WHAT IS A MENTAL MODEL

Simply put a mental model is something that develops as you develop mastery in an area. Your brain bundles together the incremental steps that are required to solve different problems. The book describes it as a sort of "Smartphone App" that your brain accesses when it needs to solve a specific problem. While these are useful they have a couple flaws SQUARE PEG IN A CIRCLE HOLE

If you are familiar with the phrase "When all you have is a hammer, all problems look like nails" (sometimes referred to as Maslow's Hammer although its line may not have originated from him) this is similar. If in your mental model you are taught a specific solution to a specific problem, when a problem that appears similar occurs you will use the solution you know even if this can lead to harmful consequences.

The book uses the example of a medical resident preforming surgery to extract a tumor from the brain. In general removing a tumor involves taking your time and working carefully around the growth. When a tumor is in the brain however the procedure involves cutting the growth out quickly and then repairing the bleeding. Luckily a neurosurgeon was called in to help the resident and the surgery was successful.

OVERCOMING MASLOWS HAMMER

This failure to recognize when a new problem requires a new solution is built into the mental model but there are ways to overcome it.

Avoid Illusions of Knowing As the chapters title suggest, you have to be able to discern when you know something and when you don't. The book often praises low stakes testing and flash cards for this sort of thing. These techniques make it clear when you know something, when you don't and what you need to improve on