User confidence and electrodermal activity during haptic exploration for perceptual comparisons using a robotic system.

Children with physical impairments may have trouble effectively performing the hand movements used in haptic exploration and may miss information about object properties. Assistive robotic systems with haptic feedback may enable children with physical impairments to haptically explore objects. However, it is important to understand if they might be encountering difficulty in assessing object properties with the system. As such, we examined two methods to ascertain a user's uncertainty or stress when doing the exploration, user confidence and electrodermal activity (EDA). Twenty adults and ten children without physical impairments manipulated four pairs of objects to examine size, roughness, hardness and shape. All participants performed the manipulation by controlling a robotic system and by manual exploration in a randomized crossover design. Adults' confidence was lower when using the robotic system and correlated with lower accuracy at determining object properties. Children's responses indicated that they may not have understood how to self-rate confidence. EDA, a potentially objective measure of stress during the task, was actually lower for adults when they used the robotic system, suggesting less physiological arousal than when using their hands. Children's EDA was variable.