“…This indicates that intra-dyad friendship effectively does increase the level of altruism: non-selfish children are willing to contribute more to their friends' material consumption. This is exactly what can be expected from friends, and falls in line with the literature (see, for example, Buhrmester, Goldfarb, and Cantrell (1992), Pilgrim and Rueda-Riedle (2002), and Eisenberg, Fabes, and Spinrad (2007)). In a sense, this also indicates that our methodology effectively does produce a sensible measure of altruism.…”