Exploring Superpower Design Through Wi-Fi Twinge
Siyi Liu

Nathan Semertzidis

Gun A. Lee

Exertion Games Lab, Department of
Human-Centred Computing, Monash
University
Melbourne, Australiasiyi.liu@monash.edu

Exertion Games Lab, Department of
Human-Centred Computing, Monash
University
Melbourne, Australia
nathan@exertiongameslab.org

Australian Research Centre forInteractive and Virtual Environments,
STEM, University of South Australia
Adelaide, Australia
gun.lee@unisa.edu.au

Florian ‘Floyd’ Mueller

Barrett Ens

Exertion Games Lab, Department of
Human-Centred Computing, Monash
University
Melbourne, Australia
floyd@exertiongameslab.org

Department of Human-Centred
ComputingMonash University
Melbourne, Australia
barrett.ens@monash.edu

Figure 1: Wi-Fi Twinge, a system that aims to help understand superpower design by twinging the user’s hand via electricalmuscle stimulation in the presence of ambient Wi-Fi.

ABSTRACTTechnology-facilitated “superpowers” are a popular topic in humancomputer interaction, providing people with the experience of having superhero-like fantastic abilities. However, science fiction literature tells us that superpowers can also be unfortunate. We designed
Wi-Fi Twinge, a system that uses electrical muscle stimulation to extend human perception to sense unseen Wi-Fi signals, giving people
an allergy-like twinge reaction to Wi-Fi: a superpower that can beseen as unfortunate while also having potential benefits. ThroughPermission to make digital or hard copies of all or part of this work for personal orclassroom use is granted without fee provided that copies are not made or distributedfor profit or commercial advantage and that copies bear this notice and the full citationon the first page. Copyrights for components of this work owned by others than theauthor(s) must be honored. Abstracting with credit is permitted. To copy otherwise, or
republish, to post on servers or to redistribute to lists, requires prior specific permission
and/or a fee. Request permissions from permissions@acm.org.
TEI ’24, February 11–14, 2024, Cork, Ireland© 2024 Copyright held by the owner/author(s). Publication rights licensed to ACM.
ACM ISBN 979-8-4007-0402-4/24/02. . . $15.00
https://doi.org/10.1145/3623509.3633352

an in-the-wild study, interviews with 12 participants revealed that
although the superpower from Wi-Fi Twinge induced negative
feelings and impacted certain day-to-day activities, it improved
awareness of self and the surrounding environment. We used theseresults to offer design tactics for creating future superpower systems that consider potential unfortunate side effects. Ultimately,
we aim to advance our understanding of technology-facilitatedsuperpowers.

CCS CONCEPTS• Human-centered computing → Interaction paradigms.

KEYWORDS
superpower, augmented human, electrical muscle stimulation, wearables, human augmentation

TEI ’24, February 11–14, 2024, Cork, Ireland

ACM Reference Format:
Siyi Liu, Nathan Semertzidis, Gun A. Lee, Florian ‘Floyd’ Mueller, and Barrett Ens. 2024. Exploring Superpower Design Through Wi-Fi Twinge. In
Eighteenth International Conference on Tangible, Embedded, and Embodied
Interaction (TEI ’24), February 11–14, 2024, Cork, Ireland. ACM, New York,NY, USA, 16 pages. https://doi.org/10.1145/3623509.3633352

1

INTRODUCTION

Technology is getting closer to the body [64, 65], in particular, people are beginning to use their bodies to interact with computers innovel ways, giving rise to human augmentation technology [26, 84]that can extend human capabilities. This can enable people to experience what it might be like to have a “superpower”, a capability
beyond natural human ability that is experienced as intrinsic (originating from the individual) [14], realising the visions shown inscience fiction. Examples of this include flying via virtual reality[85], X-ray vision via augmented reality [5], and telekinesis via
brain-computer interfaces [21].
However, as we learn from the many cautionary tales that populate the literary corpus of science fiction, superpowers often comewith unfortunate side effects. Examples include Rogue’s ability toabsorb power by touching people and leaving them in a weakened
state (X-Men) [2], and Banner’s ability to transform into the Hulk
with an enhanced body and immense strength but also uncontrolled
destructive tendencies (Marvel Comics) [1]. We call these “unfortunate” superpowers: superpowers with unpredictable negative
consequences, even if they also have fantastic positive effects. Such“unfortunate” superpowers are characterised by a lack of or lossof control, resulting in the person experiencing a reduced senseof agency, i.e., the feeling of control over actions and their consequences. With this considered, it is arguable that in addition to
the positive superpower-like experience enabled by human augmentation technologies, there also exists the potential for suchtechnologies to produce an “unfortunate” superpower experience.
While previous research has examined the side effects of enhancing human capabilities with a focus on ethics [48, 73] andprivacy issues [4, 99], the “unfortunate” experiential side effects ofenhancing human abilities have received little attention. We areinspired by prior work that has explored “dark patterns” [16, 17, 24],
which investigated the potential for deception and misuse in thedesign of new technologies, with the aim of shining light on thesebefore they can be exploited by bad actors. Given the imminent
uptake of emerging and future technologies [63], we believe that
it is critical to carefully consider and mitigate the risks that users
may face before they become widely adopted into the mainstream.
We see the opportunity to investigate “unfortunate” superpowers
as a mean to preemptively alleviate any negative side effects. As
such, we believe that there is potential to investigate intentionallydesigning “unfortunate” superpowers that still have potential benefits to provide design knowledge to help avoid mistakes that may
be difficult to rectify in hindsight.
We investigate these ideas through the design and study of “WiFi Twinge” (Figure 1), a system that extends human perception tounseen Wi-Fi signals via electrical muscle stimulation (EMS) thatmakes the user’s hand twinge in the presence of a strong Wi-Fi
signal. Wi-Fi has become a fundamental part of people’s everyday
work and social life, yet we still have no innate Wi-Fi sense: it is still

Siyi Liu, Nathan Semertzidis, Gun A. Lee, Florian ‘Floyd’ Mueller, and Barrett Ens

unseen and invisible. Considering this, we imagine a future where
humans have evolved or augmented themselves to sense streams oftechnological processes such as Wi-Fi. To explore this, we designed
Wi-Fi Twinge, which allows people to have an embodied senseof when Wi-Fi surrounds them by receiving different electricalstimulation wave patterns based on the surrounding Wi-Fi signal.
We consider sensing Wi-Fi a superpower because it provides
an opportunity to expand the human senses and provides a superhuman experience of amplifying human perception via embodied
channels inherent to human experience (i.e., the proprioceptionof flexion in reaction to Wi-Fi), in contrast to simply observing areading provided by some external device [88]. The human body
becomes an innate interface through which people experience their
extra sensory abilities. Furthermore, the experience of sensing WiFi holds similarities to science fiction superpowers, such as theability to see into the spirit realm. With sensing Wi-Fi, people can
optimise their wireless connectivity experience by maintaining a
constant network connection while moving and facilitating communication. At the same time, it is also “unfortunate” in that it creates
short-term bodily twinge reactions in the form of involuntary hand
movements through the use of EMS. This could lead to negative
impacts on daily activities, such as when the hands are involvedin other tasks and the EMS actuation interrupts and hinders thisactivity.
In this paper, we detailed the design and evaluation of Wi-Fi
Twinge through a 5-day in-the-wild study with 12 participants
who were instructed to use the prototype in their everyday lives.
We employed a statistical analysis of the Sense of Agency Scale(SoAS) and a thematic analysis of the interviews to induce insights
gained from studying the user experience of Wi-Fi Twinge. The
results suggested that Wi-Fi Twinge can elicit negative physicalsensations that lead to discomfort and inconvenience in daily life
(Figure 2), but also increases users’ awareness of their bodies andthe environment, indirectly changing their activities, facilitatesreflection on themselves, and in some cases contributes to theiroverall well-being. We interpreted these results and provided design
tactics to inform the discussion and design of superpower systems
moving forward.

Figure 2: Wi-Fi Twinge usage scenarios: (a) Finger flexion
affects operating a controller; (b) Finger flexion affects typing
at work.
In summary, this paper makes three contributions:• A system contribution in the form of an unfortunate superpower system that extends human perception to unseen
Wi-Fi signals using EMS. This contribution could be usefulExploring Superpower Design Through Wi-Fi Twinge

for system designers seeking inspiration on what types of superpower systems they could design, including unfortunate
ones.
• An empirical contribution in the form of a thematic analysis of the interviews and a statistical analysis of the Sense
of Agency Scale from an in-the-wild study with 12 participants using our system over 5 days. This contribution could
be helpful for user experience researchers interested in understanding both the negative and positive experiences ofsuperpowers.
• A design contribution in the form of a set of design tactics
for the creation of future superpowers. These design tactics
could be useful for human augmentation researchers whenaiming to analyse existing superpowers, while also guiding
the design of new systems toward the designer’s intended
user experience.
Ultimately, we aim to bring new opportunities for human augmentation through the lens of the underexplored perspective of unfortunate superpowers to advance our understanding of technologyfacilitated superpower experiences especially considering not only
their potential but also any possible unfortunate side effects andguide the future design of superpower systems.

2

RELATED WORKIn this section, we discuss related work, in particular, what welearned from prior research on superpower experiences, sensing
invisible waves, actuating the body through EMS, and the sense ofagency.

2.1

Superpower experiences

The concept of superpowers and characters with extraordinary
abilities can be traced back to ancient mythology and folklore,
which can be argued laid the groundwork for the development ofsuperpower and superhero stories in modern literature and popular
culture [40, 69, 81]. The contemporary use of the term “superpower”
that refers to the possession of abilities beyond the ordinary appeared to start in the 1930s in American comic books and we findthat it gradually found its way into other genres and media [18].
Transhumanism was then popularised, as a philosophical and intellectual movement advocating the use of technology and science
to transcend the limitations of the human condition and achieve
human augmentation and life extension [32, 61]. Likely inspired by
the rising popularity of these concepts, researchers have exploredvarious ways such as by using immersive technologies as used inhuman-computer interaction (HCI) research to give people the experience of having superpowers [100]. For example, Kenna et al.
[39] designed a head-mounted wearable device that enhances theperception of quiet and distant sounds through a set of embedded
microphones and speakers, empowering users with a super-hearing
superpower, similar to prior work on “augmented hearing” [62].
Similarly, Ishibashi et al. [34] presented the “Spider Hero” virtual
reality system that allows the wearer to jump between buildings
like Spider-Man via a web-shooting device. More recently, Kunze
et al. [43] created superhuman sports, an application field that combines the athletic elements of sports with technology in order toovercome the physical limitations of the human body to achieve

TEI ’24, February 11–14, 2024, Cork, Irelandsuperhuman senses and abilities. For example, Lehtonen et al. [45]presented the “Super Stomp” mixed-reality trampoline game that
grants players with superhuman abilities by exaggerating jump
distance and providing aural and visual feedback in the game toaugment their movement ability in the real world.
Research has shown that human augmentation provides novel
opportunities for bodily experiences [84], which encompasses many
genres: biomedical implants and prostheses that replace or restore
human functions [6, 23, 104]; exoskeletons and wearable devices
that extend physical abilities [90, 103]; and collaborative or assistive
robots that monitor and motivate human work [59]. These systems
show us that superpowers can be seen as an experience achievedby human augmentation technologies to empower the individual.
Therefore, in this paper, we consider human augmentation to be
the use of technology to realise the extension of human capabilities,
which can at times produce the experience of having a superpower.
Superpower experiences are a specific subset of experiences generated by human augmentation that involve the user perceiving
the ability bestowed on them by the augmentation as intrinsicallyemerging from their own innate abilities (e.g. their own physiology). However, the prior work overlooked the potential tendency
for such technologies to also produce negative effects. For example, what if users hear something with their augmented hearing
superpower that they do not want to or should not hear?
Although prior research found superpowers worth investigating
and various approaches have been explored in terms of technological contributions [85, 100], our knowledge of how to design
superpowers while considering their negative side effects is limited.
We believe that this is, at least in part, due to a limited understanding of the experience of having a superpower, not only including
all its benefits but also unfortunate side effects. Hence, with ourwork, we aim to address this knowledge gap. In particular, we aim
to contribute to our understanding of the design of superpowers
by beginning with an “unfortunate” superpower that triggers anallergy-like twinge reaction to Wi-Fi signals.

2.2

Sensing invisible waves

Sensing invisible waves like Wi-Fi signals through visual assistancesystems has been the subject of previous HCI research. For example,
Mann et al. [56] designed an augmented reality (AR) system thatenables users to see, understand and photograph the otherwise
invisible electromagnetic waves. Grönvall et al. [25] presented asystem to turn radio signals into visual and tactile stimuli to give
users new bodily experiences. Other examples include depth andthermal cameras for exploring environments that are invisible tothe naked eye [3], and a field-of-view visualisation system to makevision itself visible [55]. We draw from such work that investigatedsystems of sensing invisible waves to explore the angle for sensing
Wi-Fi signals via amplifying an existing perception and augmenting the current bodily response. We argue such user experiences
may be improved through using the user’s own physiology as themedium of information communication, lowering the user’s awareness of the presence of their technology, as it is integrated into daily
life and cannot be distinguished from their native senses. Whentechnologies disappear in this way, users might be able to freely use

TEI ’24, February 11–14, 2024, Cork, Irelandthem without thinking and might appear to begin to trust that thesuperpower is a permanent force from users themselves [79, 86].

2.3

Actuating the body through electricalmuscle stimulation

Over the past decades in the field of HCI, researchers have built
several systems based on electrical muscle stimulation (EMS) as
output paradigms to actuate the user’s body [53, 95]. EMS delivers
electrical signals to muscles, typically via non-invasive surface electrodes placed on the skin [80]. The electrical signals elicit action
potentials on motor nerves, which leads to muscle fibres contracting[58]. EMS electrodes allow the user to operate their hands relatively
unencumbered due to their small form factor and portability [95].
Prior research has highlighted the growing popularity of using EMS
in interactive systems, including in applications such as instructing intricate movements [94], providing force feedback [52] andplaying games with one’s own body [74, 75]. For example, Pfeiffer
et al. [80] proposed a pedestrian navigation system that changes
walking direction by stimulating the sartorius muscle. The associated systems were inspiring for us as they suggested that EMS
technology could be beneficial for superpower-like experiences as
it uses the body’s own muscles.
The use of EMS rather than other haptic feedback modalities(e.g. a vibrotactile motor) requires users to sense Wi-Fi throughinteroceptive processes (specifically proprioception) [78], whichmight heighten the experience of the sensation emerging fromtheir own innate physiological processes, speaking to the thoughtthat users might regard the ability to sense Wi-Fi to be part oftheir own abilities. Another technology we could have used would
have been an exoskeleton [15, 22]. However, we did not choose
an exoskeleton because we thought it might be difficult to wear,
hindering the user through its physical form factor in everyday
life even when it is not triggered, affecting the user’s feeling of
having a superpower by replacing it with a feeling of wearing amachine that has a superpower [13, 27]. Furthermore, we foundmost exoskeletons to be heavy, hindering our participants fromwearing them for longer periods [87].
However, even though EMS has now reached unprecedented
levels of dexterity, such as allowing individual fingers to flex independently [93], EMS-based interactions suffer from limitations on
actuation: it is an involuntary muscle contraction that can cause
discomfort or even distract the user [41]. As a result, we argue it
might be an “unfortunate” side effect if people perceive that suchmuscle movements are initiated and controlled by the EMS rather
than by themselves. When electrical muscle stimulation actuates
movement, people may not be able to recognise who is in control of
their body and experience their body as something else [75]. This
may affect their sense of control over their bodies and thus theirsense of agency, which is an important determinant of whether theaugmentation experience will be perceived as a superpower.

2.4

Sense of agency

The sense of agency (SoA) is the “experience of initiating and controlling an action” [10]. Agency involves the feeling of voluntary
control of bodily movement and the judgement of the cognitive
experience of ownership [92]. It distinguishes self-generated andSiyi Liu, Nathan Semertzidis, Gun A. Lee, Florian ‘Floyd’ Mueller, and Barrett Ens

self-controlled actions from actions generated and controlled byothers [60]. For example, we have mostly accurate and voluntary
control when we move our body, hence we know it is obedient toour own will rather than a machine or someone else compelling
us to move. Although most human actions are accompanied bysubjective experiences of agency, involuntary movements have noagency due to a lack of subjective control, such as reflex movements[28].
Research has found that physically actuating the human body(such as through EMS) can lead to a loss of feeling of agency because users have less control over their bodies [76]. However, thesense of agency is not entirely objective, and current work in EMS
showed that the user’s sense of agency can be partially preserved
by delivering EMS impulses that enable the user and the system tomove congruently, but complete retention cannot be achieved [38].
These previous works inform us that the sense of agency should
be considered when designing interactive systems. However, theassociated studies did not investigate how a sense of agency isaffected by introducing a superpower. This could be important toknow, as superpower design often involves introducing a systemcomponent that may have an impact on the control of the human
body, which can significantly shape the overall experience [67, 68].
The Sense of Agency Scale (SoAS) was developed to directly
assess the general sense of agency [96]. It was derived from a factor analysis based on a review of the psychological literature andvalidated in different populations with good psychometric properties [31]. According to the factor structure, SoAS is divided into
the Sense of Positive Agency (SoPA), including feeling in control
of one’s body, mind and environment, and the Sense of Negative
Agency (SoNA), which includes the feeling of being existentiallyhelpless, not under control. With this considered, we decided toask our participants about their sense of agency using this scale.
We hoped that this might enhance our knowledge of the design ofsuperpowers by understanding how participants’ sense of agency
is affected.
Taken together, although prior work explored superpower design
and used EMS to augment bodily experiences, there seems to be
still only limited knowledge about how to design superpowers,
especially considering not only their potential but also any possible
unfortunate side effects. To begin closing this gap, our work aims
to answer the following research question: How do we design
superpowers, especially considering both their potential and any
possible unfortunate side effects, beginning with an understandingof “unfortunate” superpowers?

3

WI-FI TWINGE DESIGN

To begin answering the question above, we designed “Wi-Fi Twinge”.
We ideated the design concept through discussions and explorations
amongst ourselves, the authors, one of whom with 25 years and oneof whom with 15 years of experience in interactive system design.
Together, we have designed over 40 interactive systems over theyears. We acknowledge that we could have engaged, for example,
potential users in the design process, following a traditional usercentred design process [72]. However, we did not do this because we
see our design as being more of a provocative artifact that serves asa research vehicle to explore a particular research question rather

Exploring Superpower Design Through Wi-Fi Twingethan a specific solution to an existing problem, speaking to theresearch-through-design tradition that values the creative craft ofthe designer [105].
Wi-Fi Twinge is a prototype system that allows users to sense
imperceptible Wi-Fi signals through the use of EMS by inducing
involuntary flexion of the hand, in particular, the fingers and wrist.
Despite providing people with the potentially fantastic ability tosense the strength of Wi-Fi signals, we anticipate that the low senseof agency people experience over their fingers and wrists when
actuated could result in an unfortunate superpower experience thatusers might prefer not to possess.

TEI ’24, February 11–14, 2024, Cork, Ireland

speaking nicely to our unfortunate side effects of superpowers.
Therefore, we believed that focusing on Wi-Fi could be a worthwhile topic to investigate as part of an unfortunate superpower.
We also considered other technologies, such as Bluetooth, however,selected Wi-Fi as it seems to be more prevalent (at least for now)
and also has a further reach in terms of physical distance and hence
would allow us to collect more data. However, we encourage future
work to investigate other phenomena that can be sensed but areusually invisible to users, to further enhance our understanding ofdesigning superpowers.
Wi-Fi Twinge system detects both 2.4 GHz and 5 GHz signals
and takes the average value of signals’ strengths in a 2-second time
window to smooth noisy data and then passes the value in 5-second
epochs to the classification system. Since Wi-Fi technology has
become ubiquitous, people are usually exposed to multiple Wi-Fi
signals, especially in the workplace and on campus. Therefore, wemeasured the total decibels relative to a milliwatt (dBm) of received
signal strength and then applied a logarithmic scale to cap out the
maximum value. The system classifies five levels of signal strength
based on the total sum of strengths, from none, weak, normal,
medium to strong, and then triggers the corresponding stimuli.

3.3

Figure 3: Wi-Fi Twinge’s components.

3.1

System architecture

Wi-Fi Twinge comprises two main components: a “Raspberry Pi”
and an EMS device (“Comfy EMS”) with 2 self-adhesive electrodepads (Figure 3). The Raspberry Pi is a small microcomputer (88 ×
58 × 19.5mm) that continuously monitors the surrounding Wi-Fi
signals’ strength. It controls the circuit via a 5 V relay connected to
the EMS device. The battery-powered EMS device then stimulates
the participant’s forearm with two electrode pads (4 × 4cm) basedon the current Wi-Fi signal strength.

3.2

Wi-Fi sensing

We chose to sense Wi-Fi signals because Wi-Fi is easily sensed withmobile devices and does not need much power, allowing our device
to feature a small form factor that enabled our participants to wear
the device for long periods. There was no need to recharge the device throughout the day. In addition, Wi-Fi is almost ubiquitous andhas become a common part of people’s daily lives, used both during
work and leisure time. As we anticipated that our participants mightwant to engage with our device at any time, using Wi-Fi would
ensure that they could do so whether it was work or leisure time.
Furthermore, Wi-Fi has been considered within the larger discussion around electromagnetic pollution that highlights the negative
consequences of too many wireless signals [35, 57, 102], hence

Mapping Wi-Fi signals to hand movements

To offer people the superpower of “feeling” Wi-Fi signals, we decided to consider sensory information in the form of muscle actuation that we hoped would facilitate an embodied experience (incontrast to, for example, reading a signal strength number on ascreen), potentially resulting in the user believing that sensing WiFi signals have become part of their own abilities (i.e., a superpower).
By mapping Wi-Fi signals to EMS-triggered hand movements wealso support the experience of perceiving Wi-Fi signals while theuser might be busy otherwise (for example, when having a conversation) all while supporting ambient awareness (i.e., without the
explicit need to click on a Wi-Fi signal strength button) [46]. Furthermore, we believe that our embodiment approach suits a wider
range of users, as our participants did not need to know how toreveal Wi-Fi strength on their laptop or mobile phone, they did notneed to know what a “high” or “low” dB value is, nor were required
to have knowledge that Wi-Fi signal strength is measured in dB. As
such, the embodiment approach could be seen as more culture- andexpertise-agnostic than the common screen-based apps for Wi-Fi
strength.
We chose EMS-triggered hand movements rather than otherparts of the body because the hand is profoundly important to mosthumans, serving a variety of basic functions such as interactingwith objects, making gestures, and communicating [36]. Therefore,
we believe that involuntary hand movements caused by muscle
actuation, as a result of an unfortunate superpower, might lead tovarious negative side effects impacting daily life. However, at thesame time, we believed that they might be seen as reasonable interms of the scope and degree of influence on the user as they do
not lead to serious loss of control compared to other parts of the
body (such as the legs that might cause a user to fall, risking serious
permanent injury).
To induce hand movements, we employed EMS as its use has
been described previously in the literature as a successful way toTEI ’24, February 11–14, 2024, Cork, Ireland

promote body movement [20, 54, 77]. In addition, we were inspiredby prior work that found that EMS use can facilitate novel bodily experiences, providing both positive and negative sensations[41, 74]. This aligned well with our intention to investigate superpower design including its positive and negative effects. The EMS
device contains two electrodes (Figure 4). The negative electrode isplaced between the finger flexors and the wrist flexors. The positive electrode is placed over the tendinous portion of the forearm.
Stimulation results in finger flexion with some wrist flexion andeven some thumb adduction.

Siyi Liu, Nathan Semertzidis, Gun A. Lee, Florian ‘Floyd’ Mueller, and Barrett Ens

sensations on the skin, however, monophonic waves are believed
to be able to generate a larger contraction torque and less fatigue
than polyphonic waves [42, 44].

4

The following section discusses the methods employed to conduct
the in-the-wild study and evaluate our system, Wi-Fi Twinge. The
5-day study was designed to understand the user experience overa longer period. We wanted to see how users experienced the superpower the first time around, but also when they became morefamiliar with it. While we could have chosen a shorter study time,
we wanted to ensure capturing a broad and comprehensive variety of experiences resulting from the EMS stimulation to ensure
rigorous analysis. Another reason was that we wanted to ensurethat participants were able to experience a variety of situations
and activities where the superpower could have been perceived aseither positive or negative. We could have also extended the study
time, however, found the duration long enough for our participants
to experience a wide range of everyday scenarios. Nevertheless,we acknowledge that future work could investigate longer study
duration, such as 1 month.

4.1
Figure 4: EMS’s electrode placement and finger flexion.

3.4

Wave patterns for muscle stimulation

The EMS device we used (“Comfy EMS”) delivers an electrical signal
at a fixed pulse width and pulse rate, where the intensity can be
adjusted only manually (through a dial on the device). We could
have designed our own EMS device to have more control, however,prior HCI research has suggested using commercial EMS devices
for actual and perceived safety reasons [41, 53]. Therefore, we choseother attributes of EMS as variables: duty cycle and frequency toform 4 different monophonic wave patterns for muscle stimulation(Figure 5). Duty cycle is the ratio between the duration of the active
signal and the total work cycle, describing the on/off phase of theelectrical pulses. A higher duty cycle indicates a higher percentage
of ON time. In descending order of signal strength, we set the
duty cycle to 0.8, 0.5, 0.29, 0.13 and 0 to reduce actuation time by
0.2 s in turns. Frequency is the count of the total work cycles (onand off phase in total) per second. Higher frequency means weturn the EMS on and off more frequently. We set the frequency
to 1 Hz, 0.83 Hz, 0.71 Hz, 0.63 Hz and 0 Hz so that the total work
cycle increases sequentially by 0.2 s to match Wi-Fi signal strength
levels.
We chose to adjust the duty cycle and frequency because webelieved that the chance of muscle fatigue could be reduced byproviding different lengths of breaks between each actuation, asprior work highlighted that EMS designers need to consider muscle
fatigue [20]. Furthermore, we believed that this approach mightenable participants to easily discern distinct stimulus wave patterns
by both extending the resting time and reducing the actuatingtime concurrently. We also considered other wave patterns, such as
polyphonic waves, which might be associated with less intense EMS

STUDYParticipants

We recruited 12 participants (6 men, 6 women, none non-binary andnone self-described), aged between 27 to 33 years (mean = 29.08,
SD = 2.02). Participants were recruited through advertisements bymeans of our lab’s mailing list and social media accounts. Elevenparticipants reported being right-handed and one left-handed. Twoparticipants had prior experience with EMS. All participants volunteered for the study. The study was approved by the ethics committee of our institution and all participants provided written informed
consent prior to their participation.

4.2

Study procedure

Before starting the study, participants received an introduction
to the system and study procedure. After informed consent was
obtained, participants were given the system and instruction on
how to use it, including how to power it on and how to operate it,
how to place the two electrodes on their non-dominant forearm
and when the system needed to be removed, for example, for showering, bathing or swimming. We also provided them with a video
containing these instructions for reference at home.
To calibrate the system, participants were asked to stretch andflex their wrists and fingers on their non-dominant forearms toidentify the best location for the electrodes. The electrodes were attached either by the participants themselves or the researcher. Next,
the researcher checked the placement and calibrated the amplitude of the EMS current. Based on repeated tests on the researchers’
bodies, we applied a constant EMS pulse-width of 200 µs and a pulserate of 100 Hz. Starting from 0 mA, participants were guided by the
researcher to slowly increase the intensity by turning a dial on the
EMS device until the desired intensity of movement was reached,
where the participants’ fingers and wrists flexed. Participants were
given approximately one minute to familiarise themselves with thestimulation. The intensity setting as shown on the EMS device’s
dial and the placement of electrodes were photographed; the photo

Exploring Superpower Design Through Wi-Fi Twinge

TEI ’24, February 11–14, 2024, Cork, Ireland

Figure 5: The EMS’s signal for four levels of Wi-Fi strength from “strong” to “weak”. Note that when the Wi-Fi strength is below“weak”, no EMS simulation is presented (i.e., 0Hz). In the diagram, 0 and 1 represent the ON and OFF states; frequency is thecount of total work cycles per second, i.e., frequency equals the inverse of the total work cycle time.
was given to the participants for later reference. During the study,
we informed participants that they could readjust the intensity levelto achieve a comfortable actuation, as long as they could ensurethat their fingers and wrists were engaging in flexion movements.
After the calibration, the study began. Each participant was asked
to wear the system for 30 − 40 minutes daily over 5 continuous days.
To ensure that participants had enough wear time and protect themfrom muscle fatigue, the system was set to turn off automaticallyafter 40 minutes. There were no prescribed tasks, as we aimed tounderstand the user experience in real-life situations. Participants
were instructed that they could use the Wi-Fi Twinge system at
any time of the day and anywhere, whether working, studying,entertaining, etc. We also instructed participants to “simply go
about their daily activities as usual” (Figure 6).
After each use, participants were asked to complete a digital
diary to record the activities they did, the time at which they wore
the system, and how they felt while wearing the system. At theend of the 5 days, participants were asked to complete the Sense
of Agency Scale (SoAS) [96]. We chose to ask participants to fillout the SoAS survey because we wanted to investigate how theexperience of initiating and controlling actions of participants wasaffected by involuntary hand movements to understand the designof superpowers that can control the human body. We used this scalebecause it has been validated with good psychometric properties[31]. Of course, other surveys would have also been possible, suchas surveys around the cognitive and physical load to understandthe mental and physical effort required by our participants in the
study [30, 91]. However, we did not investigate any specific tasks
and our participants engaged in different activities during the study.
Therefore, we believed that it would be difficult to gain meaningful
insights from this data. Taken together, we believe that our useof the survey represents a valid and practical approach to answering our research question. However, we acknowledge that othersurveys, including yet-to-be-developed ones around superpowers,
used in future studies might complement our work.
Along with completing the SOAS, participants were required totake part in a semi-structured interview that lasted approximately
30 minutes. The interviews included 16 questions about participants’ interactions with the system and any potential physical andemotional effects. Questions that we asked were, for example: “How
did you use the system? How did it feel on your arm? Did the system affect your daily life? Did it affect your emotions? When using
the system in your daily life, who do you think is in control, youor the system?” In addition, to minimise the impact of calibrationdifferences, we considered calibration differences in our interviewsby always asking what the EMS experience was like, including

TEI ’24, February 11–14, 2024, Cork, Ireland

how it felt and how the resulting movements looked. Furthermore,
we asked participants to demonstrate how they used the system,
including what intensity setting they used.

Siyi Liu, Nathan Semertzidis, Gun A. Lee, Florian ‘Floyd’ Mueller, and Barrett Ens

statistical analysis. We acknowledge that the 6-month follow-up
survey might have included other unknown confounding effects.
To analyse the interview data, we employed thematic analysis[11, 12]. The inductive thematic analysis approach was used to
identify themes by distilling and articulating meaning from thedata. Interviews were audio recorded and transcribed for qualitative
analysis in Nvivo. A question and a response from a participant
were combined and considered as one unit of data. In total, 255
units of data were included in the analysis. Two researchers thenread the transcripts three times to get familiar with the data andcoded the data via the “Delphi method” [51] in which codes were
iterated over four meetings in three weeks until codes were agreed
upon across five researchers. Then, the codes were used to generate
three high-level themes.

5

RESULTSIn this section, we detail the results yielded from the analysis ofparticipants’ responses to the Sense of Agency Scale and describe
three high-level themes that we derived from the analysis of theinterview data.

5.1
Figure 6: Some of the daily activities of the participants wearing the Wi-Fi Twinge system. (A) Turning the pages of a book.
(B) Using a scissor. (C) Using a screwdriver. (D) Walking in
the park.

4.3

Data analysis

As the Sense of Agency Scale is ordinal in a 7-point Likert scale(1 = strongly disagree, 7 = strongly agree), we performed a nonparametric one-sample Wilcoxon signed rank test for each factor
to compare with the baseline, including Sense of Positive Agency(SoPA), Sense of Negative Agency (SoNA) and total Sense of Agency(SoA) score. We asked participants to complete the same survey
again after 6 months as the baseline, in which participants directly
responded to their sense of agency in daily lives without any experimental conditions. We initially used the results of Hurault et al.’s
study [31] as a baseline. However, in considering feedback fromcolleagues, we acknowledged that employing two samples (i.e., using a sample from another study as a baseline) may introduce a
confounding effect to the comparison due to uncontrollable contextual differences inherent in the sample and design of Hurault
et al.’s study. As the SOAS is a subjective survey, the unique context of each sample may lead to differences in the interpretationof the questions, which may lead to response bias. Therefore, we
decided to conduct a second round as a new baseline to allow for a
multiple comparisons analysis which we could use to understandparticipants’ sense of agency without the use of our system. However, this was a retrospective decision made six months after thecompletion of the study, hence the time distance. Nevertheless, thiscame with the serendipitous advantage that the decay of the participant’s memory using the system may have reduced their ability
to compare their normal sense of agency with the sense of agency
they felt while using the system, thus giving a more pure reportof their everyday sense of agency, leaving comparison purely to

Quantitative analysis of sense of agency

Figure 7 shows the participants’ responses to the Sense of Agency
Scale. We found a significant difference in the SoNA score, in which
the SoNA of Wi-Fi Twinge (mean = 11.25, SD = 4.90) was higher
than the baseline (mean = 7.25, SD = 3.65), V = 66, p = 0.037 (Figure8). The comparison of SoPA (mean = 17.58, SD = 6.57) and SoA(mean = 30.33, SD = 10.09) with the baseline (SoPA: mean = 20.25,
SD = 4.41; SoA: mean = 37, SD = 6.98) revealed no statisticallysignificant difference (SoPA: p = 0.146; SoA: p = 0.064). This means
participants reported higher levels of negative agency in our study
compared to the baseline.

5.2

Qualitative analysis

Overall, participants reported that the concept and experience of WiFi Twinge were “fascinating” (P1), “surprising” (P9) and “interesting”(P11). Participants said they became more aware of their bodies
and the surrounding environment by sharing the world with the
Wi-Fi signals around them. The following sections investigate theseresults further by articulating three themes: Wi-Fi Twinge creates
fortunate out of unfortunate effects; Wi-Fi Twinge facilitates avariety of emotions and sensations over time; and Wi-Fi Twinge
facilitates varying degrees of sense of agency.
5.2.1 Theme 1: Wi-Fi Twinge creates fortunate out of unfortunate
effects.
This theme describes 92 units about how participants interactedwith and how they felt unfortunate and fortunate from Wi-Fi
Twinge. We first describe sub-themes that indicate that our system
was indeed an unfortunate superpower. Then we explain how it
was unfortunate, but also how it sometimes could be fortunate.
Physically hindering daily activities. Participants experimented
with different day-to-day life activities while using Wi-Fi Twinge,such as cooking (P1, P5, P8), commuting (P4, P6, P10, P12), working with a computer (P2, P9, P11) and watching movies at home
(P3, P7, P8), to investigate how different contexts influenced their

Exploring Superpower Design Through Wi-Fi Twinge

TEI ’24, February 11–14, 2024, Cork, Ireland

Figure 7: Participant responses to the Sense of Agency Scale.
the system again: “I didn’t like to lose control. It affects what you doevery day, you cannot work, you cannot do your daily stuff ”.
40

Mean Score30

p=0.037*

Group
Wi−Fi Twinge
Baseline

20

10Interfering with tasks that require concentration. Two participants
reported that the EMS stimulation “interfered with their concentration to do other tasks” (P7). In particular, they “felt distracted because of the stimulation feelings” (P11). So, unlike the result above
about how the EMS stimulation hindered their physical hand actions, these comments articulate how the feeling from a computercontrolled hand can interfere with other tasks cognitively. Thishighlights that with superpowers can come limitations in another(bodily) area, here, concentration.

Figure 8: The average score of the Sense of Agency Scale(SOA) and its subscales (SoPA and SoNA) compared with thebaseline. Error bars represent one standard error of the mean.

Embarrassing in social interactions. One participant reported
that they “wanted to use the system on public transport but felt
embarrassed to have weird finger twitches in public”. However, otherparticipants did not receive any comments about the system frombystanders, or mentioned feeling embarrassed wearing it in public.
This could be due to minor twitching that is not very visible fromafar.

experience of the system. Participants reported that many of their
daily activities were affected by the superpower. For example, P10
said: “I used it today [during commute]. I became very slow, andI feel hard to do what I have to do, [so] I couldn’t catch the train”.
Participants spoke about how their hand and hence hand-focused
activities were affected by the system. For example, P11 said: “When
I was working on my computer, I couldn’t spread my fingers and typecertain keys because of [the] finger twitching. And I had the sameproblem with my phone”. As a result of the influence the system
had over the participants’ bodies in different contexts, participants
modified their behaviour to adapt to the stimulation. Three participants reported that they tried to avoid using the stimulated handby instead using their other hand. P5 explained: “I didn’t use my left
hand a lot and used my right hand more because I couldn’t control
my fingers”. In addition, three participants indicated that they did
not like the superpower, and P5 explained why they would not use

Changing the way people think of Wi-Fi. Two participants mentioned that they started to realise “how densely our world is now
surrounded by Wi-Fi signals, it’s almost everywhere” (P12). Thissuggests that our system helped participants to get a better understanding of their surrounding environment. Furthermore, the word“dense” suggests that the system made them more aware of how
Wi-Fi signals can affect their lives within it, as they now have tolive in a world shared between them and the wireless signal. P10
was not only more aware of the Wi-Fi signals but also deduced thatthey can be a threat to their wellbeing: “[. . . ] the fact that my houseis full of signals, which is not good”. This led P10 to express concerns
about their children’s safety in their home: “I feel so worried about
those signals around me, too many signals. I have kids, and I feel soworried about them because some people are talking about the impactof this signal on the body and brain. And there is no scientific study
on that. I feel not okay with all these signals around me”. In thisinstance, we interpreted P10’s concerns to be referring to the belief

0

SoPA

SoNA
FactorSoATEI ’24, February 11–14, 2024, Cork, Irelandthat too much Wi-Fi exposure (both over time and intensity) canbe detrimental to one’s health, even though current scientific evidence does not support this concern [15]. This quote suggests that
our system made P10 more worried about how safe their children
are in their homes as they became more aware of the ubiquity ofthe signals in their homes. We postulate that the bodily nature of
our system could have fuelled that physiological reaction, i.e., fear,
especially if we compare it to checking the signal strength with anapp on a mobile phone, for example.
Rekindling an appreciation of the hands. Three participants reported that losing some control of their hands made them “realise
the importance of their hands” (P11). This realisation was the resultof becoming aware, thanks to our system, “how difficult it is to not
be able to control your hand” (P5). P11 explained that the system
made them think of Parkinson’s disease and empathise with the“difficulties and hardships of Parkinson’s patients”.
Encouraging people to escape Wi-Fi. Wi-Fi Twinge not only madepeople more aware of the ubiquity of Wi-Fi signals but implicitly
encouraged people to take action. Participants reported that they
were sometimes distracted by hand movements and tingling intheir arms, which interfered with their work, making them moveto another location with fewer Wi-Fi signals. For example, P11
said: “Sometimes the stimulation was too strong, I felt so annoyedand couldn’t work. So, I decided to stop work and went to the park toescape it”.
5.2.2 Theme 2: Wi-Fi Twinge facilitates a variety of emotions andsensations over time.
This theme describes 116 units about participants’ various emotions and sensations over time as a result of interacting with Wi-Fi
Twinge.
Negative physical sensations and emotions fuel each other. All
participants felt numbness as a result of involuntary muscle contractions. P7 also reported a feeling of weakness: “In addition tonumbness, there is also a sudden feeling of weakness in the arm, as if
the arm suddenly lost strength”. Four participants mentioned thatthey felt slight muscle soreness and fatigue sometimes after the
stimulation if they used a high-intensity stimulation. For example,
P11 said: “My fingers were so stiff and needed to relax for a while
after the experiment in the last two days”. It seems that continuous
EMS use affects bodily composition. P8 tried to explain the reason
for their fatigue: “30 minutes [of] stimulation is a lot, and after that,
I feel a little bit of fatigue in the forearms, but it was not annoying”. It
appears that electrical muscle stimulation may lead to some degreeof muscle overuse, but there are no other serious symptoms, andarm fatigue resolves with rest. Five participants reported that theiruncomfortable physical sensations led to negative emotions andvice versa. Three of them stated that they felt distracted and angry
during the use of the system, for example, P1 mentioned that thesystem “sometimes made me annoyed because of the continuous stimulation”. Similarly, P11 said: “At first, I was surprised, but as time
went on, my arms started to hurt, I started to feel very upset, and I
was not in the mood to do anything else. Sometimes, when I was ina bad mood, I also got a feeling of more pain, I don’t know if it’s anillusion or not”.

Siyi Liu, Nathan Semertzidis, Gun A. Lee, Florian ‘Floyd’ Mueller, and Barrett Ens

Changing attitudes towards Wi-Fi Twinge over time. Five participants were surprised by the superpower at first. For example, P9
said: “It was more of a surprise on the first day”. Another five participants felt “weird at the beginning”. For example, P5 said: “Thefirst day, of course, it was weirder, not having control, because I used
my left hand and saw my fingers move. I was a bit scared”. In addition, two participants reported that they were “slightly worriedat the beginning that the EMS may cause injury” (P4) and “when it
comes to the body, I’m a little bit cautious about the electric signals”(P1). Although these participants had different experiences, theirattitudes towards the system changed throughout the study. Six
participants discussed how this journey changed them. They spoke
about their journey from having initially felt “weird” to, over time,
getting used to their superpower. For example, P6 said: “In the firsttime I tried, the first two minutes, it was uncomfortable and weird.
But then I got used to the whole thing. So, I think the more [I] used
it, the more I was [getting] used to it, so I could wear it and keep
doing other things. And I have forgotten that it was attached to mybody”. Two participants also said that after having experienced thesystem, their concerns were alleviated, and they felt relieved. Thishighlights that any negative emotions associated with EMS can
also go through a trajectory [3]. Taken together, it seems that an
initially unusual experience quickly turned (usually within threedays) into an experience where participants became used to it, evento the point of forgetting that the stimuli were induced by the system and therefore participants have even begun to believe that thesuperpower is their natural ability.
Changing the way people see the world. As participants began
experiencing the stimulation, such as when moving from one room
to another with different levels of Wi-Fi signals, they became moreaware of their environment through bodily sensations. For example,
P12 said: “I know we are surrounded by Wi-Fi signals but didn’t feel itin such a solid way before”. This use of the word “solid” is interesting,as it suggests that the system made an abstract concept of wirelesssignals more tangible, even bodily. This allowed participants to“feel” the signal rather than just cognitively comprehend it. Our
system also changed how participants perceived their environment.
Interestingly, P12 added: “It changes a way of sensing the surrounding
environment, from vision to feeling”, which suggests that participants
seeing their environment now moved to “feeling” the environment.
Furthermore, it made participants think about what they usually
do not think about. P4 said: “It does raise my awareness to pay
attention to the Wi-Fi strength in my surroundings, which is something
I rarely think about”. P5 further explained: “When I was walking
in the street, I never paid attention to the structure of the buildings.
But when I was wearing the system and passing the buildings, I felt
their Wi-Fi signals and started guessing if there was Wi-Fi inside”. It
appears that participants not only gained a greater awareness of
their surrounding environment but also changed the ways they see
the world.
Heightening awareness of the self. Three participants commented
that the system helped them heighten their awareness of theirbodies. For example, P6 said: “I think [I am] more aware of my body
because I was concentrating on that [reaction]. So, it was like feelingmy spirit, cleaning my body”. This suggests that the system madethem more aware of their body more generally. Meanwhile, the useExploring Superpower Design Through Wi-Fi Twingeof the word “spirit” suggests that the system might have helped
participants develop a stronger understanding of their body andmind as well. This speaks to the prior theory that highlights thatbodily technology can facilitate self-awareness [43]. Furthermore,
one participant reported that the system made them reflect on their
free will, that is, how much in control their lives are in general[55]. For example, P1 said: “[I became] more conscious about how incontrol I am”.
5.2.3 Theme 3: Wi-Fi Twinge facilitates varying degrees of sense ofagency.
This theme describes 43 units about how participants perceive who
is in charge of their behaviour in terms of both initiating the action
and controlling it.

TEI ’24, February 11–14, 2024, Cork, Ireland

However, six participants reported that the system controlled
their hands. For example, P1 said: “I feel like it was controlling myhand. The device controls my body, it’s not me”. P5 emphasised theinfluence of stimulation intensity: “Especially when there was astronger signal, I couldn’t control my hand. I tried to keep my handand my fingers straight, but I couldn’t. It was a strong signal, so it’s
hard to fight it”.

6

6.1
The system initiates actions. All participants reported that theyfelt that the system initiated muscle movement rather than themselves. Specifically, P9 spoke about consciousness: “I can tell whether
it is my own consciousness or the effect of the device. These two arecompletely different”. This suggests that Wi-Fi sensing was not considered as their own ability, but something owned by the system.
In addition, participants mentioned that their sense of initiative
was affected by the presence of the system. For example, P10 statedthat this was the case “because I can see the machine”. P3 explainedthat the relay also had an impact: “The device will make a clicking
sound and some cables, so it is very clear that the stimulation cameout of this device”. However, this was different if participants were
not paying attention. P11 said: “At the beginning, I thought of thesystem, because I saw it and felt it. But sometimes when I didn’t pay
attention to it, I felt my body created that movement”. This suggeststhat participants experienced the superpower sometimes as something separate from their body, possibly exacerbated by the form
factor and relay noise, however, if not paying attention to it, they
believed it was “them” who could sense Wi-Fi.
Regaining control of the hand. Participants held varying opinions about who controls their body and hand movements. Fiveparticipants reported that they were in control of their bodies andmovements, even though their fingers were contracted involuntarily. P4 said: “I was able to either bring them under control or avoid
using them for the task I wanted to perform”, while P9 said: “Whenthe stimulation occurs, my muscles are also contracting, but the contraction is not enough to exceed my willpower”. However, willpower
can be disturbed by other tasks, thereby affecting the user’s ability
to control the body. For example, P9 mentioned that they needed
conscious control of their body: “Without paying attention to controlling the hand, I feel that the movement of the hand is completely
controlled by it”. Similarly, P2 said: “Sometimes, it gives a false impression that my hand is completely under my control. But that’s
not true. My hands still move involuntarily”. It seems the control ofthe body was not fixed and may fluctuate in different contexts. P8
echoed this notion and explained: “While I was not using my handand didn’t want to use it, definitely the device is controlling the hand,in the sense of controlling the movement of the hand, specifically
flexion. While I was not using it, but I wanted to use it, I felt in control
like I was able to fight with the stimulation and I was able to takecontrol again”.

DISCUSSION

In the following, we discuss our findings, derive design tactics
for future superpower systems, and discuss limitations and future
research work.

Unfortunate effects of Wi-Fi Twinge

Measures of the subscale Sense of Negative Agency showed a significant difference when participants used Wi-Fi Twinge compared tothe baseline. This result suggests that participants experienced a significant increase (55.17%) in the sense of negative agency when they
had the Wi-Fi sensing superpower, indicating that participants felt
significantly less control over their bodies, and felt more helpless,which speaks to unfortunate side effects by the system. This resultaligned with the goal of our study design, as our motivation was toinvestigate an unfortunate superpower with unfortunate results:
involuntary muscle contractions and finger movements, which led
to a lack of control over some parts of the body and resulted ina dramatic increase in the Sense of Negative Agency. However,the loss of control in the hands was relatively small compared to
the whole body, and the tingling sensation and finger movements
were relatively mild. As a result, participants still had the ability
to control most of their daily behaviour and take responsibility for
their actions. Thus, it may explain why Wi-Fi Twinge had a smaller
effect on the participant’s Sense of Positive Agency and overall
Sense of Agency scores.
Our finding that “Wi-Fi Twinge facilitates varying degrees ofsense of agency” confirms that loss of body control affects the senseof agency, and suggests that users’ perception of the initiator of theaction also affects the sense of agency. Our participants reported
that they saw their hands being moved passively by the machine
and therefore perceived the initiator of the hand movements tobe the system, thus indirectly reducing their sense of control overtheir bodies and affecting their sense of agency. It also reflected thetechnological mediation and human-technology relations in postphenomenology [9, 33, 98]. Wi-Fi Twinge is considered a mediatorthat influences the way we perceive and engage with our surrounding environment, and as an extension of the human body, enabling
people to sense Wi-Fi signals beyond their own capabilities.
Moreover, participants mentioned that the physical characteristics of the Wi-Fi Twinge system (such as cables, size and sound)strongly influenced this feeling, suggesting that the Wi-Fi Twinge
system was experienced as an external device rather than a partof the body. This perception is referred to as the sense of bodily
ownership and describes the feeling that the system is a part of the
body [66–68]. Our findings suggest that bodily ownership is a critical determinant in deciding whether or not a technology enables
a person to experience superpowers, and as we mentioned earlier,using a person’s own physiology can be a part of what makes it

TEI ’24, February 11–14, 2024, Cork, Irelanda superpower. Therefore, our results suggest that in addition toemploying the user’s own physiology as an interface, the technological components of the system must also be obscured or subtle inorder for users to experience the system as an innate superpower.
Taken together, the sense of agency and sense of bodily ownership permeate almost all experiences and are very important elements in examining the experience of superpower systems [7, 10].
For example, Mueller et al. [66] used them as a lens to design
the bodily integration framework, which describes the design ofhuman-computer integration systems in which the human bodyand computational machinery are coupled in a bidirectional actuation. They categorised EMS systems as “Possessed-Body” with a
low bodily agency and a high bodily ownership. However, as with
our theme “Wi-Fi Twinge facilitates varying degrees of sense ofagency”, participants were roughly evenly split on the question of
who controlled the hand movements, suggesting that participants’sense of agency when using Wi-Fi Twinge was partially influenced
by the unfortunate side effects, which is consistent with the SoAS
results, where the sense of agency score was slightly lower thanthe baseline, but not significantly different from the baseline. In
addition, through the previous analysis we recognised that theperception of action initiators and hardware features increases thesystem’s sense of presence, resulting in participants’ sense of bodily
ownership being at a low degree. The results show that the Wi-Fi
Twinge has a moderate sense of agency and low bodily ownership,
and can be considered to fall between the “Chauffered-Body” and“Tele-Body” type systems, which is slightly different from Mueller
et al. [66]. Our findings suggest that when users become aware of
involuntary movements in their bodies, they are aware that they
are not the initiators of the power, and that the movements are
not driven by themselves, but they retain the willpower to counteract these movements and believe that they are in control of theirbodies.
Furthermore, we discovered that more dark patterns existed
during the study after the exploration mentioned above, and they
did not align with our original intentions. This implies that design
elements might be misused due to an oversight of their impact on
the human experience [17]. One participant felt embarrassed to use
Wi-Fi Twinge on public transport, where the human experienceextended to socialising, including interactions and engagementswith other people. It might be used as an intentional dark pattern
to embarrass them in social situations. Some participants had bad
feelings about Wi-Fi signals and interpreted the Wi-Fi signal tobe hazardous to their health due to the unfortunate effects of thesystem and EMS. This suggests that EMS has the potential to be
more severe than simple vibrotactile output, and thus EMS could be
used as a dark mode to reinforce the severity of certain information.

6.2

Changes from sensation to cognition

Three participants admitted that they did not like the superpower
because of its negative effects. All participants reported that while
the superpower enhanced their perception of Wi-Fi, it also caused
negative emotional and behavioural effects. This suggests that asuperpower, an enhanced capability in one part of the body (sensory), might lead to decreased capability in another part of the body
(hand). This confirms the prior theory on the augmented human,

Siyi Liu, Nathan Semertzidis, Gun A. Lee, Florian ‘Floyd’ Mueller, and Barrett Ens

which said that a superpower is often a trade-off, where strengthening one part of the body through technology could limit anotherpart [70].
However, as per our theme “Wi-Fi Twinge creates fortunate outof unfortunate effects”, participants reported that when the discomfort sensation was within their acceptable range, they became moreaware of their surrounding environment because of the physicalstimuli they received. Particularly, users could infer the surrounding environmental features and get implicit guidance from theirsensations. For example, P5 said that they started guessing if there
was Wi-Fi in the buildings they passed. Our findings suggest that
unusual physical sensations may trigger deeper cognitive thinking,making people think about things they would not usually think
about, and see the world differently than before.
Moreover, participants reported that they became not only moreaware of the surrounding environment but also gained a renewed
appreciation of their hands. The EMS stimulation caused involuntary hand movements, reducing participants’ bodily control, thus,increasing emphasis on their hands. This appeared to promote empathy by allowing participants to feel physical sensations they havenever experienced before and to understand the feelings of people
with hand-twinge symptoms. It aligns with prior theories on the potential of embodied systems: research has found that embodied systems can be used to build empathy and compassion [29, 37, 89]. For
example, researchers have used augmented body suits to mimic vision, hearing and movement impairments to educate students about
the experiences of people with disabilities [47, 83]. This confirms
the prior theory that through interacting with sensory-enhancing
systems, the ability to understand and empathise with the feelingsof others may be strengthened [19, 29, 101]. This embodied experience, rather than an abstract understanding enabled by text or
speech, could make people more engaged and immersed in the environment, thereby heightening sensorial experiences and increasing
their empathy with specific groups.
Similarly, in the second theme, “Wi-Fi Twinge facilitates a varietyof emotions and sensations over time”, participants reported that
Wi-Fi Twinge helped them focus on their bodies and heightened
their awareness of their bodies. This finding confirmed that embodied interaction through the user’s own physiology can facilitate
bodily awareness [76], which is important because bodily awareness can improve mental and emotional well-being as, for example,
utilised in the recovery of trauma and as therapy for people with
autism [97].
Taken together, our findings suggest that the uncertainty and unpredictable negative side effects of superpowers can physically andcognitively interfere with people’s daily lives. These unfortunate
effects may disrupt people’s activities and concentration, however,people can adapt and cope effectively if these negative effects are
kept within reasonable limits. At the same time, these unfortunate
effects inspired the participants to harness their willpower to control their superpowers, leading to an enhanced awareness of self,and strengthening the connection between their bodies and thesurrounding environment.

Exploring Superpower Design Through Wi-Fi Twinge

6.3

Design tactics

Building on our craft knowledge of having gone through the design
process of Wi-Fi Twinge and the findings of the study, we now propose a set of tactics for designers aiming to create future fortunate
and unfortunate superpower systems.
6.3.1 Consider the mapping between input and output.
The mapping between the input and output of a superpower is complex and users can find understanding this relationship difficult thefirst time they use it. Users may feel confused and therefore requiretime to explore the mapping relationship. Norman [71] suggeststhat mapping relationships should be “natural”, using physical andbiological analogies as well as cultural standards. We agree that“natural” mapping could offer a most "intuitive" feeling, leading to
immediate understanding and a more efficient system. But it mightalso reduce creativity and playfulness because it encourages people to follow familiar and conventional interaction patterns. The“natural” mapping for Wi-Fi signals could be visual output because
Wi-Fi is a radio wave that can be seen as an invisible light. However,since we aimed to design an unfortunate superpower, we chosean unusual mapping: from Wi-Fi signals to hand movements toprovide users with a novel and unique system. Meanwhile, we used
a rather obvious mapping for hand movements and EMS, wherestronger Wi-Fi signals result in longer EMS activation times andshorter rest times. Accordingly, we suggest that designers should
consider carefully when choosing to use the “natural” or “unnatural”
mapping between input and output for fortunate and unfortunate
superpowers, especially if the enhanced ability is uncommon andinvisible. For example, if designers want to develop a hearing superpower, they could consider “natural” mapping such as mapping
sound content to text to enhance usability and efficiency, or unnatural mapping such as mapping sound volume to body temperature
to increase creativity and playfulness.
6.3.2 Consider the extent of allowing users to alter the control oversuperpowers.
Sense of agency is a complex phenomenon because each person’s
feeling is different and subjective. From the interviews, we foundthat control over superpowers was a key determinant in assessing
the sense of agency and distinguishing unfortunate superpowers.
Some participants perceived Wi-Fi Twinge as an unfortunate superpower because they could not control the superpower directly;
instead, they had to change their location to control the superpower
indirectly. Low control over superpowers appeared to limit physicaland mental demands, allowing users to focus on their own changes
and thus increase self-awareness, but users may feel uncomfortablewith feelings of helplessness and loss of control. Therefore, we
recommend that designers consider the extent of allowing users toalter their control over superpowers when designing superpowers,
especially for intentionally unfortunate systems, where a lower
degree of control and sense of agency may be more likely to leadto unfortunate superpowers. For example, it may be easier to lose
control by having the body navigate automatically throughout the
day compared to regaining control of the body when you stop.
6.3.3 Consider reducing the physical presence of the device to increase the sense of bodily ownership.

TEI ’24, February 11–14, 2024, Cork, Ireland

We recommend that designers consider reducing the physical presence of the superpower device to increase the sense of “bodily
ownership” to facilitate superhuman-like experiences. With Wi-Fi
Twinge, the cables of the device were described as annoying anddistracting, drawing the attention of participants toward the device
and reminding them it was a machine controlling their movements.
Therefore, we suggest that superpower systems should be out ofsight and mind for participants to feel integrated with their bodies.
To achieve this, designers could consider alternative technologies
that reduce participants’ attention to the device and reduce thepresence of the technology, such as microdevices, ingestible andimplantable devices [49, 50].

6.3.4 Consider indirectly facilitating intended behaviours.
Participants reported that they tried to escape places with a large
amount of Wi-Fi signals to avoid negative bodily sensations, hence
walking outside into nearby parks: this could be regarded as adesirable behaviour as being outdoors is associated with positivewell-being [8]. This finding suggests that rather than creating asystem that encourages people to go outside or a robot that moves
people outside, a designer who aims to facilitate such behaviourchange (like spending more time outdoors) could turn an action
they do not want to promote (being indoors, with too much Wi-Fi)
into an unfortunate experience where participants feel that it istheir free will that makes them go outside. If designers want tofacilitate behaviour change, they may consider indirectly allowing
users to discover the negative impacts of the unintended behaviour
to keep participants’ sense of agency. As such, the superpower
design would leave participants’ overall sense of agency unalteredwhen aiming to promote intended behaviour but engage with alittle loss of control (like our EMS twinge) instead.

6.4

Limitation and future work

Our work has several limitations. Firstly, the use of EMS requires acalibration procedure and hence can lead to calibration differences.
Previous studies have noted that such calibration is recommended
when using EMS as each body is different [82]. We note that we
could have considered the differences by logging the use of oursystem through, for example, a camera. However, we found this tobe outside the scope of this work and noted that prior work also
refrained from such data collection to consider EMS calibrationdifferences [41]. Future work could complement our approach withother methodologies to enrich our results. Secondly, we only did
the quantity analysis for the SoAS. In future work, we can imagine
evaluating the translation of Wi-Fi signals into electrical signals
with measurements based on Wi-Fi heat maps to assess the accuracy of the signal strength classification. Thirdly, we have only
investigated one particular unfortunate superpower. Future work
might want to design more prototypes around different concepts of
unfortunate superpowers to complete our understanding of designing superpowers and design tactics. Finally, we have yet to provethat our design tactics based on the exploration of unfortunate superpower systems lead to better systems. In the future, workshopswith designers who use these tactics could verify that our tactics
are effective.

TEI ’24, February 11–14, 2024, Cork, Ireland

7

CONCLUSION

In this paper, we explored human augmentation design throughthe lens of unfortunate superpowers. We designed a system called
Wi-Fi Twinge that extends human perception to Wi-Fi signals. The
system allows users to sense unseen Wi-Fi signals through electrical muscle stimulation, causing involuntary flexion of the fingers
and wrist to create an embodied experience. Through interviews
from an in-the-wild study where 12 participants engaged with thesystem over 5 days, we found that even though the unfortunate
superpower caused some hindrance to participants’ daily lives, itheightened participants’ awareness of their bodies and surrounding environment, indirectly changing their activities, facilitatesreflection on themselves, and in some cases contributed to theiroverall well-being. Taking these results together, we provided a
set of design tactics to guide future superpower system designs.
Ultimately, we aim to advance our understanding of technologyfacilitated superpower experiences especially considering not only
their potential but also any possible unfortunate side effects andguide the future design of superpower systems.

ACKNOWLEDGMENTS
Florian ‘Floyd’ Mueller acknowledges the support from the Australian Research Council, especially DP190102068, DP200102612
and LP210200656. We thank Rakesh Patibanda for his guidance oninterviews and hardware. We also thank our participants greatly
for their time and insights. Lastly, we thank those participants who
agreed to be featured in the photographic material included in thispublication.

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