Embedding Behavior Modification Strategies into a
Consumer Electronic Device: A Case Study
Jason Nawyn, Stephen S. Intille, and Kent Larson
Massachusetts Institute of Technology
77 Massachusetts Avenue, NE18-4FL
Cambridge, MA 02139
firstname.lastname@example.org; intille | kll @mit.edu
Abstract. Ubiquitous computing technologies create new opportunities for pre-
ventive healthcare researchers to deploy behavior modification strategies out-
side of clinical settings. In this paper, we describe how strategies for motivating
behavior change might be embedded within usage patterns of a typical elec-
tronic device. This interaction model differs substantially from prior approaches
to behavioral modification such as CD-ROMs: sensor-enabled technology can
drive interventions that are timelier, tailored, subtle, and even fun. To explore
these ideas, we developed a prototype system named ViTo. On one level, ViTo
functions as a universal remote control for a home entertainment system. The
interface of this device, however, is designed in such a way that it may unobtru-
sively promote a reduction in the user’s television viewing while encouraging
an increase in the frequency and quantity of non-sedentary activities. The de-
sign of ViTo demonstrates how a variety of behavioral science strategies for
motivating behavior change can be carefully woven into the operation of a
common consumer electronic device. Results of an exploratory evaluation of a
single participant using the system in an instrumented home facility are pre-
The average American watches over 4 hours of television each day . As time spent
in sedentary media consumption increases, the amount physical activity one incurs
typically decreases. This is an unsettling fact of life for many Americans, 50% of
whom feel they presently watch too much television and would like to reduce their
viewing . Meanwhile, rates of obesity have increased markedly in recent decades,
and millions of Americans report engaging in weight-control efforts on a regular basis
. Few people, however, actually succeed in altering their long-term health outlook,
in spite of accumulating evidence of the positive correlation between sedentary be-
havior and obesity  as well as lifestyle-related medical disorders such as Type 2
diabetes . Similar trends are being reported in other industrialized countries.
Successfully reducing the time spent in television viewing over the long term could
produce meaningful gains in an individual’s overall health, especially if this activity is
replaced with less sedentary alternatives. However, television habits are notoriously
difficult to modify, often exhibiting the resilience of chemically based addictions .
The nature of the television viewing experience explains its addictive properties: the
intrinsic rewards of watching television, such as relaxation and passivity are immedi-
ate and self-reinforcing. Unfortunately, these rewards diminish over time, and after
periods of extended use, TV viewers often feel worse than before they started .
In contrast, the goal of increased physical activity is routinely impeded by the per-
ceived high costs of entry into the pursuit. Engaging in exercise is typically thought to
involve getting dressed, going to the gym, working out, showering, and then returning
home. As a further impediment, the rewards of exercise—unlike television viewing—
are not immediate, often to be noticed only months or years down the road. In fact,
the main short-term effects of physical activity may be unpleasant ones, as captured
by the common expression, “no pain, no gain.”
The essential problem is that television viewing is instantaneously rewarding while
exercise is instantaneously aversive. Intervention in this area has proved challenging
in the past because successful behavior modification depends on delivery of motiva-
tional strategies at the precise place and time the behavior occurs. Advances in sen-
sor-enabled mobile computing technologies will now facilitate the creation of applica-
tions that can intervene at critical moments throughout the day. As an exploration of
how ubiquitous computing devices might enable novel approaches to improving life-
style behaviors, we describe a case study with two interrelated objectives: (1) pilot the
use of a novel technology to preempt or disrupt the stimulus-reward cycle of TV
watching and (2) pilot the use of the same novel technology to decrease the costs of
physical activity, while providing immediate positive reinforcement.
1.1 Technology-enabled behavioral modification strategies
This project builds upon prior work relevant to the motivation of lifestyle change.
Knowledge campaigns (e.g. ) and clinical interventions (e.g. ) are the two most
common approaches to the problem thus far. Other than websites and CD-ROMs,
prior efforts at using technology to reduce television viewing have focused primarily
on devices for children. The majority of these served as primitive electronic gatekeep-
ers to limit a child’s access to the TV. Specific examples include a key locking
mechanism and a token access system . These systems use forced rationing or
punishment often imposed by the parents, and therefore they are less likely to be
adopted by adults.
Several technology-related projects have attempted to simultaneously address the
problems of television viewing and inactivity by creating exercise-contingent TV
activation systems. One such system, Telecycle (see ), requires the user to pedal a
stationary bicycle continuously in order to maintain a fully resolved television picture.
While this approach is appealing in concept, it is designed to improve quality of exer-
cise, not to reduce quantity of television viewing. Furthermore, the long-term effec-
tiveness of any intervention that demands physical activity in exchange for television
time should be suspect, since it obstructs a principle objective of television viewing –
Another recent attempt to address the problem of sedentary lifestyle and TV takes
the form of a step-counting insole, Square Eyes , that allows a child to earn a
daily television allowance based on their amount of walking. As in the case of the
Telecycle, this approach effectively uses a short-term goal orientation to reward
physical activity. However, as is the case for many existing television interventions, it
does so by framing television as a conditional reward stimulus, opening up the possi-
bility that it may ultimately increase the user’s motivation to watch TV .
Research into the use of technology to increase physical activity independent of
television viewing is more extensive. The most pervasive use of technologies is for
measuring amount of ambulation and providing open-loop feedback (e.g. ). The
current market proliferation of consumer-grade pedometers provides testament to the
desire and willingness of individuals to adopt technologies that simply and non-
intrusively assist in their quest to become more active. Preliminary research also sug-
gests that more interactive just-in-time feedback such as that provided by the arcade
game Dance Dance Revolution may be successful in producing short-term motivation
for physical activity among otherwise sedentary children .
Another type of technology intervention proposes to motivate physical activity by
mimicking the type of advice (and affect) used by a human personal trainer .
When delivered on a mobile computing device, such an interface may help users
sustain an ongoing activity regimen. For individuals who do not already exercise
regularly, new interventions might consider ways to lower the startup costs by focus-
ing on small increases in physical activity that accumulate over time, rather than more
intense and therefore intimidating regimens. Research suggests that simple body
movements such as standing up, talking, and fidgeting—behaviors related to non-
exercise activity thermogenesis (NEAT) —may account for energy expenditures
of over 300 kcal per day in obese individuals . The intervention described in this
paper builds on this finding by rewarding small activity increases in addition to in-
tense or sustained exercise.
1.2 The opportunity: just-in-time interactions
The technological intervention we present relies on the same behavioral tendencies
that have been proven effective in unmediated communication: that people respond
best to information that is timely, tailored to their situation, often subtle, and easy to
process . Inexpensive sensors and mobile computing devices provide a platform
that enables the achievement of these objectives through the design of an interface
that draws upon behavioral science principles such as suggestion, goal setting, self-
monitoring and conditioning. To provide further design insight into how these strate-
gies might be embedded into consumer technologies, we have developed a prototype
system to address the growing problem of television watching and physical inactivity.
1.3 Case study overview
The physical embodiment of this intervention is a multifunction handheld device
called ViTo. This device, prototyped on a personal digital assistant (PDA) platform, is
intended as a seamless replacement for the user’s existing television remote control. It
has been designed to provide value-adding features not presently available in com-
post-study interview, the participant expressed a fair amount of enthusiasm for the use
of technology to monitor physical activity. Although it is possible that the novelty of
real-time feedback increased the use of this feature to levels that are not sustainable
for the long term, the participant’s response does support further investigation of how
activity feedback might be used to promote healthier living.
Operant conditioning. Reinforcing desirable behaviors is another strategy that may
prove viable for long-term motivation. During the course of the evaluation, the
participant was rewarded six times for engaging in sustained or vigorous activity.
Two of these were delivered during NEAT Games and another when the user was
interacting with the real-time activity graph, further supporting the notion that
computational feedback can effectively motivate meaningful changes in behavior.
Shaping. Gradually increasing the amount of physical activity necessary to earn
rewards may lead to large changes over time. For the short duration of this case study,
the effect of shaping was probably negligible, as reward thresholds were incremented
only 1% for each delivery. For use of NEAT Games, however, the impact of
incremental shaping was more apparent. At the start of the study, 72 NEAT Points
were required to resolve each game. By the end of the study, that number had risen to
90. In spite of this 25% increase in difficulty, the participant revealed in the interview
that he was unaware of the change.
Consistency. For television viewing, the participant encountered a commitment
prompt sequence (Figure 9) eleven times. Again consistent with his lack of interest in
tracking viewing time, the user did not appear to use this feature in a reflective
manner. Nine of eleven times he responded that he would watch for 30 minutes. Four
times he watched substantially less than this, four times he watched substantially
more. On one occasion the commitment sequence ended with a prompt to turn off the
television that coincided with the user’s completion of his viewing session. The
participant had left the room, so the device automatically turned off the television
after a timeout period of 3 minutes. About this the participant reponded: “I had
already finished watching and was doing something else, so I didn’t bother turning it
The results of this exploratory study may raise more questions than answers. There is
clear evidence that the participant responded strongly and positively to certain aspects
of the system design, such as value integration, ease of use, and reduction. His re-
sponses to specific persuasive elements related to physical activity—goal setting, self-
monitoring, and proximal feedback—likewise show a willingness to tolerate or even
value more proactive behavior change strategies.
Reaction to some of the more abstract strategies employed by ViTo (e.g. sugges-
tion, intrinsic motivation, and consistency) cannot be easily measured using observa-
tional and self-report techniques. Where possible, evidence relevant to the partici-
pant’s response to these strategies is presented, with the understanding that the
evaluation described in this work only begins to address the myriad questions sur-
rounding the design and use of persuasive technologies.
The study was undertaken with four goals. We successfully stress-tested the system
in a real home setting for a week. We also collected a naturalistic dataset useful for
preliminary analysis of the system, allowing evaluation of specific interactions in
some depth. We gained additional insight into how a person might use a persuasive
consumer electronic device. Finally, we used the experience to identify some issues
that should be addressed before this system is tested longitudinally.
Among the most important design observations drawn from this work are the fol-
lowing: (1) Interventions based on consumer electronics may be particularly viable if
the devices offer substantial improvement over competing technology—efforts fo-
cused on basic user experience will likely pay off in long-term adoption. (2) Design-
ers should plan for long-term use and resist the temptation to impress users with an
initial panoply of persuasive elements—strategies should be phased in over time so
the user can react to them individually. (3) Most strategies will be initially received as
novelty—user curiosity can be used to advantage by encouraging exploration of new
features. (4) Not all users will react well to all strategies—interventions should adapt
to the user’s preferences; keep strategies that work, and phase out those that don’t.
The case study evaluation featured in this research has inherent advantages as well
as limitations. Although the small size and relatively short duration of this study will
limit what conclusions can be drawn from the data, it is hoped that the results of the
present study will provoke further interest in the deployment and evaluation of per-
suasive behavior change devices.
In combining aspects of ubiquitous computing, context-aware computing, and per-
suasive technology, this research undertakes a novel approach to the problem of life-
style change. Successful demonstration of ViTo as a tool for behavior modification
would have strong implications for the future of proactive healthcare.
The outcome measures from the case study evaluation described in this document
are suggestive, lending support to the possibility that ViTo might succeed in helping
individuals lead more active lives. It is hoped that researchers in the field of public
health will find value in using a tool such as ViTo to study the wide scale deployment
of proactive health technologies, and that researchers in ubiquitous computing and
user interface design will begin to apply their expertise to create novel and high-
impact behavior modification systems that are embedded into everyday life.
This work was supported, in part, by National Science Foundation ITR grant
#0313065. The PlaceLab live-in laboratory is a joint initiative between the MIT
House_n Consortium and TIAX, LLC. The authors would like to thank the research
participant and gratefully acknowledge the help of J. S. Beaudin and S. J. Paterson.
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