A mental model is an explanation of how something works. The phrase “mental model” is an overarching term for any sort of concept, framework, or worldview that you carry around in your mind. Understanding these concepts will help you make wiser choices and take better actions. This is why developing a broad base of mental models is critical for anyone interested in thinking clearly, rationally, and effectively.
Mental models help you understand life. It is the way the person thinks about what it is they are doing or dealing with. Mental models define what people will pay attention to and how they approach and solve problems. Mental models are tools for the mind. While thinking about a problem, mental models provide you a map with which you can quickly course correct your line of inquiry.
Don't worry, you don't have to build these mental models yourself. As Issac Newton once acknowledged, “If I have seen further than others, it is by standing upon the shoulders of giants.” Newton wasn’t just being humble, he actually left a very important clue about how he learned things and became one of the greatest thinkers and scientists the world has ever seen. Vicarious learning is a very intelligent form of learning.
According to Charlie Munger, the most efficient way to learn is vicarious learning. He says, "I believe in the discipline of mastering the best that other people have ever figured out. I don’t believe in just sitting down and trying to dream it all up yourself. Nobody’s that smart."
A wide array of mental models already exists in form of big and important ideas in every discipline. These big ideas have been developed over past hundreds of years by influential thinkers who have done the hard work of thinking and framing the knowledge in form of these models.
By learning the big ideas from multiple disciplines we are allowing ourselves to stand on the shoulders of giants. People who have come before us and developed useful ideas in different subjects have already done the groundwork required for improved thinking. What remains to be done on our part is to learn these ideas, master them and begin using them in our decision making process.
Remember that mental models work well in conjunction with each other. There is no single mental model that provides a flawless explanation or solution to everything. Problem-solving becomes difficult when we think that there's only one possible way to approach it. According to Munger,
You must know the big ideas in the big disciplines, and use them routinely — all of them, not just a few. Most people are trained in one model — economics, for example — and try to solve all problems in one way. You know the old saying: to the man with a hammer, the world looks like a nail. This is a dumb way of handling problems.
There are hundreds of mental models, but about 80-90 important ones should be able to carry most of the freight in making you a wise person. I've sorted through a number of these mental models and distilled them into a short list below.