What is the Representativeness Heuristic?
The representativeness heuristic is a mental shortcut we use to make probability judgments by comparing situations to mental prototypes or stereotypes we have stored in our minds. Instead of using statistical reasoning, we rely on how "representative" or similar something appears to our expectations.
This heuristic leads to several systematic errors:
- Base Rate Neglect: Ignoring the actual frequency of events in the population
- Conjunction Fallacy: Assuming specific conditions are more probable than general ones
- Gambler's Fallacy: Expecting "balance" in random sequences
Real-World Example
Linda the Bank Teller
Meet Linda: She's 31 years old, single, outspoken, and very bright. She majored in philosophy and was deeply concerned with issues of discrimination and social justice. Which is more likely?
A) Linda is a bank teller
B) Linda is a bank teller and is active in the feminist movement
Most people choose B, even though A must be more probable (since B is a subset of A). Linda's description seems more "representative" of a feminist bank teller than just a bank teller, leading us to ignore basic probability rules.
Why the Representativeness Heuristic Matters
This heuristic affects many important areas of decision-making and judgment:
Stereotyping
We judge individuals based on group stereotypes rather than individual characteristics.
Hiring Decisions
We favor candidates who "look the part" over those with better qualifications.
Investment Mistakes
We extrapolate from small samples and ignore base rates in financial decisions.
Legal Judgments
Judges and juries may be influenced by how much a defendant fits their mental image of a criminal.
How to Overcome the Representativeness Heuristic
Consider Base Rates
Always ask: "What's the overall frequency of this event?" Before making judgments based on similarity, consider how common the outcome actually is in the population.
Look for Larger Samples
Don't draw conclusions from small samples. The larger the sample size, the more reliable the pattern. Random events naturally cluster and spread.
Use Statistical Thinking
When possible, use actual data and statistical analysis rather than intuitive judgments. Probability rules trump similarity impressions.
Question Your Prototypes
Regularly examine your mental stereotypes and assumptions. Are they based on actual data or just vivid examples and media representations?
Quick Self-Assessment
Think about a recent judgment you made about someone or something. Consider:
- Did I base my judgment on how similar this was to my expectations?
- Did I consider how common this outcome actually is?
- Was I working with a large enough sample to draw conclusions?
- What stereotypes or prototypes might have influenced my thinking?