How does 'prediction error' work in the brain?

Prediction error occurs when incoming sensory information doesn't match the brain's predictions. These errors are not directly experienced but instead serve to update the brain's model, helping it make more accurate predictions in the future. Essentially, we experience the best current prediction, which has accommodated as much error as possible.

Can we perceive true novelty?

According to the predictive brain hypothesis, absolute genuine novelty is difficult to perceive because our brains rely on existing patterns and predictions. Even with unfamiliar objects or environments, the brain uses existing models and is continually updating predictions based on new sensory input and prediction errors.

How do psychedelics like LSD and psilocybin fit into the predictive processing model?

Psychedelics, particularly at higher doses, are thought to disrupt entrenched predictions at higher levels of the brain's processing stream. This 'shaking the snow globe' effect can lead to altered perceptions and experiences like ego dissolution, by allowing for new predictions and patterns to emerge from the sensory data.

What is the role of the body in emotions, according to predictive processing?

Emotions have a strong component of bodily prediction. The feeling of an emotion is linked to the perception of bodily changes, but crucially, it's also a prediction about what's happening in the body and world in the near future, integrating contextual information for a more fine-grained experience than just raw physiological signals.

What is the connection between meditation and predictive processing?

Meditation is suggested to be a practice that helps develop greater control over the brain's precision weighting apparatus. By learning to better control how attention is distributed, individuals can allow sensory information to be processed more directly without being overly influenced by higher-level, abstract predictions.

Key Moments

Predicting Reality: A Conversation with Andy Clark (Episode #322)

Sam Harris

Science & Technology4 min read55 min video

Jun 13, 2023|30,971 views|583|203

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Key Moments

TL;DR

The brain predicts reality, reducing errors. Embodied cognition and extended mind are key.

Key Insights

The brain operates as a predictive machine, constantly generating predictions about sensory input and minimizing prediction errors.

Perception is not a passive reception of data but an active construction based on the brain's predictive models, influenced by prior experience.

Novelty is handled by updating existing predictive models through perception-action loops rather than encountering entirely new information.

Attention is understood as the process of assigning precision weightings to sensory information versus predictions to resolve discrepancies.

Bodily feelings, including pain, are largely constructed from predictions about bodily states, making them susceptible to expectations (e.g., placebo/nocebo effects).

Psychedelics can disrupt entrenched, high-level predictions, leading to experiences of novelty and altered self-perception, especially at higher doses.

Emotions involve predicting bodily changes within specific contexts, and reframing these predictions can alter the emotional experience.

Practices like meditation and hypnosis may enhance control over precision weightings, influencing conscious experience and self-regulation.

Embodied cognition and the extended mind hypothesis suggest that cognition isn't confined to the brain but involves the body and external tools.

THE PREDICTIVE BRAIN HYPOTHESIS

The core of Andy Clark's work posits that the brain functions as a predictive engine, continually generating hypotheses about incoming sensory data. Instead of passively receiving information, the brain actively constructs our experience by comparing sensory input with its predictions and minimizing prediction errors. This process, akin to generative models in AI, explains phenomena like the hollow mask illusion, where prior expectations about faces override direct visual evidence. This predictive framework provides a unified account of perception, cognition, and action.

PERCEPTION AND THE HANDLING OF NOVELTY

Our perception is shaped by the brain's predictive models, which are built over time through experience. When encountering something novel, the brain doesn't create entirely new models but rather updates existing ones. This often involves perception-action loops, where interacting with the novel object helps refine predictions. Absolute, genuine novelty is difficult to conceive within this framework; instead, we integrate new information into our existing predictive structures, adapting them as needed.

ATTENTION AND PRECISION WEIGHTING

Attention, in the predictive processing model, is understood as the process of assigning precision weightings. This refers to how much the brain trusts its predictions versus the incoming sensory information. When sensory data is heavily weighted (assigned high precision), it has a greater influence on experience, potentially overriding inaccurate predictions, as seen with fast-moving peripheral stimuli. Conversely, well-predicted stimuli, like familiar scenes, may be dampened unless attention actively maintains their salience.

PREDICTING BODILY STATES AND EMOTION

The predictive processing framework extends to internal bodily states, including pain and emotions. It suggests that feelings like thirst or pain are predictions about the body's needs or potential damage, designed to maintain homeostasis. This explains phenomena like the placebo and nocebo effects, where expectations strongly influence experienced pain. Emotions are also framed as predictions of bodily changes within a specific context, making them susceptible to cognitive reframing and interpretation.

PSYCHEDELICS AND THE SHAKING SNOW GLOBE

Psychedelics, particularly at higher doses, are theorized to disrupt the brain's entrenched, high-level predictions, akin to shaking a snow globe. This relaxation of predictive constraints allows for new patterns to emerge in perception and thought, potentially leading to ego dissolution and profound shifts in self-perception. By temporarily loosening the grip of established models, psychedelics can offer new ways of experiencing the world, which may be beneficial for conditions like depression and anxiety.

INTERVENING IN PREDICTIVE MECHANISMS

Understanding the brain as a predictive machine offers avenues for intervention and self-improvement. Practices like reframing negative experiences, self-affirmation, meditation, and hypnosis may enhance our ability to control precision weightings. By gaining conscious influence over which predictions are prioritized and how sensory information is interpreted, individuals can potentially modify their emotional responses, reduce suffering, and improve overall well-being. These techniques aim to provide greater voluntary control over our internal experience.

EMBODIED AND EXTENDED MIND

Clark's earlier work on embodied cognition and the extended mind hypothesis complements the predictive processing view. Embodied cognition emphasizes the role of the body in shaping mental processes, while the extended mind suggests that cognitive processes can extend beyond the biological brain to include external tools and environments. The predictive brain provides a functional architecture that supports these broader conceptions of the mind, integrating the brain, body, and world into a unified system for prediction and action.

Mentioned in This Episode

●Supplements

●Software & Apps

●Organizations

●Books

●Concepts

●People Referenced

Harnessing Your Predictive Brain

Practical takeaways from this episode

Do This

Reframe negative experiences, e.g., view anxiety as chemical readiness.

Practice self-affirmation to overcome mental blocks.

Utilize techniques like hypnosis to gain phenomenological control.

Develop control over your attention and precision weightings through practices like meditation.

Consider the dynamic, temporal nature of cognition rather than focusing on static snapshots.

Avoid This

Assume all internal states are direct reflections of external reality without cognitive interpretation.

Get stuck in unconscious, automatic prediction loops that may lead to misery.

Underestimate the power of expectations and predictions in shaping your experience, especially pain.

Dismiss under-exploited tools like hypnosis for managing experience.

Common Questions

The predictive brain hypothesis suggests that our brains constantly generate predictions about incoming sensory information. Our conscious experience is the result of the brain using these predictions to interpret and make sense of the world, rather than simply passively receiving data. The brain aims to minimize prediction errors.

Topics

Psychedelics Neuroscience & the Brain Mindset & Self-Improvement Science & Mathematics Mindfulness Cognitive Biases

Mentioned in this video

People

Carrot Top

Mentioned as an example of a cultural figure whose significance is disproportionate to their actual impact, contrasting with the attention given to Trump.

Hugo Critchley

Colleague of Andy Clark at Sussex, who has done work on emotions and their relation to bodily changes.

George Soros

Cited as an example of a figure targeted by conspiracy theories.

Pee-wee Herman

Mentioned as an example of a cultural figure whose significance is disproportionate to their actual impact, contrasting with the attention given to Trump.

David Chalmers

Co-author with Andy Clark of 'The Extended Mind' hypothesis.

Andy Clark

Guest on the podcast, a professor of cognitive philosophy and author whose work focuses on the predictive brain.

Lisa Feldman Barrett

Mentioned for her work on emotions, particularly as described in her book 'How Emotions Are Made'.

William James

His early theory of emotion, suggesting it's a perception of bodily changes, is discussed as a precursor to modern predictive models.

Sam Harris

Host of the Making Sense podcast, introducing the show and the guest.

Johnny Cochran

Mentioned for his famous 'if the glove don't fit, you must acquit' line, symbolizing a shift towards cynical and slogan-based reasoning.

Vanilla Ice

Mentioned as an example of a cultural figure whose significance is disproportionate to their actual impact, contrasting with the attention given to Trump.

Concepts

Robotics

An area of interest for Andy Clark that ties into embodied cognition and connectionism.

Embodied Cognition

A field of study that influenced Andy Clark's thinking, particularly regarding the role of the body in mental life.

Hollow Mask Illusion

An example used to illustrate the predictive brain hypothesis, where perception is shaped by prior expectations.

Vipassana

A type of meditation course Andy Clark has attended, related to mindfulness.

Artificial Intelligence

A field that has become highly relevant due to recent developments, and which shares principles with predictive processing.

Cortisol

Mentioned as a hormone released in response to stress, e.g., waking up abruptly versus during exercise.

Predictive Processing

A theoretical framework that Andy Clark believes provides a unified account of embodied and extended minds.

The Extended Mind

A hypothesis co-authored by Andy Clark and David Chalmers, suggesting that cognitive processes can extend beyond the brain into tools and technologies.

Connectionism

Andy Clark's early interest, referring to artificial neural networks.

Drugs & Medications

MDMA

Andy Clark has experience with MDMA, which is discussed in relation to emotion due to its non-classic psychedelic nature.

LSD

Mentioned as a powerful psychedelic drug that affects perception.

Fentanyl

Administered to a construction worker experiencing severe pain from a nail injury, highlighting the role of expectations in pain perception.

psilocybin

Mentioned as a powerful psychedelic drug that affects perception.

Software & Apps