Getting It Right

We talked yesterday about how the brain builds models of the world. These models allow us to explain the information our senses provide and build a causal understanding of how our actions can meet our needs so we can navigate the world effectively. 

Because models are simplifications of the world, they are wrong all the time: in big and little ways.  

How do I know if my model is right? Or at least if it’s good enough to get what I need?

When our senses gather information that contradicts our model of the world, we experience a familiar feeling called “surprise’ (or, in scientific terms, “prediction error”).

Think of what happens when someone you know cuts their hair — the first few times you see them, your model of how that person looks is wrong, and it takes time to adjust. “I just can’t get used to you with short hair!”  

Importantly our brains don’t just live stream information from your senses – that would be way too much information to process! Instead they use a similar mechanism to what online streaming services use 📺. They only transmit new information, what’s changed from the prior model of the world. Only surprises or prediction errors cause our brains to notice sensory information. Everything else we experience is actually just our brains’ model or best guess of the world.

What we perceive moment to moment is not reality itself. It’s not direct sensory information, but the brain’s interpretation of it. Everything we see, hear, and feel is the brain’s best guess of what’s happening in the world.

Prediction errors tell us – “wait, this model is different from what we’re seeing out here. We’ve gotta check this out.”  

Prediction errors allow us to constantly improve our models over time. The brain is trying to build you a perfect model of the world so you can perfectly meet your needs at all times. Neuroscientists believe that “minimizing prediction error” or “minimizing surprise” is literally the prime directive of the brain.

Importantly, these prediction errors are often experienced very quickly, and we react intuitively to them, rarely letting the surprise rise to the level of consciousness, making us respond with the same, intuitive script over and over again. This speed is highly efficient for the brain, but if that script isn’t effective, this speed can make it hard to change our behavior. The goal of many therapies is to slow down this surprise process to give your conscious brain the opportunity to make different, more effective decisions when prediction errors occur.