, meaning they might over- or under-estimate the importance of certain stimuli. This can disrupt the prediction-error minimization process.

Implications: This could lead to difficulties in filtering relevant from irrelevant sensory information, contributing to sensory sensitivities and social challenges.


2. Precision of Priors and Prediction Errors:This perspective emphasizes the balance between the precision of priors (predictions) and the precision of prediction errors. In autism, there might be an imbalance, with either overly precise priors or overly precise prediction errors.

Implications: This imbalance can result in either rigid behavior patterns (overly precise priors) or heightened sensory responses (overly precise prediction errors), affecting adaptability and sensory processing.


3. Adaptive Coding Hypothesis: Proposes that the coding mechanisms in the autistic brain is adaptively tuned to a different set of environmental statistics, leading to altered predictive coding processes.

Implications: This adaptive tuning might help explain both strengths (e.g., exceptional attention to detail) and challenges (e.g., difficulty with social cues) in autism.


4. Enhanced Perceptual Functioning Model: Suggests that enhanced low-level perceptual processing in autism leads to superior detail detection and discrimination but might interfere with higher-level integrative processing.

Implications: While this model is not purely predictive coding, it aligns with the idea that heightened precision in sensory processing can impact broader cognitive functions.


5. Predictive Homeostasis Theory: This theory proposes that the predictive coding system in autism might be tuned to maintain a state of homeostasis, leading to atypical responses to changes and novelty.

Implications: This could explain a preference for routine and predictability, as well as challenges in adapting to new or unexpected situations.


6. Intense World Theory: This theory posits that the autistic brain is hyper-reactive to sensory input, leading to an "intense world" experience. This hyper-reactivity is thought to result from increased neuronal connectivity and hyper-plasticity.

Implications: This heightened sensitivity can lead to sensory overload, social withdrawal, and a preference for predictable environments.


Predictive Coding Theories are not Mutually Exclusive and can co-exist in the same individual. 

It is indeed possible for an autistic to exhibit characteristics of different predictive coding theories. These mechanisms are not mutually exclusive and can coexist within the same person.

  • Cumulative Effects: The combined effects of slow updating and high precision can amplify certain characteristics of autism. For example, sensory overload (due to high precision) might be compounded by an inability to quickly adapt to new sensory information (due to slow updating).
  • Behavioral Strategies: The interplay between these mechanisms can influence behavioral strategies. For instance, repetitive behaviors may serve as a coping mechanism to manage the uncertainty from slow updating while also providing predictable sensory input to mitigate overload from high precision.

Examples of Coexistence:

Sensory Processing:

  • Slow-Updating: An individual might take longer to adapt to new sensory environments, leading to prolonged discomfort.
  • High-Precision: At the same time, the individual might be highly sensitive to specific sensory inputs, experiencing each stimulus with high intensity.

Social Interaction:

  • Slow-Updating: The person may struggle to adjust to new social information, leading to difficulties in dynamic social interactions.
  • High-Precision: Simultaneously, they might focus intensely on specific aspects of social cues (e.g., exact wording) while missing the broader context.

Routine and Predictability:

  • Slow-Updating: Routines provide a stable environment that does not require frequent updates to predictive models.
  • High-Precision: Predictable routines help manage sensory input by reducing the occurrence of unexpected stimuli.

Aberrant Salience Theory:

  • Sensory Processing: An individual might experience heightened salience of irrelevant sensory details (high-precision) and struggle to adapt to changing sensory environments (slow-updating), leading to sensory overload.
  • Social Interaction: Overemphasis on irrelevant social cues (high-precision) combined with slow adaptation to new social contexts can exacerbate social difficulties.

Precision of Priors and Prediction Errors:

  • Sensory Processing: Imbalance between overly precise prediction errors and slow updating of priors can lead to persistent sensory sensitivities and difficulties filtering sensory input.
  • Routine and Predictability: Rigid behavior patterns (overly precise priors) may coexist with slow adaptation to changes, reinforcing the need for routines.

Adaptive Coding Hypothesis:

  • Cognitive Processing: Unique tuning to environmental statistics (adaptive coding) might result in detailed-oriented processing (high-precision) and slow adaptation to new contexts (slow-updating).
  • Creative Expression: Adaptively tuned coding mechanisms can lead to exceptional detail in artistic endeavors (high-precision) while maintaining consistent themes (slow-updating).

Enhanced Perceptual Functioning Model:

  • Visual Arts: Enhanced low-level perceptual processing (high-precision) combined with slow adaptation to new techniques (slow-updating) can lead to highly detailed and consistent artistic outputs.
  • Poetry and Storytelling: Heightened perceptual detail (high-precision) coupled with a preference for familiar themes (slow-updating) can result in richly detailed and nuanced creative works.

Predictive Homeostasis Theory:

  • Behavioral Strategies: Aiming to maintain homeostasis, individuals might exhibit repetitive behaviors (slow-updating) and heightened responses to sensory changes (high-precision).
  • Social Interaction: Efforts to maintain predictive homeostasis can lead to rigid social routines (slow-updating) and heightened sensitivity to social nuances (high-precision).

Intense World Theory:

  • Sensory Processing: Hyper-reactivity to sensory input (high-precision) combined with slow adaptation to sensory changes can result in intense sensory experiences and prolonged discomfort.
  • Social Interaction: Heightened neuronal connectivity (high-precision) and slow adaptation to social stimuli can contribute to social withdrawal and challenges.


Reconciling Predictive Coding Theories with Autism Stereotypes

The stereotype that all autistic individuals are incapable of abstract thought or cannot see the big picture is a significant oversimplification and does not accurately reflect the diversity of cognitive abilities and strengths found within the autistic community. While some autistic individuals may struggle with certain aspects of abstract thinking or contextual integration, many excel in areas that require substantial abstract thinking, creativity, and nuanced understanding, such as visual arts, poetry, and storytelling.


Detail-Oriented Strengths:

  • Predictive Coding and Detail Processing: The high-precision theories suggest that autistic individuals often process sensory input with great detail and precision. This can lead to increased ability to notice and represent fine details, which is a significant asset in visual arts. 
  • Slow-Updating and Consistency: Slow-updating theories propose that individuals with autism might prefer consistency and familiarity. In the context of art, this can translate to a deep exploration of themes, techniques, or mediums, leading to highly developed skills and innovative approaches within familiar domains.


Abstract and Creative Thinking:

  • Visual Arts: Many autistic individuals excel in visual arts, an area that can involve both concrete detail and abstract thinking. The ability to focus intensely on visual details can enhance artistic creation, while abstract thinking allows for the expression of complex ideas and emotions through visual metaphors.
  • Poetry and Storytelling: These forms of expression often involve metaphor, symbolism, and abstract concepts. Autistic poets and storytellers may use their unique perspectives and attention to detail to craft deeply moving and nuanced works. Predictive coding theories can explain how these individuals might use detailed observations to build complex, abstract representations in their work.


Cognitive Flexibility and Abstract Thought:

  • Hypoprior Theory: This theory suggests that autistic individuals might assign high precision to current sensory input, potentially making it challenging to integrate broader contexts at times. However, this same precision can enable a unique and focused approach to abstract thinking, where concrete details are woven into larger, abstract themes in creative works.
  • Nuanced Understanding: Many autistic individuals demonstrate a profound understanding of abstract concepts when they align with their interests or when communicated in a manner that resonates with them. For instance, a deep interest in a particular subject can lead to abstract thinking and creative outputs that are highly nuanced and metaphorical.


Predictive coding theories provide a framework for understanding the diverse cognitive and sensory processing differences observed in autism.  However, it is crucial to recognize the limitations and oversimplifications often associated with these theories, particularly the stereotype that autistic individuals are incapable of abstract thought or broader contextual integration. In reality, many autistic individuals do engage in abstract thinking, creativity, and nuanced understanding, excelling in fields such as visual arts, poetry, and storytelling. This highlights the importance of appreciating the full spectrum of cognitive strengths within the autistic community. Understanding and acknowledging this diversity can lead to more effective research, personalized interventions, and a more inclusive and supportive environment for autistic individuals.


As always, nothing is set in stone in autism, we simply don’t know enough. A lot more research is needed that is tailored to the profile of the autistic rather than a blanket solution that applies to all.




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