Larger groups make cooperation harder to establish because reputational information spreads more thinly.

Evidence

There is also an effect of group size. For larger groups, it is more difficult to establish cooperation, because the fraction of individuals that obtain information about any particular interaction will be smaller. Therefore, more interactions are required (relative to group size) in order to discriminate against defectors. — Nowak, M. A., & Sigmund, K, Evolution of Indirect Reciprocity by…, 72

Categorization

• ADDENDUM: Supports the ‘Grafting & Growth’ or a reputation-infrastructure angle: the spread of reputational info scales poorly with group size, an information-diffusion bottleneck.
• QUESTION: This predicts gossip networks matter enormously — worth chasing the later work on who talks to whom in indirect reciprocity.
• XREF: connects to: Reputation systems need cheap information flow, not frequent repeated trade, to enforce honesty. — PAUL R. MILGRO, PAUL R. MILGRO - THE ROLE OF…, 13; Thick trust cannot extend beyond small groups except via mystified elite authority — Diego Gambetta, Trust - Making and Breaking Cooperative…, 219; Trust is a small-scale phenomenon that institutions must replace to enable large-scale cooperation (+1 more)

Related

• Group-wide reputation can bond honest behavior even between strangers who rarely meet. (similarity 0.79)
• Small groups succeed at collective action because dyadic trust motivates cooperation (similarity 0.79)

Broader Connections

• Reputation systems need cheap information flow, not frequent repeated trade, to enforce honesty. #complicates (0.75) — PAUL R. MILGRO, PAUL R. MILGRO - THE ROLE OF…, 13
• Trust is a small-scale phenomenon that institutions must replace to enable large-scale cooperation #corroborates (0.75)
• Thick trust cannot extend beyond small groups except via mystified elite authority #corroborates (0.72) — Diego Gambetta, Trust - Making and Breaking Cooperative…, 219