3D sound interactive environments for problem solving

Abstract

Audio-based virtual environments have been increasingly used to foster cognitive and learning skills. A number of studies have also highlighted that the use of technology can help learners to develop affective skills such as motivation and self-esteem. This study presents the design and usability of 3D interactive environments for children with visual disabilities to help them to solve problems related with the Chilean geography and culture. We introduce AudioChile, a virtual environment that can be navigated through 3D sound to enhance spatiality and immersion throughout the environment. 3D sound is used to orientate, avoid obstacles, and identify the position of diverse personages and objects within the environment. We have found during usability evaluation that sound can be fundamental for attention and motivation purposes during interaction. Learners identified and differentiated clearly environmental sounds to solve everyday problems, spatial orientation, and laterality.

Full text

3D Sound Interactive Environments for Problem Solving
Jaime Sánchez & Mauricio Sáenz
Department of Computer Science
University of Chile
Blanco Encalada 2120, Santiago, CHILE
{jsanchez, msaenz}@dcc.uchile.cl
ABSTRACT
Audio-based virtual environments have been increasingly used to
foster cognitive and learning skills. A number of studies have also
highlighted that the use of technology can help learners to develop
affective skills such as motivation and self-esteem. This study
presents the design and usability of 3D interactive environments for
children with visual disabilities to help them to solve problems
related with the Chilean geography and culture. We introduce
AudioChile, a virtual environment that can be navigated through 3D
sound to enhance spatiality and immersion throughout the
environment. 3D sound is used to orientate, avoid obstacles, and
identify the position of diverse personages and objects within the
environment. We have found during usability evaluation that sound
can be fundamental for attention and motivation purposes during
interaction. Learners identified and differentiated clearly
environmental sounds to solve everyday problems, spatial
orientation, and laterality.
Categories and Subject Descriptors: J.0 General.
General Terms: Human Factors.
Keywords: Hyperstories, 3D sound, virtual world, problem
solving, role-playing game.
INTRODUCTION
Children with visual disabilities are increasingly having more
contact with virtual environments [2, 4, 7, 8, 9, 10, 18, 19].
Computer games have been used for entertaining purposes through
accessibility interfaces.
Few initiatives have focused on the design of games to develop and
rehearse cognitive skills in children with visual disabilities [3, 11].
Applications conceived for users with visual disabilities have been
developed using auditory information as the main output channel
and haptic devices for input [1, 7, 8, 10, 12]. These systems have
been principally developed to help blind people to overcome their
difficulties with standard interfaces such as the Web page "reader"
Jaws. Other focus is the development of 3D audio interfaces used to
develop the user's skills to recognize spatial environments through
sound. However, we have no record of research work on virtual
environments to solve problems by children with visual disabilities.
Sound has also been used as input/output to develop learning and
cognitive skills in blind children. Most applications use spatial
sound to help children to develop abstract and short-term memory,
haptic perception, collaborative skills, spatial abstraction,
mathematics skills, and algorithmic thinking skills [9, 10, 13, 14, 17,
18].
An experience with audio stimuli to simulate visual cues for blind
learners [8] have found that 3D audio interfaces help blind people to
localize specific points in a 3D space concluding that navigating
virtual environments through sound can be a precise task for blind
people. Other studies describe positive effects of 3D audio-based
virtual environments [2].
Authors have used sensory virtual environments through force
feedback joysticks simulating real world places such as the school
concluding that providing appropriate spatial information through
compensatory channels the performance of blind people can be
improved [4].
A research work replicated a traditional computer game such as
space invader by using 3D sound. Authors used force feedback
joysticks as input interface by letting to play blind to sighted
children to share the same experience [7].
Authors evaluated the skill to hold in mind a specific localization
without concurrent perceptual information or spatial update through
the use of audio stimuli to trace specific places through sound [5].
A study to design and evaluate a spatial audio system that models
the acoustic response of a closed environment with varying sizes
and textures for blind user was implemented concluding that there
was almost no difference in user perception of room sizes between
sounds in real and simulated scenes [3].
Finally, a real-time 3D graphic game for low vision gamers was
developed to propose general methods of making real-time 3D
games accessible for virtual reality applications, e-commerce, and
distance learning [19].
Studies to enhance problem solving skills through 3D sound in blind
children are scarce. This research study presents the design,
development, and usability testing of AudioChile a 3D sound
interactive environment for children with visual disabilities. The
system was designed to assist learners to solve everyday problems
and thus knowing the life, culture, and idiosyncrasy of different
geographical regions of Chile.
RESEARCH PROBLEM
Children with visual disabilities perceive the surrounding world
differently to sighted children. Actually, to orient and mobilize in
the real world they have to learn to exploit and use other senses such
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as touch and hearing. To orient spatially within a surrounding
environment is a complex process that requires learning to explore
the smelling and textures as points of reference to search for objects
in the environment.
Children with visual disabilities need to learn how to use their ears
and interpret the surrounding world, localize sounds that serve as
cues to orient and mobilize autonomously. Spatial sound stimuli can
provide a stimulating atmosphere for developing thinking skills to
cope with everyday situations and solve current problems and issues
with independence.
AudioChile is a role playing game. Children have to travel through
main Chilean regions where different hyperstories occur. The
interaction is through sound and music. Within a region the child
performs a personage and navigates through virtual environments
looking for cues and information to do actions and take decisions.
At the end the child can get the whole picture and information about
the adventure.
PURPOSE OF THE STUDY
The main purpose of this study is to design 3D virtual environments
based on hyperstories and assisted by stereo and spatial sound to
develop problem solving skills in children with visual disabilities.
This includes searching, mobilization, localization, designing
strategies, and orientation skills.
Our study also includes a usability evaluation of the virtual
environment. We have studied: 1. 2D and 3D graphic interfaces for
children with residual vision, 2. Stereo and spatial sound interfaces,
and 3. Problem solving strategies developed when using
AudioChile.
MODEL
AudioChile is based on a model for implementing educational
software for children with visual disabilities [15,16]. Basically, the
model is centered on providing facilities for evaluation purposes and
to give prompt feedback to the user. It also clarifies, for
implementation purposes, similarities and differences between
software for people with and without visual disabilities. The
resulting architecture model after applying the developing model is
depicted in Figure 1.
AudioChile has a model (metaphor) that represents three major
Chilean cities. A personage has to navigate through these cities
searching for cues and information to solve a posed problem.
Editors consist of a virtual world and the definition of its properties,
objects, and personages.
The knowledge representation model is based on the mapping of
real world behaviors in a virtual world, state variables (physics,
kinetics, and luminous), and actions.
Figure 1. Architecture of the resulting software [15]
The strategy (AI) is in charge of following up the actions performed
by the user. It provides a compass that perceives the user´s
orientation within the virtual world, helping him/her to navigate and
take actions.
The learner model is such that as the user goes through the
adventure she/he can know and process more information to solve
the problem in order to reach the end of the story.
Evaluation consists of an evaluation of the compass to provide
information to the user to find diverse objects and personages within
the virtual world.
Projection consists of 3D images and sound virtual worlds. It
explores diverse fine representation qualities to get a high standard
of use as well as to solve the problem posed.
SOFTWARE DESCRIPTION
AudioChile is composed of diverse hyperstories [6]. Once immersed
in the 3D world the user can adopt a personage that can be a girl or a
boy. Each story consists of an adventure to explore one of three
geographical regions of Chile by navigating, interacting, and solving
tasks and problems. Basically, the child has to find a cooper ingot in
the region of Chiloé and return it to the region of Chuquicamata. To
do this the child has to follow directions and cues given by some of
the personages through the story. They constitute a subset of the
major problem concerning with returning the cooper ingot to
Chuquicamata.
Virtual personages and objects of an adventure have been designed
for a 3D virtual world. All of them are designed according to real
characters of the geographical zone in story.
Interaction occurs through actions such as to take, give, open, push,
pull, look, speak, use, travel, check the backpack, movements, and
turns (90 /180 degrees). These actions can be done by using the
joystick forcefeedback and keyboard.
Diverse interactive elements have associated actions defined by a
matrix that crosses the user’s behavior and different elements to
represent the viability of the operation.
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Through the “take” action the personage can load elements during
the adventure that can serve in future actions. To do this there is a
virtual backpack to save these elements. The backpack is an
interactive point that can be accessed and the content saved inside it
can be checked to be used in conjunction with the surrounding
environment.
All actions performed in the software such as menu actions and
actions during the story itself have an audio feedback to understand
what is happing in the story. For the menu and some actions there
are stereo sounds. To navigate through the virtual world AudioChile
uses 3D sound to get a better spatiality and immersion. Spatial
sound is provided during obstacles orientation such as the
boundaries of the labyrinth as well as the position of personages and
objects within the virtual environment. When the user performs
illegal actions for a certain element an error feedback is provided.
Interaction through the software can occur by using general and
specific planes.
AudioChile is performed in three Chilean regions: Chiloé,
Valparaíso, and Chuquicamata. Relevant zone information is
provided by hidden cues that allow users to visit and know aspects
of the geography and traditions of Chile. To travel between zones
users must attain certain objectives that can help them in futures
tasks.
Virtual world navigation is delimited by labyrinths that allow
mobility and freedom to the personage within certain parameters
(can give turns of 90 and 180 degrees, and move forward). In any
moment the user can save the performance in the story or restart it
later from the same leaving point when quitting the game. Each time
the user interacts with users a log file is created to know the results
of the session. This information is used to create a story at the end of
the adventure that summarizes the performed actions through the
game and how they solved the posed problem (see Figure 2).
Figure 2. The Navigation Map
AudioChile has a compass to orient the user when searching for
interaction with different objects and personages in order to solve
the problem posed.
The software presentation allows easy access. Users with residual
vision can identify elements on the screen through the use of
contrasting colors and well defined images.
Mazes & Interfaces
AudioChile has defined mobility environments of three Chilean
cities. They consist of three different labyrinths that the user has
to navigate through the selected personage. Also, there are objects
and personages with their defined positions within the virtual
world (see Figure 3).
Figure 3. Labyrinth of three Chilean cities: (a) Chiloé, (b)
Valparaíso, and (c) Chuquicamata. (Golden liquor is a typical
liquor of Chiloé zone)
Three virtual environments represent the three Chilean cities. Each
virtual world can be navigated through interacting with textures and
special sounds. Each city consists of an introduction through audio
and a typical music of the zone. Within the travel environment there
are some representative places of different cities in order to trace the
travel through Chile (see Figure 4).
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(a) (b)
(c) (d)
(e) (f)
Figure 4. Screenshot of the graphic interface of AudioChile: (a)
Personage menu; (b) Chiloé; (c) Travel; (d) Valparaíso; (e)
Chuquicamata, and (f) Option menu (save game)
USABILITY TESTING
Participants
The sample was consisted of 6 Chilean children with visual
disabilities, 4 boys and 2 girls ages 10 to 15 that attend a blind
school in Santiago, Chile. Three children have low vision and three
children with total blindness. Two of them are blind from birth, one
child acquired blindness during childhood, two with good residual
vision, and one with poor functional residual vision. Two special
education teachers and one usability expert also participated in the
study.
Children participated in four testing sessions each during four
months. Each session was especially dedicated to one child in other
to allow him/her to completely walkthrough the software.
Methodology
Each usability testing consisted of the following steps:
Introduction to the software. The user receives explanations about
the purpose of testing and how to use the keyboard to interact with
AudioChile. Teachers mediated to help children to orient when
using the keyboard.
Software interaction. Users have to navigate throughout the virtual
environment and according to their needs they can ask teachers for a
better orientation.
Anecdotic record. Key data and observations of the child’s
interaction with the software are registered.
Application of usability questionnaires. The user answers questions
asked by special education teachers.
Session recording through photography. Each session was
photographed to register the child behavior during interaction.
Protocol reports of the session. All the data from the child’s
interaction is registered to get comments and suggestions to improve
the software navigation.
Design and redesign. According to the comments and observations
received the software is redesigned and some new functions are
added.
Instruments
Three usability questionnaires were used during testing: 1. End-user
questionnaire, 2. Prototype interface evaluation questionnaire, and
3. Problem solving understandability questionnaire. The end-user
questionnaire was applied at the end of the usability sessions. It is
basically a software acceptance test and consists of 18 closed
statements with an answer scale of 1 to 10. It also contains 5 open
questions. The prototype interface evaluation questionnaire was
applied during the usability sessions. It is intended to evaluate
images and audio feedback by including an observation instrument
that has two parts: 1. A set of questions to identify images of
personages and objects in the software, as well as to record
observations during interaction is also included, and 2. A set of
questions to identify input/output sounds and related associations
made by blind children. It also contains observations recorded
during interaction. The problem solving understandability
questionnaire was applied during interaction and consists of a
questionnaire with 10 open questions to evaluate the
understandability of problems and tasks posed and related interface
elements such as instructions, sounds, visual and sound cues, voice,
navigation issues, and strategies to find hidden clues.
Figure 5. A blind user interacting with AudioChile
Procedure
The usability testing was first implemented in March 2004. Children
pretested early prototypes of AudioChile during interaction (see
Figure 5). The objective was to have an initial feedback about the
sounds and images of the software in order to have early in the
implementation phase information to orient the final design of
interfaces. To get more detailed information we used the interface
evaluation questionnaire.
The second stage of the usability testing was implemented in April
2004 after we processed the data from the first testing and
redesigned and improved the prototype. Therefore at this stage we
had a more advanced prototype. We used the prototype interface
evaluation questionnaire.
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The third stage of the usability testing was applied in two parts. We
applied the end-user questionnaire to the same sample in two
different moments: May and July. After each application we
analyzed data from open and closed questions and took decisions
about interface design/redesign. Both applications served to improve
the usability of AudioChile.
RESULTS
The application of the prototype interface evaluation questionnaire
gave us information about the presentation and use of the graphics
and sound interfaces. The interface for the menu to associate actions
of the personage were first planned in 2D format. These initial icons
easily understood by sighted users were not appropriated in their
representation for users with residual vision. For this reason we
changed them with more representative images of associated actions
to have a better effect on the user. This representation was made in a
3D format.
We also realized that there was a need to have sound feedback to
allow certain logic of actions. Then we associated a characteristic
sound to each action. For opposite actions we also provide the same
feedback but inversed. In the same line, we used the keystrokes that
have some relief (F, J) and those that surround them to orient easily
within the keyboard.
The design of AudioChile was specially thought for blind children.
Thus we emphasized the presentation of menus with one function at
the same time based on the concept of circular menu. This idea
came out after realizing that when designing software for sighted
children the pointer of the mouse is crucial in the interface as well as
always maintaining visibility by highlighting relevant controls and
functions. Children with visual disabilities don’t need to have a total
visibility of the menu. Actually they currently select one option and
then go through all the functions of the menu by using the keyboard.
This gives more screen space to improve the design.
The idea of mapping objects through sound according to the four
cardinal points (north, south, east, and west) worked very well for
the user allowing them to identify behaviors such as reaching to a
wall, a border of the forest, and a beach and avoiding to collide with
some elements of the virtual world.
The associated sounds to the steps of the personage in different
types of roads were modified many times to find the adequate sound
for the steps and the type of terrain where the user walked.
From the application of the problem solving understandability
questionnaire we got relevant information about the use of the
software, the understanding of main instructions, the idea of finding
a lost object, and thus understanding the whole problem. Children
used the keyboard adequately and understood that the personage can
take objects from the virtual world and save them in a backpack.
They also identified, received, and understood the information
provided by the software and applied it during the game.
Only one learner needed some mediation to navigate through the
software perhaps due to the fact that the introduction to the software
was too long. He may have lost the main objective and key
directions to use the software. This needs to be improved to get a
better mapping from users.
The application of the end-user questionnaire gave us very
important information. We present this data by contrasting the
software acceptability of children with residual vision and those
totally blind. Later we present data comparing the results of the first
and second testing.
Contrasting users
The motivation to interact with AudioChile was evaluated. To do
this we posed 6 statements in the end-user questionnaire: 1. I like
the software, 2. AudioChile is pleasant, 3. The software is
challenging, 4. AudioChile makes me to be active, 5. I would like to
play the software again, and 12. The software is motivating. The
scores were between 1 (very low) and 10 (very high).
Children with residual vision showed a great motivation to interact
with the software, with average scores of 9-10. Blind children
mentioned lower motivation but it was still high, with scores
between 7 and 9 points (see Figure 6). This is a very good result
because in general children with visual disabilities of our sample
were motivated to interact and walkthrough AudioChile.
0
1
2
3
4
5
6
7
8
9
10
Scores
ABCDEF
Statements
Residual Vision
Blind
A. I like the software
B. AudioChile is pleasant
C. The software is challenging
D. AudioChile makes m e to be
active
E. I would like to play the software
again
F. The software is motivating
Figure 6. Motivation when interacting with AudioChile
A second relevant aspect is the software utilization. The statements
considered were: 9. I felt in control of the software, 11. The
software is easy to use, and 13. AudioChile adapts to my pace.
Users with residual vision did not have difficulties when using the
software (scores 8-10). Blind users had more difficulties to map the
interaction with AudioChile (scores 5-7). Controlling the software
and the easiness of use was more complex to blind children. Most
children with visual disabilities mentioned that AudioChile adapts to
their pace (scores 7-10) (see Figure 7).
0
1
2
3
4
5
6
7
8
9
10
Scores
ABC
Statements
Residual Vision
Blind
A. I felt in control of the software
B. The software is easy to use
C. AudioChile adapts to m y pace
Figure 7. The use of AudioChile
To evaluate the sounds used in the software we considered the
following statements: 15. I like the sounds of the software, 16. The
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sound are clearly identified, and 17. The sounds of AudioChile
convey information.
As depicted in Figure 8 children with residual vision highly
accepted the sounds (score 10). Blind children also accepted the
sound of AudioChile (scores 9-10). This was a very sensitive aspect
of this study because the software relies heavily on diverse sounds
and voices.
0
1
2
3
4
5
6
7
8
9
10
Scores
ABC
Statements
Residual Vision
Blind
A. I like the s ounds of the
software
B. The sound are clearlly
identified
C. The sounds of AudioChile
convey information
Figure 8. Perception of sounds of AudioChile
Initial and Final Testing
We also analyzed the user’s final acceptance of the software before
and after we redesigned and improved the software based on the
results and requirements detected with the prototype interface
evaluation questionnaire and the problem solving understandability
questionnaire.
The contrasting results are displayed in Figures 9 and 10. We can
observe that motivation increased after redesigning the software
especially in software acceptability aspects such as likeness and
pleasantness of the software as well of the activeness of the user.
The acceptation of sounds increased after software redesign.
These results confirm our beliefs and experience concerning the
importance of testing and retesting the software during
implementation in order to design and redesign as much as it is
possible when designing software for children with visual
disabilities.
0
1
2
3
4
5
6
7
8
9
10
Scores
ABCDEF
Statements
First Testing
Last Testing
A. I like the software
B. AudioChile is pl easant
C. The software is challenging
D. AudioChile m akes me to be
active
E. I would like to play the
software again
F. The software is motivating
Figure 9. Motivation when interacting. First and last testing
0
1
2
3
4
5
6
7
8
9
10
Scores
A B C
Statements
First Testing
Last Testing
A.
I like the sounds of the
software
B.
The sound are clearly
identified
C.
The sounds of AudioChile
conve y informati on
Figure 10. Perception of sounds of AudioChile. First and last
testing
CONCLUSION
We have presented the design, implementation, and usability testing
of AudioChile, a 3D sound virtual environment to assist the learning
of problem solving in children with visual disabilities.
Children liked, accepted, used, and were very motivated with the
software. After designing and redesigning 3D sound interfaces they
mapped and navigated throughout the virtual environment.
Usability testing was crucial for mapping the end-user and the
understandability of the software. Children with visual disability
played a key role in the design and redesign of AudioChile by
making suggestions, comments, and answering questionnaires to
elicit information about how a 3D sound environment can map their
needs and way of thinking.
Before we planed the usability testing we thought that the main idea
was that the learner could discover events in the game without
including a lot of cues. However after the first testing we had to add
more instructions because learners needed many cues and
instructions to orient themselves in the software to make it similar to
their real environment.
When designing graphic interfaces for children with residual vision
we found a clear issue of mental modeling. For a sighted person it is
natural to see icons and associate them to certain actions. However,
children with residual vision besides having difficulties recognizing
certain icons did not associate them for the designed actions. After
the first usability testing we changed icons to 3D format to obtain
more fidelity in their representation. We also used stereo sounds that
were the opposite in their related actions. For instance, sounds for
opening were the opposite of closing sound.
The use of AudioChile has allowed children to differentiate and
identify surrounding sounds that helped them to orient spatially. It
also has helped them to improve the laterality and spatial concepts
of up and down in relation to the north and south coordinates within
a map. Sounds helped to catch the attention and motivated of
children. The contrasting colors of the interfaces were also
important for users with residual vision.
The visibility of graphic elements in the interface is also relevant.
While sighted users prefer the visibility of possible actions and rapid
access for a user with visual disabilities the main interaction device
was the keyboard and the use of circular menus. This made us to
design menus without caring about visibility by using representative
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icons with higher size to have a better feedback for users with
residual vision leaving screen space to improve the representation of
the interface by these users.
Finally, AudioChile is ready to be used with children with visual
disabilities. Software design and redesign have been possible with
the participation of children with visual disabilities in a Chilean
school for blind. We envision a long term application of this
software to evaluate the impact on the development of problem
solving skills and thus helping these children to solving real life
problem through sound.
FUTURE WORK
We are now working on the cognitive testing of AudioChile. We are
interested in knowing what type of problem solving strategies can
be developed by using this virtual environment as well as the paths
followed and how sound help these children to develop cognitive
strategies to solve everyday problems outside the virtual software.
ACKNOWLEDGMENTS
This report was funded by the Chilean National Fund of Science and
Technology, Fondecyt, Project 1030158.
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