Table 5.

Comparison of variables influencing urinary oxytocin concentrations across different behavioural or social contexts. (a) Model 3a—contrasting grooming and food sharing only. Predictor variables and parameters entered in the model: behavioural context (grooming, food sharing), sex of subject (female, male). Random factors: subject ID, partner ID, dyad ID. Likelihood ratio test: χ² = 19.11, d.f. = 2, p < 0.001. (b) Model 3b—contrasting behavioural context and dyads' bond quality. Predictor variables and parameters entered in the model: behavioural context (control (resting or feeding), grooming with non-bond partner, grooming with bond partner, food sharing with non-bond partner, food sharing with bond partner), sex of subject (female, male). Random factor: subject ID. Likelihood ratio test: χ² = 36.47, d.f. = 5, p < 0.001. n = 182 samples, 34 subjects. (a,b) Parameter estimates: the context with 0 was compared with remaining contexts; parameter estimates of variables in italics were taken from a re-run of the same model with a different order of parameter entry. Bold: p < 0.05. Response variable: log₁₀ oxytocin (pg mg⁻¹ crea).

predictor	d.f.	F	p	parameter	β	t	p
(a) model 3a
behavioural context	1	16.496	<0.001	grooming	−0.42	−4.062	<0.001
				food sharing	0	0	0
sex of subject	1	4.193	0.044	female	0.20	2.048	0.044
(b) model 3b
behavioural context	4	9.821	<0.001	control	−0.51	−4.667	<0.001
				groom non-bond	−0.64	−5.183	<0.001
				groom bond	−0.28	−2.403	0.017
				food-share non-bond	−0.03	−0.145	0.885
				food-share bond	0	0	0
				control	−0.48	−2.959	0.004
				groom non-bond	−0.61	−3.538	0.001
				groom bond	−0.25	−1.522	0.130
				food-share non-bond	0	0	0
sex of subject	1	0.245	0.624	female	0.04	0.494	0.624