Coupling dynamics influence haptic communication.

<p>(A) Haptic tracking control experiment to measure how the tracking error, or the noise in the haptic information, increases with the coupling stiffness (plots are mean±standard error). 8 individually recruited subjects received no visual feedback of the target, instead relying only on the haptic feedback from the elastic connection between the wrist and the target. (B) The tracking errors from the haptic tracking experiment were considered in the <i>neuromechanical goal sharing</i> model, which combines information from vision with the haptic sensing of the partner’s goal to improve tracking performance while taking into account the additional noise in haptic sensing arising from the softness of the interaction. The predictions from this model closely resemble the data, exhibiting modulation of both the improvement and interaction effort due to the coupling stiffness. This shows that the effort expended during interaction is not a strategy per se, but the outcome of maximizing the sensory information of the target’s motion.