the building blocks of making

better decisions


Mental models are a way of explaining how things work. Throughout our lives, we build up a personal collection of mental models to understand the world around us.

Mental models aren't perfect but developing a rich toolbox of them can be useful in navigating the complexities of life. Learning to intuitively apply the right models in the right situations is something we develop with practice.

This website is a curated collection of models with broad applicability in everyday life. There’s a focus on brief descriptions and simple, real life examples of the models in use.

Weekly Mental Model

Gambler's Fallacy

The mistaken belief that a random event is more or less likely to occur based on past outcomes.


Past occurrences of an independent random event have no impact of future occurrences. For instance, the probability of getting heads in a coin toss is 1/2 regardless of the previous tosses. If we encounter a dozen heads in a row, we may feel that the next toss will be tails to balance things out. This is a mistaken belief--the probability of tails remains 1/2, the same as in previous tosses.


  • A game of roulette at Monte Carlo Casino on August 18, 1913 is perhaps the most iconic example of the fallacy. The ball fell in the black 26 times in a row causing gamblers to lose millions in the mistaken belief that the probability of red was now higher.