Prosocial behavior, social reward and empathy in adult male and female mice

Prosocial behavior, defined as voluntary behavior intended to benefit another, has long been regarded as an almost uniquely human characteristic. In recent years, it was reported that laboratory animals also favor prosocial choices in various experimental paradigms, thus demonstrating that prosocial behaviors are likely evolutionarily conserved. Here, we investigated prosocial choices in adult male and female C57BL/6 laboratory mice in a task where a mouse is rewarded for either choice, but only one of the choices rewards an interaction partner. Additionally, we assessed social reward using a conditioned place preference task and empathy-like behavior in a task that measures sensitivity to the affective state of interaction partners (i.e., relieved or hungry vs. neutral). We find that female, but not male, mice increased frequency of prosocial choices from pretest to test. At the same time, both male and female animals showed similar rewarding effects of social contact in the conditioned place preference test, and similarly, there was no effect of sex on the preference for interaction with a hungry or relieved partner. While the difference between sexes observed in prosocial task would be consistent with reported higher propensity for prosocial behavior in women, similar sensitivity to the affective state of the interaction partners is at odds with human results.