niversity of Chicago Press, Chicago, 1990. [8] Ronald A. Fisher. The Genetical Theory of Natural Selection. Dover, New York, 2nd edition, 1958. [9] William D. Hamilton. The genetical evolution of social behavior, I. Journal of Theoretical Biology, 7(1):1-16, July 1964. HOUSE_OVERSIGHT_011168 --- PAGE BREAK --- 15

tives, even at a cost, translates to helping ones genes move on into the next generation — an insight developed by the British evolutionary biologist William D. Hamilton. When cooperation involves unrelated others, nonhuman animals attempt to circumvent the sucker’s problem by working with a small number of familiar o