Top: the probability to meet the target investment, average payoff, total investment and investment in the first and second half of the game. With smaller group size (a) and interest (c), contributions started at . With interest, investments mainly occur in the first half of the game. If the target varies, they only start for (e) and the success frequency decreases. Bottom: the total investments in the game (all payoffs and investments are measured in proportions of the total endowment). In general the behavior occurs at high frequencies for low . (b) For small groups, the behavior dominates for . (d) With interest, the behavior dominates for . (f) If the target is uncertain, the behavior dominates for and occurs for very large (averages over generations from independent samples, parameters were , , , , , , otherwise stated in the figure).