Predictive processing is one of the most influential ideas in contemporary [[Neuroscience]], and it underpins much of [[Lisa Feldman Barrett]]’s work. --- ### **Predictive Processing: The Brain as a Prediction Engine** At its core, **predictive processing**, also called _the predictive brain_ or _the Bayesian brain_ (from [[Bayes' Rule]]) proposes that the brain’s primary function is not to _react_ to the world, but to _predict_ it. The brain is constantly generating a **model of what it expects to happen next**, based on past experience and contextual cues. This model shapes what we [[Perception|perceive]], feel, and even how we move. --- ### **1. Prediction and Sensory Input** - The brain continually sends **top-down predictions** to the senses: “This is what you’re likely to see, hear, or feel next.” - Incoming sensory data from the world provides **bottom-up signals**. - The brain compares its predictions with these inputs. If the prediction matches the input, perception feels stable. If there’s a mismatch — a **prediction error** — the brain must update its model or change the body’s state to bring the world in line with expectation. --- ### **2. Hierarchical Loops** This process happens across **many layers** of the brain: - Lower levels predict simple features (shapes, sounds, textures). - Higher levels predict complex patterns (faces, language, social meaning). Each level sends predictions downward and receives errors upward — a constant negotiation between expectation and evidence. --- ### **3. Action and Emotion as Prediction** Prediction isn’t just about perception; it governs **action** and **emotion** as well. - The brain predicts _what sensory input will result from its own movements_ — allowing us to act smoothly. - It also predicts _what bodily states will occur in certain contexts_ — forming the basis for [[Emotions]]. For example, your brain predicts “heart racing” when you run, and “calm” when you rest. If your heart races while standing still, the brain must interpret this: fear? excitement? caffeine? This is where **Barrett’s constructed emotion theory** fits — emotions are _the brain’s interpretations of its own predictive models about bodily states_. --- ### **4. Efficiency and Illusion** Because prediction dominates, perception is a kind of **controlled hallucination** — the world you experience is mostly the brain’s best guess, corrected just enough by sensory input to stay in touch with reality. It’s efficient: prediction uses less energy than constant raw processing. But it also explains why bias, illusion, and cultural learning shape experience so profoundly — we see what we expect to see. --- In essence: > Predictive processing describes a brain that _minimises surprise_. It survives not by reacting to the world as it is, but by continually guessing what the world will be — and acting to make those guesses come true. --- Would you like me to write a **shorter, visually structured version** of this (something fit for an Obsidian note or infographic — e.g., three levels: “Predict – Compare – Update”)? `Concepts:` `Knowledge Base:`