Intentional binding reflects pair dynamics and sense of agency in embodied joint action in human-human dyads but not in human-computer dyads.

Summary

Intentional binding, a measure of how people perceive time between their actions and outcomes, was tested in individual, human-computer, and human-human joint button-pressing tasks using haptic devices. Contrary to expectations from we-agency theory, the overall strength of binding did not differ between partner types. However, within human pairs, participants who reported a stronger sense of agency showed stronger binding, linked to leader-follower movement dynamics. No such link appeared in human-computer interactions. The findings indicate that temporal binding primarily reflects sensorimotor predictability rather than social context or intentionality, and may serve as a signature of how partners co-regulate their actions.

Study at a glance

Abstract

Intentional binding has been proposed as an implicit measure of shared sense of agency in joint action, yet it remains unclear whether it distinguishes between individual and different forms of joint control. We compared intentional binding across individual action, human-computer joint control, and human-human joint control in a physically coupled button-pressing task using haptic feedback devices. Binding magnitude was analyzed both intra-subjectively across conditions and inter-subjectively in relation to reported sense of agency and movement dynamics. Contrary to predictions from the we agency literature, we found no intra-subjective main effect of partner type on binding magnitude. However, within human-human dyads, participants who reported a stronger sense of agency exhibited stronger binding effects, corresponding to emergent leader-follower dynamics in their movement trajectories. No comparable relationship was observed in human-computer interactions. These findings suggest that temporal binding effects primarily reflect sensorimotor predictability rather than intentionality or social context per se. While binding alone does not provide a sufficient marker of "human-like" agency in artificial systems, it may reflect the distribution of predictive control within a dyad and thus serve as a quantifiable signature of how effectively partners co-regulate their actions.