by Tzu-Hui Wu et al.
Group mood and engagement are invisible currents that shape how people collaborate at work, emerging through everyday interactions rather than isolated individual states. While positive socio-emotional dynamics support collaboration and productivity, they remain difficult to sense and interpret unobtrusively. This work investigates whether posture-based behavioral cues sensed through everyday objects can provide insight into group mood and engagement. We present a pressure-sensing chair prototype that captures changes in weight distribution during meetings. In a study with 14 groups (N = 46), we combine postural cues with participants’ retrospective video annotation to triangulate engagement and mood. Our results show that posture activity is associated with engagement and mood arousal, while moments of shared group mood co-occur with increased postural synchrony. We further identify synchronized behavioral patterns reflecting affective convergence and contagion. These findings demonstrate how situated sensing through everyday objects can reveal socio-emotional dynamics and inform the design of collaborative systems.









