Definition
The Representativeness Heuristic is a mental shortcut used to estimate the probability of an event or the category of an object based on how similar it is to a typical prototype in the mind. It leads to the error of overestimating probability while ignoring the base rate.
Why It Matters
This is the mechanism behind stereotyping and Base Rate Neglect. Mistaking ‘vividness’ for ‘truth’ leads to misdiagnosis in medicine and prejudice in society, as we ignore the statistical reality in favor of a compelling but rare prototype.
Core Concepts
- Prototype Matching: Assuming that because an individual has features typical of a group (e.g., “looks like an engineer”), they must belong to that group.
- Base Rate Neglect: Failing to consider how common the category is in the general population. A person who looks like a rare “zebra” is still more likely to be a common “horse.”
- Predictive Value Error: Mistaking a typical feature for a specific or predictive one. A symptom may be typical of a rare disease but also typical of a common cold.
- Stereotyping: The heuristic is the psychological mechanism behind the formation and application of social and cultural stereotypes.