Division of labour is biased towards equality amongst collaborators in a dyadic short-term memory task

Human workers often divide labour on the basis of individual qualities. However, contemporary work on decision-making suggests collaborators value opinions equally, even when they are unequally skilled. We investigated whether this equality bias extends to division of labour in a collaborative game that leverages inter-individual short-term memory capacity differences. Pairs were shown eight memorisable items to divide among themselves, only communicating through their computer screens that displayed who claimed which items. After this, participants recalled randomly selected claimed items. To incentive collaboration, pairs were rewarded for their combined recall accuracy. Although we hypothesised they would maximise reward by dividing items according to each individuals’ capacities, pairs divided the number of items to-be-remembered equally. Furthermore, individuals’ collaboration ratings were unaffected by capacity or performance, but instead negatively correlated with task-irrelevant variability in claimed item locations. Finally, differences in claimed item numbers correlated with inter-individual differences in conscientiousness and social apathy. Our findings suggest humans have an equality bias when dividing labour between collaborators, even if they are of unequal skill.