Figure 4 : “Local-to-global” reciprocity is invariant to the size of the group.

From: Think global, act local: Preserving the global commons

Figure 4

(a) We take advantage of random variation across sessions in the number of participants: the size of the group does not have an effect on the level of contributions in the final round of the game in the treatment condition. Indeed, a threefold increase in group size does not affect contributions when “local-to-global” reciprocity is possible. (b) In a second experiment (see SI Section 1), we recruited 1,000 participants to play the same large-scale PGG over 10 rounds. Participants in treatment, where “local-to-global” reciprocity with the PD partner was possible, made stable PGG contributions, while participants in control decreased their contributions over time. (Upper and lower bounds are +/− robust standard errors clustered on double-pairs; see SI Section 2 for statistical details).