Vicarious reward unblocks associative learning about novel cues in male rats

Abstract

Many species, including humans, are sensitive to social signals and their valuation is important in social learning. When social cues indicate that another is experiencing reward, they could convey vicarious reward value and prompt social learning. Here, we introduce a task that investigates if vicarious reward delivery in male rats can drive reinforcement learning in a formal associative learning paradigm. Using the blocking/unblocking paradigm, we found that when actor rats have fully learned a stimulus-self reward association, adding a cue that predicted additional partner reward unblocked associative learning about this cue. In contrast, additional cues that did not predict partner reward remained blocked from acquiring associative value. Preventing social signal exchange between the partners resulted in cues signaling partner reward remaining blocked. Taken together, these results suggest that vicarious rewards can drive reinforcement learning in rats, and that the transmission of social cues is necessary for this learning to occur.