Physicist’s notes show math solution for choosing among restaurants

Researchers decoded handwritten notes from physicist Richard Feynman that outline a mathematical approach to choosing among restaurants over repeated visits. The notes, written in the 1970s, remained unpublished after Feynman’s death in 1988. The notes address a stopping problem: how to decide whether to return to a known restaurant or try a new one when the total number of dining occasions is fixed.

Feynman derived a threshold that declines as the number of remaining nights decreases.

Threshold calculation Early in the sequence, the threshold is set high so that only an exceptionally high-scoring restaurant triggers a return visit. On the final night, the threshold drops to the average score, and any restaurant above that level is selected.

The calculation assumes each restaurant is equally likely to be good, average, or poor. When that distribution changes, the threshold equation adjusts accordingly.

Survey of decision strategies Computational cognitive scientist Brian Christian and colleagues reported the findings June 2 in the Proceedings of the National Academy of Sciences. They also surveyed more than 2,500 people online to compare actual choices with the calculated optimum.

Participants did not follow the exact threshold rule. They applied a simpler method that produced comparable total scores. Christian, of the University of California, Berkeley, stated that people rely on heuristics that approximate the optimal strategy without requiring full computation.