Table 5. Results of Study 1 (Toy-Task).
| Coefficient | z | SE | p | |
|---|---|---|---|---|
| Fixed effects | ||||
| Level 2 | ||||
| Intercept | 0.98 | 4.53 | 0.22 | <.001 |
| I 1t | -0.60 | -2.06 | 0.29 | .041 |
| I 2t | 0.59 | 2.04 | 0.29 | .043 |
| S t | 0.34 | 1.17 | 0.29 | .242 |
| A t | -0.01 | -0.66 | 0.01 | .512 |
| S t A t | <-.01 | -0.01 | 0.03 | .993 |
| I 1t S t | 0.83 | 1.97 | 0.42 | .051 |
| I 2t S t | -0.32 | -0.84 | 0.38 | .400 |
| I 1t A t | 0.02 | 1.03 | 0.02 | .305 |
| I 2t A t | < .01 | 0.14 | 0.03 | .886 |
| I 1t S t A t | 0.04 | 0.97 | 0.04 | .335 |
| I 2t S t A t | 0.02 | 0.50 | 0.04 | .621 |
| Random effects | ||||
| s 2(υ 0t) | 0.82 | 6.55 | 0.13 | <.001 |
I 1t and I 2t are Indicator or Dummy variables indicating the stimulus category (I 1t: 1 = African infants, 0 = Caucasian infants; I 2t: 1 = dog puppies, 0 = Caucasian infants). S t represents participants’ sex (0 = male, 1 = female). A indicates participants’ age (0 = mean age of the sample).
Robust estimators were used for statistical inference with respect to fixed effects and variance components to account for possible violations of model assumptions, such as normality of Level-2 residuals. Degrees of freedom were computed based on the Satterthwaite’s Approximation to account for the moderate sample size at Level 2 [46]. Therefore, the degrees of freedom were not necessarily integers and could vary across tests independent of the number of parameters.