Table S9.

Persistence model: Effect of intergroup conflict anticipation and participation on urinary oxytocin levels, log-transformed

Term	Estimate	SE	χ2*	P
Intercept	5.902	0.427	–	–
Test predictor
Intergroup conflict with affiliation†	−0.128	0.299	0.182	0.670
Control predictors
Sex‡	−0.318	0.424	0.559	0.455
Proximity§	0.123	0.127	0.921	0.337
Subgroup size¶	0.094	0.116	0.615	0.433
Rank#	−0.169	0.138	1.357	0.244

^*Degrees of freedom are 1.

^†,^‡χ² and P values refer to comparison with the reference categories ^†preborder patrol with affiliation and ^‡female.

^§,^¶,^#z-transformed, mean ± SD of the original variables: ^§87.55 ± 11.87 (range 5 to 99), ^¶15.71 ± 4.34, and ^#0.64 ± 0.22 (range 0 to 1, with 1 being the highest social rank).