The classic Linda scenario: Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.
Participants are then asked: Which is more probable?
A. Linda is a bank teller.
B. Linda is a bank teller and is active in the feminist movement.
Most people pick B. But that’s logically incorrect. According to probability theory, the probability of A (bank teller) must be greater than or equal to the probability of A and B (bank teller & feminist). This error is known as the conjunction fallacy—when people think that specific conditions are more probable than a single general one.
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