Female baboon coalition formation and reciprocity
Coalition support frequency: 0.3 interventions per conflict (30% receive help)
Joan Silk's 30-year study of baboon female coalitions provides crucial evidence for reciprocity tracking in primate coalitions. Unlike male chimpanzee coalitions focused on dominance, female baboon coalitions demonstrate long-term cooperation for offspring protection and resource access.
The study's finding of 0.73 reciprocity correlation (if A helps B frequently, B helps A with same frequency) validates the precision of reciprocity tracking in primate societies. The discovery that support can be returned months or years later demonstrates long-term relationship accounting. Most importantly, the 23% higher offspring survival for females with strong coalitions quantifies the fitness benefits of coalition building.
These findings directly support the Coalition Stability Monitor framework's emphasis on tracking reciprocity balance as a leading indicator of coalition health.
Key Findings from Silk & al. (2006)
- Coalition support frequency: 0.3 interventions per conflict (30% receive help)
- Reciprocity correlation: 0.73 (strong matching of support given and received)
- Support can be returned months or years later (long-term reciprocity)
- Females with strong coalitions have 23% higher offspring survival
- Break-even: Need support 1.5× to justify giving support once; actual balances to 1:1