Group size and label framing: Experimental evidence on cooperative behaviour

Sammanfattning: Cooperation is a fundamental element of human society and essential to tackle the global challenges we face. This thesis addressed two questions: (1) does cooperation decline with increasing group size and (2) is cooperation higher when a community label is applied as opposed to a neutral label? I also conducted two explorative analyses of (1) individual-specific determinants of cooperation and (2) motives for cooperating or defecting. To fulfil these aims, I conducted a monetarily incentivized N-person Prisoner’s Dilemma (NPD) experiment in which the group size was set to 3, 7 or 25, and the NPD was referred to as “community dilemma” or “dilemma”. No significant group size effect was found, but the results indicated a negative effect for 25- relative to 3-person groups. No label framing effect was found. A novel finding was that left-wing voters cooperated more than right-wing voters and those of other political affiliation. Cooperators were most motivated by efficiency, Kantian reasoning and fairness, while defectors were most motivated by profitability, zero-profit avoidance and concerns for a low probability of reaching social optimum.