Illusory Correlation: How to Spot This Common Mental Error

An illusory correlation happens when we mistakenly over-emphasize one outcome and ignore the others.

Example: you visit a big city, you have 2 or 3 negative experiences and in the end, you conclude that people living in big cities are rude. But you are forgetting all the other perfectly normal and nice encounters you had with the people that live there because they were not notable.

We tend to overestimate the importance of events we can easily recall and underestimate the importance of events we have trouble recalling. 

The easier it is to remember, the more likely we are to create a strong relationship between two things that are weakly related or not related at all.