Save 200 people or let 400 die — same choice, opposite answers

Given a disease expected to kill 600 people, most chose a certain option over a gamble when it was framed as 'saves 200 lives' — but chose the gamble when the identical option was framed as '400 people will die.' The two options are mathematically the same; only the wording changed. It became one of the founding demonstrations of prospect theory.

— Amos Tversky, Daniel Kahneman, The Framing of Decisions and the Psychology of Choice — Science, 1981