Judging Linda's job by how she 'seems' rather than what's actually likely
Shown a description of 'Linda' as a bright, outspoken philosophy graduate concerned with social justice, most people asked to rank likely careers rate 'bank teller and active in the feminist movement' as more probable than plain 'bank teller' — even though adding a condition can only make an outcome less likely, never more. Tversky and Kahneman named this the representativeness heuristic: people judge probability by how well something matches a mental stereotype, not by the actual statistics.