Training differences predict dogs' (Canis lupus familiaris) preferences for prosocial others

Humans evaluate other agents' behavior on a variety of different dimensions, including morally, from a very early age. For example, human infants as young as 6-months old prefer prosocial over antisocial others and demonstrate negative evaluations of antisocial others in a variety of paradigms (Hamlin et al. in Nature 450(7169):557, 2007; Dev Sci 13(6):923-929, 2010; Proc Natl Acad Sci 108(50):19931-19936, 2011). While these tendencies are well documented in the human species, less is known about whether similar preference emerge in non-human animals. Here, we explore this question by testing prosocial preferences in one non-human species: the domestic dog (Canis lupus familiaris). Given the ubiquity of dog-human social interactions, it is possible that dogs display human-like social evaluation tendencies. Unfortunately, prior research examining social evaluation in dogs has produced mixed results. To assess whether differences in methodology or training differences account for these contrasting results, we tested two samples of dogs with different training histories on an identical social evaluation task. Trained agility dogs approached a prosocial actor significantly more often than an antisocial actor, while untrained pet dogs showed no preference for either actor. These differences across dogs with different training histories suggest that while dogs may demonstrate preferences for prosocial others in some contexts, their social evaluation abilities are less flexible and less robust compared to those of humans.