Shaping Egocentric Experienceswith Wearable Cybernic Interfaces

Jun NishidaUniversity of Tsukuba Japan JSPS (-201903) University of Chicago USA JSPS (201904-)

junnishidaacmorg

ABSTRACTEmbodied experiences such as muscle activity that shouldbe shared between patients and therapists or a lower per-spective of a child that should be shared with designers arebroadly categorized as embodied knowledge that cannot beacquired by conversations or visual media but only throughactive physical experiencesI hypothesize that changing a personrsquos body including

onersquos perceptions actions and interactions to that of anotherperson such as a child or a patient while allowing activeinteraction with the surrounding objects and people in a real-world environment would provide more valuable as well asempathic knowledge to school teachers product designersand medical sta when designing living environments orcommunicating with others To achieve these new paradigmsto acquire embodied knowledge of personal experiences Idesigned the following two types of corporeal changes 1)changing the visual and haptic perspectives into those of achild and 2) changing the kinesthetic perspective to that ofa patientTo achieve this I developed wearable devices that can

sense and intervene in human body functions directly forchanging onersquos bodily sensation or perspective This allowsthe wearer to experience changes in perception action andinteraction while preserving the active embodied and socialexperiences within a real environment this is a benecialmethod for supporting the acquisition of embodied knowl-edge for the scenarios that are experienced

I investigated the wearerrsquos perceptions actions and inter-actions throughout lab and eld studies and discuss how thewearable systems contribute to the change of bodily sensa-tion These studies veried that the devices have changed thewearerrsquos embodied and social experiences and also gainedembodied knowledge and empathy toward dierent peo-ple through the wearerrsquos active engagement with existingenvironments Interestingly not only the wearer but alsothe surrounding people changed their interaction towardthe wearer It is assumed that the change in the wearerrsquosbody created new social context with surrounding peopleenhancing the shaping of bodily sensation

Active InteractionsSocial amp Physical

Existing Environment

DeviceIntervention

Embodied Knowledge

Figure 1 Acquiring Embodied Knowledge of Onersquos Experi-ence through Shaping Bodily Sensation

1 INTRODUCTIONUnderstanding the embodied and social experiences of aperson can play an important role in gaining knowledge orempathy toward an individual or enhancing onersquos experiencein the elds of rehabilitation design and education Theseembodied experiences such as muscle activity that shouldbe shared between patients and therapists or a lower per-spective of a child that should be shared with designers arebroadly categorized as embodied knowledge that cannot beacquired by conversations or visual media but only throughactive physical experiencesWith the recent advancements in wearable technologies

and virtual reality techniques humanrsquos embodied experi-ences are being augmented beyond the limitations of spaceand time Wearable devices have already achieved an exten-sion of the userrsquos presence in a remote place by sharing theirrst-person perspective [13] or by surrogating onersquos bodyinto a robot [32] or other person as an actuator [19 30] Re-cent studies have also allowed users to not only extend theirpresence but also extend their sense of ownership into an an-other personrsquos body [27] or another life form [15] to gainingknowledge by sharing multiple visual perspectives amongpeople [11] or to provide a third eye on their back to see be-hind them [6] Interestingly it was mentioned that changingbodily sensations through such technologies also changesonersquos perceptions and actions [16] Several design tools thatassists in conveying or reproducing onersquos experience havebeen proposed based on changing bodily sensations

Patients

ChildrenTeachers | Designers | Therapists

Visual Persepctiveinto a Smaller-person

Haptic Persepctiveinto a Smaller-person

Kinesthetic Persepctiveinto a Patient

Figure 2 Shaping Visual Haptic and Kinesthetic Perspec-tives into that of a Smaller Person and a Patient

Reproducing Onersquos Experience for LearningVideomaterials [31] an illusion technique used for extendingthe sense of ownership to a small doll [33] or an immersivevirtual reality technique for converting the userrsquos body intoa smaller avatar [1] have been used to create the sense ofbeing a smaller person through which the userrsquos experiencemay feel passive Several studies have achieved to changeonersquos bodily sensation into that of elderly [5] and impairedindividuals [28] by wearable visual haptic or kinestheticsystems while preserving the wearerrsquos active interactions

Active Embodied and Social Experiences should beProvided for Therapists Designers and TeachersThese conventional tools are able to partially transmit thecharacteristics or experiences of a personrsquos embodiment andtheir special needs to other people symbolically and visuallyhowever the following drawbacks still remain

(1) Users receive the bodily information in a passive man-ner from these media while embodied knowledge canbe acquired actively with physical actions

(2) It is dicult to provide embodied interactions whichinvolve proprioceptive feedback that play importantroles in learning or even altering bodily sensation

(3) It is hard to generate social interactions with peoplethrough these tools which is also an important formof feedback for the userrsquos physical actions because theuser is in a virtual space this may result in isolationfrom the social and physical contexts

If it becomes possible to understand onersquos experiencesin a real-world environment in an active embodied andsocial manner a more empathic experience will be providedfor product designers and educational sta when trying todesign living environments or communicating with otherpeople

2 SHAPING EGOCENTRIC EXPERIENCESIn this research a new paradigm is proposed in order tochange onersquos experience consists of perceptions actions andinteractions by changing onersquos body into that of another per-son while allowing active interactions with the surroundingobjects and people in a real-world environment as shownin Fig 1 This would provide embodied and empathic knowl-edge of onersquos experience rather than describing or simplypresenting it in a symbolical or visual manner The threehuman factors onersquos perceptions actions and interactionswould play important roles in dening physical and socialexperiences and contexts with objects and people thus con-stituting the sum of onersquos embodied and social experiencesBecause all actions and interactions in the proposed ex-

perience style should be performed in a same interactionmanner with that in an existing daily life the userrsquos con-scious act which consists of voluntarily initiating actionsdened as subjective agency [9] should be preserved

I call this experience that particularly includes both subjec-tive agency to initiate actions and active interactions with auserrsquos intention as egocentric experience in that a user isable to have an intention to initiate then initiate and freelyperform actions and interactions with hisher own intentionand timingNeuroscience studies have revealed that active interac-

tions foster the change in bodily sensation particularly bodyrepresentation [17 18 26] therefore I fully exploit a userrsquosegocentric actions and interactions for changing the bodilysensation to change the userrsquos bodily sensation

It is assumed that a userrsquos egocentric experience and bodilysensation would continue to be changed with the activeinteractions thus I call this modication of the experienceas shaping as related studies in neuroscience also use thesame term [7 8]Interfaces which satisfy design goals including wearable

form factor interactivity and IO correspondence as awear-able cybernic interface

Smaller-person Experience (Fig 3)Overview In this research I attempts to change the wearerrsquosbody representation to have a small-personrsquos perspective ina real environment with a capability of full body interac-tion by using wearable devices (Fig 2) The feasibility andproperties of active smaller-person experience in a RE wereinvestigated through both eld and lab studies to discuss itschallenges and opportunities To allow this the concept ofa body representation transformation into a smaller personusing a wearable VR device has been proposed [21 24 25]Visual stimuli plays an important role in recognizing the rela-tionship between a userrsquos own body representation Chang-ing the height of the eye level to a lower position while

2

Figure 3 A wearable visual device that allows a user tochange their body representation in realtime to that of asmall-person

allowing for FOV control will allow an egocentric visualperspective of a smaller person to be achieved Tiny handsand a shorter length of the upper limbs are other importantfactors enhancing the sense of being smaller [4 14]

Contributions(1) Conceptual representation of shaping visual and

haptic perspective into that of a smaller-person(2) Development of two wearable devices 1) a visual

translator for mapping the wearerrsquos eyesight level ontohisherwaist position by using a head-mounted display(HMD) and a wearable camera module and 2) a pairof passive hand exoskeletons for miniaturizing handgestures by using motion conversion mechanisms

(3) Conducted user studies at a nursing school a mu-seum and a lab to explore how a wearerrsquos experienceregarding perceptions of interpersonal distance (study1) actions during handshaking and a peg manipulation(study 2) and interactions (study 3) can be changed

Blending Kinesthetic Experience (Fig 4)Overview In this research I aim to assist mutual understand-ing of onersquos bodily activity during rehabilitations or sportstraining by sharing kinesthetic experiences with multiplepersons such as muscle contraction and joint rigidity whichare dicult to observe visually (Fig 2) To achieve this Ipropose a blended kinesthetic interaction that allows syn-chronizing adding or subtracting muscle activities betweentwo personsA novel style of interpersonal kinesthetic communica-

tion between two persons using wearable kinesthetic input-output (IO) devices was proposed [22] The system calledbioSync is illustrated in Fig 4 Using this system which con-sists primarily of a pair of devices muscle contractions of oneuser are detected by means of electromyogram (EMG) mea-surement and are reproduced by means of electrical muscle

bioSyncDevice

MuscleActivity

KinestheticFeedback

MuscleActuation

Biosignal

Figure 4 Representative Image of Blending Kinesthetic Ex-perience

stimulation (EMS) as muscle contractions of the other userand vice versa

Contributions

(1) Modeling of the blending kinesthetic experience basedon EMG measurement and EMS

(2) Proposed a method for muscular stimulation with dy-namic adjustment over a wide frequency range whilepreserving EMG measurement capability

(3) Implementation of bioSync devices with the sameelectrodes used for EMG measurement and EMS toachieve kinesthetic IO at 100 Hz via wireless commu-nication

(4) User studies of the interaction and the system inwhich kinesthetic IOwith low communication latency(approx 20 ms) allowed synchronization of rhythmicmuscle contraction without visual and auditory feed-back and allowed perception of presented EMS con-tractions while users were contracting their own mus-cles

3 DEVICE IMPLEMENTATIONSmaller-person ExperienceTo realize the concept of changing a body representationinto that of a smaller person I have been developing a wear-able device to change the visual perspective as shown inFig 5 The visual translator comprises an HMD a stereocamera module a sensor belt a single-board computer withprocessing software and a mobile battery The developedstereo camera module which is equipped with two sh-eyecameras (ELP-USBFHD01M-L180 Ailipu Technology CoLtd HD60fps) was developed Each camera module has a180 sh-eye lensThe wearer attaches the sensor belt at theirwaist position It has a nine-axis motion sensor (MPU-9250Invensense Inc) and a microcontroller (Atmel SAMD21 At-mel) for measuring the wearerrsquos waist orientation in theyaw-pitch-roll format

3

Single-board Computer(Openframeworks)

Accelerometer

Gyroscope

Magnetmeter

Fish-eye Cameras

Microphones

Fish-eye Imagesamp Stereo AudioUSB20

WaistOrientationUSB20

9-Axis MotionSPI

StereoImages amp AudioHDMI

Head OrientationUSB20

Microcontroller(Ateml SAMD21)

HMD Hand Exoskeleton

Wire to contrainrange of motion

Figure 5 System Architecture

Figure 6 (a) System Architecture (b) Process Diagram

The exoskeleton transforms the scale of the wearerrsquos handgestures into the smaller hand size by using a custom linkmechanism called a multiple quadric crank mechanism Theexoskeleton has small urethane nger skins connected to thewearerrsquos hand by link mechanisms so that the wearerrsquos ngermovement can be transmitted to the nger part directlyBecause the urethane-made child hand is actuated by themechanical link system the wearer is able to receive real-time haptic feedback from objects while interacting

Blending Kinesthetic ExperienceTo achieve the proposed interaction in an actual environ-ment I developed a paired wearable kinesthetic IO devicescalled bioSync (Fig 6 (a)) Each bioSync device is equippedwith a custom designed electrode system that performs EMGmeasurement and EMS simultaneously (Fig 6 (b)) In orderto achieve fast and simultaneous measurement and stimula-tion operations using common electrodes a gate switchingmechanism and a mechanism for discharging residual po-tential (the body retains a net charge following the stimulus)were implemented Each bioSync is also equipped with awireless communication module and a radio-frequency iden-tication (RFID) tag which is used to detect and pair withother bioSync devices by touching the wearerrsquos wrist to thepartnerrsquos bioSync device

4 USER STUDIESSmaller-person ExperienceTo investigate how the wearerrsquos perceptions actions and in-teractions can be modied through the proposed egocentric

EY_STA EY_SIT HC_STA HC_SIT WC_STA

Participant Experimenter

HMD Camera

Figure 7 Wearerrsquos Perception (a) Experiment overview (b)When the participant calls ldquostop (c) Experiment conditions

Recorded Video(POV from waist)

Participant Experimenter

Figure 8 Wearerrsquos Action Experiment Setup and Condi-tions (a) Watching a Video (b) Small-person Experience

experience of a smaller person the following three factorswhich are essential for the understanding of the users wereinvestigated1)Wearerrsquos perception In this study which was a per-

sonal space evaluation when the participant felt smallerusing the developed device (WC_STA condition) the largestpersonal distance was observed (Fig 7) This could have beencaused by an oppressive feeling toward the approaching ex-perimenter induced by the feeling of being small

2)Wearerrsquos action It was observed that the participantsraised their hands higher than usual when trying to shakehands with the experimenter because they perceived theirown body representation as being smaller (Fig 8) It wasconrmed that the experience of being a smaller personchanged the physical relationship of the wearer and thesurroundings

3) Wearerrsquos interaction The wearerrsquos interactions withthe developed device during demonstrations at conferencesand exhibitions were observed (Fig 9) It was often observedthat the visitors behaved like a child such as performinga protective pose when surrounded by adults or talkinglike a child Interestingly surrounding people such as youngstudents also treated the wearers like a child and behavedas teachers or parents by acting in an overbearing manner

4

Figure 9 Wearerrsquos Interaction Interaction Observation

IO ElectrodesPartition

Vibration Motors

Hand Dynamometer

JointCompliance

Figure 10 Transferring the wrist compliance by sharing an-tagonist muscle activity

Blending Kinesthetic ExperienceTo investigate how the wearerrsquos perceptions actions and in-teractions can be modied through the proposed egocentricexperience of a patient I investigated the following threefactors1)Wearerrsquos perception Through the perceptual exper-

iment it was veried that the bioSync users were able torecognize reproduced muscle contractions and rate themon a ve-point scale while they were contracting their ownmuscles at 50 25 0 maximum voluntary contractionAnother perceptual study of sharing the level of wrist com-pliance between two persons was also performed (Fig 10)which demonstrated that the participants recognized thelevel of the confederatersquos wrist compliance at four levels[23]

2)Wearerrsquos action I conducted a series of tests to verifythat the interpersonal communication via the kinestheticchannel could support the synchronization of two personsrsquorhythmic muscle contraction timing (Fig 11) The resultswere used to assess whether the bioSync device could beemployed in practical scenarios such as clinical gait rehabil-itation and sports training in which the synchronization oftiming plays an important role The average measured sync

Figure 11 Rhythmic Activity Synchronization

Figure 12 Demonstration Impairment Experience

time was 81s (SD=391s) and the average reported sync timewas 138s (SD=394s)

3)Wearerrsquos interaction I also conducted a pilot study onproviding a simulated embodied impairment experience atexhibitions and conferences (Fig 12) The participants triedto grab a spoon and to scoop up gummy candies with thereproduced tremor The results suggested that reproducingthe neurological action of Parkinsonrsquos tremors could enhancethe understanding of the disease

5 DISCUSSIONSSmaller-person ExperienceEye level aected the personal spaceFrom the result the eye level of the participant aected theperception of interpersonal distance because there is a signif-icant dierence between (3)HC_STA and (5)WC_STA condi-tions The dierence in eye level would create an oppressivefeeling toward the approaching experimenter In additionthe large neck angle in pitch axis also aected the perception

5

of social relationship with the experimenter because thenursing teachers usually interact with 5-years-old childrenOne participant reported that heshe has a frustrating feel-ing rather than an oppressive or scary feeling because theparticipant could not move the perspective higher althoughtheir legs were fully extended It is also presumed that theirinternal body representation also contributed to the changeof personal space

Perceived arm length and distanceThe participants could think their arm length had becomeshorter as had their height resulting in an increase in theperceived distance between hands A similar phenomenonwas also reported in which the arm length changed the per-ceived distance in a virtual environment [14]

Familiar objects as a referenceSeveral participants stated that they realized the change ineye level only after they saw the experimenter facing themalthough they had visited the experiment room several timesbefore and saw the desks positioned 2 m away from thestanding location during the experiment From such com-ments it is assumed that the participants used more familiarobjects as a reference to recognize the physical relation-ship between their body and space It should be noted thatthe participants knew the height of the experimenter andhad sucient experience with each other through conversa-tions because they are from the same local organization Therecorded head orientations also showed that the participantslooked up higher under (2) smaller person condition thanunder (1) video condition From the result and observationsmany participants looked at the experimenterrsquos face beforethe handshake suggesting that the level of face could beused as a reference Such existing knowledge based on motorand social experience could help the wearers recognize theirspace and physical relationship

Blending Kinesthetic ExperienceSubjective Perceptual ExperimentIn the perceptual experiment the participants could recog-nize reproduced muscle contractions and rate them on ave-point scale accurately while they were contracting theirown muscles It was observed that the standard deviationincreased when the pulse width increased This might bethe eect of the wearerrsquos voluntary contractions on the per-ception of the reproduced contractions Another perceptualexperiment would be required to study this phenomenon indetail and to assess the relevance of the signal-dependencynoise theory [10] which indicates that neural control signalsare corrupted by noise that increases in variance as with thesize of the motor control signal increases

Rhythmic Activity SynchronizationIn the user study of the synchronization of rhythmic actionsubject 1 reported that excessive involuntary contractionsaected the performance of the synchronization This couldhave been caused by the electrode positioning and personalmuscular characteristics This indicates that a prior adjust-ment is required for each subject to normalize the perceptualand kinesthetic experience among users Another aspect Iwould like to address is the learning eect which I could notverify in the current experiment since the number of trialsfor each participant was small However I found that syn-chronization time is always shorter when the experimenterwho had longer prior training and participated in the en-tire experiment follows the participantrsquos rhythmic actionAnother preliminary experiment showed that the rhythmicactions of two persons could be synchronized even if theyare not assigned as an experimenter or a follower and aretreated equally [29]

Embodied Impairment ExperienceIn the pilot study on the simulated embodied Parkinsonrsquosexperience I received considerable feedback comments thatindicated the existence of kinesthetic memory after the exper-iment This suggests that reproduced kinesthetic impairmentexperience may be more eective in learning the neurologi-cal characteristics of the impairment than learning throughsome other modality Some visitors also reported experi-encing the existence of a remote userrsquos presence throughthe kinesthetic channel while synchronizing muscle activ-ity between two persons Thus interpersonal kinestheticcommunication is capable of enhancing the feeling of togeth-erness and reality of existence in a manner similar to thatof interpersonal haptic communication [2 3 20]

6 CONCLUSIONSmaller-person ExperienceIn this research I explored how human perceptions actionsand interactions can be changed through the egocentric ex-perience of a smaller person in a real world environmentFrom study 1 which was a personal space evaluation

when the participant felt smaller using the developed devicethe largest personal distance was observed This could havebeen caused by an oppressive feeling toward the approachingexperimenter induced by the feeling of being small

In study 2 it was observed that the participants raised theirhands higher than usual when trying to shake hands withthe experimenter because they perceived their own bodyrepresentation as being smaller It was conrmed that theexperience of being a smaller person changed the physicalrelationship of the wearer and the surroundings In additionto this using a rehabilitation peg board it was observed that

6

the developed exoskeleton decreased the userrsquos chronologi-cal hand function which would reproduce a smaller-personrsquosphysical capability while preserving the wearerrsquos develop-mental hand functionIn study 3 I observed the wearerrsquos interactions during

demonstrations at conferences and exhibitions It was oftenobserved that the visitors behaved like a child such as per-forming a protective pose when surrounded by adults ortalking like a baby Interestingly surrounding people suchas young students also treated the wearers like a child andbehaved as teachers or parents by acting in an overbearingmanner

These ndings challenges and design considerations willbenet further studies on the design of user experiencesbased on changes in body representation while preservingactive and embodied interactions in a real-world environ-ment

Blending Kinesthetic ExperienceIn this research I proposed and modeled a novel style ofinterpersonal kinesthetic communication called the blendedkinesthetic interaction that allows people to mutually per-ceive and interrupt each otherrsquos muscle activityThrough the perceptual experiment it was veried that

the bioSync users were able to recognize reproduced mus-cle contractions and rate them on a ve-point scale whilethey were contracting their own muscles It was also veri-ed that the kinesthetic interpersonal communication allowspeople to synchronize the rhythmic action without visualand audio feedback I also conducted a pilot study on pro-viding a simulated embodied impairment experience Theresults suggested that reproducing the neurological actionof Parkinsonrsquos tremors could enhance the understanding ofthe impairmentThe pilot study regarding faster kinesthetic reaction and

the sense of agency not only demonstrated that the humanrsquosresponsive action can be accelerated by wiring the two per-sons but also suggested that their sti voluntary to performactions with reward at the right timing allows their senseof egocentricity the subjective feeling of producing a de-sired consequence or performance initiated by their ownvoluntary to be generated Further investigation regardingthe intervention timing and the sense of agency have beeninvestigated [12]These ndings would provide design ideas for the kines-

thetic interaction and contribute to potential applicationssuch as education design and medical activities that revealsnew aspects of human behaviors for embodied and socialexperiences

Shaping Egocentric ExperienceThe general conclusion regarding shaping egocentric experi-ences with wearable cybernic interfaces derived from designdevelopment and evaluation were described In contrast tothe related works that attempted to append or extend physi-cal body functions the proposed experience have success-fully amplied the participantsrsquo knowledge and particularlyembodied the knowledge of onersquos embodied and social expe-riences Hence I proposed the conceptual representation ofshaping a body representation in a real-world environmentbased on active interactions to reproduce onersquos embodiedand social experiencesA major attribute of the proposed experiences was that

the interaction could be initiated by the participantrsquos vol-untary action The participant must create interpret andreview narratives of the experience by themselves throughreaching seeing touching and speaking thus increasingtheir participation level toward the experienceAs another attribute the interaction styles involved the

surrounding people thereby allowing the participants to in-crease their awareness of other people This situation allowedfor the surrounding people apart from the wearer to per-ceive as the wearer became a smaller person or a Parkinsonrsquospatient These new social and physical contexts including anoppressive conversation protective posture conceited looklonger interpersonal distance and more supportive behaviorcontributed to shaping the body representation repeatedly

7 ACKNOWLEDGMENTSThis work was supported by Grant-in-Aid for JSPS ResearchFellow (JP16J03777) and Scientic Research on InnovativeAreas (JP18H04182)

BIOGRAPHYJun Nishida is a PhD candidate in Human Informatics atUniversity of Tsukuba Japan His research interests includedesigning experiences in which all people can maximize andshare their physical and cognitive capabilities to supporteach other in the elds of rehabilitation education and de-sign The latest version of this manuscript is available on myportfolio site (httpjunnishidanet)

REFERENCES[1] Domna Banakou Raphaela Groten and Mel Slater 2013 Illusory

ownership of a virtual child body causes overestimation of object sizesand implicit attitude changes Proceedings of the National Academy ofSciences of the United States of America 110 31 (July 2013) 12846ndash12851httpsdoiorg101073pnas1306779110

[2] Scott Brave and Andrew Dahley 1997 inTouch In CHI rsquo97 extendedabstracts ACM Press New York New York USA 363 httpsdoiorg10114511202121120435

[3] Scott Brave Cliord Nass and Erenee Sirinian 2001 Force-Feedbackin computer-mediated communication HCI (2001) httpsdblporg

7

Patients

ChildrenTeachers | Designers | Therapists

Visual Persepctiveinto a Smaller-person

Haptic Persepctiveinto a Smaller-person

Kinesthetic Persepctiveinto a Patient

Figure 2 Shaping Visual Haptic and Kinesthetic Perspec-tives into that of a Smaller Person and a Patient

Reproducing Onersquos Experience for LearningVideomaterials [31] an illusion technique used for extendingthe sense of ownership to a small doll [33] or an immersivevirtual reality technique for converting the userrsquos body intoa smaller avatar [1] have been used to create the sense ofbeing a smaller person through which the userrsquos experiencemay feel passive Several studies have achieved to changeonersquos bodily sensation into that of elderly [5] and impairedindividuals [28] by wearable visual haptic or kinestheticsystems while preserving the wearerrsquos active interactions

Active Embodied and Social Experiences should beProvided for Therapists Designers and TeachersThese conventional tools are able to partially transmit thecharacteristics or experiences of a personrsquos embodiment andtheir special needs to other people symbolically and visuallyhowever the following drawbacks still remain

(1) Users receive the bodily information in a passive man-ner from these media while embodied knowledge canbe acquired actively with physical actions

(2) It is dicult to provide embodied interactions whichinvolve proprioceptive feedback that play importantroles in learning or even altering bodily sensation

(3) It is hard to generate social interactions with peoplethrough these tools which is also an important formof feedback for the userrsquos physical actions because theuser is in a virtual space this may result in isolationfrom the social and physical contexts

If it becomes possible to understand onersquos experiencesin a real-world environment in an active embodied andsocial manner a more empathic experience will be providedfor product designers and educational sta when trying todesign living environments or communicating with otherpeople

2 SHAPING EGOCENTRIC EXPERIENCESIn this research a new paradigm is proposed in order tochange onersquos experience consists of perceptions actions andinteractions by changing onersquos body into that of another per-son while allowing active interactions with the surroundingobjects and people in a real-world environment as shownin Fig 1 This would provide embodied and empathic knowl-edge of onersquos experience rather than describing or simplypresenting it in a symbolical or visual manner The threehuman factors onersquos perceptions actions and interactionswould play important roles in dening physical and socialexperiences and contexts with objects and people thus con-stituting the sum of onersquos embodied and social experiencesBecause all actions and interactions in the proposed ex-

perience style should be performed in a same interactionmanner with that in an existing daily life the userrsquos con-scious act which consists of voluntarily initiating actionsdened as subjective agency [9] should be preserved

I call this experience that particularly includes both subjec-tive agency to initiate actions and active interactions with auserrsquos intention as egocentric experience in that a user isable to have an intention to initiate then initiate and freelyperform actions and interactions with hisher own intentionand timingNeuroscience studies have revealed that active interac-

tions foster the change in bodily sensation particularly bodyrepresentation [17 18 26] therefore I fully exploit a userrsquosegocentric actions and interactions for changing the bodilysensation to change the userrsquos bodily sensation

It is assumed that a userrsquos egocentric experience and bodilysensation would continue to be changed with the activeinteractions thus I call this modication of the experienceas shaping as related studies in neuroscience also use thesame term [7 8]Interfaces which satisfy design goals including wearable

form factor interactivity and IO correspondence as awear-able cybernic interface

Smaller-person Experience (Fig 3)Overview In this research I attempts to change the wearerrsquosbody representation to have a small-personrsquos perspective ina real environment with a capability of full body interac-tion by using wearable devices (Fig 2) The feasibility andproperties of active smaller-person experience in a RE wereinvestigated through both eld and lab studies to discuss itschallenges and opportunities To allow this the concept ofa body representation transformation into a smaller personusing a wearable VR device has been proposed [21 24 25]Visual stimuli plays an important role in recognizing the rela-tionship between a userrsquos own body representation Chang-ing the height of the eye level to a lower position while

2

Figure 3 A wearable visual device that allows a user tochange their body representation in realtime to that of asmall-person

allowing for FOV control will allow an egocentric visualperspective of a smaller person to be achieved Tiny handsand a shorter length of the upper limbs are other importantfactors enhancing the sense of being smaller [4 14]

Contributions(1) Conceptual representation of shaping visual and

haptic perspective into that of a smaller-person(2) Development of two wearable devices 1) a visual

translator for mapping the wearerrsquos eyesight level ontohisherwaist position by using a head-mounted display(HMD) and a wearable camera module and 2) a pairof passive hand exoskeletons for miniaturizing handgestures by using motion conversion mechanisms

(3) Conducted user studies at a nursing school a mu-seum and a lab to explore how a wearerrsquos experienceregarding perceptions of interpersonal distance (study1) actions during handshaking and a peg manipulation(study 2) and interactions (study 3) can be changed

Blending Kinesthetic Experience (Fig 4)Overview In this research I aim to assist mutual understand-ing of onersquos bodily activity during rehabilitations or sportstraining by sharing kinesthetic experiences with multiplepersons such as muscle contraction and joint rigidity whichare dicult to observe visually (Fig 2) To achieve this Ipropose a blended kinesthetic interaction that allows syn-chronizing adding or subtracting muscle activities betweentwo personsA novel style of interpersonal kinesthetic communica-

tion between two persons using wearable kinesthetic input-output (IO) devices was proposed [22] The system calledbioSync is illustrated in Fig 4 Using this system which con-sists primarily of a pair of devices muscle contractions of oneuser are detected by means of electromyogram (EMG) mea-surement and are reproduced by means of electrical muscle

bioSyncDevice

MuscleActivity

KinestheticFeedback

MuscleActuation

Biosignal

Figure 4 Representative Image of Blending Kinesthetic Ex-perience

stimulation (EMS) as muscle contractions of the other userand vice versa

Contributions

(1) Modeling of the blending kinesthetic experience basedon EMG measurement and EMS

(2) Proposed a method for muscular stimulation with dy-namic adjustment over a wide frequency range whilepreserving EMG measurement capability

(3) Implementation of bioSync devices with the sameelectrodes used for EMG measurement and EMS toachieve kinesthetic IO at 100 Hz via wireless commu-nication

(4) User studies of the interaction and the system inwhich kinesthetic IOwith low communication latency(approx 20 ms) allowed synchronization of rhythmicmuscle contraction without visual and auditory feed-back and allowed perception of presented EMS con-tractions while users were contracting their own mus-cles

3 DEVICE IMPLEMENTATIONSmaller-person ExperienceTo realize the concept of changing a body representationinto that of a smaller person I have been developing a wear-able device to change the visual perspective as shown inFig 5 The visual translator comprises an HMD a stereocamera module a sensor belt a single-board computer withprocessing software and a mobile battery The developedstereo camera module which is equipped with two sh-eyecameras (ELP-USBFHD01M-L180 Ailipu Technology CoLtd HD60fps) was developed Each camera module has a180 sh-eye lensThe wearer attaches the sensor belt at theirwaist position It has a nine-axis motion sensor (MPU-9250Invensense Inc) and a microcontroller (Atmel SAMD21 At-mel) for measuring the wearerrsquos waist orientation in theyaw-pitch-roll format

3

Single-board Computer(Openframeworks)

Accelerometer

Gyroscope

Magnetmeter

Fish-eye Cameras

Microphones

Fish-eye Imagesamp Stereo AudioUSB20

WaistOrientationUSB20

9-Axis MotionSPI

StereoImages amp AudioHDMI

Head OrientationUSB20

Microcontroller(Ateml SAMD21)

HMD Hand Exoskeleton

Wire to contrainrange of motion

Figure 5 System Architecture

Figure 6 (a) System Architecture (b) Process Diagram

The exoskeleton transforms the scale of the wearerrsquos handgestures into the smaller hand size by using a custom linkmechanism called a multiple quadric crank mechanism Theexoskeleton has small urethane nger skins connected to thewearerrsquos hand by link mechanisms so that the wearerrsquos ngermovement can be transmitted to the nger part directlyBecause the urethane-made child hand is actuated by themechanical link system the wearer is able to receive real-time haptic feedback from objects while interacting

Blending Kinesthetic ExperienceTo achieve the proposed interaction in an actual environ-ment I developed a paired wearable kinesthetic IO devicescalled bioSync (Fig 6 (a)) Each bioSync device is equippedwith a custom designed electrode system that performs EMGmeasurement and EMS simultaneously (Fig 6 (b)) In orderto achieve fast and simultaneous measurement and stimula-tion operations using common electrodes a gate switchingmechanism and a mechanism for discharging residual po-tential (the body retains a net charge following the stimulus)were implemented Each bioSync is also equipped with awireless communication module and a radio-frequency iden-tication (RFID) tag which is used to detect and pair withother bioSync devices by touching the wearerrsquos wrist to thepartnerrsquos bioSync device

4 USER STUDIESSmaller-person ExperienceTo investigate how the wearerrsquos perceptions actions and in-teractions can be modied through the proposed egocentric

EY_STA EY_SIT HC_STA HC_SIT WC_STA

Participant Experimenter

HMD Camera

Figure 7 Wearerrsquos Perception (a) Experiment overview (b)When the participant calls ldquostop (c) Experiment conditions

Recorded Video(POV from waist)

Participant Experimenter

Figure 8 Wearerrsquos Action Experiment Setup and Condi-tions (a) Watching a Video (b) Small-person Experience

experience of a smaller person the following three factorswhich are essential for the understanding of the users wereinvestigated1)Wearerrsquos perception In this study which was a per-

sonal space evaluation when the participant felt smallerusing the developed device (WC_STA condition) the largestpersonal distance was observed (Fig 7) This could have beencaused by an oppressive feeling toward the approaching ex-perimenter induced by the feeling of being small

2)Wearerrsquos action It was observed that the participantsraised their hands higher than usual when trying to shakehands with the experimenter because they perceived theirown body representation as being smaller (Fig 8) It wasconrmed that the experience of being a smaller personchanged the physical relationship of the wearer and thesurroundings

3) Wearerrsquos interaction The wearerrsquos interactions withthe developed device during demonstrations at conferencesand exhibitions were observed (Fig 9) It was often observedthat the visitors behaved like a child such as performinga protective pose when surrounded by adults or talkinglike a child Interestingly surrounding people such as youngstudents also treated the wearers like a child and behavedas teachers or parents by acting in an overbearing manner

4

Figure 9 Wearerrsquos Interaction Interaction Observation

IO ElectrodesPartition

Vibration Motors

Hand Dynamometer

JointCompliance

Figure 10 Transferring the wrist compliance by sharing an-tagonist muscle activity

Blending Kinesthetic ExperienceTo investigate how the wearerrsquos perceptions actions and in-teractions can be modied through the proposed egocentricexperience of a patient I investigated the following threefactors1)Wearerrsquos perception Through the perceptual exper-

iment it was veried that the bioSync users were able torecognize reproduced muscle contractions and rate themon a ve-point scale while they were contracting their ownmuscles at 50 25 0 maximum voluntary contractionAnother perceptual study of sharing the level of wrist com-pliance between two persons was also performed (Fig 10)which demonstrated that the participants recognized thelevel of the confederatersquos wrist compliance at four levels[23]

2)Wearerrsquos action I conducted a series of tests to verifythat the interpersonal communication via the kinestheticchannel could support the synchronization of two personsrsquorhythmic muscle contraction timing (Fig 11) The resultswere used to assess whether the bioSync device could beemployed in practical scenarios such as clinical gait rehabil-itation and sports training in which the synchronization oftiming plays an important role The average measured sync

Figure 11 Rhythmic Activity Synchronization

Figure 12 Demonstration Impairment Experience

time was 81s (SD=391s) and the average reported sync timewas 138s (SD=394s)

3)Wearerrsquos interaction I also conducted a pilot study onproviding a simulated embodied impairment experience atexhibitions and conferences (Fig 12) The participants triedto grab a spoon and to scoop up gummy candies with thereproduced tremor The results suggested that reproducingthe neurological action of Parkinsonrsquos tremors could enhancethe understanding of the disease

5 DISCUSSIONSSmaller-person ExperienceEye level aected the personal spaceFrom the result the eye level of the participant aected theperception of interpersonal distance because there is a signif-icant dierence between (3)HC_STA and (5)WC_STA condi-tions The dierence in eye level would create an oppressivefeeling toward the approaching experimenter In additionthe large neck angle in pitch axis also aected the perception

5

of social relationship with the experimenter because thenursing teachers usually interact with 5-years-old childrenOne participant reported that heshe has a frustrating feel-ing rather than an oppressive or scary feeling because theparticipant could not move the perspective higher althoughtheir legs were fully extended It is also presumed that theirinternal body representation also contributed to the changeof personal space

Perceived arm length and distanceThe participants could think their arm length had becomeshorter as had their height resulting in an increase in theperceived distance between hands A similar phenomenonwas also reported in which the arm length changed the per-ceived distance in a virtual environment [14]

Familiar objects as a referenceSeveral participants stated that they realized the change ineye level only after they saw the experimenter facing themalthough they had visited the experiment room several timesbefore and saw the desks positioned 2 m away from thestanding location during the experiment From such com-ments it is assumed that the participants used more familiarobjects as a reference to recognize the physical relation-ship between their body and space It should be noted thatthe participants knew the height of the experimenter andhad sucient experience with each other through conversa-tions because they are from the same local organization Therecorded head orientations also showed that the participantslooked up higher under (2) smaller person condition thanunder (1) video condition From the result and observationsmany participants looked at the experimenterrsquos face beforethe handshake suggesting that the level of face could beused as a reference Such existing knowledge based on motorand social experience could help the wearers recognize theirspace and physical relationship

Blending Kinesthetic ExperienceSubjective Perceptual ExperimentIn the perceptual experiment the participants could recog-nize reproduced muscle contractions and rate them on ave-point scale accurately while they were contracting theirown muscles It was observed that the standard deviationincreased when the pulse width increased This might bethe eect of the wearerrsquos voluntary contractions on the per-ception of the reproduced contractions Another perceptualexperiment would be required to study this phenomenon indetail and to assess the relevance of the signal-dependencynoise theory [10] which indicates that neural control signalsare corrupted by noise that increases in variance as with thesize of the motor control signal increases

Rhythmic Activity SynchronizationIn the user study of the synchronization of rhythmic actionsubject 1 reported that excessive involuntary contractionsaected the performance of the synchronization This couldhave been caused by the electrode positioning and personalmuscular characteristics This indicates that a prior adjust-ment is required for each subject to normalize the perceptualand kinesthetic experience among users Another aspect Iwould like to address is the learning eect which I could notverify in the current experiment since the number of trialsfor each participant was small However I found that syn-chronization time is always shorter when the experimenterwho had longer prior training and participated in the en-tire experiment follows the participantrsquos rhythmic actionAnother preliminary experiment showed that the rhythmicactions of two persons could be synchronized even if theyare not assigned as an experimenter or a follower and aretreated equally [29]

Embodied Impairment ExperienceIn the pilot study on the simulated embodied Parkinsonrsquosexperience I received considerable feedback comments thatindicated the existence of kinesthetic memory after the exper-iment This suggests that reproduced kinesthetic impairmentexperience may be more eective in learning the neurologi-cal characteristics of the impairment than learning throughsome other modality Some visitors also reported experi-encing the existence of a remote userrsquos presence throughthe kinesthetic channel while synchronizing muscle activ-ity between two persons Thus interpersonal kinestheticcommunication is capable of enhancing the feeling of togeth-erness and reality of existence in a manner similar to thatof interpersonal haptic communication [2 3 20]

6 CONCLUSIONSmaller-person ExperienceIn this research I explored how human perceptions actionsand interactions can be changed through the egocentric ex-perience of a smaller person in a real world environmentFrom study 1 which was a personal space evaluation

when the participant felt smaller using the developed devicethe largest personal distance was observed This could havebeen caused by an oppressive feeling toward the approachingexperimenter induced by the feeling of being small

In study 2 it was observed that the participants raised theirhands higher than usual when trying to shake hands withthe experimenter because they perceived their own bodyrepresentation as being smaller It was conrmed that theexperience of being a smaller person changed the physicalrelationship of the wearer and the surroundings In additionto this using a rehabilitation peg board it was observed that

6

the developed exoskeleton decreased the userrsquos chronologi-cal hand function which would reproduce a smaller-personrsquosphysical capability while preserving the wearerrsquos develop-mental hand functionIn study 3 I observed the wearerrsquos interactions during

demonstrations at conferences and exhibitions It was oftenobserved that the visitors behaved like a child such as per-forming a protective pose when surrounded by adults ortalking like a baby Interestingly surrounding people suchas young students also treated the wearers like a child andbehaved as teachers or parents by acting in an overbearingmanner

These ndings challenges and design considerations willbenet further studies on the design of user experiencesbased on changes in body representation while preservingactive and embodied interactions in a real-world environ-ment

Blending Kinesthetic ExperienceIn this research I proposed and modeled a novel style ofinterpersonal kinesthetic communication called the blendedkinesthetic interaction that allows people to mutually per-ceive and interrupt each otherrsquos muscle activityThrough the perceptual experiment it was veried that

the bioSync users were able to recognize reproduced mus-cle contractions and rate them on a ve-point scale whilethey were contracting their own muscles It was also veri-ed that the kinesthetic interpersonal communication allowspeople to synchronize the rhythmic action without visualand audio feedback I also conducted a pilot study on pro-viding a simulated embodied impairment experience Theresults suggested that reproducing the neurological actionof Parkinsonrsquos tremors could enhance the understanding ofthe impairmentThe pilot study regarding faster kinesthetic reaction and

the sense of agency not only demonstrated that the humanrsquosresponsive action can be accelerated by wiring the two per-sons but also suggested that their sti voluntary to performactions with reward at the right timing allows their senseof egocentricity the subjective feeling of producing a de-sired consequence or performance initiated by their ownvoluntary to be generated Further investigation regardingthe intervention timing and the sense of agency have beeninvestigated [12]These ndings would provide design ideas for the kines-

thetic interaction and contribute to potential applicationssuch as education design and medical activities that revealsnew aspects of human behaviors for embodied and socialexperiences

Shaping Egocentric ExperienceThe general conclusion regarding shaping egocentric experi-ences with wearable cybernic interfaces derived from designdevelopment and evaluation were described In contrast tothe related works that attempted to append or extend physi-cal body functions the proposed experience have success-fully amplied the participantsrsquo knowledge and particularlyembodied the knowledge of onersquos embodied and social expe-riences Hence I proposed the conceptual representation ofshaping a body representation in a real-world environmentbased on active interactions to reproduce onersquos embodiedand social experiencesA major attribute of the proposed experiences was that

the interaction could be initiated by the participantrsquos vol-untary action The participant must create interpret andreview narratives of the experience by themselves throughreaching seeing touching and speaking thus increasingtheir participation level toward the experienceAs another attribute the interaction styles involved the

surrounding people thereby allowing the participants to in-crease their awareness of other people This situation allowedfor the surrounding people apart from the wearer to per-ceive as the wearer became a smaller person or a Parkinsonrsquospatient These new social and physical contexts including anoppressive conversation protective posture conceited looklonger interpersonal distance and more supportive behaviorcontributed to shaping the body representation repeatedly

7 ACKNOWLEDGMENTSThis work was supported by Grant-in-Aid for JSPS ResearchFellow (JP16J03777) and Scientic Research on InnovativeAreas (JP18H04182)

BIOGRAPHYJun Nishida is a PhD candidate in Human Informatics atUniversity of Tsukuba Japan His research interests includedesigning experiences in which all people can maximize andshare their physical and cognitive capabilities to supporteach other in the elds of rehabilitation education and de-sign The latest version of this manuscript is available on myportfolio site (httpjunnishidanet)

REFERENCES[1] Domna Banakou Raphaela Groten and Mel Slater 2013 Illusory

ownership of a virtual child body causes overestimation of object sizesand implicit attitude changes Proceedings of the National Academy ofSciences of the United States of America 110 31 (July 2013) 12846ndash12851httpsdoiorg101073pnas1306779110

[2] Scott Brave and Andrew Dahley 1997 inTouch In CHI rsquo97 extendedabstracts ACM Press New York New York USA 363 httpsdoiorg10114511202121120435

[3] Scott Brave Cliord Nass and Erenee Sirinian 2001 Force-Feedbackin computer-mediated communication HCI (2001) httpsdblporg

7

Figure 3 A wearable visual device that allows a user tochange their body representation in realtime to that of asmall-person

allowing for FOV control will allow an egocentric visualperspective of a smaller person to be achieved Tiny handsand a shorter length of the upper limbs are other importantfactors enhancing the sense of being smaller [4 14]

Contributions(1) Conceptual representation of shaping visual and

haptic perspective into that of a smaller-person(2) Development of two wearable devices 1) a visual

translator for mapping the wearerrsquos eyesight level ontohisherwaist position by using a head-mounted display(HMD) and a wearable camera module and 2) a pairof passive hand exoskeletons for miniaturizing handgestures by using motion conversion mechanisms

(3) Conducted user studies at a nursing school a mu-seum and a lab to explore how a wearerrsquos experienceregarding perceptions of interpersonal distance (study1) actions during handshaking and a peg manipulation(study 2) and interactions (study 3) can be changed

Blending Kinesthetic Experience (Fig 4)Overview In this research I aim to assist mutual understand-ing of onersquos bodily activity during rehabilitations or sportstraining by sharing kinesthetic experiences with multiplepersons such as muscle contraction and joint rigidity whichare dicult to observe visually (Fig 2) To achieve this Ipropose a blended kinesthetic interaction that allows syn-chronizing adding or subtracting muscle activities betweentwo personsA novel style of interpersonal kinesthetic communica-

tion between two persons using wearable kinesthetic input-output (IO) devices was proposed [22] The system calledbioSync is illustrated in Fig 4 Using this system which con-sists primarily of a pair of devices muscle contractions of oneuser are detected by means of electromyogram (EMG) mea-surement and are reproduced by means of electrical muscle

bioSyncDevice

MuscleActivity

KinestheticFeedback

MuscleActuation

Biosignal

Figure 4 Representative Image of Blending Kinesthetic Ex-perience

stimulation (EMS) as muscle contractions of the other userand vice versa

Contributions

(1) Modeling of the blending kinesthetic experience basedon EMG measurement and EMS

(2) Proposed a method for muscular stimulation with dy-namic adjustment over a wide frequency range whilepreserving EMG measurement capability

(3) Implementation of bioSync devices with the sameelectrodes used for EMG measurement and EMS toachieve kinesthetic IO at 100 Hz via wireless commu-nication

(4) User studies of the interaction and the system inwhich kinesthetic IOwith low communication latency(approx 20 ms) allowed synchronization of rhythmicmuscle contraction without visual and auditory feed-back and allowed perception of presented EMS con-tractions while users were contracting their own mus-cles

3 DEVICE IMPLEMENTATIONSmaller-person ExperienceTo realize the concept of changing a body representationinto that of a smaller person I have been developing a wear-able device to change the visual perspective as shown inFig 5 The visual translator comprises an HMD a stereocamera module a sensor belt a single-board computer withprocessing software and a mobile battery The developedstereo camera module which is equipped with two sh-eyecameras (ELP-USBFHD01M-L180 Ailipu Technology CoLtd HD60fps) was developed Each camera module has a180 sh-eye lensThe wearer attaches the sensor belt at theirwaist position It has a nine-axis motion sensor (MPU-9250Invensense Inc) and a microcontroller (Atmel SAMD21 At-mel) for measuring the wearerrsquos waist orientation in theyaw-pitch-roll format

3

Single-board Computer(Openframeworks)

Accelerometer

Gyroscope

Magnetmeter

Fish-eye Cameras

Microphones

Fish-eye Imagesamp Stereo AudioUSB20

WaistOrientationUSB20

9-Axis MotionSPI

StereoImages amp AudioHDMI

Head OrientationUSB20

Microcontroller(Ateml SAMD21)

HMD Hand Exoskeleton

Wire to contrainrange of motion

Figure 5 System Architecture

Figure 6 (a) System Architecture (b) Process Diagram

The exoskeleton transforms the scale of the wearerrsquos handgestures into the smaller hand size by using a custom linkmechanism called a multiple quadric crank mechanism Theexoskeleton has small urethane nger skins connected to thewearerrsquos hand by link mechanisms so that the wearerrsquos ngermovement can be transmitted to the nger part directlyBecause the urethane-made child hand is actuated by themechanical link system the wearer is able to receive real-time haptic feedback from objects while interacting

Blending Kinesthetic ExperienceTo achieve the proposed interaction in an actual environ-ment I developed a paired wearable kinesthetic IO devicescalled bioSync (Fig 6 (a)) Each bioSync device is equippedwith a custom designed electrode system that performs EMGmeasurement and EMS simultaneously (Fig 6 (b)) In orderto achieve fast and simultaneous measurement and stimula-tion operations using common electrodes a gate switchingmechanism and a mechanism for discharging residual po-tential (the body retains a net charge following the stimulus)were implemented Each bioSync is also equipped with awireless communication module and a radio-frequency iden-tication (RFID) tag which is used to detect and pair withother bioSync devices by touching the wearerrsquos wrist to thepartnerrsquos bioSync device

4 USER STUDIESSmaller-person ExperienceTo investigate how the wearerrsquos perceptions actions and in-teractions can be modied through the proposed egocentric

EY_STA EY_SIT HC_STA HC_SIT WC_STA

Participant Experimenter

HMD Camera

Figure 7 Wearerrsquos Perception (a) Experiment overview (b)When the participant calls ldquostop (c) Experiment conditions

Recorded Video(POV from waist)

Participant Experimenter

Figure 8 Wearerrsquos Action Experiment Setup and Condi-tions (a) Watching a Video (b) Small-person Experience

experience of a smaller person the following three factorswhich are essential for the understanding of the users wereinvestigated1)Wearerrsquos perception In this study which was a per-

sonal space evaluation when the participant felt smallerusing the developed device (WC_STA condition) the largestpersonal distance was observed (Fig 7) This could have beencaused by an oppressive feeling toward the approaching ex-perimenter induced by the feeling of being small

2)Wearerrsquos action It was observed that the participantsraised their hands higher than usual when trying to shakehands with the experimenter because they perceived theirown body representation as being smaller (Fig 8) It wasconrmed that the experience of being a smaller personchanged the physical relationship of the wearer and thesurroundings

3) Wearerrsquos interaction The wearerrsquos interactions withthe developed device during demonstrations at conferencesand exhibitions were observed (Fig 9) It was often observedthat the visitors behaved like a child such as performinga protective pose when surrounded by adults or talkinglike a child Interestingly surrounding people such as youngstudents also treated the wearers like a child and behavedas teachers or parents by acting in an overbearing manner

4

Figure 9 Wearerrsquos Interaction Interaction Observation

IO ElectrodesPartition

Vibration Motors

Hand Dynamometer

JointCompliance

Figure 10 Transferring the wrist compliance by sharing an-tagonist muscle activity

Blending Kinesthetic ExperienceTo investigate how the wearerrsquos perceptions actions and in-teractions can be modied through the proposed egocentricexperience of a patient I investigated the following threefactors1)Wearerrsquos perception Through the perceptual exper-

iment it was veried that the bioSync users were able torecognize reproduced muscle contractions and rate themon a ve-point scale while they were contracting their ownmuscles at 50 25 0 maximum voluntary contractionAnother perceptual study of sharing the level of wrist com-pliance between two persons was also performed (Fig 10)which demonstrated that the participants recognized thelevel of the confederatersquos wrist compliance at four levels[23]

2)Wearerrsquos action I conducted a series of tests to verifythat the interpersonal communication via the kinestheticchannel could support the synchronization of two personsrsquorhythmic muscle contraction timing (Fig 11) The resultswere used to assess whether the bioSync device could beemployed in practical scenarios such as clinical gait rehabil-itation and sports training in which the synchronization oftiming plays an important role The average measured sync

Figure 11 Rhythmic Activity Synchronization

Figure 12 Demonstration Impairment Experience

time was 81s (SD=391s) and the average reported sync timewas 138s (SD=394s)

3)Wearerrsquos interaction I also conducted a pilot study onproviding a simulated embodied impairment experience atexhibitions and conferences (Fig 12) The participants triedto grab a spoon and to scoop up gummy candies with thereproduced tremor The results suggested that reproducingthe neurological action of Parkinsonrsquos tremors could enhancethe understanding of the disease

5 DISCUSSIONSSmaller-person ExperienceEye level aected the personal spaceFrom the result the eye level of the participant aected theperception of interpersonal distance because there is a signif-icant dierence between (3)HC_STA and (5)WC_STA condi-tions The dierence in eye level would create an oppressivefeeling toward the approaching experimenter In additionthe large neck angle in pitch axis also aected the perception

5

of social relationship with the experimenter because thenursing teachers usually interact with 5-years-old childrenOne participant reported that heshe has a frustrating feel-ing rather than an oppressive or scary feeling because theparticipant could not move the perspective higher althoughtheir legs were fully extended It is also presumed that theirinternal body representation also contributed to the changeof personal space

Perceived arm length and distanceThe participants could think their arm length had becomeshorter as had their height resulting in an increase in theperceived distance between hands A similar phenomenonwas also reported in which the arm length changed the per-ceived distance in a virtual environment [14]

Familiar objects as a referenceSeveral participants stated that they realized the change ineye level only after they saw the experimenter facing themalthough they had visited the experiment room several timesbefore and saw the desks positioned 2 m away from thestanding location during the experiment From such com-ments it is assumed that the participants used more familiarobjects as a reference to recognize the physical relation-ship between their body and space It should be noted thatthe participants knew the height of the experimenter andhad sucient experience with each other through conversa-tions because they are from the same local organization Therecorded head orientations also showed that the participantslooked up higher under (2) smaller person condition thanunder (1) video condition From the result and observationsmany participants looked at the experimenterrsquos face beforethe handshake suggesting that the level of face could beused as a reference Such existing knowledge based on motorand social experience could help the wearers recognize theirspace and physical relationship

Blending Kinesthetic ExperienceSubjective Perceptual ExperimentIn the perceptual experiment the participants could recog-nize reproduced muscle contractions and rate them on ave-point scale accurately while they were contracting theirown muscles It was observed that the standard deviationincreased when the pulse width increased This might bethe eect of the wearerrsquos voluntary contractions on the per-ception of the reproduced contractions Another perceptualexperiment would be required to study this phenomenon indetail and to assess the relevance of the signal-dependencynoise theory [10] which indicates that neural control signalsare corrupted by noise that increases in variance as with thesize of the motor control signal increases

Rhythmic Activity SynchronizationIn the user study of the synchronization of rhythmic actionsubject 1 reported that excessive involuntary contractionsaected the performance of the synchronization This couldhave been caused by the electrode positioning and personalmuscular characteristics This indicates that a prior adjust-ment is required for each subject to normalize the perceptualand kinesthetic experience among users Another aspect Iwould like to address is the learning eect which I could notverify in the current experiment since the number of trialsfor each participant was small However I found that syn-chronization time is always shorter when the experimenterwho had longer prior training and participated in the en-tire experiment follows the participantrsquos rhythmic actionAnother preliminary experiment showed that the rhythmicactions of two persons could be synchronized even if theyare not assigned as an experimenter or a follower and aretreated equally [29]

Embodied Impairment ExperienceIn the pilot study on the simulated embodied Parkinsonrsquosexperience I received considerable feedback comments thatindicated the existence of kinesthetic memory after the exper-iment This suggests that reproduced kinesthetic impairmentexperience may be more eective in learning the neurologi-cal characteristics of the impairment than learning throughsome other modality Some visitors also reported experi-encing the existence of a remote userrsquos presence throughthe kinesthetic channel while synchronizing muscle activ-ity between two persons Thus interpersonal kinestheticcommunication is capable of enhancing the feeling of togeth-erness and reality of existence in a manner similar to thatof interpersonal haptic communication [2 3 20]

6 CONCLUSIONSmaller-person ExperienceIn this research I explored how human perceptions actionsand interactions can be changed through the egocentric ex-perience of a smaller person in a real world environmentFrom study 1 which was a personal space evaluation

when the participant felt smaller using the developed devicethe largest personal distance was observed This could havebeen caused by an oppressive feeling toward the approachingexperimenter induced by the feeling of being small

In study 2 it was observed that the participants raised theirhands higher than usual when trying to shake hands withthe experimenter because they perceived their own bodyrepresentation as being smaller It was conrmed that theexperience of being a smaller person changed the physicalrelationship of the wearer and the surroundings In additionto this using a rehabilitation peg board it was observed that

6

the developed exoskeleton decreased the userrsquos chronologi-cal hand function which would reproduce a smaller-personrsquosphysical capability while preserving the wearerrsquos develop-mental hand functionIn study 3 I observed the wearerrsquos interactions during

demonstrations at conferences and exhibitions It was oftenobserved that the visitors behaved like a child such as per-forming a protective pose when surrounded by adults ortalking like a baby Interestingly surrounding people suchas young students also treated the wearers like a child andbehaved as teachers or parents by acting in an overbearingmanner

These ndings challenges and design considerations willbenet further studies on the design of user experiencesbased on changes in body representation while preservingactive and embodied interactions in a real-world environ-ment

Blending Kinesthetic ExperienceIn this research I proposed and modeled a novel style ofinterpersonal kinesthetic communication called the blendedkinesthetic interaction that allows people to mutually per-ceive and interrupt each otherrsquos muscle activityThrough the perceptual experiment it was veried that

the bioSync users were able to recognize reproduced mus-cle contractions and rate them on a ve-point scale whilethey were contracting their own muscles It was also veri-ed that the kinesthetic interpersonal communication allowspeople to synchronize the rhythmic action without visualand audio feedback I also conducted a pilot study on pro-viding a simulated embodied impairment experience Theresults suggested that reproducing the neurological actionof Parkinsonrsquos tremors could enhance the understanding ofthe impairmentThe pilot study regarding faster kinesthetic reaction and

the sense of agency not only demonstrated that the humanrsquosresponsive action can be accelerated by wiring the two per-sons but also suggested that their sti voluntary to performactions with reward at the right timing allows their senseof egocentricity the subjective feeling of producing a de-sired consequence or performance initiated by their ownvoluntary to be generated Further investigation regardingthe intervention timing and the sense of agency have beeninvestigated [12]These ndings would provide design ideas for the kines-

thetic interaction and contribute to potential applicationssuch as education design and medical activities that revealsnew aspects of human behaviors for embodied and socialexperiences

Shaping Egocentric ExperienceThe general conclusion regarding shaping egocentric experi-ences with wearable cybernic interfaces derived from designdevelopment and evaluation were described In contrast tothe related works that attempted to append or extend physi-cal body functions the proposed experience have success-fully amplied the participantsrsquo knowledge and particularlyembodied the knowledge of onersquos embodied and social expe-riences Hence I proposed the conceptual representation ofshaping a body representation in a real-world environmentbased on active interactions to reproduce onersquos embodiedand social experiencesA major attribute of the proposed experiences was that

the interaction could be initiated by the participantrsquos vol-untary action The participant must create interpret andreview narratives of the experience by themselves throughreaching seeing touching and speaking thus increasingtheir participation level toward the experienceAs another attribute the interaction styles involved the

surrounding people thereby allowing the participants to in-crease their awareness of other people This situation allowedfor the surrounding people apart from the wearer to per-ceive as the wearer became a smaller person or a Parkinsonrsquospatient These new social and physical contexts including anoppressive conversation protective posture conceited looklonger interpersonal distance and more supportive behaviorcontributed to shaping the body representation repeatedly

7 ACKNOWLEDGMENTSThis work was supported by Grant-in-Aid for JSPS ResearchFellow (JP16J03777) and Scientic Research on InnovativeAreas (JP18H04182)

BIOGRAPHYJun Nishida is a PhD candidate in Human Informatics atUniversity of Tsukuba Japan His research interests includedesigning experiences in which all people can maximize andshare their physical and cognitive capabilities to supporteach other in the elds of rehabilitation education and de-sign The latest version of this manuscript is available on myportfolio site (httpjunnishidanet)

REFERENCES[1] Domna Banakou Raphaela Groten and Mel Slater 2013 Illusory

ownership of a virtual child body causes overestimation of object sizesand implicit attitude changes Proceedings of the National Academy ofSciences of the United States of America 110 31 (July 2013) 12846ndash12851httpsdoiorg101073pnas1306779110

[2] Scott Brave and Andrew Dahley 1997 inTouch In CHI rsquo97 extendedabstracts ACM Press New York New York USA 363 httpsdoiorg10114511202121120435

[3] Scott Brave Cliord Nass and Erenee Sirinian 2001 Force-Feedbackin computer-mediated communication HCI (2001) httpsdblporg

7

Single-board Computer(Openframeworks)

Accelerometer

Gyroscope

Magnetmeter

Fish-eye Cameras

Microphones

Fish-eye Imagesamp Stereo AudioUSB20

WaistOrientationUSB20

9-Axis MotionSPI

StereoImages amp AudioHDMI

Head OrientationUSB20

Microcontroller(Ateml SAMD21)

HMD Hand Exoskeleton

Wire to contrainrange of motion

Figure 5 System Architecture

Figure 6 (a) System Architecture (b) Process Diagram

The exoskeleton transforms the scale of the wearerrsquos handgestures into the smaller hand size by using a custom linkmechanism called a multiple quadric crank mechanism Theexoskeleton has small urethane nger skins connected to thewearerrsquos hand by link mechanisms so that the wearerrsquos ngermovement can be transmitted to the nger part directlyBecause the urethane-made child hand is actuated by themechanical link system the wearer is able to receive real-time haptic feedback from objects while interacting

Blending Kinesthetic ExperienceTo achieve the proposed interaction in an actual environ-ment I developed a paired wearable kinesthetic IO devicescalled bioSync (Fig 6 (a)) Each bioSync device is equippedwith a custom designed electrode system that performs EMGmeasurement and EMS simultaneously (Fig 6 (b)) In orderto achieve fast and simultaneous measurement and stimula-tion operations using common electrodes a gate switchingmechanism and a mechanism for discharging residual po-tential (the body retains a net charge following the stimulus)were implemented Each bioSync is also equipped with awireless communication module and a radio-frequency iden-tication (RFID) tag which is used to detect and pair withother bioSync devices by touching the wearerrsquos wrist to thepartnerrsquos bioSync device

4 USER STUDIESSmaller-person ExperienceTo investigate how the wearerrsquos perceptions actions and in-teractions can be modied through the proposed egocentric

EY_STA EY_SIT HC_STA HC_SIT WC_STA

Participant Experimenter

HMD Camera

Figure 7 Wearerrsquos Perception (a) Experiment overview (b)When the participant calls ldquostop (c) Experiment conditions

Recorded Video(POV from waist)

Participant Experimenter

Figure 8 Wearerrsquos Action Experiment Setup and Condi-tions (a) Watching a Video (b) Small-person Experience

experience of a smaller person the following three factorswhich are essential for the understanding of the users wereinvestigated1)Wearerrsquos perception In this study which was a per-

sonal space evaluation when the participant felt smallerusing the developed device (WC_STA condition) the largestpersonal distance was observed (Fig 7) This could have beencaused by an oppressive feeling toward the approaching ex-perimenter induced by the feeling of being small

2)Wearerrsquos action It was observed that the participantsraised their hands higher than usual when trying to shakehands with the experimenter because they perceived theirown body representation as being smaller (Fig 8) It wasconrmed that the experience of being a smaller personchanged the physical relationship of the wearer and thesurroundings

3) Wearerrsquos interaction The wearerrsquos interactions withthe developed device during demonstrations at conferencesand exhibitions were observed (Fig 9) It was often observedthat the visitors behaved like a child such as performinga protective pose when surrounded by adults or talkinglike a child Interestingly surrounding people such as youngstudents also treated the wearers like a child and behavedas teachers or parents by acting in an overbearing manner

4

Figure 9 Wearerrsquos Interaction Interaction Observation

IO ElectrodesPartition

Vibration Motors

Hand Dynamometer

JointCompliance

Figure 10 Transferring the wrist compliance by sharing an-tagonist muscle activity

Blending Kinesthetic ExperienceTo investigate how the wearerrsquos perceptions actions and in-teractions can be modied through the proposed egocentricexperience of a patient I investigated the following threefactors1)Wearerrsquos perception Through the perceptual exper-

iment it was veried that the bioSync users were able torecognize reproduced muscle contractions and rate themon a ve-point scale while they were contracting their ownmuscles at 50 25 0 maximum voluntary contractionAnother perceptual study of sharing the level of wrist com-pliance between two persons was also performed (Fig 10)which demonstrated that the participants recognized thelevel of the confederatersquos wrist compliance at four levels[23]

2)Wearerrsquos action I conducted a series of tests to verifythat the interpersonal communication via the kinestheticchannel could support the synchronization of two personsrsquorhythmic muscle contraction timing (Fig 11) The resultswere used to assess whether the bioSync device could beemployed in practical scenarios such as clinical gait rehabil-itation and sports training in which the synchronization oftiming plays an important role The average measured sync

Figure 11 Rhythmic Activity Synchronization

Figure 12 Demonstration Impairment Experience

time was 81s (SD=391s) and the average reported sync timewas 138s (SD=394s)

3)Wearerrsquos interaction I also conducted a pilot study onproviding a simulated embodied impairment experience atexhibitions and conferences (Fig 12) The participants triedto grab a spoon and to scoop up gummy candies with thereproduced tremor The results suggested that reproducingthe neurological action of Parkinsonrsquos tremors could enhancethe understanding of the disease

5 DISCUSSIONSSmaller-person ExperienceEye level aected the personal spaceFrom the result the eye level of the participant aected theperception of interpersonal distance because there is a signif-icant dierence between (3)HC_STA and (5)WC_STA condi-tions The dierence in eye level would create an oppressivefeeling toward the approaching experimenter In additionthe large neck angle in pitch axis also aected the perception

5

of social relationship with the experimenter because thenursing teachers usually interact with 5-years-old childrenOne participant reported that heshe has a frustrating feel-ing rather than an oppressive or scary feeling because theparticipant could not move the perspective higher althoughtheir legs were fully extended It is also presumed that theirinternal body representation also contributed to the changeof personal space

Perceived arm length and distanceThe participants could think their arm length had becomeshorter as had their height resulting in an increase in theperceived distance between hands A similar phenomenonwas also reported in which the arm length changed the per-ceived distance in a virtual environment [14]

Familiar objects as a referenceSeveral participants stated that they realized the change ineye level only after they saw the experimenter facing themalthough they had visited the experiment room several timesbefore and saw the desks positioned 2 m away from thestanding location during the experiment From such com-ments it is assumed that the participants used more familiarobjects as a reference to recognize the physical relation-ship between their body and space It should be noted thatthe participants knew the height of the experimenter andhad sucient experience with each other through conversa-tions because they are from the same local organization Therecorded head orientations also showed that the participantslooked up higher under (2) smaller person condition thanunder (1) video condition From the result and observationsmany participants looked at the experimenterrsquos face beforethe handshake suggesting that the level of face could beused as a reference Such existing knowledge based on motorand social experience could help the wearers recognize theirspace and physical relationship

Blending Kinesthetic ExperienceSubjective Perceptual ExperimentIn the perceptual experiment the participants could recog-nize reproduced muscle contractions and rate them on ave-point scale accurately while they were contracting theirown muscles It was observed that the standard deviationincreased when the pulse width increased This might bethe eect of the wearerrsquos voluntary contractions on the per-ception of the reproduced contractions Another perceptualexperiment would be required to study this phenomenon indetail and to assess the relevance of the signal-dependencynoise theory [10] which indicates that neural control signalsare corrupted by noise that increases in variance as with thesize of the motor control signal increases

Rhythmic Activity SynchronizationIn the user study of the synchronization of rhythmic actionsubject 1 reported that excessive involuntary contractionsaected the performance of the synchronization This couldhave been caused by the electrode positioning and personalmuscular characteristics This indicates that a prior adjust-ment is required for each subject to normalize the perceptualand kinesthetic experience among users Another aspect Iwould like to address is the learning eect which I could notverify in the current experiment since the number of trialsfor each participant was small However I found that syn-chronization time is always shorter when the experimenterwho had longer prior training and participated in the en-tire experiment follows the participantrsquos rhythmic actionAnother preliminary experiment showed that the rhythmicactions of two persons could be synchronized even if theyare not assigned as an experimenter or a follower and aretreated equally [29]

Embodied Impairment ExperienceIn the pilot study on the simulated embodied Parkinsonrsquosexperience I received considerable feedback comments thatindicated the existence of kinesthetic memory after the exper-iment This suggests that reproduced kinesthetic impairmentexperience may be more eective in learning the neurologi-cal characteristics of the impairment than learning throughsome other modality Some visitors also reported experi-encing the existence of a remote userrsquos presence throughthe kinesthetic channel while synchronizing muscle activ-ity between two persons Thus interpersonal kinestheticcommunication is capable of enhancing the feeling of togeth-erness and reality of existence in a manner similar to thatof interpersonal haptic communication [2 3 20]

6 CONCLUSIONSmaller-person ExperienceIn this research I explored how human perceptions actionsand interactions can be changed through the egocentric ex-perience of a smaller person in a real world environmentFrom study 1 which was a personal space evaluation

when the participant felt smaller using the developed devicethe largest personal distance was observed This could havebeen caused by an oppressive feeling toward the approachingexperimenter induced by the feeling of being small

In study 2 it was observed that the participants raised theirhands higher than usual when trying to shake hands withthe experimenter because they perceived their own bodyrepresentation as being smaller It was conrmed that theexperience of being a smaller person changed the physicalrelationship of the wearer and the surroundings In additionto this using a rehabilitation peg board it was observed that

6

the developed exoskeleton decreased the userrsquos chronologi-cal hand function which would reproduce a smaller-personrsquosphysical capability while preserving the wearerrsquos develop-mental hand functionIn study 3 I observed the wearerrsquos interactions during

demonstrations at conferences and exhibitions It was oftenobserved that the visitors behaved like a child such as per-forming a protective pose when surrounded by adults ortalking like a baby Interestingly surrounding people suchas young students also treated the wearers like a child andbehaved as teachers or parents by acting in an overbearingmanner

These ndings challenges and design considerations willbenet further studies on the design of user experiencesbased on changes in body representation while preservingactive and embodied interactions in a real-world environ-ment

Blending Kinesthetic ExperienceIn this research I proposed and modeled a novel style ofinterpersonal kinesthetic communication called the blendedkinesthetic interaction that allows people to mutually per-ceive and interrupt each otherrsquos muscle activityThrough the perceptual experiment it was veried that

the bioSync users were able to recognize reproduced mus-cle contractions and rate them on a ve-point scale whilethey were contracting their own muscles It was also veri-ed that the kinesthetic interpersonal communication allowspeople to synchronize the rhythmic action without visualand audio feedback I also conducted a pilot study on pro-viding a simulated embodied impairment experience Theresults suggested that reproducing the neurological actionof Parkinsonrsquos tremors could enhance the understanding ofthe impairmentThe pilot study regarding faster kinesthetic reaction and

the sense of agency not only demonstrated that the humanrsquosresponsive action can be accelerated by wiring the two per-sons but also suggested that their sti voluntary to performactions with reward at the right timing allows their senseof egocentricity the subjective feeling of producing a de-sired consequence or performance initiated by their ownvoluntary to be generated Further investigation regardingthe intervention timing and the sense of agency have beeninvestigated [12]These ndings would provide design ideas for the kines-

thetic interaction and contribute to potential applicationssuch as education design and medical activities that revealsnew aspects of human behaviors for embodied and socialexperiences

Shaping Egocentric ExperienceThe general conclusion regarding shaping egocentric experi-ences with wearable cybernic interfaces derived from designdevelopment and evaluation were described In contrast tothe related works that attempted to append or extend physi-cal body functions the proposed experience have success-fully amplied the participantsrsquo knowledge and particularlyembodied the knowledge of onersquos embodied and social expe-riences Hence I proposed the conceptual representation ofshaping a body representation in a real-world environmentbased on active interactions to reproduce onersquos embodiedand social experiencesA major attribute of the proposed experiences was that

the interaction could be initiated by the participantrsquos vol-untary action The participant must create interpret andreview narratives of the experience by themselves throughreaching seeing touching and speaking thus increasingtheir participation level toward the experienceAs another attribute the interaction styles involved the

surrounding people thereby allowing the participants to in-crease their awareness of other people This situation allowedfor the surrounding people apart from the wearer to per-ceive as the wearer became a smaller person or a Parkinsonrsquospatient These new social and physical contexts including anoppressive conversation protective posture conceited looklonger interpersonal distance and more supportive behaviorcontributed to shaping the body representation repeatedly

7 ACKNOWLEDGMENTSThis work was supported by Grant-in-Aid for JSPS ResearchFellow (JP16J03777) and Scientic Research on InnovativeAreas (JP18H04182)

BIOGRAPHYJun Nishida is a PhD candidate in Human Informatics atUniversity of Tsukuba Japan His research interests includedesigning experiences in which all people can maximize andshare their physical and cognitive capabilities to supporteach other in the elds of rehabilitation education and de-sign The latest version of this manuscript is available on myportfolio site (httpjunnishidanet)

REFERENCES[1] Domna Banakou Raphaela Groten and Mel Slater 2013 Illusory

ownership of a virtual child body causes overestimation of object sizesand implicit attitude changes Proceedings of the National Academy ofSciences of the United States of America 110 31 (July 2013) 12846ndash12851httpsdoiorg101073pnas1306779110

[2] Scott Brave and Andrew Dahley 1997 inTouch In CHI rsquo97 extendedabstracts ACM Press New York New York USA 363 httpsdoiorg10114511202121120435

[3] Scott Brave Cliord Nass and Erenee Sirinian 2001 Force-Feedbackin computer-mediated communication HCI (2001) httpsdblporg

7

Figure 9 Wearerrsquos Interaction Interaction Observation

IO ElectrodesPartition

Vibration Motors

Hand Dynamometer

JointCompliance

Figure 10 Transferring the wrist compliance by sharing an-tagonist muscle activity

Blending Kinesthetic ExperienceTo investigate how the wearerrsquos perceptions actions and in-teractions can be modied through the proposed egocentricexperience of a patient I investigated the following threefactors1)Wearerrsquos perception Through the perceptual exper-

iment it was veried that the bioSync users were able torecognize reproduced muscle contractions and rate themon a ve-point scale while they were contracting their ownmuscles at 50 25 0 maximum voluntary contractionAnother perceptual study of sharing the level of wrist com-pliance between two persons was also performed (Fig 10)which demonstrated that the participants recognized thelevel of the confederatersquos wrist compliance at four levels[23]

2)Wearerrsquos action I conducted a series of tests to verifythat the interpersonal communication via the kinestheticchannel could support the synchronization of two personsrsquorhythmic muscle contraction timing (Fig 11) The resultswere used to assess whether the bioSync device could beemployed in practical scenarios such as clinical gait rehabil-itation and sports training in which the synchronization oftiming plays an important role The average measured sync

Figure 11 Rhythmic Activity Synchronization

Figure 12 Demonstration Impairment Experience

time was 81s (SD=391s) and the average reported sync timewas 138s (SD=394s)

3)Wearerrsquos interaction I also conducted a pilot study onproviding a simulated embodied impairment experience atexhibitions and conferences (Fig 12) The participants triedto grab a spoon and to scoop up gummy candies with thereproduced tremor The results suggested that reproducingthe neurological action of Parkinsonrsquos tremors could enhancethe understanding of the disease

5 DISCUSSIONSSmaller-person ExperienceEye level aected the personal spaceFrom the result the eye level of the participant aected theperception of interpersonal distance because there is a signif-icant dierence between (3)HC_STA and (5)WC_STA condi-tions The dierence in eye level would create an oppressivefeeling toward the approaching experimenter In additionthe large neck angle in pitch axis also aected the perception

5

of social relationship with the experimenter because thenursing teachers usually interact with 5-years-old childrenOne participant reported that heshe has a frustrating feel-ing rather than an oppressive or scary feeling because theparticipant could not move the perspective higher althoughtheir legs were fully extended It is also presumed that theirinternal body representation also contributed to the changeof personal space

Perceived arm length and distanceThe participants could think their arm length had becomeshorter as had their height resulting in an increase in theperceived distance between hands A similar phenomenonwas also reported in which the arm length changed the per-ceived distance in a virtual environment [14]

Familiar objects as a referenceSeveral participants stated that they realized the change ineye level only after they saw the experimenter facing themalthough they had visited the experiment room several timesbefore and saw the desks positioned 2 m away from thestanding location during the experiment From such com-ments it is assumed that the participants used more familiarobjects as a reference to recognize the physical relation-ship between their body and space It should be noted thatthe participants knew the height of the experimenter andhad sucient experience with each other through conversa-tions because they are from the same local organization Therecorded head orientations also showed that the participantslooked up higher under (2) smaller person condition thanunder (1) video condition From the result and observationsmany participants looked at the experimenterrsquos face beforethe handshake suggesting that the level of face could beused as a reference Such existing knowledge based on motorand social experience could help the wearers recognize theirspace and physical relationship

Blending Kinesthetic ExperienceSubjective Perceptual ExperimentIn the perceptual experiment the participants could recog-nize reproduced muscle contractions and rate them on ave-point scale accurately while they were contracting theirown muscles It was observed that the standard deviationincreased when the pulse width increased This might bethe eect of the wearerrsquos voluntary contractions on the per-ception of the reproduced contractions Another perceptualexperiment would be required to study this phenomenon indetail and to assess the relevance of the signal-dependencynoise theory [10] which indicates that neural control signalsare corrupted by noise that increases in variance as with thesize of the motor control signal increases

Rhythmic Activity SynchronizationIn the user study of the synchronization of rhythmic actionsubject 1 reported that excessive involuntary contractionsaected the performance of the synchronization This couldhave been caused by the electrode positioning and personalmuscular characteristics This indicates that a prior adjust-ment is required for each subject to normalize the perceptualand kinesthetic experience among users Another aspect Iwould like to address is the learning eect which I could notverify in the current experiment since the number of trialsfor each participant was small However I found that syn-chronization time is always shorter when the experimenterwho had longer prior training and participated in the en-tire experiment follows the participantrsquos rhythmic actionAnother preliminary experiment showed that the rhythmicactions of two persons could be synchronized even if theyare not assigned as an experimenter or a follower and aretreated equally [29]

Embodied Impairment ExperienceIn the pilot study on the simulated embodied Parkinsonrsquosexperience I received considerable feedback comments thatindicated the existence of kinesthetic memory after the exper-iment This suggests that reproduced kinesthetic impairmentexperience may be more eective in learning the neurologi-cal characteristics of the impairment than learning throughsome other modality Some visitors also reported experi-encing the existence of a remote userrsquos presence throughthe kinesthetic channel while synchronizing muscle activ-ity between two persons Thus interpersonal kinestheticcommunication is capable of enhancing the feeling of togeth-erness and reality of existence in a manner similar to thatof interpersonal haptic communication [2 3 20]

6 CONCLUSIONSmaller-person ExperienceIn this research I explored how human perceptions actionsand interactions can be changed through the egocentric ex-perience of a smaller person in a real world environmentFrom study 1 which was a personal space evaluation

when the participant felt smaller using the developed devicethe largest personal distance was observed This could havebeen caused by an oppressive feeling toward the approachingexperimenter induced by the feeling of being small

In study 2 it was observed that the participants raised theirhands higher than usual when trying to shake hands withthe experimenter because they perceived their own bodyrepresentation as being smaller It was conrmed that theexperience of being a smaller person changed the physicalrelationship of the wearer and the surroundings In additionto this using a rehabilitation peg board it was observed that

6

the developed exoskeleton decreased the userrsquos chronologi-cal hand function which would reproduce a smaller-personrsquosphysical capability while preserving the wearerrsquos develop-mental hand functionIn study 3 I observed the wearerrsquos interactions during

demonstrations at conferences and exhibitions It was oftenobserved that the visitors behaved like a child such as per-forming a protective pose when surrounded by adults ortalking like a baby Interestingly surrounding people suchas young students also treated the wearers like a child andbehaved as teachers or parents by acting in an overbearingmanner

These ndings challenges and design considerations willbenet further studies on the design of user experiencesbased on changes in body representation while preservingactive and embodied interactions in a real-world environ-ment

Blending Kinesthetic ExperienceIn this research I proposed and modeled a novel style ofinterpersonal kinesthetic communication called the blendedkinesthetic interaction that allows people to mutually per-ceive and interrupt each otherrsquos muscle activityThrough the perceptual experiment it was veried that

the bioSync users were able to recognize reproduced mus-cle contractions and rate them on a ve-point scale whilethey were contracting their own muscles It was also veri-ed that the kinesthetic interpersonal communication allowspeople to synchronize the rhythmic action without visualand audio feedback I also conducted a pilot study on pro-viding a simulated embodied impairment experience Theresults suggested that reproducing the neurological actionof Parkinsonrsquos tremors could enhance the understanding ofthe impairmentThe pilot study regarding faster kinesthetic reaction and

the sense of agency not only demonstrated that the humanrsquosresponsive action can be accelerated by wiring the two per-sons but also suggested that their sti voluntary to performactions with reward at the right timing allows their senseof egocentricity the subjective feeling of producing a de-sired consequence or performance initiated by their ownvoluntary to be generated Further investigation regardingthe intervention timing and the sense of agency have beeninvestigated [12]These ndings would provide design ideas for the kines-

thetic interaction and contribute to potential applicationssuch as education design and medical activities that revealsnew aspects of human behaviors for embodied and socialexperiences

Shaping Egocentric ExperienceThe general conclusion regarding shaping egocentric experi-ences with wearable cybernic interfaces derived from designdevelopment and evaluation were described In contrast tothe related works that attempted to append or extend physi-cal body functions the proposed experience have success-fully amplied the participantsrsquo knowledge and particularlyembodied the knowledge of onersquos embodied and social expe-riences Hence I proposed the conceptual representation ofshaping a body representation in a real-world environmentbased on active interactions to reproduce onersquos embodiedand social experiencesA major attribute of the proposed experiences was that

the interaction could be initiated by the participantrsquos vol-untary action The participant must create interpret andreview narratives of the experience by themselves throughreaching seeing touching and speaking thus increasingtheir participation level toward the experienceAs another attribute the interaction styles involved the

surrounding people thereby allowing the participants to in-crease their awareness of other people This situation allowedfor the surrounding people apart from the wearer to per-ceive as the wearer became a smaller person or a Parkinsonrsquospatient These new social and physical contexts including anoppressive conversation protective posture conceited looklonger interpersonal distance and more supportive behaviorcontributed to shaping the body representation repeatedly

7 ACKNOWLEDGMENTSThis work was supported by Grant-in-Aid for JSPS ResearchFellow (JP16J03777) and Scientic Research on InnovativeAreas (JP18H04182)

BIOGRAPHYJun Nishida is a PhD candidate in Human Informatics atUniversity of Tsukuba Japan His research interests includedesigning experiences in which all people can maximize andshare their physical and cognitive capabilities to supporteach other in the elds of rehabilitation education and de-sign The latest version of this manuscript is available on myportfolio site (httpjunnishidanet)

REFERENCES[1] Domna Banakou Raphaela Groten and Mel Slater 2013 Illusory

ownership of a virtual child body causes overestimation of object sizesand implicit attitude changes Proceedings of the National Academy ofSciences of the United States of America 110 31 (July 2013) 12846ndash12851httpsdoiorg101073pnas1306779110

[2] Scott Brave and Andrew Dahley 1997 inTouch In CHI rsquo97 extendedabstracts ACM Press New York New York USA 363 httpsdoiorg10114511202121120435

[3] Scott Brave Cliord Nass and Erenee Sirinian 2001 Force-Feedbackin computer-mediated communication HCI (2001) httpsdblporg

7

of social relationship with the experimenter because thenursing teachers usually interact with 5-years-old childrenOne participant reported that heshe has a frustrating feel-ing rather than an oppressive or scary feeling because theparticipant could not move the perspective higher althoughtheir legs were fully extended It is also presumed that theirinternal body representation also contributed to the changeof personal space

Perceived arm length and distanceThe participants could think their arm length had becomeshorter as had their height resulting in an increase in theperceived distance between hands A similar phenomenonwas also reported in which the arm length changed the per-ceived distance in a virtual environment [14]

Familiar objects as a referenceSeveral participants stated that they realized the change ineye level only after they saw the experimenter facing themalthough they had visited the experiment room several timesbefore and saw the desks positioned 2 m away from thestanding location during the experiment From such com-ments it is assumed that the participants used more familiarobjects as a reference to recognize the physical relation-ship between their body and space It should be noted thatthe participants knew the height of the experimenter andhad sucient experience with each other through conversa-tions because they are from the same local organization Therecorded head orientations also showed that the participantslooked up higher under (2) smaller person condition thanunder (1) video condition From the result and observationsmany participants looked at the experimenterrsquos face beforethe handshake suggesting that the level of face could beused as a reference Such existing knowledge based on motorand social experience could help the wearers recognize theirspace and physical relationship

Blending Kinesthetic ExperienceSubjective Perceptual ExperimentIn the perceptual experiment the participants could recog-nize reproduced muscle contractions and rate them on ave-point scale accurately while they were contracting theirown muscles It was observed that the standard deviationincreased when the pulse width increased This might bethe eect of the wearerrsquos voluntary contractions on the per-ception of the reproduced contractions Another perceptualexperiment would be required to study this phenomenon indetail and to assess the relevance of the signal-dependencynoise theory [10] which indicates that neural control signalsare corrupted by noise that increases in variance as with thesize of the motor control signal increases

Rhythmic Activity SynchronizationIn the user study of the synchronization of rhythmic actionsubject 1 reported that excessive involuntary contractionsaected the performance of the synchronization This couldhave been caused by the electrode positioning and personalmuscular characteristics This indicates that a prior adjust-ment is required for each subject to normalize the perceptualand kinesthetic experience among users Another aspect Iwould like to address is the learning eect which I could notverify in the current experiment since the number of trialsfor each participant was small However I found that syn-chronization time is always shorter when the experimenterwho had longer prior training and participated in the en-tire experiment follows the participantrsquos rhythmic actionAnother preliminary experiment showed that the rhythmicactions of two persons could be synchronized even if theyare not assigned as an experimenter or a follower and aretreated equally [29]

Embodied Impairment ExperienceIn the pilot study on the simulated embodied Parkinsonrsquosexperience I received considerable feedback comments thatindicated the existence of kinesthetic memory after the exper-iment This suggests that reproduced kinesthetic impairmentexperience may be more eective in learning the neurologi-cal characteristics of the impairment than learning throughsome other modality Some visitors also reported experi-encing the existence of a remote userrsquos presence throughthe kinesthetic channel while synchronizing muscle activ-ity between two persons Thus interpersonal kinestheticcommunication is capable of enhancing the feeling of togeth-erness and reality of existence in a manner similar to thatof interpersonal haptic communication [2 3 20]

6 CONCLUSIONSmaller-person ExperienceIn this research I explored how human perceptions actionsand interactions can be changed through the egocentric ex-perience of a smaller person in a real world environmentFrom study 1 which was a personal space evaluation

when the participant felt smaller using the developed devicethe largest personal distance was observed This could havebeen caused by an oppressive feeling toward the approachingexperimenter induced by the feeling of being small

In study 2 it was observed that the participants raised theirhands higher than usual when trying to shake hands withthe experimenter because they perceived their own bodyrepresentation as being smaller It was conrmed that theexperience of being a smaller person changed the physicalrelationship of the wearer and the surroundings In additionto this using a rehabilitation peg board it was observed that

6

the developed exoskeleton decreased the userrsquos chronologi-cal hand function which would reproduce a smaller-personrsquosphysical capability while preserving the wearerrsquos develop-mental hand functionIn study 3 I observed the wearerrsquos interactions during

demonstrations at conferences and exhibitions It was oftenobserved that the visitors behaved like a child such as per-forming a protective pose when surrounded by adults ortalking like a baby Interestingly surrounding people suchas young students also treated the wearers like a child andbehaved as teachers or parents by acting in an overbearingmanner

These ndings challenges and design considerations willbenet further studies on the design of user experiencesbased on changes in body representation while preservingactive and embodied interactions in a real-world environ-ment

Blending Kinesthetic ExperienceIn this research I proposed and modeled a novel style ofinterpersonal kinesthetic communication called the blendedkinesthetic interaction that allows people to mutually per-ceive and interrupt each otherrsquos muscle activityThrough the perceptual experiment it was veried that

the bioSync users were able to recognize reproduced mus-cle contractions and rate them on a ve-point scale whilethey were contracting their own muscles It was also veri-ed that the kinesthetic interpersonal communication allowspeople to synchronize the rhythmic action without visualand audio feedback I also conducted a pilot study on pro-viding a simulated embodied impairment experience Theresults suggested that reproducing the neurological actionof Parkinsonrsquos tremors could enhance the understanding ofthe impairmentThe pilot study regarding faster kinesthetic reaction and

the sense of agency not only demonstrated that the humanrsquosresponsive action can be accelerated by wiring the two per-sons but also suggested that their sti voluntary to performactions with reward at the right timing allows their senseof egocentricity the subjective feeling of producing a de-sired consequence or performance initiated by their ownvoluntary to be generated Further investigation regardingthe intervention timing and the sense of agency have beeninvestigated [12]These ndings would provide design ideas for the kines-

thetic interaction and contribute to potential applicationssuch as education design and medical activities that revealsnew aspects of human behaviors for embodied and socialexperiences

Shaping Egocentric ExperienceThe general conclusion regarding shaping egocentric experi-ences with wearable cybernic interfaces derived from designdevelopment and evaluation were described In contrast tothe related works that attempted to append or extend physi-cal body functions the proposed experience have success-fully amplied the participantsrsquo knowledge and particularlyembodied the knowledge of onersquos embodied and social expe-riences Hence I proposed the conceptual representation ofshaping a body representation in a real-world environmentbased on active interactions to reproduce onersquos embodiedand social experiencesA major attribute of the proposed experiences was that

the interaction could be initiated by the participantrsquos vol-untary action The participant must create interpret andreview narratives of the experience by themselves throughreaching seeing touching and speaking thus increasingtheir participation level toward the experienceAs another attribute the interaction styles involved the

surrounding people thereby allowing the participants to in-crease their awareness of other people This situation allowedfor the surrounding people apart from the wearer to per-ceive as the wearer became a smaller person or a Parkinsonrsquospatient These new social and physical contexts including anoppressive conversation protective posture conceited looklonger interpersonal distance and more supportive behaviorcontributed to shaping the body representation repeatedly

7 ACKNOWLEDGMENTSThis work was supported by Grant-in-Aid for JSPS ResearchFellow (JP16J03777) and Scientic Research on InnovativeAreas (JP18H04182)

BIOGRAPHYJun Nishida is a PhD candidate in Human Informatics atUniversity of Tsukuba Japan His research interests includedesigning experiences in which all people can maximize andshare their physical and cognitive capabilities to supporteach other in the elds of rehabilitation education and de-sign The latest version of this manuscript is available on myportfolio site (httpjunnishidanet)

REFERENCES[1] Domna Banakou Raphaela Groten and Mel Slater 2013 Illusory

ownership of a virtual child body causes overestimation of object sizesand implicit attitude changes Proceedings of the National Academy ofSciences of the United States of America 110 31 (July 2013) 12846ndash12851httpsdoiorg101073pnas1306779110

[2] Scott Brave and Andrew Dahley 1997 inTouch In CHI rsquo97 extendedabstracts ACM Press New York New York USA 363 httpsdoiorg10114511202121120435

[3] Scott Brave Cliord Nass and Erenee Sirinian 2001 Force-Feedbackin computer-mediated communication HCI (2001) httpsdblporg

7

the developed exoskeleton decreased the userrsquos chronologi-cal hand function which would reproduce a smaller-personrsquosphysical capability while preserving the wearerrsquos develop-mental hand functionIn study 3 I observed the wearerrsquos interactions during

demonstrations at conferences and exhibitions It was oftenobserved that the visitors behaved like a child such as per-forming a protective pose when surrounded by adults ortalking like a baby Interestingly surrounding people suchas young students also treated the wearers like a child andbehaved as teachers or parents by acting in an overbearingmanner

These ndings challenges and design considerations willbenet further studies on the design of user experiencesbased on changes in body representation while preservingactive and embodied interactions in a real-world environ-ment

Blending Kinesthetic ExperienceIn this research I proposed and modeled a novel style ofinterpersonal kinesthetic communication called the blendedkinesthetic interaction that allows people to mutually per-ceive and interrupt each otherrsquos muscle activityThrough the perceptual experiment it was veried that

the bioSync users were able to recognize reproduced mus-cle contractions and rate them on a ve-point scale whilethey were contracting their own muscles It was also veri-ed that the kinesthetic interpersonal communication allowspeople to synchronize the rhythmic action without visualand audio feedback I also conducted a pilot study on pro-viding a simulated embodied impairment experience Theresults suggested that reproducing the neurological actionof Parkinsonrsquos tremors could enhance the understanding ofthe impairmentThe pilot study regarding faster kinesthetic reaction and

the sense of agency not only demonstrated that the humanrsquosresponsive action can be accelerated by wiring the two per-sons but also suggested that their sti voluntary to performactions with reward at the right timing allows their senseof egocentricity the subjective feeling of producing a de-sired consequence or performance initiated by their ownvoluntary to be generated Further investigation regardingthe intervention timing and the sense of agency have beeninvestigated [12]These ndings would provide design ideas for the kines-

thetic interaction and contribute to potential applicationssuch as education design and medical activities that revealsnew aspects of human behaviors for embodied and socialexperiences

Shaping Egocentric ExperienceThe general conclusion regarding shaping egocentric experi-ences with wearable cybernic interfaces derived from designdevelopment and evaluation were described In contrast tothe related works that attempted to append or extend physi-cal body functions the proposed experience have success-fully amplied the participantsrsquo knowledge and particularlyembodied the knowledge of onersquos embodied and social expe-riences Hence I proposed the conceptual representation ofshaping a body representation in a real-world environmentbased on active interactions to reproduce onersquos embodiedand social experiencesA major attribute of the proposed experiences was that

the interaction could be initiated by the participantrsquos vol-untary action The participant must create interpret andreview narratives of the experience by themselves throughreaching seeing touching and speaking thus increasingtheir participation level toward the experienceAs another attribute the interaction styles involved the

surrounding people thereby allowing the participants to in-crease their awareness of other people This situation allowedfor the surrounding people apart from the wearer to per-ceive as the wearer became a smaller person or a Parkinsonrsquospatient These new social and physical contexts including anoppressive conversation protective posture conceited looklonger interpersonal distance and more supportive behaviorcontributed to shaping the body representation repeatedly

7 ACKNOWLEDGMENTSThis work was supported by Grant-in-Aid for JSPS ResearchFellow (JP16J03777) and Scientic Research on InnovativeAreas (JP18H04182)

BIOGRAPHYJun Nishida is a PhD candidate in Human Informatics atUniversity of Tsukuba Japan His research interests includedesigning experiences in which all people can maximize andshare their physical and cognitive capabilities to supporteach other in the elds of rehabilitation education and de-sign The latest version of this manuscript is available on myportfolio site (httpjunnishidanet)

REFERENCES[1] Domna Banakou Raphaela Groten and Mel Slater 2013 Illusory

ownership of a virtual child body causes overestimation of object sizesand implicit attitude changes Proceedings of the National Academy ofSciences of the United States of America 110 31 (July 2013) 12846ndash12851httpsdoiorg101073pnas1306779110

[2] Scott Brave and Andrew Dahley 1997 inTouch In CHI rsquo97 extendedabstracts ACM Press New York New York USA 363 httpsdoiorg10114511202121120435

[3] Scott Brave Cliord Nass and Erenee Sirinian 2001 Force-Feedbackin computer-mediated communication HCI (2001) httpsdblporg

7

recconfhciBraveNS01[4] Nicola Bruno and Marco Bertamini 2010 Haptic perception after a

change in hand size Neuropsychologia 48 6 (May 2010) 1853ndash1856httpsdoiorg101016jneuropsychologia201001006

[5] Carlos Cardoso and P John Clarkson 2010 Simulation in user-centreddesign helping designers to empathise with atypical users Journalof Engineering Design 23 1 (April 2010) 1ndash4 httpsdoiorg10108009544821003742650

[6] Kevin Fan Jochen Huber Suranga Nanayakkara and Masahiko In-ami 2014 SpiderVision In the 5th Augmented Human InternationalConference ACM Press New York New York USA 1ndash8 httpsdoiorg10114525820512582100

[7] Alessandro Farnegrave Atsushi Iriki and Elisabetta Lagravedavas 2005 Shapingmultisensory actionndashspace with tools evidence from patients withcross-modal extinction Neuropsychologia 43 2 (Jan 2005) 238ndash248httpsdoiorg101016jneuropsychologia200411010

[8] Patrick Gruumlneberg Hideki Kadone Naomi Kuramoto Tomoyuki UenoYasushi Hada Masashi Yamazaki Yoshiyuki Sankai and Kenji Suzuki2018 Robot-assisted voluntary initiation reduces control-related dif-culties of initiating joint movement A phenomenal questionnairestudy on shaping and compensation of forward gait PLoS ONE 133 (March 2018) e0194214ndash15 httpsdoiorg101371journalpone0194214

[9] Patrick Gruneberg Hideki Kadone and Kenji Suzuki 2015 Vol-untary initiation of movement multifunctional integration of sub-jective agency Frontiers in Psychology 6 320 (May 2015) 3ndash14httpsdoiorg103389fpsyg201500688

[10] CMHarris and DMWolpert 1998 Signal-dependent noise determinesmotor planning Nature 394 6695 (Aug 1998) 780ndash784 httpsdoiorg10103829528

[11] Shunichi Kasahara Mitsuhito Ando Kiyoshi Suganuma and JunRekimoto 2016 Parallel Eyes In Proceedings of the 2016 CHI Con-ference on Human Factors in Computing Systems - CHI rsquo16 httpsdoiorg10114528580362858495

[12] Shunichi Kasahara Jun Nishida and Pedro Lopes 2019 PreemptiveAction- Accelerating Human Reaction using Electrical Muscle Stim-ulation Without Compromising Agency In In Proceedings of the CHIConference on Human Factors in Computing Systems CHI ACM NewYork NY USA

[13] Shunichi Kasahara and Jun Rekimoto 2014 JackIn - integrating rst-person view with out-of-body vision generation for human-humanaugmentation AH (2014) 1ndash8 httpsdoiorg10114525820512582097

[14] Sally A Linkenauger Heinrich H Buumlltho and Betty J Mohler 2015Virtual armŒşs reach inuences perceived distances but only afterexperience reaching Neuropsychologia 70 C (April 2015) 393ndash401httpsdoiorg101016jneuropsychologia201410034

[15] Xin Liu Yedan Qian and Pattie Maes 2017 Tree httpswwwmediamiteduprojectstreeoverview

[16] Lara Maister Mel Slater Maria V Sanchez-Vives and Manos Tsakiris2015 Changing bodies changes minds owning another body aectssocial cognition Trends in Cognitive Sciences 19 1 (Jan 2015) 6ndash12httpsdoiorg101016jtics201411001

[17] Angelo Maravita and Atsushi Iriki 2004 Tools for the body (schema)Trends in Cognitive Sciences 8 2 (Feb 2004) 79ndash86 httpsdoiorg101016jtics200312008

[18] Marie Martel Lucilla Cardinali Alice C Roy and Alessandro Farnegrave2016 Tool-use An open window into body representation and itsplasticity Cognitive neuropsychology 33 1-2 (June 2016) 82ndash101 https

doiorg1010800264329420161167678[19] Kana Misawa and Jun Rekimoto 2015 Wearing anotherrsquos personality

In the 2015 ACM International Symposium ACM Press New York NewYork USA 125ndash132 httpsdoiorg10114528020832808392

[20] Hideyuki Nakanishi Kazuaki Tanaka and Yuya Wada 2014 Remotehandshaking In the 32nd annual ACM conference ACM Press NewYork New York USA 2143ndash2152 httpsdoiorg10114525562882557169

[21] Jun Nishida Soichiro Matsuda Mika Oki Hikaru Takatori KosukeSato and Kenji Suzuki 2019 Egocentric Small-person Experience byChanging a Visual Perspective In In Proceedings of the CHI Conferenceon Human Factors in Computing Systems CHI ACM New York NYUSA httpsdoiorg10114532906053300926

[22] Jun Nishida and Kenji Suzuki 2017 bioSync In the 2017 CHI ConferenceACM Press New York New York USA 3316ndash3327 httpsdoiorg10114530254533025829

[23] Jun Nishida and Kenji Suzuki 2018 Wearable Kinesthetic IO Devicefor Sharing Muscle Compliance In The 31st Annual ACM SymposiumACM Press New York New York USA 57ndash59 httpsdoiorg10114532660373266100

[24] Jun Nishida Hikaru Takatori Kosuke Sato and Kenji Suzuki 2015CHILDHOOD In ACM SIGGRAPH 2015 Emerging Technologies ACMPress New York New York USA 1ndash1 httpsdoiorg10114527827822792501

[25] Jun Nishida Hikaru Takatori Kosuke Sato and Kenji Suzuki 2015CHILDHOOD In the 2015 Virtual Reality International ConferenceACM Press New York New York USA 1ndash4 httpsdoiorg10114528061732806190

[26] Mariella Pazzaglia and Marco Molinari 2016 The embodiment ofassistive devicesmdashfrom wheelchair to exoskeleton Physics of lifereviews 16 (March 2016) 163ndash175 httpsdoiorg101016jplrev201511006

[27] B Philippe D Gonzalez-Franco A Pointeau C Cherene Prix Ars Elec-tronica and 2014 [n d] The Machine to be Another-Embodied Telep-resence using human performers httpscholargooglecomjavascriptvoid(0)

[28] Gastone Pietro Rosati Papini Marco Fontana and Massimo Berga-masco 2016 Desktop Haptic Interface for Simulation of Hand-Tremor IEEE Transactions on Haptics 9 1 (Jan 2016) 33ndash42 httpsdoiorg101109TOH20152504971

[29] Hiroka Sabu Tomoyo Morita Hideyuki Takahashi Eiichi Naito andMinoru Asada 2018 Being a leader in a rhythmic interaction activatesreward-related brain regions Neuroscience Research (Aug 2018) 1ndash7httpsdoiorg101016jneures201808009

[30] MHD Yamen Saraiji Tomoya Sasaki Reo Matsumura Kouta Mi-namizawa and Masahiko Inami 2018 Fusion In ACM SIGGRAPH2018 Emerging Technologies ACM Press New York New York USA1ndash2 httpsdoiorg10114532149073214912

[31] Ida Shino and Yamanaka Toshimasa 2000 A study on the usabilityof environment objects by the dierence in eye level (In Japanese) InJapan Society of the Science of Design

[32] Susumu Tachi Kouichi Watanabe Keisuke Takeshita Kouta Mi-namizawa Takumi Yoshida and Katsunari Sato 2011 Mutual Telex-istence Surrogate System - TELESAR4 - telexistence in real environ-ments using autostereoscopic immersive display IROS (2011) 157ndash162httpsdoiorg101109IROS20116094543

[33] Bjoumlrn van der Hoort Arvid Guterstam and H Henrik Ehrsson 2011Being Barbie The Size of Onersquos Own Body Determines the PerceivedSize of the World PLoS ONE 6 5 (May 2011) e20195ndash10 httpsdoiorg101371journalpone0020195

8