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An Interdisciplinary Journal on Humans in ICT Environments
ISSN: 1795-6889
www.humantechnology.jyu.fi Volume 4(2), November 2008, 96–122
96
USER-CENTERED TECHNOLOGIES FOR BLIND CHILDREN
Abstract: The purpose of this paper is to review, summarize, and illustrate research
work involving four audio-based games created within a user-centered design
methodology through successive usability tasks and evaluations. These games were
designed by considering the mental model of blind children and their styles of interaction
to perceive and process data and information. The goal of these games was to enhance
the cognitive development of spatial structures, memory, haptic perception,
mathematical skills, navigation and orientation, and problem solving of blind children.
Findings indicate significant improvements in learning and cognition from using audio-
based tools specially tailored for the blind. That is, technologies for blind children,
carefully tailored through user-centered design approaches, can make a significant
contribution to cognitive development of these children. This paper contributes new
insight into the design and implementation of audio-based virtual environments to
facilitate learning and cognition in blind children.
Keywords
:
blind children, user-centered design, audio-based interfaces, learning and
cognition.
INTRODUCTION
The increasing pace of technological growth and development has been difficult to follow for
the average citizen. This situation is more critical for people with disabilities, since many of
them do not have easy access to new technologies. The possibilities for them to access
information and to work with technological devices are highly restricted, preventing them
from becoming more active in a globalized world.
Although sighted users have many different mental models
1
, similarities exist among
people from the same culture and with similar experiences. Moreover, digital natives
2
and
digital immigrants
3
have varying intuitive mental models that determine the pace at which
they can access information and develop a diverse array of strategies, but they do not have
any major difficulties in the long run.
Children with visual disabilities have entirely different ways to structure, order, and
perceive the world, assuming a singular mental model quite distinct from sighted children. This
© 2008 Jaime Sánchez and the Agora Center, University of Jyväskylä
URN:NBN:fi:jyu-200810245832
Jaime Sánchez
Department of Computer Science
University of Chile
Chile
User-Centered Technologies for Blind Children
97
is a major issue affecting access to digital technologies based on graphical user interfaces:
Children with nonvisual mental models have to cope with devices designed for children with
visual mental models. In this paper, the term blind refers to children who are either totally
blind or have some residual vision (known collectively as legally blind).
Some research initiatives have incorporated screen readers and text-to-speech technology
into diverse computing environments for people with visual disabilities, but these are not
sufficient because the core applications are designed for a user with a rather different mental
model (Pitt & Edwards, 1996; Weber, Kochaneck, Stephanidis, & Homatas, 1993). Virtual
environments with three-dimensional (3D) sound
4
have been developed to help legally blind
users construct a mental representation of a virtual environment and to develop cognitive
abilities (Mereu & Kazman, 1996). Loomis, Lippa, Klatzky, and Golledge’s (2002) field
study sought to understand the spatial updating of locations specified by 3D sound and spatial
language. Savidis, Stepanidis, Korte, Crispien, and Felbaum (1996) incorporated a direct
manipulation system for hierarchical navigation in nonvisual interaction. Schneider and
Strothotte (2000) studied the constructive exploration of spatial navigation by blind users.
Kurniawan, Sporka, Nemec, and Slavik (2004) designed and fully evaluated a spatial audio
system for blind children. The work of Morley, Petrie, O’Neill & McNally (1998) presented
blind users with the task of developing navigational strategies in order to represent complex
spatial structures that pose cognitive difficulties to these users. This system was developed
for use with various output devices, such as a concept keyboard, tablets, haptic interfaces
(Lange, 1999), and joysticks with force feedback (Ressler & Antonishek, 2001).
In response to the issue of developing user-centered technology for blind children,
diverse interface designs have been implemented for users with visual disabilities that allow
them to utilize the technology more fully. One initiative in this line of research is centered on
sound-based interfaces used to enhance cognition in blind children. This researcher’s group
has been using 3D sound to convey information and knowledge by exploiting users’ auditory
senses to cope with their loss of vision. Systematic usability evaluations have been performed
during the development of the interface in order to inform the design of user-centered
interfaces. Specifically, the research group has identified key interface issues used to map the
blind users’ mental models, needs, and ways of thinking (Sánchez, Baloian, Hassler, &
Hoppe, 2003; Sánchez & Lumbreras, 1999; Sánchez & Sáenz, 2006a, 2006b, 2006c).
Spatial, sound-based virtual environments have been oriented toward assisting the
cognitive development of children with visual disabilities through the development of tempo-
spatial structures, short-term and abstract memory, haptic perception, problem solving,
mathematics learning skills, and orientation and mobilization skills. Relevant data from these
studies are helping to map the role that spatial sound can play in the cognitive development of
blind children. Researchers are progressively accepting the hypothesis that computer-
delivered spatial sound has a critical impact on the cognitive development of blind children
(Baldis, 2001; Cernuzzi, Paniagua, & Chenú, 2004; Lahav & Mioduser, 2004; McCrindle &
Symons, 2000; Sánchez & Flores, 2004, 2005; Sánchez, Flores, & Sáenz, 2005; Sánchez &
Sáenz, 2005; Winberg & Helltrom, 2000).
Interfaces without visual cues for blind children have been critical for exploring the auditory
means for enhanced cognition. In such research, digital applications for sighted children have not
been embedded with audio, nor have screen readers been used in applications intended for blind
children. As a result, through continuous testing in usability practices, researchers have been able
Sánchez
98
to define the particular mental models that blind users employ to perceive their real surroundings.
Such research allows designers to improve embedded interface tools that help blind users to map
their own virtual surroundings and access opportunities to become more fully integrated into their
societies that are relying more regularly on technological access.
The purpose of this paper is to review, summarize, and illustrate the work on four audio-
based games designed to assist blind children in mapping
5
their virtual environments and to
improve their cognitive development. The development process of this research employed a
user-centered design methodology through successive usability tasks and evaluations.
RELATED WORK
Hardware for Blind Children
One of the most traditional techniques blind people use for transferring and storing
information comes from the creation of tactile-explored characters. Louis Braille created a
system based on dots arranged in two columns of three points each and forming a cell that
represents an alphabetic character. Paper or plastic sheets printed with these characters
constitute permanent reading sources for visually impaired people, such as traditional books
for sighted people. Today, Braille cells have been developed technically as a set of elements
electrically configured in such a way that, when organized in lines, constitute a Braille line.
When this line is used with a computer terminal and with appropriate software and interfaces,
it is capable of reproducing a line of conventional text in Braille. The user reads the line by
moving his or her finger over these Braille cells as if it were a printed line. Once read, a new
set of characters takes the place of the previous one and the process continues in this way
until a given text is completed. The use of bidimensional mechanisms, such as using Braille
lines and haptic devices, is also seen as a viable alternative to help improve the social
integration and inclusion of sight-impaired people (Ramstein, 1996).
Virtual reality systems often lack significant tactile stimulation. Currently, interaction is
used primarily through visual cues. Likewise, no standard mechanisms exist that prohibit or
help users avoid virtual collisions with objects in the digital world (since there is no sensation
of contact). Recent literature proposes some possible alternatives to solving this problem by
using haptic interfaces (Tan, 2000). Haptics relates to the sense of touch. It is applied in the
digital environment by combining the tactile abilities with virtual reality.
Some haptic devices are capable of providing feedback through interaction with muscles
and tendons, and, in this way, a feeling of applying force over a certain object is provided.
Moreover, some devices use tactile terminals to provide information about temperature, texture,
and pressure. For example,
PHANT
o
M
is a pointer device that provides force feedback in such
a way that the user can feel the volume and force simulated inside the virtual environment with
his or her hand (Yu & Brewster, 2002). This provides for greater feedback during the
interaction with objects inside a certain application, from menus to entire virtual worlds.
Among the many diverse uses of this device is the design of regular and irregular geometrical
figures, represented in order to allow blind users to identify shapes, reliefs, and textures. The
PHANT
o
M
also allows for the modeling of a virtual environment with corridors, streets, rooms,
buildings, and so forth, through which the user can navigate, assisted by the same device.
User-Centered Technologies for Blind Children
99
In a similar vein, the use of force feedback joysticks in software interaction introduces a
new field of action for blind people. Such devices produce a decreased need for audio stimuli,
which lowers the acoustic contamination. Force feedback joysticks are devices with a high
potential for use, as they provide a sufficient number of buttons, button arrangements, sizes,
and the like, to facilitate software interaction (Sánchez et al., 2003). The increased tactility
provided through these joysticks and other haptic interfaces, coordinated with audio assistance,
represents an important complement for user interaction and immersion in the virtual world.
Finally, tablets are devices used in conjunction with a pen and operate in a way similar to
a mouse. They are very helpful in aiding interfaces for users with visual disabilities (Van den
Doel et al., 2004). It is very easy to design objects and guide the interaction by locating
spaces represented on screen areas of the tablet. The use process is similar to that of a mouse,
but the tablet includes a grille with reliefs on it that permit the blind user to locate and select
certain screen areas.
Software for Blind Children
Even though mental models are different for each human being, there are several similarities
between people with similar lifestyles, cultures, experiences, training background, and
knowledge. Digital immigrants and digital natives have intuitive mental models for accessing
information via technologies without major problems. On the contrary, however, the way
users with visual impairments shape, order, and perceive the world is completely different
from sighted users, and thus they approach the virtual and real environment through an
entirely different mental model. This is, without a doubt, the most critical challenge that blind
users face when using technologies with interfaces that have not been designed and planned
specifically for them. It is not enough to simply give them accessibility to information
technology: They cannot interact with games in the same manner as their sighted peers. Such
access must be designed from the beginning for users with visual impairments.
Tactile input/output hardware is not the only way to provide blind people with the
information from codified texts in the computer’s memory. Voice synthesizing software,
known as text-to-speech (TTS), allows for the interpretation of written information through
hearing it spoken aloud. There are many applications known as screen readers that allow
users to navigate through a visual screen and to have access to software based on text mode
and graphical interfaces that are supported by the operating system’s message system. The
main concern with this type of support is the proper design of the dialog between the sight-
impaired user and the computer, because when the usability is not appropriately created, it
may become useless (Pitt & Edwards, 1996).
Simply adding TTS to the software is not sufficient to achieve an adequate management
of tools, due primarily to the distinctiveness between the blind and sighted users’ mental
models. As a consequence, some interface designs and developments for users with visual
disabilities adopt a rather different paradigm in order to orient these special users to the
management of technology, which would imply important achievements for blind users in the
management of computer and mobile devices.
Audio-based virtual environments have helped to improve learning and cognition in
blind children. They have assisted the development of tempo-spatial skills (Sánchez &
Lumbreras, 1999), haptic perception, and abstract memory (Sánchez et al., 2003). The
Sánchez
100
development and practice of short-term memory skills has also been attained during
interactions with virtual environments (Sánchez & Flores, 2004).
Based on this research, a game based on the board game Memory was designed (Sánchez
& Flores, 2004). By considering the specific needs of blind children and their level of
psychological development, educational topics were also included in order to go beyond
entertainment and sociability and to delve more deeply into their learning. The cognitive
emphasis of this software was on boosting short-term and long-term memory. Another
software program helped blind children to identify and differentiate sound-enhancing
orientation, navigation, and mobility skills in their everyday life (Sánchez and Sáenz, 2006a).
In this paper, the research emphasizes the results obtained after use of the four games
specially designed for legally blind children: AudioMath, The Farm of Theo & Seth,
AudioVida, and AudioChile. These
games include both audio (for the totally blind) and visual
(for those with residual vision) interfaces that were adapted to the specific needs and
characteristics of the blind children.
THE METHODOLOGY OF THE STUDIES
For more than a decade now, researchers have developed software and games for blind users
under the criterion that interfaces are appropriate for—that is, tailored—to the needs and
interests of the user’s mental model. In designing and developing software for blind people,
researchers have established a methodology and instruments for usability and cognitive
evaluation of software. These methods provide relevant data that can be used to redesign
virtual environments and produce pertinent user-oriented interfaces. In this paper, four games
are presented that were especially designed and implemented for children with visual
disabilities and targeted to enhance specific cognitive skills (see Figure 1).
Participants
A total sample of 67 learners who were attending the Santa Lucia School in Santiago, Chile,
was selected, although not all learners tested the games. All learners were classified as legally
blind and most of them also had learning disabilities, such as varying degrees of intellectual
development. Special education teachers and usability experts also participated in each study
as facilitators. Usability experts were software engineers with human-computer interaction
research and practice experience that fully evaluated the interfaces to map and tailor correctly
the game use to blind children.
As displayed in Table 1, 37 of the 67 students evaluated the usability of the games, and
30 participated in the cognitive evaluation. The usability evaluation involved children who
did not participated in the cognitive evaluation. The idea was that the children who interacted
with the game for the cognitive evaluation did not have any previous experience with the
software that could contaminate the studies. The usability evaluation did not consider a
control group; all 37 children interacted with and used the games.
User-Centered Technologies for Blind Children
101
(A) (B)
(C) (D)
Figure 1.
A user interacting with different software: (A) AudioMath, (B) The Farm of Theo & Seth, (C)
AudioVida and (D) AudioChile. For the games shown in A, B and C, the setting is stereo sound. In the case
of AudioChile, the actual setting for 3D sound interaction is also shown in D.
Table 1.
Participants in the Usability and Cognitive Evaluations of the Four Games.
Participants
AudioMath
The Farm of
Theo & Seth
AudioVida AudioChile TOTAL
Usability Evaluation 19 9 3 6 37
Cognitive Evaluation 10 6 9 5 30
29 15 12 11 67
It is important to note that all of the studies were conducted in Spanish with native
speakers of Spanish using Spanish-language programs. The information has been translated
for the purpose of this paper.
Usability Evaluation
For the usability of AudioMath, the sample consisted of 19 children, 9 boys and 10 girls, aged
6–15 years. Children had diverse intellectual development, such as normal, slow normal,
borderline, below normal, and mentally deficient.
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102
The usability evaluation of The Farm of Theo & Seth was implemented with a sample
consisting of 9 children aged 8 years old. Four of them were blind (2 girls and 2 boys) and
five had residual vision (4 girls and 1 boy).
For the usability evaluation of the game AudioVida, researchers selected a sample of three
blind children, aged 10–15 years. One of them was blind from birth and the other two acquired
blindness during childhood.
The sample for the usability evaluation of AudioChile consisted of 6 children with visual
disabilities, 4 boys and 2 girls, aged 10–15 years. Three children had low vision and the other
three had total blindness. Two of them were blind from birth, one child acquired blindness
during childhood, two had good residual vision, and one had poor functional residual vision.
Cognitive Evaluation
The cognitive evaluation of AudioMath was implemented with 10 children, aged 8–15 years,
5 girls and 5 boys. The evaluation of The Farm of Theo & Seth was implemented with 6
children, aged 7–8 years, 3 girls and 3 boys. The sample for the evaluation of AudioVida
consisted of 9 children with visual disabilities, 7 boys and 2 girls, aged 10–15 years. Five
children had low vision (three had good residual vision, and two had poor functional residual
vision) and four were totally blind (two of them were blind from birth, two acquired blindness
during childhood). The sample for the evaluation of AudioChile sample consisted of 5
children with visual disabilities, 3 girls and 2 boys, aged 8–12 years. Four of them had total
blindness and one had low vision.
Research Stages
Special care has been put into the software design for blind children because an effective
outcome cannot be created from the mindset of a designer who simply closes his/her eyes:
The designer must understand the blind children’s behavior and way of thinking and
reasoning. Therefore, the methodology used for these studies was user-centered design for
blind children, meaning that we started from the needs and interests of blind children and
then designed audio-based software accordingly. Blind children participated in the studies,
interacting with and evaluating the usability and cognitive impact of AudioMath, The Farm of
Theo & Seth, AudioVida, and AudioChile as they were being developed. The intervention is
explained here, specifying the major stages in the methodology, followed by the games used,
the system requirements, the evaluation instruments, the cognitive tasks employed, and
experimentation procedure.
The following methodological stages were established in order to evaluate the usability
and cognitive impact of game-based virtual environments for blind children (see also Figure 2).
1. Analysis. In this stage, the cognitive skills to be improved were considered as a baseline
component of the software, and were defined through software features and interaction modes.
In addition, the corresponding technologies were defined following an analysis of the current
technologies and the solutions they provide. Evaluation instruments were also analyzed and
selected. The usability and cognitive effectiveness of current research was evaluated by using
already validated instruments. Cognitive tests varied according to the cognitive skill studied.
User-Centered Technologies for Blind Children
103
They ranged from general domain skills (problem solving) to specific domain skills
(mathematics). The instruments used are fully explained in the Instruments subsection below.
2. Design. In this stage, storyboards, scripts, frameworks and other aspects of the software
were defined, along with key interface usability issues. Usability evaluation involved the
evaluation of software interfaces. The cognitive evaluation involved cognitive tasks
implemented during interaction with the game and comprised concrete, hands-on activities that
students performed and which involved solving problems similar to those encountered when
playing the virtual game. There were fixed goals and procedures for these tasks in order to be
able to later replicate the experience several times with different learners.
Figure 2
.
Research processes model. The research process starts with the analysis stage, then continues with
design, implementation, and validation. The usability and cognitive aspects are considered in all research.
The idea was to combine gaming with cognitive tasks—completed by using concrete
work materials—in order to form an integrated whole in the learning process of the blind
children. This process helped to improve the perception and abstract representation of
software elements, story personages, places, and scenarios. Blind children can understand
more easily and thoroughly when working and learning with concrete materials first, and then
interacting with the software (Roth, Petrucci, & Pun, 2000).
3. Implementation. During this stage, the software development was based on user-
centered design, which makes the users and their opinions, interests, needs, thoughts,
emotions, and behaviors key factors in the software’s success. The same children that
participated in Stage 2 also evaluated each iteration of the same program. The rapid
prototyping model (Boehm, 1988) for software engineering was used.
4. Validation. The end users’ usability evaluation was crucial in evaluating the blind
user’s understanding, affordances
6
, visibility
7
, mapping, and mental modeling of the
software. The results obtained in the usability experience were later used for redesigning the
software by tailoring it to the specific needs and mental models of blind children.
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Based on the work of Shneiderman (1992), the researchers followed seven phases in each
session of usability evaluation with end users:
a. Introduction to the virtual environment. The purpose of the testing and how to use
input devices to interact with the applications were explained to the user. Facilitators
(experienced special education teachers who specialize in working with visually impaired
children) mediated the orientation process when the children were using the input devices;
b. Software interaction. Children navigated throughout the virtual environment and,
according to their needs, they were encouraged to ask the facilitators for help in order to
improve their orientation within the software.
c. Anecdotal record. Relevant data and observations of the child’s interaction with the
software were registered onto observation sheets by facilitators;
d. Usability evaluation. The facilitators asked the user questions from prepared
questionnaires regarding issues such as icon usability and understandability during the
software interaction, as well as an end-user questionnaire. These questionnaires are fully
explained in the Instruments subsection below. On certain occasions, the children had to
solve concrete tasks;
e. Session record. Each session was photographed
and videotaped to register the child’s
behavior during the interaction;
f. Protocol reports of the session. All data from the child’s interaction were archived for
later analysis and revision. From these data we obtained comments, feedback, and
suggestions in order to improve software navigation and interaction;
g. Software design and redesign. Each usability test ended with suggestions and
comments from the children for redesign, change, and improvement. According to the
comments and observations received from the session, the software was redesigned and new
functions were added.
Following usability testing, a separate group of the blind users fully interacted with the
software and solved problems using concrete cognitive tasks, thus learning cognitive skills as
a consequence of interacting and using the software. They used real-world tasks and the
virtual environment to assist in their learning and cognition. Cognitive evaluation is
important in order to determine the impact that the use of the software has on learning and the
development of cognitive skills, as demonstrated through cognitive tasks. The evaluation is
based on the application of both qualitative and quantitative evaluation measures. These data,
collected by different instruments, are described in the Instruments subsection below.
Game-Based Virtual Environments
AudioMath
This game (Sánchez & Flores, 2005; Sánchez et al., 2005) was modeled with mathematical
content, and allows for the practice of audio memory by legally blind children, and for the
practice of visual memory by children with residual vision. The tasks embedded in the game
include the exercise of audio/oral, visual/oral, audio/image, and visual/image memory. By
opening pairs of tokens on a board with several levels of difficulty, the child has to find the
corresponding pair of tokens that agree with the current mathematical content presented. The
User-Centered Technologies for Blind Children
105
game emphasizes the establishment of correspondence and equivalence relationships, the
development of memory, and the distinguishing of tempo-spatial notions (see Figure 3).
AudioMath was designed to go beyond merely enhancing general domain skills, such as
memory and tempo-spatial notions, by integrating mathematical content. The researchers
embedded the game with mathematical concepts like position value, sequences, additive
decomposition, multiplication, and division.
The Farm of Theo & Seth
This farm-themed game (Sánchez & Sáenz, 2005) presents the objective of learning
mathematical concepts, such as position value, sequences, additive decomposition, addition,
subtraction, and cardinality. This game includes motivating and engaging activities for
learning through different levels of complexity, and stimulates the relationship between
entertainment and learning, thus motivating children to interact with the game (see Figure 4).
(A) (B)
Figure 3.
Screenshots of the graphic user interface (GUI) of AudioMath. GUIs are used by users with
residual vision. (A) The user starts a new game by selecting the entrance interface: keyboard, joystick or
tablet. (B) The game interface: On the left side there is a grid with paired cards and corresponding
mathematics exercises; on the right side is the control menu.
(A) (B)
Figure 4.
Screenshots of the graphic interface of The Farm of Theo & Seth. (A) The main game interface
puts the user into the context. (B) The Operations Henhouse requires the user to complete addition and
subtraction exercises.
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106
The game is separated into various learning areas in which the child can learn numbers
and solve basic operations and problems. This spatial farm metaphor provides two major
virtual environments: the numbers kitchen and the operations henhouse. The kitchen has two
subenvironments: serving the food and interaction with kitchen utensils. Serving the food
covers ordinal numbers (through the creation of a “numbers soup”) and the kitchen utensils
involves cardinal numbers (the position of utensils in numerical order, and information about
preceding and succeeding numbers). The operations henhouse is a virtual space where
children learn how to add and subtract. It also includes a help option to familiarize children
with the keyboard.
AudioVida
This game, introduced in Sánchez & Sáenz (2006c), is targeted toward assisting with the
development of problem solving skills. AudioVida emphasizes the implementation of
different routes for displacement in a complex virtual environment, based on audio
stimulation to facilitate reaching a specific destination and locating a particular object. To
achieve this goal, the learner must analyze and interpret the virtual space by applying notions
of spatiality and temporality. This favors the child’s ability to recognize different possibilities
for displacement, to exercise audio discrimination through the navigation of the virtual
environment, to make a mental representation of the virtual space while moving, and to
elaborate strategies used to navigate the environment through shortcuts (see Figure 5).
The user navigates the labyrinth assisted by audio orientation. The learner’s immersion
in the virtual environment is induced through spatial sound effects that indicate their position
and provide references about walls, doors, elements with which they can interact, and
intersections within the labyrinth. Children are informed about contextual changes through
volume and the positional variations of the sound sources. When contexts are changing,
learners receive an audio signal that defines the direction and closeness of the various game
components, motivating learners to “walk through” the virtual labyrinth as they would do it
physically.
AudioChile
This game attempts to analyze the development of problem-solving strategies (Sánchez &
Sáenz, 2006a). The goal is for children to develop strategies for problem identification and
planning, to execute those strategies for subsequent verification, and to develop a capacity for
verification, reflection, and the generalization of their strategies for use in solving other
problems in a given virtual hyperstory (see Figure 6).
Once immersed in the game’s 3D world, the user can adopt a main character that could
be a girl or boy. AudioChile takes place in three different regions of Chile: Chiloé,
Valparaíso, and Chuquicamata. Information relevant to each zone is provided by searchable
clues that allow children to visit and learn about aspects of Chilean geography and cultural
traditions.
The clues are specified by the different personages within the game, so if the user
does not talk with these personages, he/she will never find the clues. To be able to virtually
travel between the different zones, children must attain certain objectives that will help
them in future tasks. Navigation in the virtual world is delimited by labyrinths that allow for
User-Centered Technologies for Blind Children
107
(A) (B)
Figure 5.
Screenshots of the graphic interface of AudioVida. (A) The main menu of the game shows that a
new game will start. (B) The user navigates game labyrinths and encounters different elements that result
in winning or losing a game, depending on the decisions made
.
(A) (B)
Figure 6.
Screenshots of the graphic interface of AudioChile. (A) Once the user has chosen to start a new
game, an avatar from the virtual world is selected. (B) The user interacts with virtual persons in the
game.
the character’s mobility and freedom within certain parameters. Interaction occurs through
avatar behaviors, such as taking, giving, opening, pushing, pulling, looking, speaking, using,
traveling, and checking the backpack, as well as movements and turns. These actions are
performed via the force feedback joystick and the keyboard.
All activities performed in the game, such as accessing the menu and actions taken
during the story itself, have audio feedback (e.g., stereo sounds) so that the user can
understand what is happening within the story. In navigating the virtual world, AudioChile
uses 3D sound to provide a better sense of spatiality and immersion in the game.
System Requirements
All of these games were developed for a PC platform with the following system requirements:
PC with the equivalent of a 1 GHz processor or higher, Microsoft Windows XP SP2, 128MB of
RAM (256MB recommended), 32 MB DirectX 8 compatible video card required, sound card, 4
speakers or headphones required for audio (depending on the game) and keyboard.
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AudioMath, The Farm of Theo & Seth, and AudioChile were developed using a
Macromedia Director 8.5 framework, with Lingo language. In particular, AudioMath and
AudioChile were developed with a library of routines for external joystick control, Xtra
RavJoystick. AudioVida was developed with C++ language and an OpenGL library.
Instruments
Table 2 shows the use of the different evaluation instruments in the various methodology
stages of each game’s production.
Table 2
.
Evaluation Instruments Used for Each Methodological Stage
.
Instruments
Methodology
Stage
Usability Cognition
Design
Icon usability questionnaire
Heuristic evaluation questionnaire
Understandability questionnaire
Implementation End-user questionnaire
Validation End-user questionnaire Cognitive Tests
Usability Evaluation
The main instruments used for the usability evaluation were icon usability, heuristic usability,
understandability, and end-user questionnaires.
1. Icon Usability Questionnaire. This instrument was used for early evaluations of the
interface. An icon evaluation questionnaire was taken during the usability sessions to evaluate
the images and audio feedback by including an observation instrument with two parts: (a) a set
of questions to identify the images of persons and objects in the game (for children with
residual vision), as well as a section to record observations during the interaction, and (b) a set
of questions to identify input/output sounds and any related associations made by the blind
children. It also contained observations recorded during the interaction.
2. Heuristic Evaluation Questionnaire. The heuristic evaluation was based on systematic
inspections of the interface made by two usability experts per each game. Researchers used
heuristic evaluation questionnaires (Sánchez, 2000), designed using Shneiderman’s (1992)
“golden rules” and Nielsen’s (1993, 1994) usability heuristics. The resulting test consisted of 12
heuristics, embracing a total of 25 items. These items were presented as a series of statements
about which usability engineer experts had to indicate their appreciation using a 5-point Likert-
type scale, ranging from strongly agree to strongly disagree. The 12 heuristics considered were:
visibility of system status; the match between the system and the real world; user control and
freedom; consistency and standards; error prevention; recognition rather than recall; flexibility and
efficiency of use; aesthetic and minimalist design; assistance for children to recognize, diagnose,
and recover from errors; help and documentation; content design; and media use.
User-Centered Technologies for Blind Children
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3. Understandability Questionnaire. The problem-solving understandability questionnaire
was applied during the interaction and consisted of 10 open-ended questions. The instrument
was used to evaluate the understandability of the problems and tasks posed to the children,
and of the related interface elements, such as instructions, sounds, visual and audio cues,
voice, navigation issues, and strategies to find hidden cues.
4. End-user questionnaire. This instrument (Sánchez, 2003) was applied at the end of the
usability sessions. It was basically a game acceptance test and consisted of 18 closed-ended
questions based on a 5-point Likert-type scale, ranging from strongly agree to strongly
disagree. Each of the answers was matched to a scoring scale from 5 to 1 respectively. The
results can be grouped within five categories: (a) game satisfaction, (b) game control, (c)
game usage, (d) quality of the game sound effects, and (e) game image and color quality.
Cognitive Evaluation
To evaluate the impact of virtual environments on blind children’s cognition, researchers used
a set of cognitive tests validated and adapted to the children’s cognitive level and to the degree
of their blindness. The Precalculus Test (Milicic & Schmidt, 2003) and Mathematics
Knowledge Test of Benton & Luria, adapted for children with special needs by Chadwick &
Fuentes (1980), were used to evaluate the impact of AudioMath and The Farm of Theo & Seth
on the learning and practice of mathematical concepts. The purpose of the Precalculus Test is
to measure the development of the mathematical skills of first-grade learners. The
Mathematics Knowledge Test measures the capacity to understand oral and written numbers;
the skills to make oral and written calculations; the skills to count numeric series and graphic
elements; and mathematical reasoning skills. In the case of AudioVida and AudioChile, a part
of the WISC-R (Wechsler Intelligence Scale for Children-Revised) test (Wechsler, 1981) was
used. This test contains a subtest in two scales: manual and verbal. In particular, the verbal
scale of comprehension was used because it did not need to be adapted for blind children. This
scale determines the child’s capacity to use practical judgments in the social situations of real
life, referring to the child’s common sense in real situations, and provides questions that can
be asked in such situations. This is especially linked to the capacity of problem solving
because the user has to be able to detect when and how to use his/her judgment and to ask
questions to find a solution.
Cognitive Tasks
Once all the usability tests were completed, we evaluated the cognitive impact of each game.
To do that, children who were not involved in the iterative usability interaction with the
software were exposed to cognitive tasks during their interaction with the games. These tasks
were designed and presented with concrete materials that represent structural and functional
aspects of the virtual navigation, in order to develop and enhance different cognitive
processes. Children understand some processes more fully when modeling and solving tasks
with concrete materials during interaction with a virtual environment (Roth et al., 2000;
Sánchez & Flores, 2004). Therefore, this methodology helps to improve the perception and
abstract representation of interface elements. Audio-based virtual environments with
accompanied cognitive tasks are crucial user-centered technologies for blind children.
Sánchez
110
For the cognitive tasks, researchers used concrete materials, and macro-type writing
(traditionally in black ink for children with residual vision) and Braille (for children without
vision) for the text portions. The idea was that children would transfer the tasks solved during
virtual gaming to real-world tasks. For the games designed for mathematics learning, the
researchers used the follow tasks (see Figure 7).
(A) (B)
Figure 7.
A blind user solves cognitive tasks related to mathematical concepts. (A) The user solves
tasks of AudioMath by playing a Game of Slug. (B) The user solves the tasks of
The Farm of Theo & Seth by playing the Lottery.
1. Roulette. Learners spun the roulette to obtain a number and indicated the numbers
coming before and after that number. Then the students exchanged questions with their peers
about the numbers prior to and following other specific numbers. The idea was to motivate
students to ask related questions and to prepare answers to correct their peers, if necessary.
2. Game of Slugs. Children participated in a race
against time with four stops, each one
with a mathematical exercise. Each child had to go through the four stops by solving the
exercises. Once a child solved the four exercises, another student started the game
3. The Lottery. Learners played the lottery in which the teacher randomly chose a number
from the raffle box that indicated a mathematical exercise (addition or subtraction) for all the
children to answer simultaneously. Once the exercise was solved, it was written on the player’s
card. The winner was the child who first solved an entire line of exercises across his or her card
or filled the whole card with solved exercises, depending on the version of the game. The game
continued until all children had at least a chance to successfully fill a line of correct answers.
4. The Store. The classroom was transformed into a small supermarket where learners
could spend a certain amount of money. Each student entered individually and was assisted by
a teacher. Learners had to plan and choose what to buy, and made as many subtractions and
additions as was necessary to make their shopping needs fit the monetary limitations.
In regard to assisting the users with analytic and problem-solving skills, the children had
several problem-solving games to conduct. They developed their own activities to solve three
cognitive tasks associated with the virtual games (see Figure 8):
Task 1. To identify and comprehend the use of skills to solve problems posed by
the virtual environment;
Task 2. To plan and design a strategy to fulfill the goal of the game;
User-Centered Technologies for Blind Children
111
Task 3. To recognize the spaces navigated in the virtual environment through
concrete mock-ups.
The children then had to apply the same strategy they used virtually to meet the final goal in
the physical world. All of these cognitive tasks were considered in analyzing the strategies used to
solve problems when children with visual disabilities interacted with AudioVida and AudioChile.
(A) (B)
Figure 8.
A Blind user solving cognitive tasks related to problem solving. (A) The user undertakes
a spatiality and temporality task after she interacted with AudioVida. (B) The child solves a
problem in which she must represent in the concrete mock-up the spaces that she navigated
in the virtual environment AudioChile.
Procedure
The four games used for the research are sound-based virtual environments that support the
learning and cognition of legally blind children. AudioMath and The Farm of Theo & Seth are
games that assist in the learning of basic mathematics concepts through the use of different
metaphors and dissimilar learning methodologies. AudioMath uses stereo sound and the user has
to move through a grid. The Farm of Theo & Seth uses stereo sound too, but the child can
navigate freely and autonomously by interacting with different interfaces. AudioVida and
AudioChile are virtual environments to support the development of problem-solving skills. They
differ in the way of representing the contexts. AudioVida uses stereo sound and the movement is
made through a rigid labyrinth, while AudioChile uses 3D sound and the child can move more
freely. These four games were implemented and evaluated concurrently.
The usability testing was implemented in three stages during 5 months at the Santa Lucía
School. The first stage, during the initial development of the games, consisted of pretesting the
various modules and prototypes with the participants, assisted by the facilitators. The objective
was to obtain initial feedback about the sounds and images of the games, with the information
used to form the design of the interfaces in the beginning of the implementation phase. To
obtain more detailed information, researchers used the icon evaluation questionnaire.
The second stage was implemented after researchers processed the data from the initial
testing and redesigned and improved the prototypes. Researchers used the heuristic
evaluation and problem-solving understandability questionnaires to evaluate these more
advanced prototypes.
Sánchez
112
In the third stage the researchers applied the end-user questionnaire to the same children at
two different times following their interaction with each game. After each questionnaire was
administered, researchers analyzed the data from both the open- and closed-ended questions
and made decisions concerning the interface design/redesign. Both tests served to improve the
usability of the game.
Interacting with the games and solving the cognitive tasks were the main emphasis of the
overall studies. During these steps, the children were observed and assisted by two special
education teachers, who filled in check lists and recorded the behaviors that they observed.
The teachers also administered the usability evaluation tests and observed the children.
Also
the children were video recorded and photographed for a later evaluation.
Finally, upon completion the usability studies, the second group of children were
administered cognitive tests during two 1-hour sessions per week, over a 3-month period. They
followed the steps of the pretest by taking the cognitive test and then interacting with the virtual
games. The cognitive tasks of the Roulette, Game of Slugs, Lottery and Store were then applied
of AudioMath and The Farm of Theo & Seth, and separate problem-solving cognitive tasks
were applied to AudioVida and AudioChile, where the children solved real-world tasks. Finally,
the children were posttested by taking the cognitive test.
RESULTS
Usability
The development process of the four games for blind children resulted in relevant data that has
implications beyond this paper. The implications of these results should be considered and used
when other learning games are created, designed, and developed for blind end users.
From the understandability questionnaire, applied to all games, researchers primarily learned
that sounds must always convey information to the blind user. The audio elements should not be
used as simple interface ornaments, as they are in some software for sighted people. Further, it is
important to maintain normalized sounds. They must be coherent with what is being represented.
The icon usability tests provided researchers with essential knowledge about the design
of the graphical interface for children with residual vision. From the AudioChile evaluation,
we found that a simplistic set of icon buttons is not adequate for these children; rather the
design should be clear and direct, representing the associated functionality more exactly by
considering the appropriate affordances. Moreover, to keep confusion to a minimum, it is
important to provide clear instructions to children before and during the game interaction and
that a guide should be present to facilitate complete understanding of the required task. As the
user gains experience with the game, these instructions may be reduced. The visually
impaired and, most importantly, totally blind children need a diversity of cues and
instructions to make for a better orientation because their navigation through the virtual
environment should be as much like their real environment as possible.
From the end-user questionnaire of the four games, researchers found that the motivation
of both residual vision and totally blind children for using audio-based virtual environments
was triggered by their acceptance of sounds and acoustics. Interacting with some of the
virtual environments described above allowed the learners to differentiate and identify
User-Centered Technologies for Blind Children
113
environmental sounds that helped them to navigate and orient themselves spatially in the
virtual world. In the case of AudioChile, this interaction also contributed to improving their
laterality and spatial concepts of up, down, left and right. When children recognized and
accepted the sounds that were embedded in the virtual environments, they attained better
control and navigability of the game. Moreover, the audio communication was fundamental
for blind children to feel motivated to use and interact with sound-based game environments.
Blind children needed clear and significant sound stimuli.
From AudioChile, the visibility
7
of the menus used in software applications for blind
children was directly associated with their ability to navigate the games
infinitely, thus creating
a circular style of navigation. While sighted children expect to see all of the functions of the
menu on their screens, the graphical interfaces for children with residual vision do not
necessary need to provide all of the audio functions of the menu. Instead, it is enough to present
the current item and allow the user to rotate through the other options, when necessary.
Furthermore, although many graphical interface elements are recognizable and used
frequently by sighted children, there is no guarantee that the same results would apply to
children with residual vision. The same applies to audio cues: Different sounds were tested and
accepted by children throughout the series of studies summarized in this paper, generating a
library of recognizable cues for blind children. Moreover, the classic ways of representing and
performing actions in software is through the menus, which are organized in a certain hierarchy
that allows for the visibility of the menu and direct access with a pointer, resulting in a
multisensory interaction. However, when a blind user interacts with the menus through the
keyboard (with or without the total visibility of the actions) he or she accesses only one action
at a time. Therefore, the priority should not be the visibility but rather the ease of the user’s
navigation through the different options in the menu. For this reason the menus must be
circular, allowing the blind user to select better the way he or she wishes to navigate.
The use of high contrast colors in the visuals of the four games was fundamental for
children with residual vision, who will always try to use their vision for aiding the interaction
within game-based virtual environments. The use of graphical screens allows for a higher
degree of integration when sharing their experiences with sighted children. The majority of the
characters and objects created in these
games were identified by the children with residual
vision, in some cases without the exact details but with enough clarity to recognize the context.
Figure 9 shows the results of the first and last usability tests. These are the average
results obtained from all four of the games. For each of the statements the score goes from 1
point (very low) to 10 points (very high). Findings indicate that the interfaces developed are
highly usable, especially in their acceptance, design, and use of audio and associated actions.
The average score in the analyzed dimensions of the four games was 5.8 points in the first
usability test and was improved to 7.4 points in the second usability test.
From the usability evaluation of AudioMath and AudioChile, the researchers found that
the use of force feedback joysticks was an excellent aid for interaction. These devices
allowed for information to be provided in conjunction with the audio, avoiding the excessive
presence of sounds that could saturate and even confuse the user.
When a keyboard is used as an input interface in games, the keys that are easily
recognizable for blind children, such as Enter, Space, Tab, and the directional arrows, should
be utilized. Further, all QWERTY keyboards should have marks on the F and J keys that can
be used as a reference for identifying and using the keys around them.
Sánchez
114
Figure 9.
Combined mean scores of usability testing results for the four games for blind children:
AudioMath, The Farm of Theo & Seth, AudioVida and AudioChile.
Cognition
From the application of the cognitive tests and tasks, researchers gathered data concerning the
actual support that each game provided for the specifically targeted cognitive skills. From the
analysis of AudioMath and The Farm of Theo & Seth, learners demonstrated that they can
become quite agile in mental calculation when performing basic operations such as addition,
subtraction, multiplication, and division. There also have been substantial gains in the
learning of the abstract mathematical concepts involved in such operations (Sánchez &
Flores, 2005; Sánchez et al., 2005). The children who worked with the mathematical games
and associated cognitive tasks increased their knowledge of basic concepts remarkably. They
also increased their ability to solve basic mathematics operations.
The mean score obtained in the pretest for AudioMath was 40.5 points and, after
interacting with the game, the children demonstrated important gains, obtaining a posttest
mean score of 74.3 points (see Table 3 and Figure 10). For The Farm of Theo & Seth, there
was also an important pretest/posttest gain. In the pretest, children obtained 74 points; in the
posttest children obtained 90.2 points.
Table 3
.
Pretest/Posttest Mean Scores in Mathematics Achievement after Playing
AudioMath and The Farm of Theo and Seth.
SOFTWARE PRETEST POSTTEST
Audiomath
Mean 40.4900 74.2800
N 10 10
Std. Deviation 13.7259 12.2848
Theo and Seth
Mean 74.000 90.1667
N 6 6
Std. Deviation 23.5966 24.2439
Total Mean 53.0563 80.2375
N 16 16
Std. Deviation 24.0701 18.6968
User-Centered Technologies for Blind Children
115
Figure 10.
Children’s achievement in mathematical skills following interaction with the virtual games
AudioMath and The Farm of Theo & Seth.
By comparing AudioMath and The Farm of Theo & Seth, it can be seen in Table 3 that
AudioMath children obtained lower pretest scores, but showed a higher pretest/posttest gains
than The Farm of Theo & Seth children (34 points). The Farm of Theo and Seth children
obtained a higher pretest and posttest performance scores than AudioMath children but a
lower pretest/postest gains (16 points). It is important to notice that the games were applied to
different aged user groups. The ages of the AudioMath children were from 8 to 15 years,
while those for The Farm of Theo and Seth were between 7 and 8 years.
To analyze the statistical significance of pretest–posttest gains in AudioMath, the paired
samples t-test was used. Significant pretest–posttest differences (t = -5.6; p < 0.05) were
found between the groups, so it is possible to think that the game is the key factor for the
increase in the scores (see Table 4).
For the game The Farm of Theo and Seth, pretest–posttest differences (t = -3.5; p < 0.05)
were also significant. In this case we can also consider that the game was the main factor in
explaining the differences in the scores (Table 5).
The analysis of AudioVida focused on verifying the children’s skills in identifying the
shortest paths from a fixed starting point to a certain goal. For this, a task was developed that
consisted of locating one object inside the maze through several routes, and then indicating
which one was the shortest path. Graphs, such as the one in Figure 11, were constructed using
the information analyzed in these tests, showing that the more frequently the children utilized
the game, the better they were able to accomplish the goal of identifying the most efficient
route, thus decreasing radically the distance employed to attain the same objective.
In this case, the virtual environment and issues that the children faced in the problem-solving
game allowed for the generation of adequate experiences for them to identify successfully the
problematic situations, resolve them, and evaluate their actions. This was supported by the
application of standardized tests to evaluate these types of skills. The results obtained from the
evaluation of the impact of AudioVida on blind children have shown that these children can
anticipate problems, plan, and apply different problem-solving strategies, explain the strategy
proposed in the game and used to solve the problems, and transfer strategies to other contexts.
From the same analysis, researchers found that, once children explored the virtual
environments, they were able to represent these environments through the use of concrete
Sánchez
116
Table 4.
Paired Samples Test of AudioMath.
Paired Differences
95% Confidence
Interval of the
Difference
Mean
Std. Dev.
Std. Error
Mean
Lower Upper
t
df
Sig. (2-
tailed)
Pair 1 PRETEST-POSTTEST
-33.7900 19.0141 6.1280 -47.919 -20.1881 -5.620 9 .000
Table 5
.
Paired Samples Test of The Farm of Theo & Seth.
Paired Differences
95% Confidence
Interval of the
Difference
Mean
Std. Dev.
Std. Error
Mean
Lower Upper
t
df
Sig. (2-
tailed)
Pair 1 PRETEST-POSTTEST
-16.1667 11.4266 4.6649 -28.1581 -4.1752 -3.466 5 .018
Figure 11
.
Learners’ performances during interaction with AudioVida.
materials, showing exceptional skills for spatial and abstract memory. Due to the fact that they
memorized the number of turns and the sequences necessary to obtain a representation of the
explored route, the real-world reconstruction of the virtual map was directly related to the number
of turns the user had to make, as well as to the number of times it took him or her to explore the
labyrinth. When the user explored more than four times a certain route with no more than four
turns, the resulting reconstruction was very faithful to the virtual environment. It is important to
understand the degree of complexity of a space that a user can explore without getting lost.
User-Centered Technologies for Blind Children
117
The analysis of the impact of interacting with AudioChile on problem-solving data shows
a different scene. As displayed in Table 6 and Figure 12, prestest/posttest mean scores show
slight gains (from 6.2 points to 7.6 points). This was a small gain and a statistically
nonsignificant difference between scores (t = -1.9; p = 0.13) was found between the groups.
The game was not key factor in increasing significantly the scores even though there was a
slight difference in the pretest/posttest mean scores (see Table 7).
Even though there was no statistically significant difference between the scores, learners
were observed to have developed problem-solving skills after interacting with AudioVida and
AudioChile (see Figure 12; see also Sánchez & Sáenz, 2006a,c). The different virtual
environments and issues that the children had to face in the problem-solving games allowed
for the generation of adequate experiences for them to identify successfully the problematic
situations, resolve them, and evaluate their actions.
Table 6
.
Pretest/Postest Problem-Solving Mean Scores of AudioChile
.
Mean Sample Standard Deviation Standard Error Mean
Pair PRETEST 6.2000 5 4.0866 1.8276
1 POSTTEST 7.6000 5 2.9665 1.3266
Figure 12.
Pretest/postest problem-solving mean scores of AudioChile.
Table 7.
Paired Samples Test for Problem-Solving Results of AudioChile.
Paired Differences
95% Confidence
Interval of the
Difference
Mean
Std. Dev.
Std. Error
Mean
Lower Upper
t
df
Sig. (2-
tailed)
Pair 1 PRETEST-POSTTEST
-1.4000 1.6733 .7483 -3.4777 .6777 -1.871 4 .135
Sánchez
118
DISCUSSION
The purpose of this report was to review, summarize, and illustrate the work of four audio-
based games created through a user-centered design methodology of successive usability
tasks and evaluations. Frequent usability testing was crucial to be able to map the end users
and their understanding of the game-based applications. Learners liked, accepted, used, and
were very motivated by the games. After designing and redesigning the 3D sound interfaces,
the children were able to map and navigate comfortably throughout the virtual environments.
The main axis of the researchers’ line of research was the development of audio-based
interfaces to increase blind children’s learning and cognition, in which audio was used to
convey information and knowledge. The research studies’ analyses identified key interface
issues necessary to map blind children’s mental models, needs, and ways of interacting. It is
very important to be aware of such matters when designing games for blind children because
these considerations can determine the success or failure of a software project.
These findings confirm the idea that it is not enough to simply add audio to an existing
application or to use screen reader tools to assist blind children in their interactions with
technology. The mental model of blind users is unlike that of sighted people in that their styles
of interaction to perceive and process stimuli and information are quite different. The challenge
then is to create custom-made games for these children, such as the ones presented in this paper.
These studies demonstrate that the sense of hearing is a capable substitute for vision in
its capacity for perceiving information and in the quantity and nature of the information that
can be perceived. This reality should be considered for software design purposes when the
children are sight-impaired. In the development of these interfaces, it is relevant to implement
numerous usability evaluation methods to identify the interfaces’ proximity to the blind
children’s needs, interactive modes, and mapping of mental models. It is also necessary to
consider the methodology, instruments for evaluation, and the cognitive tasks used to design
and implement usable interfaces for blind children.
Generally, the tools introduced in this report have allowed blind children to differentiate
and identify ambient sounds that help them to orient themselves in various spaces, and to
navigate and interact with objects and entities in virtual worlds. They have also contributed to
improving cognitive laterality and spatial concepts, such as up, down, left, and right. Spatial
sound has always been an important interface component in the research on game-based virtual
environments. However, it is a critical aspect in the blind children’s cognition that widens the
scope for the use of other senses for learning and cognition. Thus through an ample variety of
audio stimuli, children can stay alert and be motivated during their interaction with the game.
Perhaps most importantly, audio can help them to actively construct knowledge. Spatial sound
is especially required for newly blind children, who urgently need to minimize the deficiencies
in accessibility that separates them from the cognitive experiences of sighted children.
Cognitive tasks accompanying the audio-based games were very helpful for children
with visual disabilities who participated in the cognitive evaluation because the tasks
improved the children’s active tactile experience. Researchers observed that when children
enjoyed using the concrete materials, and when the experiences were based on real life, the
interest in learning and exploring increased. This is fundamental for children with visual
disabilities because, with the total or partial loss of vision, the ability to understand through
tactility allows them to construct meaningful learning experiences. For this reason, software
User-Centered Technologies for Blind Children
119
designed for the sight impaired should be accompanied by related cognitive tasks so that the
learning achieved virtually can be constructed tangibly and effectively. Such a process
permits the knowledge to be transferred to different settings and experiences. Finally, these
studies have demonstrated that sight-impaired children can learn with a decrease in
verbalism, which is the typical teaching behavior for children with visual disabilities.
As a result, significant improvements were achieved in learning and cognition by using
audio-based games that were specially tailored as a medium for interaction through user-
centered technology for blind children. These findings indicate that user-centered software
for blind children can help to support and develop their intellectual capabilities, thus helping
to close the gap between sighted and blind children.
ENDNOTES
1. Mental model: Users’ individual thinking and reasoning about themselves, others, the surrounding world,
and the interacting objects.
2. Digital native: A user who has been surrounded by technologies since birth, and thus is capable of using
them naturally and transparently.
3. Digital immigrant: A user who has learned to use and adapt to technology.
4. Three-dimensional (3D) Sound: Sound that comes from all directions surrounding the user, allowing the
person to determine the distance and location of the sound.
5. Mapping: The natural relation between the control of an interface and its functions.
6. Affordances: Properties that determine how objects should be used.
7. Visibility: Major parts of an interface should be easily identifiable.
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Author’s Note
This report was funded by the Chilean National Fund of Science and Technology, Fondecyt, Project 1060797
and
PBCT
-
CONICYT
, Project CIE-05.
All correspondence should be addressed to:
Jaime Sánchez
Department of Computer Science
Universidad de Chile
Blanco Encalada 2120,
Casilla 2777, Santiago
Chile
jsanchez@dcc.uchile.cl
Human Technology: An Interdisciplinary Journal on Humans in
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