Vicarious reward unblocks associative learning about novel cues in male rats

Many species, including humans, are sensitive to social signals and their valuation is important in social learning. When social cues indicate that a conspecific is experiencing reward, they could convey vicarious reward value and prompt social learning. Here, we introduce a task that investigates if mutual reward delivery in male rats can drive social reinforcement learning in a formal associative learning experiment. 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 reward to a partner unblocked associative learning about this cue. In contrast, additional cues that did not predict partner reward remained blocked from acquiring positive associative value. Importantly, this social unblocking effect was still present when controlling for secondary reinforcement but absent when social information exchange was impeded, when mutual reward outcomes were disadvantageously unequal ...