A common fallacy wherein people determine the probability or frequency of an event based on assumptions or past experience. This mindset is based in the idea that we as a people need to categorize our lives (like so many other psychological theories state). Sometimes when we cannot manage to fit a situation into a defined category, we continue to try to find meaning by assigning it to a secondary level of an already completed organizational system. For instance, maybe we have only met people who were rich that lived in Connecticut…this knowledge will therefore make us generalize that most people in Connecticut are wealthy.
Another Example: Many people erroneously support the so-called gambler’s fallacy, the belief that runs in good and bad luck can occur. For example, if a coin toss turns up heads multiple times in a row, many people think that heads is a more likely occurrence in the next toss to “even things out”, even though each toss is an independent event not connected to the toss before or after it.