In many competitive situations, our investments increase our gains: Developing better products or research proposals may lead to higher contracts or patents or larger grants. Does increasing investment in such cases always guarantee higher gains? We used an experimental repeated competition game in which prizes depended on contestants’ investments (n=108). Contestants invested more when they increased the potential prize (“enlarge the market”), yet in some cases this tendency was counterproductive (“decrease the profit”): Contestants in fact diminished their earnings, compared to sitting out the competition and keeping their initial funds. Moreover, when a contestant’s investment decreased an opponent’s prize, the contestant tended to invest less; this effect, in turn, led to higher overall gains for both contestants. This result implies that prosocial considerations are at play. Notably, in certain situations, excessive competitive tendencies may lead to a larger waste of resources.
