Table 1.

Mixed-effect models predicting net transfers (calories per day) from older nuclear family i to younger nuclear family j, as a function of genetic relatedness, net caloric need and their interaction. Net transfers and need are standardized to have mean = 0 and s.d. = 1. n = 3279 family–family dyads. Further details on the models and variables are given in the electronic supplementary material, S2.2. p-values indicate whether the regression coefficient B deviates significantly from the null expectation of zero.

predictors of net transfer fam. i → fam. j	1. estimated net need model			2. measured net need model
	B	s.e.	p-value	B	s.e.	p-value
intercept	0.013	0.146	0.121	0.011	0.146	0.137
r	1.010	0.278	0.001	1.135	0.271	<0.001
net need of i	−0.001	0.020	0.497	−0.019	0.021	0.123
net need of j	0.010	0.020	0.306	0.019	0.021	0.172
net need of i × r	−1.465	0.298	<0.001	−1.656	0.268	0.001
net need of j × r	0.607	0.250	0.010	0.774	0.221	0.001