On the Effects of Leader–Follower Roles in Dyadic Human–Robot Synchronization

The spread of cobots working side by side to humans has recently drawn attention to the psychological aspects of human–robot interaction. We propose an exploratory study that investigates whether and how the role is taken on by the robot during a collaborative task influences the human’s psychophysiological response and production rate. We assume the cobot can either take the lead with respect to the human operator or comply with the partner’s decision; namely, being the leader or the follower within the dyad. Against this background, we examined the effects of the leader–follower paradigm on a collaborative tower-building task. We evaluated the stress induced on the subject by the cooperation with the robot, based on both the ECG measurements and on positive and negative affect scale (PANAS) and state-trait anxiety inventory questionnaires. Moreover, based on the measured cycle time, we estimated the user’s production rate. The results highlighted that when the human takes the lead, he/she is subject to a lower physiological stress and is less productive compared to the case where he/she follows the robot strategy.