887: Andy Clark | How Our Minds Predict and Shape Reality
Aug 29, 2023
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Andy Clark, a cognitive philosophy professor at the University of Sussex, dives deep into how our brains predict and shape reality. He explains that our minds act as prediction machines, often misinterpreting data from our senses. The conversation touches on phenomena like phantom vibrations and auditory hallucinations, revealing what they say about our brain's predictive powers. Clark also explores the efficacy of placebos and the complexities of perception, especially under stress, shedding light on the ethical implications in healthcare and decision-making.
Our brain operates as a prediction machine, constructing our perception of reality based on available data and prior information.
The brain's predictions shape our perception of colors, as demonstrated by the viral dress illusion.
The placebo effect is influenced by the brain's predictions, leading to actual symptom relief.
Deep dives
The Brain as a Prediction Machine
The podcast episode explores the concept of the brain as a prediction machine. The brain takes in sensory data and constructs our reality based on predictions. It constantly makes guesses about what is happening in order to keep us functioning successfully in the world. Our brain's predictions can sometimes lead to errors or quirks in perception. Understanding the role of prediction in brain processing can shed light on various phenomena, such as auditory and visual illusions, the placebo effect, and even hallucinations.
The Dress Illusion
The podcast discusses the viral dress illusion that sparked debate about its color. People either saw the dress as white and gold or blue and black. Vision scientists explained that this difference in perception is due to individual brains making different assumptions about the direction of light. The brain's predictions about the lighting conditions guide how we perceive colors. The dress illusion highlights how our brain constructs our perception of reality based on predictions and prior information.
Auditory Illusion: Green Needle vs. Brainstorm
The podcast introduces an auditory illusion where individuals hear either 'green needle' or 'brainstorm' depending on their focus and expectation. The brain actively predicts and fills in gaps in the sensory information it receives. By priming the brain with a specific word or thought, it can influence what one hears. This demonstrates how our brain's predictions can shape our auditory perception.
Placebo Effects and Predictions
The podcast explores the placebo effect and how it relates to predictive processing. Placebos can be effective in analgesia, reducing pain, and mitigating fatigue. The brain's predictions about the effect of a treatment can influence physiological responses, leading to actual symptom relief. Understanding the role of predictions in placebo effects can inform potential applications and interventions in healthcare.
Psychological effects of psychedelics on predictive brain
Research conducted by the psychedelics lab in London led by Robin Carhart-Harris suggests that classic psychedelics like LSD and magic mushrooms can release the brain from the grip of top-level self-predictions. At high doses, these substances can disrupt entrenched predictions and allow individuals to experience themselves and the world in new and liberating ways. The psychedelics act on the areas of the brain involved in high-level self-prediction, shaking up the snow globe of predictions and opening the door to different perspectives and experiences.
Predictive brain and the impact on perceptions of self and others
The predictive brain plays a significant role in our perceptions of ourselves and others. It can lead to conditions like body dysmorphia, where individuals have unrealistic perceptions of their own body. Virtual reality interventions have shown promise in challenging these perceptions by altering predictions and providing new experiences. Additionally, the predictive brain can influence our ability to read others accurately, as it relies on predictions based on superficial evidence. This can result in misunderstandings and misjudgments. Insights from research on the predictive brain shed light on the potential impact of predictions on our psychological well-being and interpersonal interactions.
University of Sussex cognitive philosophy professor Andy Clark joins us to discuss how our brains experience and manipulate the reality that surrounds us.
What We Discuss with Andy Clark:
How your brain operates as a prediction machine that constructs an estimation of reality based on available data rather than relaying an entirely precise narrative of the outside world.
The problems that arise when the senses through which your brain gathers data don't always convey an accurate picture of reality.
What phantom vibration syndrome and auditory hallucinations may indicate about your brain's capacity for prediction.
How your brain fills in the gaps when sensory information is missing or incomplete.
Why placebos are often effective — even when you know they're placebos.
