Table 2. Influence of independent factors on the number of prosocial behavior from bystanders in Analysis 1, Model 1.

Independent term
Factors	Level	Coef	SE (coef)	t	P (>|t|)
Intercept		−0.28	0.35	−0.80	0.42
Context	PP	2.48	0.24	10.24	<0.001
Familiarity between focal children and bystanders		1.51	0.93	1.61	0.11
The focal children’s usual frequency of receiving prosocial behavior		0.01	0.05	0.15	0.88

We analyzed the data in 566 sessions (283 PP-MC pairs, focal child = 12, bystander = 56, focal-bystander dyad = 144) in Analysis 1, Model 1. The generalized linear mixed model with Poisson error structures was used in the analysis. In the linear model with categorical independent variables, one of the levels was treated as a criterion, and the parameters of the other levels were estimated as the difference from the criterion level. In this model, in the factor “context”, the level “MC” was treated as a criterion, and the coefficient of “PP” was shown as the differences from the level of “MC”.