Table 4 Regression analysis

Model	Slope	Adjusted R²	P-value
A: log(S_d,1) ∼ log(N_e,2)	1.90 (1.64, 2.16)	0.70	<0.001
B: log(s_d,2) ∼ log(N_e,2)	0.88 (0.63, 1.13)	0.34	<0.001
C: log(S_d,1) ∼ log(N_e,2) + log(s_d,2)	N_e: 1.35 (0.98, 1.50)	0.81	<0.001
C: log(S_d,1) ∼ log(N_e,2) + log(s_d,2)	s_d: 0.63 (0.46, 0.80)	0.81	<0.001
A’	1.42 (1.29, 1.58)	0.40	<0.001
B’	0.52 (0.01, 1,02)	0.08	<0.05
C’	N_e: 1.02 (0.57, 1.48)	0.63	<0.001
C’	s_d: 0.68 (0.36, 0.85)	0.63	<0.001

A’, B’, and C’ refer to the models with only humans, bonobos, western chimpanzees, and central chimpanzees for direct comparison with the simulated data (see Supplemental Analyses). Values in parentheses are bootstrap 95% CI.