Social Value Unblocks Pavlovian Reinforcement Learning in Male Rats

Many species, including humans, are sensitive to social signals and the valuation of these social cues is important in maintaining social interactions. Social value, derived from social cues, thus could act as a reinforcer and influence reward learning. Here, we introduce a novel task in rats that investigates if social value can drive reinforcement learning about novel stimuli. Using the blocking/unblocking paradigm originally developed in the (non-social) reinforcement learning literature, we found that when actor rats have fully learned a stimulus-reward association producing reward for themselves, adding a cue that predicted an additional reward delivery to a partner rat unblocked associative learning about this cue in the actor rats. In contrast, additional cues that did not predict additional reward remained blocked from acquiring associative value. In a control experiment where putative social cue exchange between the partnered rats was prevented, the normally unblocked cues now remained blocked as expected. Taken together, these results suggest that social value can drive reinforcement learning in rats, and that the transmission of social cues is necessary for this learning, driven by social value, to occur.