A mental model is simply a representation of how something works.

Mental models are how we understand concepts and, through them, the world. Not only do they help us understand complex theories, they help us make connections with what we already know.

Mental models are great tools for learning. They help simplify complexity. We cannot keep all the details of the world in our brains, so we use models to simplify the complex into understandable and organizable chunks.

In 1990, in a famous speech, Charlie Munger, a billionaire investor and the vice chairman of Warren Buffett’s investment firm, Berkshire Hathaway summed up the approach to practical wisdom through understanding mental models.

“Well, the first rule is that you can’t really know anything if you just remember isolated facts and try and bang ’em back. If the facts don’t hang together on a latticework of theory, you don’t have them in a usable form. You’ve got to have models in your head. And you’ve got to array your experience both vicarious and direct on this latticework of models. You may have noticed students who just try to remember and pound back what is remembered. Well, they fail in school and in life. You’ve got to hang experience on a latticework of models in your head.”

Metal Motels are tools for thinking

The quality of our thinking is proportional to the models in our head and their usefulness in the situation at hand. The more models you have — the bigger your toolbox — the more likely you are to have the right models to see reality. It turns out that for improving your ability to make decisions variety matters.

Here is a list of some useful metal models:

Pareto’s Principle — “For many outcomes roughly 80% of consequences come from 20% of the causes.”
Murphy’s Law — “Anything that can go wrong, will.”
Fear of Missing Out (FOMO) — “A pervasive apprehension that others might be having rewarding experiences from which one is absent.”
Butterfly Effect — “The concept that small causes can have large effects.”
Parkinson’s Law — “Work expands to fill the time available for its completion.”
Hofstadter’s Law, “It always takes longer than you expect, even when you consider Hofstadter’s Law.”
Eisenhower’s decision matrix — “what is important is seldom urgent, and what is urgent is seldom important.”
Imposter Syndrome — “High-achieving individuals, marked by an inability to internalize their accomplishments and a persistent fear of being exposed as a ‘fraud.’”
Deliberate Practice — “How expert one becomes at a skill has more to do with how one practice than with merely performing a skill many times.”
First principles thinking — Breaking down a problem into its fundamental building blocks, and then reassembling them from the ground up. It is one of the best ways to reverse-engineer complicated problems and unleash creative possibilities.
Second-order thinking—Thinking farther ahead than just the first level. Not only the immediate consequences of an action but the subsequent effects of those actions as well. Like a chess player thinking many moves ahead.
Inversion — Solving hard problems by inverting them or addressing them backward. For example, spend less time trying to be brilliant and more time trying to avoid obvious stupidity.

There are hundreds more mental models. Do you have a favorite one? One which you use a lot.

I used it quite a lot in my writing. I have written about them in an article Mental Models For Writers.