seeing is comforting: effects of teleoperator visibility

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Seeing is Comforting: Effects of Teleoperator Visibility in Robot-Mediated Health Care Kory Kraft, William D. Smart AbstractTeleoperated robots can be used to provide medical care to patients in infectious disease outbreaks, alleviating work- ers from being in dangerous infectious zones longer than abso- lutely needed. Nevertheless, patients’ reactions to this technology have not been tested. We test three hypotheses related to patients’ comfort and trust of the operator and robot in a simulated Ebola Treatment Unit. Our findings suggest patients trust the robot teleoperator more when they can see the teleoperator. I. I NTRODUCTION Providing medical care to people with highly infectious diseases exposes health care work to the risk of becoming infected themselves. This is especially significant when the diseases are either highly contagious or extremely lethal. Both of which were true with the 2014 outbreak of Ebola Virus Disease (EVD) in West Africa. Health care profession- als had to wear high levels of personal protective equipment (PPE) in order to safeguard against infection [1], [2]. This PPE, when coupled with the high heat and humidity of the region, meant that health care workers could only work for 40-minute shifts before being at risk for heatstroke. This dramatically decreased the quality of care that they were able to provide and contributed to the high mortality rate of the outbreak. We are investigating the use of teleoperated robots in this setting to allow health care workers to perform some of their duties at a safe distance from infected patients. However, these robots can be scary things, especially when hovering over a medical cot with a patient in it. In this paper, we investigate whether being able to directly observe the human teleoperator makes the patient feel more trusting and comfortable, when being attended to by a robot. Specifically, we address the following hypotheses: H1: A patient’s increased visibility of the operator leads to higher levels of patient trust in the operator. H2: A patient’s increased visibility of the operator leads to higher levels of patient trust in the robot system. H3: A patient’s increased visibility of the operator leads to higher levels of overall patient comfort. We test these hypotheses under two conditions where the operator was either visible or not visible to the patient. The patient lay in a simulated Ebola Treatment Unit (ETU) while a human-sized mobile robot performed various tasks Kory Kraft and William D. Smart, Robotics Program, School of Mechanical, Industrial, and Manufacturing Engineering, Oregon State University, Corvallis, OR 97331, United States. email: {kraftko, smartw}@oregonstate.edu Fig. 1: The robot moves an IV fluid pole during a study session. via teleoperation. Questionnaires and psychophysiological responses were used to evaluate the hypotheses. Our major contribution suggests that greater visibility of the operator gives patients higher levels of trust in the operator. Our results raise important questions regarding the current adoption and style of telemedicine systems, as companies currently sell remote medical telepresence devices [3] and pursue remote telesurgery platforms [4]. These results also have immediate practical implications for the design of a teleoperation control unit to be deployed in the field. While the latest Ebola outbreak was the stimulus for our work, the principles and practices learned here generalize to other types of infectious disease outbreaks, especially those requiring workers to wear PPE. II. BACKGROUND AND RELATED WORK We give background information and related work per- taining to Ebola and infectious diseases and robotics, the importance and measures of trust and comfort in medicine and human-robot interaction. A. Ebola and Infectious Diseases The costs of infectious disease outbreaks can be far- reaching. They can claim lives, disrupt economies, and set back a generation’s development [5], [6]. The recent Ebola outbreak is a good example of the potential destruction caused by infectious disease. The EVD outbreak, declared in March 2014, took 11,261 lives out of 27,642 cases as of the time of writing [7]. These deaths took place in a region already beset by medical fragility. EVD is both highly infectious and can be highly virulent (the mortality rate ranges from 20-90%) [2], [8]. Despite © IEEE 2016. This article is free to access and download, along with rights for full text and data mining, re-use and analysis. Authorized licensed use limited to: IEEE Xplore. Downloaded on May 05,2022 at 01:30:10 UTC from IEEE Xplore. Restrictions apply.

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Page 1: Seeing is comforting: Effects of teleoperator visibility

Seeing is Comforting: Effects of Teleoperator Visibilityin Robot-Mediated Health Care

Kory Kraft, William D. Smart

Abstract— Teleoperated robots can be used to provide medicalcare to patients in infectious disease outbreaks, alleviating work-ers from being in dangerous infectious zones longer than abso-lutely needed. Nevertheless, patients’ reactions to this technologyhave not been tested. We test three hypotheses related to patients’comfort and trust of the operator and robot in a simulated EbolaTreatment Unit. Our findings suggest patients trust the robotteleoperator more when they can see the teleoperator.

I. INTRODUCTION

Providing medical care to people with highly infectiousdiseases exposes health care work to the risk of becominginfected themselves. This is especially significant when thediseases are either highly contagious or extremely lethal.Both of which were true with the 2014 outbreak of EbolaVirus Disease (EVD) in West Africa. Health care profession-als had to wear high levels of personal protective equipment(PPE) in order to safeguard against infection [1], [2]. ThisPPE, when coupled with the high heat and humidity of theregion, meant that health care workers could only work for40-minute shifts before being at risk for heatstroke. Thisdramatically decreased the quality of care that they wereable to provide and contributed to the high mortality rate ofthe outbreak.

We are investigating the use of teleoperated robots inthis setting to allow health care workers to perform someof their duties at a safe distance from infected patients.However, these robots can be scary things, especially whenhovering over a medical cot with a patient in it. In this paper,we investigate whether being able to directly observe thehuman teleoperator makes the patient feel more trusting andcomfortable, when being attended to by a robot.

Specifically, we address the following hypotheses:

• H1: A patient’s increased visibility of the operator leadsto higher levels of patient trust in the operator.

• H2: A patient’s increased visibility of the operator leadsto higher levels of patient trust in the robot system.

• H3: A patient’s increased visibility of the operator leadsto higher levels of overall patient comfort.

We test these hypotheses under two conditions where theoperator was either visible or not visible to the patient.The patient lay in a simulated Ebola Treatment Unit (ETU)while a human-sized mobile robot performed various tasks

Kory Kraft and William D. Smart, Robotics Program, School ofMechanical, Industrial, and Manufacturing Engineering, Oregon StateUniversity, Corvallis, OR 97331, United States. email: {kraftko,smartw}@oregonstate.edu

Fig. 1: The robot moves an IV fluid pole during a studysession.

via teleoperation. Questionnaires and psychophysiologicalresponses were used to evaluate the hypotheses.

Our major contribution suggests that greater visibility ofthe operator gives patients higher levels of trust in theoperator. Our results raise important questions regardingthe current adoption and style of telemedicine systems, ascompanies currently sell remote medical telepresence devices[3] and pursue remote telesurgery platforms [4]. These resultsalso have immediate practical implications for the design ofa teleoperation control unit to be deployed in the field.

While the latest Ebola outbreak was the stimulus for ourwork, the principles and practices learned here generalize toother types of infectious disease outbreaks, especially thoserequiring workers to wear PPE.

II. BACKGROUND AND RELATED WORK

We give background information and related work per-taining to Ebola and infectious diseases and robotics, theimportance and measures of trust and comfort in medicineand human-robot interaction.

A. Ebola and Infectious Diseases

The costs of infectious disease outbreaks can be far-reaching. They can claim lives, disrupt economies, and setback a generation’s development [5], [6].

The recent Ebola outbreak is a good example of thepotential destruction caused by infectious disease. The EVDoutbreak, declared in March 2014, took 11,261 lives out of27,642 cases as of the time of writing [7]. These deathstook place in a region already beset by medical fragility.EVD is both highly infectious and can be highly virulent(the mortality rate ranges from 20-90%) [2], [8]. Despite

© IEEE 2016. This article is free to access and download, along with rights for full text and data mining, re-use and analysis.Authorized licensed use limited to: IEEE Xplore. Downloaded on May 05,2022 at 01:30:10 UTC from IEEE Xplore. Restrictions apply.

Page 2: Seeing is comforting: Effects of teleoperator visibility

ample fear and political pressure it still took a year to beginextensive human trials of a promising EVD vaccine [9].

B. Medical and Health Care Robotics

Okamura et al. segment the Medical and Health CareRobotics field into six application areas: surgical and in-terventional robotics, robotic replacement of diminished/lostfunction, robot-assisted recovery and rehabilitation, behav-ioral therapy, personalized care for special-needs popula-tions, and wellness/health promotion [10].

This partitioning, while helpful in its specificity, misses alarge part of what happens in many hospitals and doctors’offices: general medical diagnosis and treatment involvingcomplex patient-doctor interactions. They also miss thebehind-the-scenes organizational and logistical work neededfor stable medical infrastructures.

The commercial robotics sector is addressing some ofthese issues. Aethon Inc’s TUG robot, used for transportationand delivery of goods in hospitals and warehouses, has“travelled over 1,000,000 miles” [11]. Xenex sells a xenonultraviolet disinfection robot that irradiates rooms to preventhospital acquired infections. It is set up via a touch screenand remains stationary during irradiation [12].

There has been research on general nursing robots thatinvolve physical interactions with patients [13] [14]. Despitesome advances, most commercial robotic systems are either1) stationary manipulator platforms for executing precisiontasks or 2) mobile platforms without manipulators meantto connect people together, move goods around, or performstatic ultraviolet decontamination. In this work, however, weare interested in exploring a more general robotic platformthat is mobile and manipulator-capable in a domain thathas been largely ignored – responding to infectious diseaseoutbreaks.

C. Trust in Medicine

Trust is an important component of medical care, yet itis multifaceted and culturally dependent. Trust in medicalsystems can be influenced by a variety of factors (e.g., pay-ment method) and is linked with a variety of outcomes (e.g.,patient retention and likelihood to seek medical services inthe future) [15]–[18].

One important factor in our study is the link between trustof physicians and the willingness of patients to seek futuremedical treatment. This is especially important in outbreakconditions. PPE obscured the human appearance enough thatit distanced potential patients from health care providers.Medicins Sans Frontiers (MSF) doctors value physician-patient trust so highly that they have learned to go intonew communities, regardless of contamination risk, withoutwearing their PPE in order to gain communities’ trust [19].

The Wake Forest Physician Trust Scale (PTS) is one stan-dard measure for patient-physician trust and has undergoneverification and testing [20]. We use the PTS in our pre-experiment survey.

In our post experiment survey, we examine both thepatient’s trust of the robot system and the operator of the

robot using similar language and style to the PTS. This isdiscussed more in Section IV-E.

D. Trust in HRI

Trust has been examined in a number of contexts inHRI. For example, Freedy et al. developed a task-specific,objective measurement of trust for a collaborative human-robot task [21]. Desai et al. found that reliability impacts usertrust in shared-autonomy robots as evidenced by increasedswitching to manual mode in driving a robot [22]. Bainbridgeet al. examine the trust of a robot versus a video-displayedagent both by using questionnaires and examining the like-lihood of participants to follow through with certain actions[23]. Similarly Salem et al examine participants likelihoodto trust a “faulty” robot versus a properly functioning robot[24]. All of these studies include quantitative measures fortrust using post-hoc questionnaires.

There is a growing trend to quantitatively evaluate trustby counting the number of times participants allow a robotto do an action autonomously or, as in [21] and [24], followthrough with a request from the robot. In each of thesestudies the participants played a much more active role ininteracting with the robot than a hospitalized patient would.The passive role of the patient in our experimental settingrequires the use of subjective, self-reported data instead ofmore objective, observational data.

E. Comfort in Medicine

Comfort is seen as “central” to medical practice amongstpractitioners [25]. MSF doctors in the Ebola outbreak wentthrough the trouble of putting a picture of themselves withtheir handwritten name next to it on the front of their PPE.This offset the unease brought on by the obfuscating PPEand made patients feel more comfortable with doctors [19].

The nursing literature provides a rich set of theory andtradition for measuring and valuing patient comfort. Theliterature includes studies that assess comfort for both pa-tients and caregivers using questionnaires and ethnographicinterviews [26], [27].

The health care and medical literature sometimes definescomfort as the absence of pain and use measures such asthe Visual Analog Scale for Pain [28], [29]. However, this isnot relevant to our study because our study did not inducephysical pain.

F. Comfort in HRI

Comfort has been studied in the context of socially-awarerobots that optimize for people’s comfort when navigatingaround them [30] [31], in human-robot handovers [32], andin response to robot touch in a nursing context [14]. [30] usesa 5-point Likert scale questionnaire to evaluate comfortableapproach paths, speeds, and distances by robots. [33] devel-oped a unique hand-held device that allows users to inputcurrent comfort ratings for the duration of the experiment;this method has the obvious drawback of requiring the par-ticipant to continually assess and report their comfort level.[31] defined and modelled pedestrians’ walking comfort as

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the “subjective impression of one’s easiness of traversingan environment.” They recorded pedestrians’ traversal usinglaser range finders and then averaged three 7-point Likertitems to calculate comfort.

Robots like the Paro and MEDi (built on the NAO robot)are being trialled in health care settings to provide comfortto patients [34]–[37].

We define comfort as the relative absence of stress andarousal and test this using questionnaires and physiologicalmethods. Following Chen et al. we use a Galvanic SkinResponse (GSR) system to measure skin conductance whichis linearly correlated with valence and arousal [14]. Ourmethods are described more in Sections IV-F and IV-E.

III. IMPLEMENTATION

This section outlines the robot, robotic control, and envi-ronment used in the experiment.

A. Robot Description

For this study, we used a PR2 humanoid robot [38]. ThePR2 has two 7 degree-of-freedom arms. The mobile baseallows for semi-holonomic motion. In addition, the PR2 hasa telescoping spine and ranges in height from 1.33-1.64m.

The PR2 is equipped with a variety of sensors: two laserrange-finding sensors (one on the base and one on the head),an Asus Xtion RGB-D camera mounted on top of the robot’shead, a wrist camera for each arm, and stereo cameras. Eachof these sensors, except for the stereo cameras, was used toprovide situational awareness to the robot operator.

The robot ran on battery power, but was tethered viaEthernet for data transmission. To simplify networking, aremote desktop was connected via Ethernet to the serviceport of the robot.

B. Robot Control

An operator teleoperated the robot using the Robot Oper-ating System (ROS) PR2 Surrogate package [39], [40]. Thisallows the teleoperator to control the position of the robot’sarms via Razer Hydra motion sensing controllers [41].

The operator holds the controllers, moves his/her handsfreely, and presses the enable button when he/she desiresthe robot’s end effectors to match that of the operators. Anopen gripper, close gripper, and killswitch button are mappedto the controller. The killswitch immediately disengages therobot’s joint actuator forces.

The operator relied on an Robot Visualization (RVIZ)graphical user interface (GUI) to perform the teleoperation.The operator’s GUI gives access to a variety of informationincluding a live feed from the robot’s sensors, the three ETUenvironment cameras, and a model of the robot as it appearsin the world. The operator relied solely on the vizualizationfound on the monitors to move the robot and complete eachtask.

The operator was trained by repeatedly completing thetasks in the ETU without any human subjects. The trainingtime took roughly 2 hours. The primary author of this paperacted as the operator.

C. Environment

The robot performed tasks in a simulated Ebola treatmentunit (ETU) built according to information found from MSF[42]. Our scaled-down ETU is resemblant of a high-risk zonewithin a larger Ebola treatment center.

The ETU is an enclosed space approximately 4m x 5m x2.5m. It is covered in anti-static, fire-retardant white plasticfor a ceiling and walls and has a concrete floor. There isonly one entryway measuring approximately 2m H x 1m W.The space includes: 2 single cots (195cm L x 66cm W x40.6cm H), an IV pole and bags, 2 bedpans, a medical tray,and sundry first aid supplies. The full-size simulated patient’scot is located in the middle of the room, while the humansubject’s cot is next to the walls.

The ETU is equipped with 1 regular webcam and 2ultra wide angle webcams. These provide greater situationalawareness for the teleoperator and the safety attendant.The sensors were controlled via ROS drivers on a desktopmachine on the outside of the ETU.

Fig. 2: Patient’s perspective of the room, including view ofsimulated patient and medical supplies.

D. Safety

The PR2 robot is equipped with both onboard and wire-less emergency stops. A human safety attendant continuallymonitored the scene via a remote screen with live feed from3 different cameras in case intervention was needed. Therobot’s maximal gripper effort was set to 30N. Participantswere given an orange flag with instructions to raise it in casethey desired to stop the experiment.

A thorough explanation of the experiment and the inherentrisks was given to each potential participant before the ex-periment started. Consent was required, and each participantwas free to stop or leave the experiment at any time, for anyreason. The university’s IRB approved the study.

IV. METHODS

A. Experiment Design Overview

To test our 3 hypotheses we conduct a 2 condition,between-subjects experiment wherein we vary the partici-pant’s visibility of the operator. Participant visibility of theoperator is broken into 2 conditions described below.

The study is broken into 3 stages and takes roughly 35minutes. The initial stage consists of informing the partic-ipant of the study via a brief overview, obtaining writtenconsent to participate, and filling out an initial questionnaire.The participant is then taken to the simulated ETU and

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Page 4: Seeing is comforting: Effects of teleoperator visibility

Fig. 3: The participants view in the no visibility (top) andvisibility (bottom) conditions.

shown how the E-stop works on the robot. Following that,the participant puts on an exercise heart rate monitor and thepatient gown. This stage takes approximately 10 minutes.

In the second stage the participant is led into the ETU. TheGSR is attached to the participant’s left hand. The subject isthen instructed to lay down. Recording of the psychometricsignals begins, as well as video and audio recording if thesubject gives consent. A 2 minute baseline of the signals iscollected, with the operator in the ETU standing beside therobot for roughly 1 minute. The operator then leaves the ETUand closes the door based on the visibility condition. Therobot is activated and executes 5 tasks in close proximity tothe participant via teleoperation. Execution of the tasks takesapproximately 8 minutes.

The participant is then led out of the ETU and instructedto take off the gown. The post-hoc survey is administered.The participant takes off the exercise heart rate monitor, ispaid $20 for their time, and allowed to ask questions.

B. Participant Visibility Conditions

In both conditions, the teleoperator is located outside theETU approximately 5m away from the the participant’s cot.The only thing changed between conditions is the materialof the entryway door covering. Participants are randomlyassigned a condition.

In the no visibility condition an opaque sheet of plastic,of the same material as the rest of the ETU, is drawn overthe entryway to the room. Thus, the operator is not visibleto the participant at all during the robot’s task execution.In the visibility condition the participant and operator arephysically separated by a sheet of 4mm clear plastic drawnover the entryway to the room, allowing the participant fullvisibility of the operator, constrained by the participant’srequirement to stay on the cot. The participant’s view ofboth conditions is shown in Figure 3 .

C. Tasks

The robot performed five tasks in the ETU, in closeproximity to the participant:

1) Deliver wrapped gauze to the medical tray2) Pick up a no-touch thermometer and hold it over

participants torso3) Move IV pole closer to the participant’s cot4) Remove the wash cloth hanging on the wall next to

the participant and place it in a bucket5) Move the bucket from the end of the cot to the other

side of the ETU entranceThe primary criteria for task selection is that each had to

be feasible and consistently repeatable. This was a two-folddecision. First, we were interested in what robotic technologycould actually do in the near-future. Second, we wantedstandardize robot performance between participants.

We also wanted realistic tasks that would lighten theworkload of the health care staff. The selected tasks weredeemed helpful based on conversations with trained medicalpersonnel (nurses and doctors), some of whom were principalleaders in the latest Ebola response [19].

Lastly, we wanted tasks that are generalizable to othertasks in this domain. The selected tasks involve the robotpicking up objects of various sizes, stiffness, textures andcolors that requires the robot to use its full range of heightand to traverse much of the ETU space.

D. Participant Arrangement

Participants were recruited from the surrounding commu-nity and campus. They were required to proficiently speakand read English and be at least 18 years old. 23 peopleparticipated in the study (8 females and 15 males, ages 18to 55, median of 24). All but one had at least some collegeexperience. 19 participants gave consent to allow us to recordaudio and video.

We wanted the participant to feel like he/she was in amedical environment as much as possible. Not only was ourETU realistically modelled, we also sprayed a small amountof bleach under the participant’s bed before entering to givethe room a sterilized smell.

In the initial briefing for the experiment, the participantwas told that we were interested “in human-robot interac-tions” and “how to use robots to help in the fight againstinfectious diseases.” We framed the robot to the participant as“a robot, controlled by a human operator” twice in the studyoverview and once in the consent form. With the exceptionof specifying that the robot would be “moving the IV polefrom one cot to another,” the actions of the robot were notspecified in advance. We characterized the robot’s actions as“general health care tasks in the ETU.” It was not disclosed tothe participants that we were studying their levels of comfortand trust. The initial briefing and surveys were conductedoutside of the ETU, with partitions blocking the subject’sview of the ETU.

The participant was shown how the emergency stop func-tions on the robot in the ETU before putting on a heart

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Page 5: Seeing is comforting: Effects of teleoperator visibility

Operator Trust, Cronbach’s α = 0.68I trust the operator.The operator is extremely thorough and careful.I thought the operator would hit something.I would allow the operator to lay a sheet over me usingthe robot.The operator was skilled.The operator ensured my safety while performing thetasks.Robot Trust, Cronbach’s α = 0.78I trust the robot system.The robot system is extremely thorough and careful.The robot system frightened me.I would allow the robot system to lay a sheet over me.The robot system accomplished its tasks well.The robot system made sure I was safe while perform-ing tasks.Comfort, Cronbach’s α = 0.95I was comfortable in the room.I liked being in the room.I felt scared in the room.I felt relaxed in the room.My time was peaceful.

TABLE I: Survey questions per category.

rate monitor in another room. Then the participant put ona standard hospital gown over his/her clothes. He/she wasled into the ETU where the GSR was hooked up. Furtherquestions by the participants were deferred until the end ofthe study unless the questions regarded safety practices.

E. Questionnaires

An initial questionnaire was administered to each par-ticipant following the consent process. Basic demographicinformation was collected, including 4 items relating to age,gender, level of education and current employment status.Each participant then took the Negative Attitude TowardsRobots (NARS) [43] survey and the PTS.

Following the robot task execution stage, the participantsreturned to the initial study area to take a post-experimentsurvey. The post-experiment survey is broken into threecategories: operator trust, robot trust, and comfort (see TableI). Each question is on a 5-point Likert scale, with 5 being“Strongly Agree.” The operator and robot trust questionswere designed to follow the language and spirit of the trustquestions found in the PTS and the work by Chen et. al [14],[20]. Means are calculated per category. Negative questionsare inverted to follow the same scale as the other questions.Analysis of variance and 1-sided t-tests are done to test thesignificance of the comparisons.

F. Pyschophysiological Response Measures

We measured participants’ GSR and heart rate during therobot task execution, but in this paper only report GSR data.Baseline monitoring began two minutes before the robotstarted its task execution. The participant lay down on thecot during baseline monitoring. Monitoring stopped after therobot returned to its starting location and folded its arms.

1) Galvanic Skin Response Monitor: Following Chen etal. we used Qubit System’s S220 GSR with the C410 LabProInterface and C901 Logger Pro software to measure GSR[14], [44]. Since the sensor is highly sensitive to physicalmovement, the participant was instructed to lie on his/herback with his/her instrumented hand on the cot for the entirerobot task execution stage. The GSR outputs 0-5v and wassampled at a rate of 3.3 Hz.

The second minute of recording was used to calculate abaseline for the individual participant using Equation 1. Abaseline is needed since the gain has to be hand-adjusted inthe initial reading period and since the initial reading periodvaries per individual.

Baseline(gsrp) =

400∑t=200

voltt

200(1)

This is used to calculate a proportional GSR value:

PropGSRt(gsrp, baselinep) =voltt

baselinep(2)

Task-phase proportional means (TPPM) for each partic-ipant are calculated using Equation 3. Start and end timesfor the task-phases were calculated by taking the mean ofhand-coded times from the recorded sessions.

TPPM(gp, bp) =

phaseend∑t=phasestart

PropGSRt(gp, bp)

phaseend − phasestart(3)

This is used to calculate the proportional mean during atask-phase for an entire conditional group using Equation 4.

CondTPPM([p], [g], [b]) =

n∑i=1

PPM(pi, gi, bi)

n(4)

One-sided t-tests are performed on TPPMs between sig-nificance to check for significant differences.

V. RESULTS

A. Questionnaire Results

For the survey responses, n=11 for the no visibility con-dition and n=12 for the full visibility condition.

Figure 4 is a boxplot for trust in the operator betweenconditions. A higher y-value represents a higher level oftrust in the human operator. The median and mean areabove the neutral line for operator trust for both conditions.However, the full visibility condition had a higher mean thanthe no visibility condition (M=4.38 vs. M=3.95). Thus, thefull visibility group expressed higher levels of trust in thehuman operator than the no visibility group. This differenceis significantly explained by the condition (p<0.05, Cohen’sd=0.81) and supports H1.

Figure 5 shows the boxplot for trust in the robot by eachcondition. Again, a higher y-value indicates higher levels oftrust. The medians are equal whereas the mean in the fullvisibility condition is higher than the no visibility condition

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Page 6: Seeing is comforting: Effects of teleoperator visibility

Fig. 4: Boxplot of operator trust means per condition.

Fig. 5: Boxplot of the robot trust means per condition.

mean (M=3.77 vs M=3.56). While interesting, this result isnot statistically significant enough (p>0.1, Cohen’s d=0.30)to support H2.

Figure 6 shows the self-reported level of comfort for theeach condition. Comfort levels determined by the question-naire show a lower mean and median in the full visibilitygroup. While in contrast to our initial inclination, theseresults are not significant enough to reject H3 (p>0.1,Cohen’s d=0.34).

B. GSR Results

Three of the participants’ data had to be excluded fromanalysis because the signal was saturated immediately fol-lowing the baseline time period, indicating a poor gainsetting. Thus, for the GSR data, n=9 for the no visibilitycondition and n=11 for the visibility condition.

Figure 7 shows the average proportional GSR reading forboth conditions (note again that minute 2 was used as abaseline and the robot did not start moving until after minute2). A higher proportional GSR reading indicates greaterlevels of arousal and excitement. The no visibility group hada higher level of arousal compared to the full visibility groupthroughout the trial. Both conditions experienced an increasebetween minutes 3 and 4, but the rise for the no visibility

Fig. 6: Boxplot of comfort means per condition.

Fig. 7: Mean proportional GSR over time, per condition.

condition was much higher. The full visibility condition’ssignal looks much smoother, indicating fewer changes inarousal across time.

Figure 8 shows the proportional task-phase mean GSR val-ues by condition. The no visibility condition’s mean is higherthan the full visibility condition at each stage and acrossall time. The difference in the proportional mean across alltime yields a marginal degree of significance (p<0.1). Thissuggests that the no visibility condition had higher levels ofarousal/valence compared to the full visibility group duringthe robot’s task execution, and only marginally supports H3.

Fig. 8: TPPM GSR for each task phase and whole experi-ment, with standard error bars.

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In agreement with our intuition, Figure 8 suggests thatthe “Thermometer” phase, where the robot held a no touchthermometer over the torso of the participant, is the mostarousing/exciting task-phase for both groups, aside from thebaseline reading.

VI. DISCUSSION

In support of H1, our results suggest that people are lesstrusting of the the human operator when the operator isunseen. The reason for this effect is still unknown. Thepatients may tend to project more autonomy on the robotwhen the operator remains unseen during task execution, andthis might lead them to doubt the operator’s ability to com-mand and control the robot. Contrast this to the full visibilitycondition where the patient is continually reminded of theoperator’s role in the control and manipulation of the robot.This might bolster the patient’s trust of the operator becausethe patient can constantly link the operator’s capabilities andpower to the robot’s actions.

In this experimental design, the operator was introducedto the patient before the robot even began to move and hadat least 5 minutes of interaction with the patient during theconsent process and safety explanation. The patient evenwalks by the operator’s control unit. We hypothesize thatthe effect size may have been much greater if the patient didnot meet the operator beforehand or see the control station.A less-rational state due to medication or symptoms mayalso increase the effect, causing patients to project moreautonomy to the robot, further decreasing their perceivedability of the operator to control the robot.

From the support of H1 it follows that a patient-centeredrobotic ETU would feature a mobile teleoperator controlunit that could be temporarily stationed outside of patients’rooms. This would allow each patient to see the operatorwhile the operator controls the robot. This would be incontrast to a central teleoperation control unit which wouldnot allow patients to see the person manipulating the robot.

The deeper implication of H1 is to question the currentand imagined-future form of telemedicine. Obscuring theoperator behind the robot could be disconcerting and off-putting for many people in regards to their trust of theoperator unless, as with most current robot surgery, thepatient is unconscious. A loss of operator trust could mean adecrease in long-term physician-patient relations and a lowerlikelihood to seek future medical care. More work needsto be done to evaluate how things such as screens, speechcommunication, or even greater familiarity with robots canhelp overcome this specific barrier to operator trust intelemedicine applications involving physical action aroundthe patient.

Our results do not support H2; nevertheless, it is veryinteresting to find that the patient’s trust of the operatorvaried significantly while the trust in the robot did not.Participants may have been assessing different attributes oftrust when evaluating the operator versus the robot. The trustattributes assessed for the operator (e.g., level of control) mayhave varied greatly between conditions. The same measured

trust attributes might not have varied as much for the robot.This might help explain why there was not a significantdifference in robot trust.

Our results are somewhat mixed in regards to H3. The sur-vey responses do not support H3, and if anything, point theother way. The GSR data however shows that the no visibilitycondition experienced significantly more arousal across timecompared to the full visibility condition in support of H3.The higher levels of excitement in the no visibility conditioncoincide with their lower levels of operator trust. The lowerlevels of arousal in the full visibility condition coincide withtheir higher levels of operator trust. Our results then fit aninverse pattern between trust levels (in the operator) andGSR response. This seems to make intuitive sense that, allelse being equal, the more trust a person has in the humanoperator, the calmer he/she would be. Thus, the GSR datanot only supports H3, it also fits with H1.

Participants may have responded to the comfort questionswith more regards to the physical attributes of the ETU ratherthan the overall situation of the robot moving around in thespace. This could explain variation in the results.

There appears to be a general downward trend in the GSRresults for both conditions. This may suggest that peopleadjust to the robot over time. The downward trend could alsobe explained by the variation in the tasks. People were moreexcited when the robot hovered over them with a no-touchthermometer than when the robot dropped the towel in thebucket. To better understand the overall downward trend theGSR baseline should not start until the person’s GSR voltagestabilizes and tasks should be varied. Also, these results aredrawn from a limited interaction time between the robot andtest subject; it is unclear how longer interaction times, onthe order of days or hours, would impact the levels.

There are limitations to the current study. While thesupport of H1 is statistically significant with a large effectsize, the result is limited in statistical power. Ideally, atleast double the number of participants is needed to increasestatistical power. Lastly, interviews may have aided in theinterpretation of the results.

VII. CONCLUSION

In this work we explored how patients’ visibility ofthe teleoperator affects their own levels of trust in theoperator, robot, and their overall comfort. We tested ourthree respective hypotheses by having a human-sized robotcomplete general health care tasks around participants undertwo conditions of operator visibility. The experiment tookplace in a simulated Ebola treatment unit.

Our major contribution suggests that a patient’s increasedvisibility of the operator leads to higher levels of patient trustin the operator. More needs to be done to assess the reasonsfor this effect and ways to potentially overcome this barrierto trust. The mixed results regarding H3 invite more researchand clarification into how visibility impacts patient comfort.

Robotic technology in infectious disease outbreaks ispoised to offer tremendous benefits to health care worker

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Page 8: Seeing is comforting: Effects of teleoperator visibility

safety but the particular challenges of deploying these sys-tems around human patients needs to be further explored.

VIII. ACKNOWLEDGEMENTS

This project was funded by the National Science Founda-tion under award IIS 1518652 and IIS 1540483.

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