(I hope you enjoy this very revealing mind teaser!)
Please consider Linda, a 31-year-old woman, single and bright. When she was a student, both in high school and college, she was deeply concerned with discrimination and social justice, and also participated in anti-nuclear protests.
Which is more probable about Linda’s occupation today? (a) Linda is a bank teller; (b) Linda is a bank teller and active in the environmental movement.
Quick, what’s your answer? (a) or (b)?
If you answered (b), you are wrong, and in good company. That’s what most of my colleagues and I answered the first time we saw this teaser in one of our Stanford Organizational Behavior classes.
It is more probable that Linda is a bank teller, which is a whole category, that she is both a bank teller AND also active in the environmental movement, which is a subset of that whole category.
A recent Wall Street Journal article explains the phenomenon:
Free to Choose, But Often Wrong:
“When psychologists Daniel Kahneman and the late Amos Tversky conducted an experimental survey in the early 1980s asking people to answer this simple question, they discovered, to their surprise, that most respondents picked “b,” even though this was the narrower choice and hence the less likely one. It seems that saliency in this case, Linda’s passionate political profile trumps logic.”
Related reading and teasers:
- Why Smart Brains Make Stupid Decisions