Mice copy conspecifics when uncertain during joint perceptual decision-making

In social species, signals from conspecifics can help interpret ambiguous sensory information crucial for survival, such as locating food sources or detecting predators. To investigate the influence of conspecific cues on goal-directed decision-making, we devised a two-alternative forced-choice task for pairs of freely moving mice positioned facing each other. Water-restricted mice were trained to discriminate between visual stimuli indicating the location of a water reward. To evaluate their reliance on conspecific cues under conditions of uncertainty, we positioned the reward on the same side for both mice and presented visual stimuli with varying contrast levels. Once individual mice surpassed a performance threshold, they were paired and quickly learned to coordinate actions and inititate trials within a few sessions. Kinematic data, extracted from high-speed video recordings, allowed us to determine whether a mouse made its choice before or after its partner on a trial-by-trial basis. Employing a probabilistic choice model, we demonstrated that generally, mice tended to copy their conspecific's choice when uncertain about the visual stimulus. To discern whether this behavior was reinforced by congruent stimulus-reward conditions for both mice, we trained pairs where each mouse had independent stimulus-reward conditions. While some mice successfully disregarded social cues, others persisted in relying on them, even when they provided no advantage in discriminating the reward location. In conclusion, mice are more inclined to rely on conspecific cues when faced with uncertainty and when their partner is deemed reliable, indicating that the value of information from others is contingent on the context.