When robots reshape teams: neurodynamic insights into taskwork and teamwork in search and rescue.

Introduction: Beyond traditional, dyadic human-robot interaction, embedding robots into multi-human teams, such as search and rescue (SAR), requires an understanding of fundamental aspects of team composition and dynamics. While considerable work has examined how robot agents influence both taskwork and teamwork, few studies have focused on identifying which factor best explains differences in team outputs. This research investigates the neurodynamics of taskwork and teamwork as SAR teams transition between multi-human (mH) and multi-human-robot (mHR) configurations. Methods: Electroencephalogram (EEG) has been a key tool in human teamwork research because of its sensitivity to changes in cognitive states such as mental workload, sustained attention, and engagement. Specifically, EEG power spectral density (PSD), particularly frontal theta activity (4-7 Hz), has been used to assess variations in mental workload and social cognition associated with task performance. EEG hyperscanning, which evaluates interbrain synchrony between two or more individuals, using metrics such as weighted phase lag index (wPLI), has been widely employed to study teamwork among humans. In this study, PSD and EEG hyperscanning were used to analyze taskwork and teamwork in 22 teams comprising a highly engaged SAR team member (mission commander), a less-involved member (safety officer), and a navigator as they searched for victims in a virtual emergency environment. The navigator was either a trained researcher posing as a participant or a virtual robot, with the robot's performance manipulated using the Wizard of Oz technique. Results: Results for taskwork show that the social-cognitive abilities of mission commanders, but not those of safety officers, are adversely impacted by a robot navigator compared with a human navigator, despite the perceived workload remaining stable. Although team trust outcomes were similar, neural synchrony across occipital, parietal, and temporal regions increased in mHR teams relative to mH teams, indicating different neurodynamical patterns of teamwork. Discussion: The study findings provide evidence that both taskwork and teamwork are fundamentally altered in mHR teams, regardless of the effectiveness of robotic capabilities and functions, compared with mH teams. Therefore, beyond dyadic interactions, multi-human robot teaming must be viewed as a fundamentally distinct team construct rather than simply an extension of human-human teaming.