The representativeness heuristic is a mental shortcut that helps people make judgments about the probability of an event based on how closely it resembles a typical case. For example, if someone meets a person who is quiet and enjoys reading, they might assume that this person is a librarian rather than a salesperson, even if there are more salespeople than librarians in the population. This heuristic can lead to errors in judgment, as it often ignores relevant statistical information. People may overlook the actual likelihood of different categories, focusing instead on how well an example fits their mental image, which can result in biased conclusions.