Tsunahiki task: A newly developed group-based operant task for mice

A group of social animals, including humans, distributes work and rewards and establishes inter-individual relationships through shared experiences of working together. Understanding the neural mechanisms underlying group work is essential for elucidating how social relationships are formed. Thus, a behavioral paradigm for studying group work in laboratory rodents is required. Here, we developed a Tsunahiki task, a novel group-based operant task for mice. In this task, three mice jointly pulled three ropes, and once all ropes were pulled out, all members gained access to a reward area, regardless of who performed the work. The mice acquired the task within a few days. Importantly, repeated experience with the Tsunahiki task led to a shift in workload toward subordinate individuals and induced rank consolidation. These findings suggest that group work induces consolidation of intra-group disparities based on the dominance hierarchy. The Tsunahiki task provides a useful framework for investigating the neurobiological mechanisms underlying collaborative work, group formation, and social inequality in rodents. TeaserA group-based operant task for mice was newly developed, in which hierarchy affected work and reward distributions.