in a quiet house in the suburbs something strange happened someone was washing dishes in the kitchen as they turned off the water they looked into the shiny faucet to see their reflection but they saw nothing no reflection appeared at all they felt a rush of confusion and quickly counted their fingers six fingers not five everything around looked normal but something was very wrong the clock on the microwave showed the right time but it didn't make sense anymore it seemed like a dream but everything felt too real this made them wonder about what we really see
when we look around scientists say that what we see and hear is all made up in our brains like a big dream we all share it's hard to believe but it means that everything we see and hear might not be exactly real this experience as scary as it was made them think deeply about how we see the world it seemed like just another day but it turned into a moment of big questions about life and what's real we tend to believe that what we see is a direct reflection of reality it feels simple your eyes
capture an image of the world which your brain then processes and interprets that's how Vision Works right but modern science suggests it actually happens in Reverse what we see is not a mirror of reality but rather a projection of our own minds an ongoing controlled hallucination that only adjusts when reality forces it to this idea is part of what's called predictive processing a new model in Neuroscience gaining momentum lately backs this up although the concept itself dates back to the Middle Ages essentially it proposes that the brain operates as a prediction machine constantly forming expectations
about what it will perceive based on past experiences and present context these predictions shape everything you sense shapes sounds smells when the sensory input from the environment aligns with these predictions the brain assumes they're correct and continues operating with them for example if if you're walking through a forest and spot a tree-shaped object your brain quickly matches that input with its internal expectation based on past encounters with trees and you recognize it as a tree without consciously thinking about it when the brain's prediction doesn't match the sensory input this is called a prediction error these
errors occur when something unexpected happens like hearing a sudden loud noise in a quiet room or seeing something unusual like a blue tree the brain is organized as a hierarchical prediction machine meaning it processes information in layers higher layers of the brain attempt to predict the larger causes behind the sensory input coming from lower layers this is known as topdown prediction neurons at these higher levels generate predictions about incoming signals and these are constantly compared to the signals received from lower levels called bottomup signals when the top-down predictions match the bottom up sensory input there's
an agreement but if they don't match a prediction error occurs this can happen at any level of the processing hierarchy the brain uses these prediction errors to update its internal model of the world through a process called prediction error minimization it's like a feedback loop the brain makes a prediction receives sensory input and if there's a miss match it adjusts its model to better reflect reality in essence prediction errors highlight what our best guess is missed helping the brain become more accurate and efficient over time if some of this feels unclear don't worry these ideas
will be explained further in the video but first let's walk through an example to make it easier to understand imagine you're walking through a forest from a top- down perspective you expect to see typical Forest scenery green and brown tree-shaped objects however your eyes don't simply capture an image like a camera W instead you see two distinct images each with a significant blind spot where the optic nerve connects to your eye moreover these images are inverted and include visible blood vessels so your brain anticipates seeing something closer to this modified view even though the image
in your mind might resemble the actual scene more accurately now if everything you see aligns with these expectations there's no surprise but if you were to see something unexpected like a blue tree this would disrupt your brain's predictions this discrepancy a bottomup sensation from your eyes creates a prediction error your brain then uses this error to update its internal model of the world consequently the next time you encounter a blue tree you might not be as taken a back instead you'll likely identify it simply as a blue tree allowing you to conserve time and energy
by adjusting your expectations you might already be familiar with the concept of using prediction to minimize information from video compression as it operates on a very similar principle when you stream a video online not every pixel is sent over the internet instead parts of the IM IM that remain unchanged from one frame to the next are transmitted just once the video player updates only the changing elements reducing the need to process all the raw data with each new frame and focusing only on the unexpected changes our brains function in much the same way to enhance
Energy Efficiency by focusing on sensory information that deviates from what is anticipated from an evolutionary standpoint this efficiency is crucial as our brains are not just supported by scientific evidence but also shaped by evolutionary pressures to prioritize survival and reproduction over accurate reality representation our brains have evolved not to provide an accurate depiction of reality but to offer a simplified interface optimized for survival and reproduction consider the concept of predictive processing with a simple everyday example watching a magician perform a card trick when the magician shuffles and then predicts a card you picked your brain
expects to see the card you chose based on the trick setup however if the magician reveals a different card your expectation doesn't match the outcome similar to a prediction error in the brain this mismatch forces you to adjust your understanding of how the trick works just as your brain uses errors to refine its predictions about the world you use the surprise in the trick to update your understanding of The Magician's methods this principle shows that our brains are not just passively receiving information but actively predicting and adjusting to new information all to conserve energy and
focus on what's most important much like deciphering a magic trick rather than seeing each movement in isolation the real world is incredibly complex so our brains simplify it by making assumptions that aren't entirely accurate similar to how computer icons hide the complicated code behind our devices our perceptions offer simplified versions of reality that help us navigate day-to-day life think of physical objects and time like desktop icons their useful shortcuts but they don't reflect the true complexity of What Lies Beneath since we never directly perceive a objective reality our senses can be easily fooled leading us
to experience things that aren't actually there as shown in psychological experiments in conclusion the idea that reality is a controlled hallucination stems from the understanding that our brains are constantly generating predictions about the world based on past experiences and sensory input rather than directly perceiving reality what we see hear and feel is not an objective reflection of the external world but a simplified internal model constructed to help us navigate and survive these controlled hallucinations are shaped by both top-down predictions and bottom up sensory signals with our brains constantly adjusting when there is a mismatch or
prediction error
