Rochester Institute of Technology · Public domain

Simon argued that people don't actually maximize when they make decisions — they satisfice, settling for an option that's good enough because gathering and weighing every alternative isn't realistic. That idea, bounded rationality, reshaped how economists, psychologists, and computer scientists think about decision-making, and won him the Nobel Memorial Prize in Economic Sciences in 1978. He'd already won the Turing Award in 1975, jointly with Allen Newell, for early work on artificial intelligence. He spent most of his career at Carnegie Mellon, where he helped found one of the world's first computer science departments.