Mental compression is a tool that your mind uses to master skills. If you have never heard of the term or concept before, dig in; it can help you become a better learner.
When your brain attempts to acquire "new knowledge" or concepts or grasp new facts that you have never heard or learned before, it has to recruit millions of neurons to do so.
Neurons fire to make sense of what you are hearing, seeing, or experiencing. In the world of computing, neurons are expensive. It is like the chips on the computer that I am using to write this article. There are only that many.
So obviously, your brain wishes to reduce the load as soon as possible. Your brain is extremely clever, so it does not make these choices automatically or in the beginning. It waits to see how much priority you assign to the new information. Are you learning it again and again? So much so that it needs to keep using the neurons? In that case, it will attempt mental compression.
Mental compression is the process by which information is reduced to easier, smaller bits of information. It is like your brain saying, Yes, ok, I got that, and I do not need to keep firing neurons to understand.
You would experience this as understanding or even a habit. The habit of being able to navigate a 3000-pound sedan at 70 miles an hour while other sedans are trying to overtake or run you over. So what is the lesson?
Your brain likes efficiency. It likes to automate things that it needs to learn, understand, and use in order to survive. It will apply the same logic to calculus, history, or politics. So where you spend your time, building mental compression and habits matters.
Not just for what you know but also for how you feel. Spend all your time being sad, despondent and depressed and your brain will learn mental compression around those beliefs. Spend it being content and happy and that is what your brain learns.