Base rate fallacy

We tend to overvalue the specific information - rather than integrating it with general information like the base rate.

Example

Consider this problem: Steve is shy - is Steve a librarian or a sales person? Most people assume that Steve is a librarian - but there are way more sales people than librarians - so it's more likely that he is a sales person.

Cause

Research has shown that human probabilistic thinking is fundamentally flawed and error-prone.