Sensorimotor training lightens the perceived weight of body augmentation devices

Abstract

Wearable haptic and robotic devices must transmit useful forces and tactile information without remaining perceptually intrusive. Here we show that perceived weight provides a behavioral marker of this transition toward transparency. Participants judged the weight of their hand with or without a finger-extending exoskeleton before and after object-manipulation training with either the exoskeleton or a structurally matched control device. Psychometric modelling decomposed perceived effector weight into biological-hand and artificial-device components. Attachment produced baseline attenuation of both hand and device weight, whereas training selectively increased attenuation of the finger-extending exoskeleton. Thus, active use made the augmenting device contribute less to perceived effector weight while leaving perceived hand weight stable. These findings suggest that wearable devices become perceptually lighter when their mechanical consequences are integrated into sensorimotor control. Perceived weight offers a compact metric for evaluating transparency, embodiment, and usability in wearable haptic and robotic interfaces. SummarySensorimotor training makes wearable finger-extending exoskeletons feel lighter.