ering up with indirect reci- procity in a large-scale field experiment. Proceedings of the National Academy of Sciences, 110(Suppl. 2), 10424-10429. Zahavi, A. (1975). Mate selection: A selection for a handicap. Journal of Theoretical Biology, 53(1), 205-214. HOUSE_OVERSIGHT_015528

to explain phenomena such as animal sex ratios (Fisher, 1958), territoriality (Smith & Price, 1973), coop- eration (Trivers, 1971), sexual displays (Zahavi, 1975), and parent—offspring con- flict (Trivers, 1974). More recently, evolutionary dynamic models have been applied in human contexts where conscio

gh? When a mantis shrimp uses his powerful claw to thump the sand at an intruder, will he go further, thumping the intruder who continues to advance? Zahavi’s solution was based in economics: signals are honest if and only if they are costly to produce, where cost is relative to current condition or healt