Table 2. Predictors of the spatial associations recorded across mother-infant, infant-infant and mother-mother dyads.

Significant predictors (p<0.05) are in bold (GLMM with negative binomial response family and log link). The reported dispersion parameter is the so-called shape parameter of the negative binomial distribution.

		Mother-infant associationN=580 dyadsDispersion parameter = 2.43				Infant-infant associationN=282 dyadsDispersion parameter = 2.635				Mother-mother associationN=325 dyadsDispersion parameter = 1.281
		χ2	p > χ2	Estimate	Standard error	χ2	p > χ2	Estimate	Standard error	χ2	p > χ2	Estimate	Standard error
Predictors	Infants’ facial distance (residuals)	7.72	0.005	–0.14	0.05	5.30	0.021	–0.16	0.07	1.33	0.248	–0.08	0.07
	Infants’ matriline*	18.11	<0.001	0.70	0.15	7.85	0.005	0.61	0.21	3.45	0.063	0.44	0.23
	Mothers’ relatedness	31.17	<0.001	0.27	0.05	24.04	<0.001	0.32	0.06	17.01	<0.001	0.31	0.07
	Mothers’ rank difference	37.47	<0.001	–0.37	0.06	10.74	0.001	–0.28	0.08	28.49	<0.001	–0.44	0.08
	Infants’ age difference†	13.77	<0.001	–0.23	0.06	10.49	0.001	–0.27	0.09	6.20	0.013	–0.20	0.08
	Infants’sex†	1.39	0.499	FF: –0.20	FF: 0.21	0.66	0.719	FF: –0.21	FF: 0.27	8.94	0.011	FF: –0.72	FF: 0.25
				FM: –0.18	FM: 0.15			FM: –0.11	FM 0.21			FM: –0.50	FM: 0.19

^*Reference: different matrilines.

^†Reference: MM (male-male).