Grocery Hunter: A Fun Mobile Game
for Children to Combat Obesity
Hyungsin Kim 1,2, Anya Kogan4, Chandan Dasgupta5, Michael Misha Novitzky2,
and Ellen Yi-Luen Do1,2,3
GVU Center1
College of Computing2 & College of Architecture3
Georgia Institute of Technology
Atlanta, GA, USA
4
HUGE
New York, USA
Learning Sciences Research Institute5
University of Illinois at Chicago
Chicago, IL, USA
{hyungsin, misha}@gatech.edu, akogan@hugeinc.com, cdasgu2@uic.edu, ellendo@gatech.edu
ABSTRACT
associated with the complications of these medical
conditions. It is crucial to work on both prevention and
treatment of child obesity. Thus, our design focuses on
encouraging healthy eating habits in school age children.
This paper presents a handheld mobile game, Grocery
Hunter that encourages children to take on healthy eating
habits. Children can use a pocket PC to play the Grocery
Hunter game to learn about food nutrition and healthy food
choices. Childhood obesity in the United States has already
reached epidemic proportions. The best way to help
children attain and maintain healthy weight is through
physical activity and nutritious eating. Our design addresses
nutrition directly by teaching children healthy eating habits
using an interactive game in the grocery store.
The target users for the system are children ages from 7 to
11. This period in child development is called middle
childhood because it occurs in between early childhood and
adolescence. It is also referred to as the school years
because it is at this point in their development when they
are attending elementary school. In general, children of this
age group are capable of self-care such as dressing
themselves, brushing their teeth, and washing themselves.
This age group can entertain themselves. Their reading
levels vary greatly from barely being able to read and write
simple sentences to being able to read small novels. The
children in this age range physically grow at a steady rate. A
typical 10 year old will weigh 70 pounds and be 4 ½ feet
tall. In general, a child will gain 5 to 7 pounds while
increasing in height by 2 inches a year [2]. A child is
considered overweight if they are up to twenty percent
above what the ideal weight is for their age and height and
are considered obese if they pass the twenty percent
threshold. More specifically, a ten-year old child is more at
risk for becoming an overweight adult if they are already
obese than whether or not their parents were obese. This
suggests that intervention in this age group will have
everlasting effects.
Author Keywords
Interactive design, mobile devices for children, health
communications, just-in-time learning
ACM Classification Keywords
H.5.1 Multimedia Information Systems
General Terms
Human Factors, Experimentation, Design.
INTRODUCTION
The Grocery Hunter is a mobile system which teaches
children to make smart choices at the grocery store while
they are shopping with their parents. The prevalence of
obesity in the United States has skyrocketed in the last 30
years [5]. In particular, childhood obesity in the United
States has already reached epidemic proportions with 17%
of children being classified as overweight [6]. Robinson
and Killen [7] describe the major reasons for the increase in
childhood obesity are the lack of exercise, consumption of
poorer-quality food, excess television watching, and
cultural values. Obese children are less likely to exercise
and are more likely to have high blood pressures which in
adulthood have shown to correlate with heart disease,
stroke, and diabetes in middle adulthood [4]. Not only are
the children who are overweight or obese affected but
society is financially impacted with the health costs
DESIGN
The Grocery Hunter is a mobile gaming system which
teaches children to make smart nutritional choices. There
are several studies about using games to teach children how
to eat the right food [1, 3]. The Grocery Hunter is used by
kids when accompanying their parents on shopping trips.
The system provides the child with a clue about a healthy
grocery store item located in the vicinity of the unit, thus
keeping the child near their parents and not interfering with
the parents’ shopping tasks. Once the child has found what
they think is the appropriate item, they simply scan the item
with the Grocery Hunter. If their choice was correct, the
system confirms and provides nutritional information for
that item. Otherwise, it indicates that the response was
incorrect and provides them with an additional clue.
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PROTOTYPE IMPLEMENTATION
Advantages of the system design as well as the game flow
diagram are described below.
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For prototyping purposes, a Pocket PC was used running an
interactive program developed with Adobe Flash. The user
interacts with the program through the touch screen. The
system is geared towards children between 7 and 11 years
old. Figure 1 left shows the startup screen of the Grocery
Hunter game displayed in a handheld mobile device, and
Figure 1 right shows one example quest that ask the
children to “Go and find the orange vegetable that is good
for your eyes” in the Grocery Hunter game.
Directly addresses obesity: The Grocery Hunter
directly addresses the objective of battling childhood
obesity by encouraging healthy eating habits. While
the children are searching for healthy items in the
grocery store, they are either learning new information
about healthy foods or are reinforcing prior knowledge.
By encouraging children in this manner, they may
increase the amount of nutritious food purchased and
therefore consumed.
Grow to be health conscious adults: Nutritionally
educated children will grow into nutritionally
conscious adults. In turn, they will be more likely to
purchase and eat more nutritious food.
Education through a game: The system educates the
children about nutritious foods and their benefits by
using gaming technology with which they become
actively engaged. This type of system is a natural
extension of a child’s inclination for play.
Only focus on healthy food: This system does not harp
on the negative 'junk' food. Instead, it includes solely
nutritious foods. This may help shift children’s
attention away from junk food and towards healthy
food in a nonabrasive fashion.
Figure 1. Grocery Hunter Screenshot
SPECIFIC JUSTIFICATION FOR PROTOTYPING
USER SCENARIO
There are several aspects of the prototype implementation
that were chosen in order to appeal to the target audience
(7-11 years of age) more effectively.
The following narrative describes a Grocery Hunter usage
scenario in a grocery store.
Mrs. Marcy Gray has just picked up her daughter, Jane, from afterschool care. She knows that her refrigerator is near empty at home
and needs to stop by the grocery store before driving home. She
usually tries to leave Jane with a babysitter during these trips, but
could not do so today. She begrudgingly stops by the grocery store
with Jane. Jane is already beginning to whine, as she hates sitting
still in the cart while her mom looks through the aisles for Jane
seems like an eternity. However, today is different. As Mrs. Gray
enters the store, a grocery clerk politely offers a digital toy, called
Grocery Hunter, for her daughter. Mrs. Gray accepts. She looks
briefly at it, and then hands it to her daughter to figure out how it
works. Accustomed to mobile toys, her daughter quickly takes the
device and enters her age to begin. As Mrs. Gray is wheeling the
cart through the vegetable aisle the device prompts Jane to look for
an orange vegetable that is good for her eyes. Jane sees an apple and
points the Grocery Hunter at it. The device responds, “Nice try, but
this is an apple. It is great for your teeth. Would you like another
hint about the orange vegetable?” Jane rejects the help and continues
to point at other foods until she finally locates the carrots. The avatar
congratulates her on the find and asks if she would like to play
again. Jane agrees. As she plays round after round of this digital
scavenger hunt, she barely notices the time pass. Soon, her mom is
checking out and they are ready to go home. Mrs. Gray drops off the
device at the checkout making a note to herself to be sure to use the
device again next time.
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Cartoon-like look and feel: The cartoons used in the
design were meant to appeal to children within the
target age range.
Identifiable avatar: During consultation with members
of the Cartoon Network, it was suggested that the main
avatar in the Grocery Hunter be a popular cartoon
character Bloo from their show 'Foster's Home for
Imaginary Friends.' It was believed that this would
allow children to quickly identify and thus enjoy using
the Grocery Hunter.
Adobe Flash: Adobe Flash was chosen for the
development of the Grocery Hunter prototype for
several reasons. Aesthetically, it was able to support
the cartoon look and feel. Functionally, it supported
the desired touch screen. Finally, the team members
had previous experience using Flash, thus reducing
overall implementation time.
Pocket PC: The Pocket PC was the best touch screen
hardware available for implementing our prototype at
the time. The Pocket PC allows for a responsive system
that is predictable given its onscreen mapping of
buttons with overlapping text. Additionally, the Pocket
PC has multiple methods of communication with other
hardware devices such as USB, Bluetooth, and Wi-Fi
which makes it ideal if a situation requires
communication with a server unit.
USABILITY TESTING METHODS
Usability testing consisted of observation of the system
usage as well as pre- and post- opinion surveys from both
children and parents. Here, we describe our participants,
environment, and procedure. For our preliminary user
study, we recruited 6 children and their respective 6 parents
for a total of 12 participants. All participation was
voluntary. All child participants were between 7 and 11years-old. Parents also participated by watching their
children play, listening to our explanation of the final
prototype, and then completing a questionnaire.
Grocery Hunter is designed for use in a real grocery store
which has plenty of items children want to eat. However,
usability testing in real grocery stores was impractical
within the context of this project and at this preliminary
stage. Thus, we created an artificial store outside of a local
Jujutsu studio where kids took classes. We placed a set of
groceries on a table. They included items for which the
children had to search in the game, as well as other foods
including healthy and non-healthy options to act as a
distraction. The extra amount of food added realistic
complexity to a task that was outside of its intended
environment (grocery store). Having put the table outside in
a public place, we also simulated the distractions that are
found in an authentic grocery store. While running the test,
one experimenter walked with the child, while another
videotaped the screens and the third stayed with the parents.
Figure 2 shows how a child used the game during the study.
Figure 2. Child using the game during study
If the child walked back and forth along the table several
times, it is likely that they did not know which food to
choose. During the active portion of this experiment, we
were observing, taking notes, and videotaping the
participants at the same time. We did not have the child
think aloud, as that may have been confusing for them due
to their young age and lack of experience with such
protocol. However, detailed observations were noted during
each task. Children were encouraged to complete the tasks
on their own without asking anyone for help. If questions
arose, we encouraged them to think through the solution for
themselves and we only intervened when absolutely
necessary. Once intervention had begun, we gave them
minimal hints to the solution to avoid giving out answers
until no other alternative was possible. In a real scenario,
the designers would not be present to explain their products
to users. Therefore, we wanted to see how the child would
use the device without us, so as to have the most
generalizable test results possible. After each child
completed the five clues available, they were given a verbal
questionnaire by the same experimenter who followed them
around the table. This way, the child was already
comfortable with that person and more likely to be
complete in their responses. They were given the questions
verbally because children were assumed to be unfamiliar
with questionnaires and could not be relied upon to answer
fully and accurately on their own. By asking the questions
aloud, the experimenter could judge the child’s
comprehension of the topic and elaborate if needed. While
the children verbally answered their questions, their parents
were given a written questionnaire. In the case of an adult, a
written questionnaire was advisable so that the participants
were more inclined to be honest when not being directly
observed by an experimenter. The entire experiment,
including the questionnaires, took each participant 30
minutes.
PROCEDURE
The children received instructions from an experimenter on
how to play with the Grocery Hunter. Parents were
encouraged to observe their child, but were encouraged to
abstain from aiding them. They were told that the intention
was to study the child’s individual interaction with the
system. In a real scenario, some parents would help the
child with the game, while others would not. Since we were
testing only a small number of participants, we needed to
minimize the number of independent variables in our
system in order to obtain meaningful results. Therefore, we
chose to control for parent intervention. We set up a videorecording of the experiment in order to capture each child’s
finger movements on the game screen as well as their
overall body movement as they searched for the proper
foods on the table.
Recording this behavior allowed us further analysis after
the experiment itself, avoiding sole reliance on the
behaviors that we were able to capture in our notes while
on-site. Finger movements can be a good indicator of
participant’s mental perception of the system. For instance,
if we saw them wavering between two buttons on the
screen, we could hypothesize that the functionality of the
two buttons was difficult to understand and predict. The
body movements could also be an indicator of the difficulty
of the clues.
RESULTS AND DISCUSSION
A specific goal for the Grocery Hunter was to teach
children healthier eating habits. The game was intended to
be used in the context of a relevant task (i.e. shopping in a
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infancy, specifically in children between seven and elevenyears-old. Fitness and nutrition are the two key solutions to
obesity. Having developed several innovative ideas that
focused on either fitness or nutrition, we finally chose a
concept that tackled nutrition explicitly. Our solution, the
Grocery Hunter, teaches children to make smart eating
choices, while growing them into smart adult shoppers and
easing the lives of their parents during a shopping trip. The
Grocery Hunter exemplifies one of many potential new and
interesting ways of placing nutritional facts in front of our
users during key decision times. Since some children found
the questions presented too hard, while others found them
too easy, we think that creating an adaptive system would
broaden the appeal of the game. We believe that once these
and other findings are addressed, the Grocery Hunter has
high market potential and would be capable of positively
impacting the fight against childhood obesity. In future
studies, we plan to develop more game modules that
harness the knowledge of additional nutrition specialists.
We also intend to explore the relationship between eating
behavior changes and game play.
grocery store) so that it could be more engaging and
meaningful for the children. Had the same information
about nutrient content in various food items been given to
the children while they were at home, it would not have
been as relevant. Hence the key element here is the
presence of an educational tool within a relevant
environmental context. What this means is that the Grocery
Hunter draws its power from its portable design and
contextual implementation. All the children who used the
Grocery Hunter prototype conveyed to us that they enjoyed
using it and thought that it would benefit them by helping
them make informed decisions while they were shopping
with their parents. That the children enjoyed interacting
with the Grocery Hunter is further strengthened by the fact
that all the children indicated that they would like to play
with it again. This enthusiasm also bears testimony to this
design’s ability to hold the user’s attention. Even the adults
who accompanied the children thought that the Grocery
Hunter would help them while they were shopping. This
kind of help actually happens at two levels – engagement
and epistemology. At the level of engagement, the children
are busy interacting with the Grocery Hunter and this
alleviates the parents’ concern of having to “run after” their
kids. The game has been designed in such a way that the
clues being given are both interesting and informative to the
right extent. “Informative to the right extent” means that the
correct information is presented in a succinct manner that
does not overwhelm or bore the user. The effectiveness of
the design is enhanced by the just-in-time manner in which
the information is presented. The second level,
epistemology, is perhaps more important. Our game teaches
the user to “think healthy”. As long as the user is inside the
store, the game encourages them to think about food items
around them from a nutritional perspective instead of the
purely flavor-focused perspective. Inherently, we are all
impulsive buyers and our decisions on what to buy are
influenced a lot by the look-and-feel of the item. If
something looks good and appealing, we are inclined to buy
it. With kids, especially, various kinds of chocolates,
candies, and chips are the hottest to-buy items. The game
helps under such circumstances by keeping the user focused
on the nutritional perspective of all the items in the store.
Association of items with their nutritional advantages and
disadvantages tends to carry over to situations outside the
grocery store as well. Because of the level and duration of
engagement with the game inside the store, the items
become more closely associated with their nutritional
characteristics. Thus, a carrot becomes more likely to evoke
the thought of something orange and good for eyes. We feel
that this sort of association will bear a strong influence on
the kind of food choices the person makes as they grow up.
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CONCLUSION
We learned about the many health hazards of obesity and
that the best time to challenge this epidemic is in its
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