We see a bird flapping its wings. Because we have memories from experiences with birds, we don’t need much thought power to generate the expectation that it will fly. We predict the wings will flap as the bird rises.
After the hundreds or thousands of times we’ve seen birds fly, we have seen birds take flight, we don’t or can’t remember the first times. Those first times, we watched more intently, because we didn’t know what would happen next. As children, we had the energy and unused brain cells to connect into an understanding of “how things work”.
And we used that energy. While as adults our brains take 20$ of our body’s energy, it is estimated that a 5 year old is in “learning machine mode”, and can use 50% or even 60% of their energy for running their brains.
Now that we know the usual, we can predict, and watch for the unusual.
We have mapped the patterns, tested them as we predicted and compared against the results. As we see birds now, we would probably only remember the birds which didn’t fly, or spun around in circles due to an injury, or some similar difference from the expected outcome. From different parts of our brains, we bring up the expected patterns of the situation (in this case a bird flying), so that we don’t have to create these predictions.
We save mental energy by coasting along the predictive path.
This path saves us from the high mental energy of watching as we guess what might happen next. We are built to usually operate with a primal desire to save energy.
The smug human brain has a valuable self-serving, energy-conserving function. It is a survival trait, important when food is scarce. It can keep us alive, by allowing the brain to save it’s own energy for “important thinking”. It also can divert energy away from the body, so that the brain has more energy. The “smug brain” in effect says “I am the most important, because I think for the whole body, so I get to decide where the energy goes.”
Wrapping up, our brains are always processing what is happening, and predicting what might happen next. Assuming the brain gets the feedback, it will also compare what is observed against the prediction. A correct prediction is kind of boring, while a prediction error gets attention!