Effect of experimenter language and age on prosociality scores in preschoolers.

Experimenter language (Native vs. Foreign) had a significant effect on 4- and 5-year-old preschoolers’ prosociality scores (Wald χ2 = 7.94, df = 1, p = .005), with overall lower scores in the Foreign condition than in the Native condition (U = 16684, p = .001). The interaction between Partner language and Age was also significant (Wald χ2 = 16.10, df = 3, p = .001), as Experimenter language had a significant effect in 5-year-olds but not in 4-year-olds (Wald χ2 = 11.32, df = 1, p = .001; Wald χ2 = 2.05, df = 1, p = .15, respectively). This shows that 5-year-old preschoolers, unlike 4-year-olds, were significantly more reluctant to help or to cooperate when the experimenter was foreign as compared to when she was a native person.