The first, at least as likely as the second: every feminist bank teller is a bank teller, so adding a detail can never raise the odds. The second simply sounds more like Linda. Tversky and Kahneman put these two statements to 142 students in 1983, and 85% picked the second. Asked to rank eight statements about her, decision-science doctoral students at Stanford put the second above the first just as often: 85% (Tversky & Kahneman, 1983).
Tversky, A., & Kahneman, D. (1983). Extensional versus intuitive reasoning: The conjunction fallacy in probability judgment. Psychological Review, 90(4), 293-315.
Conjunction Fallacy
Judging a detailed scenario as more likely than a simpler one
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