Predicting, not just reacting
What Does Your Brain Do?
Your brain builds a running model of the world and corrects it against your senses.
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It is built from billions of connected cells.
Around 86 billion neurons, each connected to thousands of others. Thinking is patterns of signals crossing that network.
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Senses are slow, so it predicts ahead.
Nerve signals take time. To catch a ball, the brain predicts where it will be rather than reacting to where it was.
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Senses mainly report the errors.
Rather than sending everything, the senses largely flag where reality differs from the prediction. That is a huge saving in effort.
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Which is why illusions work.
An illusion sets up a situation where the prediction is confidently wrong. You see the guess, not the input — and knowing does not fix it.
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It rewires itself as you learn.
Connections used often get stronger; unused ones fade. Practising a skill is physically reshaping the network that performs it.
Your brain is about 2 percent of your body weight and uses roughly 20 percent of your energy.
The short version
The brain runs a constant prediction of the world and uses the senses to correct it, which is why illusions fool you.
Try it yourself
Search for the checker shadow illusion. Two squares are identical greys, and knowing that does not make them look it.
Topics
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