APA Dictionary of Psychology

a classic route-picking puzzle used in studies of problem solving in both human and nonhuman animals. The individual is presented with a number of points and must choose the most efficient possible route between them, as would a salesperson needing to stop at several locations. Humans often find the shortest route when there are only a few points, but when there are many stops, they instead use the “nearest neighbor” system (repeatedly selecting the location closest to their current one) to produce solutions.