On inequity aversion in nonhuman primates.

P. G. Roma, A. Silberberg, A. M. Ruggiero, and S. J. Suomi (2006) noted that the results S. F. Brosnan and F. B. M. de Waal (2003) attributed to inequity aversion could also be explained as a frustration effect. Roma et al. redressed this confound by designing a procedure that could have supported either of these interpretations. Nevertheless, they found that only a frustration effect accounted for both their data and those of Brosnan and de Waal (2003). The criticisms Brosnan and de Waal (2006) offered of Roma et al. ignored the fact that Brosnan and de Waal's (2003) research design was not capable of offering an unequivocal demonstration of inequity aversion. This conclusion holds no matter what the claimed inadequacies of Roma et al.'s procedures might have been. Caution is urged in inferring the existence of inequity aversion in nonhuman primates.