HOUSE_OVERSIGHT_015505.jpg

Morality Games
293

Fig. 2 The Hawk–Dove game. The Nash equilibria of the game are circled

H D

H V/2 - C (V)

D (0) V/2

does not necessarily affect the payoffs, but does distinguish between the players, such as who arrived at the territory first or who built the object. If one conditions on the event (say, plays Hawk when she arrives first), then it is optimal for the other to condition on the event (to play Dove when the other arrives first).

As our reader is likely aware, this was the logic provided by Maynard Smith to explain animal territoriality—why animals behave aggressively to defend territory that they have arrived at first, even if incumbency does not provide a defensive advantage and even when facing a more formidable intruder. Over the years, evidence has amassed to support Maynard Smith’s explanation, such as experimental manipulation of which animal arrives first (Davies, 1978; Sigg & Falett, 1985).

Like other animals, we condition how aggressively we defend a resource on whether we arrive first. Because our behaviors are motivated by beliefs, we are also more likely to believe that the resource is “ours” when we arrive first. Studies have shown these effects with children’s judgments of ownership, in ethnographies of prelegal societies, and in computer games. In one such illustration, DeScioli and Wilson (2011) had research subjects play a computer game in which they contested a berry patch. Subjects who ended up keeping control of the patch usually arrived first, and this determined the outcome more often than differences in fighting ability in the game.

This sense of ownership is codified in our legal systems, as illustrated by the quip “possession is 9/10ths of the law,” and in a study involving famous legal property cases conducted by Descioli and Karpoff (2014). In a survey, these researchers asked participants to identify the rightful owner of a lost item, after reading vignettes based on famous property rights legal cases. Participants consistently identified the possessor of the found item as its rightful owner (as the judges had at the time of the case). This sense of ownership is also codified in our philosophical tradition, e.g., in Locke (1988), who found property rights in initial possession. Note that, as has also been found in animals, possession extends to objects on one’s land: In DeScioli and

HOUSE_OVERSIGHT_015505