Appropriation behaviour predicted by environmental uncertainty, but not social uncertainty, in a common-pool resource game

The tragedy of the commons is a difficult problem. Overfishing, for example, is detrimental to all, but is a social dilemma for the fishers: do they overfish (maximising one’s benefit) – or do they inhibit their consumption (accepting a reduced benefit)? Our study investigated factors that contribute to inhibition. Using a common-pool resource game, we recorded the consumption choices of 83 dyads (166 participants) in a multi-round game where each player decided on how many units of currency to consume from the common pool. The game had four rules: (1) the game ends if the dyad jointly consumes $$\ge $$ ≥ 100% of the pool, (2) the game continues if the dyad jointly consumes $$\le $$ ≤ 50% of the pool (pool is then replenished), (3) the game continues if the dyad jointly consumes 51-99% (“depletion”: pool is not replenished) and (4) no communication between players. Our study had a 2x2x3 factorial design: first factor (within-dyad) had two levels – pre or post-depletion – comparing consumption before/after a depletion event. The next two factors (between dyads) were “environmental uncertainty” (where players had complete or incomplete knowledge of the pool size) and “social uncertainty” (based on whether players knew each other in real life). In our results, we found no significant effects of social uncertainty, but significant effects for depletion and environmental uncertainty. While consumption decreased across all participants after resource depletion, the magnitude of this reduction differed depending on the certainty condition: the decrease was especially pronounced when the resource availability was initially uncertain. Furthermore, games lasted longer when there was certainty. In our results, we found no significant effects of social uncertainty, but significant effects for depletion and environmental uncertainty. While consumption decreased across all participants after resource depletion, the magnitude of this reduction differed depending on the certainty condition: the decrease was especially pronounced when the resource availability was initially uncertain. Furthermore, games lasted longer when there was certainty.