Sensorimotor Oscillations During a Reciprocal Touch Paradigm With a Human or Robot Partner.

Nathan J Smyk,Peter J Marshall,Staci Meredith Weiss

doi:10.3389/fpsyg.2018.02280

Abstract

Robots provide an opportunity to extend research on the cognitive, perceptual, and neural processes involved in social interaction. This study examined how sensorimotor oscillatory electroencephalogram (EEG) activity can be influenced by the perceived nature of a task partner – human or robot – during a novel “reciprocal touch” paradigm. Twenty adult participants viewed a demonstration of a robot that could “feel” tactile stimulation through a haptic sensor on its hand and “see” changes in light through a photoreceptor at the level of the eyes; the robot responded to touch or changes in light by moving a contralateral digit. During EEG collection, participants engaged in a joint task that involved sending tactile stimulation to a partner (robot or human) and receiving tactile stimulation back. Tactile stimulation sent by the participant was initiated by a button press and was delivered 1500 ms later via an inflatable membrane on the hand of the human or on the haptic sensor of the robot partner. Stimulation to the participant’s finger (from the partner) was sent on a fixed schedule, regardless of partner type. We analyzed activity of the sensorimotor mu rhythm during anticipation of tactile stimulation to the right hand, comparing mu activity at central electrode sites when participants believed that tactile stimulation was initiated by a robot or a human, and to trials in which “nobody” received stimulation. There was a significant difference in contralateral mu rhythm activity between anticipating stimulation from a human partner and the “nobody” condition. This effect was less pronounced for anticipation of stimulation from the robot partner. Analyses also examined beta rhythm responses to the execution of the button press, comparing oscillatory activity when participants sent tactile stimulation to the robot or the human partner. The extent of beta rebound at frontocentral electrode sites following the button press differed between conditions, with a significantly larger increase in beta power when participants sent tactile stimulation to a robot partner compared to the human partner. This increase in beta power may reflect greater predictably in event outcomes. This new paradigm and the novel findings advance the neuroscientific study of human–robot interaction.

Highlights

As automation and technology become more ubiquitous in society, it is increasingly commonplace for interactions that have typically occurred between humans to occur between humans and robots
Follow-up analyses indicated that mu event-related spectral perturbation (ERSP) over the contralateral centroparietal region was significantly reduced when participants expected tactile stimulation to self, compared to trials when no tactile stimulation was expected
We investigated sensorimotor oscillations during a reciprocal touch paradigm, using EEG measures to compare aspects of brain oscillatory responses to receiving and initiating tactile stimulation during a joint task involving either a human or robot partner

Summary

Introduction

As automation and technology become more ubiquitous in society, it is increasingly commonplace for interactions that have typically occurred between humans to occur between humans and robots. Robots are designed as social agents, capable of interacting with humans in varied natural settings (Fong et al, 2003). Social robots designed for these domains are often embodied, with varying degrees of human likeness; there is evidence that embodied social agents are more judged more favorably than disembodied social agents (Lee et al, 2006), especially within the context of social touch (Cramer et al, 2009a,b). People empathize more with robots when they are physically embodied and present, compared with agents that are disembodied (Kwak et al, 2013). Given the embodied nature of social robots, it is likely that our interactions with such machines will increasingly involve tactile experiences (Huisman et al, 2013)

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