Computer graphics technology enables us to
create a remarkable variety of digital images and displays that,
given the right conditions, effectively enrich education [Clark
1983]. Real-time computer graphics are an essential component
of the multi-sensory environment of Virtual Reality (VR). This
article addresses the unique characteristics of emerging VR technology
and the potential of virtual worlds as learning environments.
I will describe several key attributes of VR environments and
discuss them in relationship to educational theory and pedagogical
practice. I will then identify three challenges that must be
met before VR can be integrated into educational settings: cost,
usability, and fear of the technology.
The practical potential of VR is still being
explored. Of the number of application areas that suggest themselves,
education is clearly worth immediate investigation. VR was devised
to enable people to deal with information more easily, and it
has been successfully developed to facilitate learning and task
performance for over 20 years in the U.S. Air Force [Furness
1978]. Public education and training applications are a natural
extension of this work.
The national mandate for educational improvement is based on increasingly grim statistics. Between 25%-30% of our children donít graduate from high school, and of those who do, at least 700,000 are functionally illiterate. Our students rank at the bottom of 19 industrial nations in reading, writing, and arithmetic. ìOne thing is for certain: the information revolution is changing our lives, and we need to prepare ourselves to cope with its promise and potential.î [Gore 1991] How might VR help?
Virtual Reality as a Learning Environment
Using a head-mounted audio-visual display,
6-D position sensors, and tactile interface devices, we can inhabit
computer-generated environments. We can see, hear and touch virtual
objects. We can create, modify and manipulate them in much the
same way we do physical objects, but without those pesky real-world
limitations. VR is not only virtual: we can meet real people
in virtual worlds, we can tele-exist in real places all over the
world and beyond, and we can superimpose virtual displays onto
the physical world.
VR offers teachers and students unique experiences
that are consistent with successful instructional strategies:
hands-on learning, group projects and discussions, field trips,
simulations, and concept visualization. Within the limits of
system functionality, we can create anything imaginable and then
become part of it. The VR learning environment is experiential
and intuitive; it is a shared information context that offers
unique interactivity and can be configured for individual learning
and performance styles.
"If there are limits on the human ability to respond to learning environments, we are so far away from the limits as to make them presently inconsequential. Throughout human history to date, it has been the environments, not the human beings, that have run up against limitations." [Leonard 1968]
1. VR is experiential.
We actively inhabit a spatial multi-sensory environment. We are
both physically and perceptually involved in the experience, and
we feel a sense of presence within a virtual world. ìWe
are immersed in a very high bandwidth stream of sensory input,
organized by our perceiving systems, and out of this ëbathí
of sensation emerges our sense of being in and of the world.î
[Zeltzer 1990] We experience the environment as if it were
real, while still fully aware that it is computer-generated.
Educational theorists have agreed on the fundamental
importance of experiential learning for over a hundred years:
"Learning is the development of experience into experience."
[James 1892] "Knowledge begins with enaction." [Bruner
1962] "To learn is to make sense out of experience."
[Silberman 1970]
"If you can be a gear, you can understand
how it turns by projecting yourself into its place and turning
with it...As well as connecting with the formal knowledge of mathematics,
it also connects with the ìbody knowledgeî , the
sensory-motor schemata of a child. It is this double relationship--both
abstract and sensory--that gives a transitional object the power
to carry mathematics into the mind." [Papert 1980]
Text, oral, and screen-based presentations
address subsets of human capacity. In contrast, the VR learning
environment provides a context that includes the multiple nature
of human intelligence: verbal/linguistic, logical/mathematical,
auditory, spatial, kinesthetic, interpersonal and intrapersonal.
The importance of affective learning has been
carefully explored [Kohlberg 1968, Rogers 1969]. It is apparent
that we must consider the whole learner in his or her effort to
attain educational goals [Belkin 1977]. VRís experiential
computing environment allows the ìpurposeful movement that
coordinates the cognitive, the psychomotor, and the affective
domainsî [Harrow 1972]. VR provides a context for both
cognitive and affective learning by engaging us in a process that
is rational and emotional, practical and whimsical, organized
and spontaneous.
2. The VR learning environment allows intuitive
human-computer interaction. The
technology is designed to fit human architecture. A virtual world
empowers us to move, talk, gesture, and manipulate objects and
systems in a natural way: to move an object, you reach out your
hand and pick it up; to see what you hear going on behind you,
you turn around and look. The skills needed to function within
a virtual world are the same skills weíve been practicing
in the physical world since birth. This method of representing
and interacting with information is fundamentally different from
the way we are now using computers. Novices require minimum
accommodation time [M. Bricken 1990]. Skilled users can represent
and manipulate increasingly complex information in forms that
are easy to remember and interpret [Furness 1988].
The motivation to learn hinges on interest,
and most people find VR a very interesting experience. It has
a magical quality, which fascinates children of all ages. You
can fly, you can make objects appear, disappear, and transform.
You can have these experiences without learning an operating
system or programming language, without any reading or calculation
at all. But the magic trick of creating new experiences requires
basic academic skills, thinking skills, and a clear mental model
of the system.
3. The VR learning environment is a shared
experience. A personal computer
is designed for solitary operation; there is one keyboard, one
mouse, and one display. Virtual worlds can be both individual
and social contexts. Networked VR allows multiple participants
to interact simultaneously in the same audio-visual environment,
sharing control naturally while conversing with augmented capability
(ìIíll show you what I mean. It sounds like this...î).
Research in collaborative learning abounds
with evidence of its educational value: "The learner tends
to be more productive in a group situation than working in isolation.
Ongoing discussion involves the active participation of students
in the teaching-learning process; attention is then directed toward
the learning activity." [Belkin 1977] ìChildren solve
practical tasks with the help of their speech, as well as with
their eyes and hands...Human learning presupposes a specific social
nature and a social process by which children grow into the intellectual
life of those around them.î [Vygotsky 1978]
For the most part, our schools exist separately
from the world that they teach about. Virtual worlds can be linked
to the physical world through telepresence; distance learning
systems could be expanded to allow students and teachers to share
worldwide learning environments. Through virtual participation
in local and international activities, students become active
in the process of culture, and can see more clearly their relationship
to the whole of humanity. Students can learn about different
electronic communication and information networks through participation.
They can learn how to deal with different forms of electronic
data, building computer skills and data management skills. Real-time
access to a multitude of people and information sources opens
the virtual world -- and the classroom -- to the world at large:
ìWhen heterogeneous students interact
within a context characterized by positive goal interdependence,
a process of acceptance is promoted, resulting in increased interaction,
convictions of peer encouragement and acceptance, more accurate
understanding of each otherís perspectives, feelings of
success and self-esteem, and expectation of rewarding future interactions.î
[Johnson 1983]
4 . VR learning environments allow entirely
new capabilities and experiences.
This is a powerful context, in which you can control time, scale,
and physical laws. Participants have unique capabilities, such
as the ability to fly through the virtual world, to occupy any
object as a virtual body, to observe the environment from many
perspectives. The ability to understand multiple perspectives
is both a conceptual and a social skill; enabling children to
practice this skill in ways we cannot achieve in the physical
world may be an especially valuable attribute of VR.
ìWe know the world in different ways,
from different stances, and each of the ways in which we know
it produces different structures or representations, or, indeed,
ërealitiesí...we become increasingly adept at seeing
the same set of events from multiple perspectives or stances and
at entertaining the results as, so to speak, alternative possible
worlds. The child is less adept at achieving such multiple perspectives...There
is every reason to insist that this capacity must be present in
some workable form in order for the child to master understanding.î
[Bruner 1986]
VR provides a developmentally flexible, interdisciplinary
learning environment. A single intraface provides teachers and
trainers with an enormous variety and supply of virtual learning
"materials" that do not break or wear out. VR focuses
our attention on the tasks and elements at hand, excluding extraneous
information and reducing the distraction.
The virtual environment allows safe experiences
of distant or dangerous locations and processes. We can tele-exist
in a nuclear reactor or under the sea, experiment with virtual
chemistry and biology and inhabit macro- and micro-cosmic systems
scaled for human participation.
Creative expression is given a new medium,
allowing students to instantiate their imaginations in a multi-sensory
context, participating in experiential worlds of art, music, theater,
and literature. Presentation skills are exercised in new ways;
students can demonstrate what they learn and communicate their
ideas through virtual experiences that can be shared with teachers,
parents, and peers.
5. VR learning environments can be tailored
to individuals. Teachers can represent
information in forms that are most compatible with a studentís
particular learning style, selecting interactivity options that
match student performance characteristics. Tools for movement
and manipulation within the virtual world can be configured to
the physical needs of the individual and the requirements of the
task.
In VR, we adopt a virtual body for group interaction. What forms will children choose, and what will those choices tell us? Gender, age, social status, and physical attributes, and the cultural expectations associated with them, can be left behind when we enter a virtual world. By what criteria will will students learn to evaluate each other if physical appearance is arbitrary?
Challenges To Be Met
Using VR in schools and for training introduces
both technical and cultural challenges. I consider cost, usability
of software and interface devices, and fears about the technology.
1. Cost:
Today, commercial VR systems that are sophisticated enough to
offer complex models and diverse functionality are expensive relative
to personal computers. About a quarter of a million dollars will
get you the basics for a very small network of worlds. However,
increasingly powerful computer systems are becoming more affordable
each year, and low-end VR environments are being developed in
the United States, Japan, and the United Kingdom.
Tomorrow, communications experts envision VR
as a public utility with powerful centralized processing that
allows anyone low-cost access to internationally networked virtual
worlds. [Elias 1991]
As a former teacher and administrator, I am
well aware that inadequate teacher salaries and overcrowded classrooms
take precedence over new technology in the minds of most educators.
Serious funding for the implementation of VR in schools will
be predicated on two things. First, we need conclusive demonstrations
of educational effectiveness, measured by substantial learning
and performance increases directly attributable to VR technology.
Second, we need to identify sources of funding that do not call
on the severely limited resources of educational institutions.
The burden of cost is appropriately assumed
by those with the highest vested interest in a successful educational
system. Not only families, schools and government are affected
by inadequate education: business and industry spend $25 billion
yearly to train/retrain their employees. ìLearning has
become the single most critical determinant of national economic
competitivenessî [Perelman 1990] The decreasing levels
of competence of entering employees is motivating many corporations
to invest in educational change. ìThe necessity of technology
in schools is clear. However, bringing these critical tools to
the classroom presents a challenge that must be met by the business
community in partnership with government.î [Gardner 1990]
2. Usability:
A crucial issue for integrating VR into classrooms is system
usability -- by students of various ages, by teachers, and by
curriculum developers. The following comments are not intended
as product reviews but are my assessment of how well current VR
tools work, based on the systems Iíve used to build virtual
worlds and on my teaching experience in classrooms from kindergarten
through college.
Designing virtual learning environments is
substantially different from both traditional interface design
[M. Bricken 1991] and traditional curriculum design. Because
the whole learner is engaged in virtual activity, we must design
at many levels, considering multi-modal representation of information,
multiple methods of interaction, physiologically appropriate virtual
contexts, and the choice and structure of the content to be explored.
2.1. Modeling Software: Virtual worlds are
presently created on the computer screen. Worlds that run on
commercially available systems are limited in size and complexity.
The graphical models are simple, constrained on different systems
to between 500 and 10,000 polygons (sides of objects). We can
locate four channels of sound in the world and link them to graphical
objects. We can achieve somewhat more complex environments by
linking worlds together, but each world is experienced separately.
The first step in designing a virtual world
is to define it: what do you want to do there, how do you want
to do it, what elements will you need to do it with, what is the
context of the experience? We can model a world that includes
an airplane like the VRX [M. Bricken 1990], that has interesting
functionality and flies through a cubist terrain. But we canít
even come close to expanding this world to include the airport
or the people in it, much less the luggage or vending machines
or the printed pages of tickets. As it is, the VSX pushes system
limits at 10,000 polygons, and has a noticeably sluggish frame-rate.
Designing useful worlds within present limitations is possible,
but expanding these limits is prerequisite to building the complex
environments that can be envisioned for education.
You can model virtual worlds with one of several
3-D graphics design products. Modelling software varies widely
in ease of use and capability. Iíve had the most experience
with Swivel 3-D™, making worlds that run on the VPL RB1™
system. The maximum scale of Swivel worlds is approximately 12í
square in physical space; if our virtual body was rendered at
its real size, we would be immense giants in Virtual Seattle
[M. Bricken 1990], which is at maximum scale. We need modeling
software with refined metrics that allow us to create large worlds,
scaled to human proportion.
In is easy to interact with objects in Swivel; even young children can learn how to get primitives on the screen, rotate and translate them, and link them together. But creating complex topology requires skill and patience. Accurately naming, aligning, and linking objects to form multiple-component objects requires looking at each intersection from several angles and distances, frequently unlinking, repositioning and relinking objects relative to each other.
The VSX took me weeks to model, and there are
still things I should change. (Iíve found that virtual
worlds are never ìdoneî. Changes and refinements
continually suggest themselves: VR is a process, not a product.)
If extensive low-polygon object libraries were included with
modelling software, useful worlds would be relatively straightforward
to assemble.
3-D modeling packages with more sophisticated
functionality, such as Alias™ and Wavefront™, are proportionally
more difficult to learn. Some of the most powerful features
of these modelers (multiple light sources, radiosity, mirror surfaces,
shading options, and batch animation capabilities) are presently
unusable for real-time rendering. Also, the object linking mechanisms
are not as flexible as they need to be.
I did some conceptual design in AutoCAD™ for a PC-based VR prototype system that could render small (500 polygon) models. It was great training for minimalist world design, but after working with larger models, Iíve concluded that 500 polygons just isnít enough to stock a dynamic, surprising world with interesting objects. AutoCAD provided me with the most useful architectural design capabilities, but once again, its complex functionality requires more learning time than most teachers and students have available.
The software that HITL uses to model 3-D sound is an extension of FocalPoint™. While I have only begun to integrate sound into virtual worlds, it is clearly a compelling component of the environment. Using vision-only systems in schools would not be doing VR; the multi-modality of the experience is an essential feature for educational applications.
2.2. Dynamics Programming Software: After
you model the world, you program the dynamics of the environment.
You add viewpoint control, command structures, collision detection
for manipulating objects, movement constraints, animations, and
object behaviors.
Body Electric™ is VPLís dynamics software, and although successive versions of this complex package are increasingly streamlined, effective use requires a clear understanding of interface device functionality, of the network of platform components, of the modelís structure, and of the intention of the design. You also have to program, using a data flow network that converts raw data input into intended behavior.
HITLís VR software, VEOS (Virtual Environment
Operating Shell), is a platform-independent Unix network that
allows multiple concurrent worlds and as many users as you have
equipment for [W. Bricken 1991]. VEOS worlds are specified in
a LISP-like language. The ability to program complex object behavior
allows more life-like dynamics in a virtual environment. In Body
Electric, I can put a bird on a fixed flight path through the
world. In VEOS, I can program the bird to seek out food, prefer
some foods to others, avoid cats, and come when its called. Our
current interface build will provide first generation tools for
the public domain.
We need software that is specifically intended for creating virtual worlds, that provides straightforward methods for modelling, modifying, and assigning behaviors to elements of the environment. Ideally, we should be able to use the same basic set of tools both on screen and inside VR. Specialized VR software packages are being developed by several companies and universities, but I expect that several iterations of tool design will be necessary before a simple, reliable VR software toolkit is available for classroom use.
2.3. Interface devices: A variety of head-mounted
displays (HMDs) have been developed by the Air Force and NASA.
Others are marketed by companies such as VPL, W-Industries, LEEP
Optics, and Arvis. They are all based on aerial imaging technology,
in which we view a picture focused at infinity that is projected
in front of our eyes. This is, of course, not the way we see
objects in the real world, where our focus changes to converge
on objects located at different distances from us. Although binocular
viewing does give us a feeling of three-dimensionality, it is
difficult to judge the relative location of objects in aerial
displays without redundant cues such as familiar size, occlusion
and parallax. Alternative display technologies, such as direct
retinal scanning, are being investigated [Furness 1990].
Current HMDís are bulky, heavy and fairly
fragile. Present displays are very low-resolution, making small
objects and details of virtual worlds difficult to see. Some
distort vision with a fish-eye effect, and others do not show
color. Most do not include audio capacity. All HMDs have cables
which restrict our movement. A rugged, lightweight, high-resolution
audio-visual HMD that can tolerate the daily use of rambunctious
students is prerequisite for classroom VR.
Position sensing and tracking devices translate
our movements into data streams that the computer uses to update
display images and sounds according to our location. Some VR
systems use a Polhemus Isotrack™, which generates a small
electro-magnetic field and tracks the movement of receptors within
it. By placing the receptors on our head and hand, the rotation
and translation of those parts of our physical body are mapped
onto our virtual body. We need to stay within the generated field
and we are attached to the tracking devices with wires. Passive
video tracking is used in artificial reality systems such as Mandala™,
and could be applied for some applications of inclusive VR. The
challenge is to improve the technology for wider range, wireless
communication, faster update rate, and greater accuracy.
We interact with elements of the virtual world
using 6-D control devices such as the DataGlove™, the Virtex™
Glove, the Bird™, and the SpaceBall™. The DataGlove
has gotten enough use so that we have some information about how
it works as an interface device. Getting our hand into the virtual
environment increases our sense of presence and allows us to manipulate
virtual objects in a more natural, efficient and intuitive way
[Sturman 1989]. However, gesture commands are limited by the
number of finger positions that can be defined as unique, mutually
exclusive, and comfortable. Gestures can require a degree of
manual dexterity that many people do not have.
I have found that pointing to fly gets mixed
reviews; alot of people find it an unending source of fun, but
other people report tired arms and motion sickness. When moving
by pointing, directional accuracy is approximate, stopping exactly
where you want to can be difficult, and speed control is awkward.
Inadvertent gestures can trigger unintentional commands; for
example, when people first use the buttons on the control panel
of the VSX, they extend their index finger to press the button
and fly right through their target. There are proprietary issues
regarding the use of computerized gloves which will affect price,
performance and availability.
The Bird is a 6-D mouse, which can select and move objects in 3-space. The SpaceBall is a 6-D pressure-sensitive trackballs which can be used to select and manipulate objects or control viewpoint. Moving your viewpoint through a virtual world with a Ball is very smooth. Unlike a glove, it can be used to tumble and swivel. This capacity is very useful for object manipulation, but moving your viewpoint with unconstrained freedom can be very disorienting.
The challenge is to determine which interface
devices are appropriate for particular tasks and individuals.
3. Fears:
Educators are concerned that more technology that they arenít
trained to use will be dropped into the classroom, and that it
wonít really help them to teach more effectively. On a
broader level, there is anxiety about the misuse of VR and fear
that the technology may have some inherently negative attributes
(see the collected abstracts of the Second International Conference
on Cyberspace, Santa Cruz CA, 1991).
Brenda Laurel addresses the fear of computer
technology and identifies its components:
ï the archtypical taboo on presuming to imitate God
ï the fear of fallibility: ìintelligentî software entities may turn out to be crude, lifeless representations; or, we may create monsters -- war, environmental destruction -- with technology
ï the fear of loosing identity, becoming dependent ìslaves of cybernetic symbiosis"
ï the fear of loosing control to alien
life: software entities may NOT be crude and lifeless -- new,
improved sentience may emerge and take over [Laurel 1990]
We can now identify new fears that have emerged
about VR in particular:
ï fear of loosing control to unidentifiable others -- invisible hackers, masked tricksters, faceless corporate/governmental manipulators: how do we know who a virtual person really is, how do we know if information is being distorted, how are individual rights established, how are conflicts managed, who is in control?
ï fear of denied access: Whether VR is a wonderful or a terrible place, everyone should have the right to be there; who gets in and how?
ï fear of abandonment: what if VR is so
compelling that people donít want to come out, who will
mind reality? If I donít get virtual, will I be left all
alone?
Fear of the technology may be both the most
subtle and the most important challenge to public acceptance of
VR as a suitable medium for children. Once we acknowledge this
fear, we can address it rationally. Of course, fear is not rational,
it is emotional and not easily assuaged. However, I will suggest
three approaches to reducing VR technophobia:
3.1. Education: We need first to understand
what VR is and is not. We must separate science from fiction;
VR is not a book by William Gibson, it is an interface technique
that now allows us more immediate access to a subset of what computers
already do. We can make the technology available in the public
domain for widespread exploration and evaluation. VR is a new
information medium, and like any media, can be used to disseminate
propaganda, advertisement, and misinformation. Curriculum that
addresses the use and misuse of media exists in most schools,
and can easily be expanded to include computer-mediated information
spaces.
3.2. Research and Co-development: By sharing
experiences as we continue to explore, observe, evaluate and refine
VR, we increase professional and public understanding of the technology.
Developers present progress reports and research papers on their
systems in professional and public conferences internationally.
Educators are initiating formal research on VR issues such as
transfer of learning, appropriate curriculum implementation, elements
of effective VR design, multi-modal perception and work-load distribution
in VR, and the psychological and social impact of the technologyís
use.
Interface experts stress the value of involving end-users in the development of computer technology during the design phase. Given evidence that VR is safe and useful, we can refine learning applications along with the technology itself by establishing a dialogue between developers and the educational community to determine the appropriate use of VR in schools and in training.
3.3. Historical perspective: People, individually and collectively, learn from mistakes. The big lesson of the Twentieth Century is that careless implementation of technology can cause large-scale and lasting negative effects. It is difficult to reverse the momentum of old mistakes, but it is easier to avoid new ones. Issues of power, control and access in VR are being addressed in the context of Constitutional rights: the Electronic Frontier Foundation exists to encourage the legal extension of First Amendment assurances of freedom and privacy into electronically mediated environments.
Worrying about humanity seems to be an inevitable
component of social consciousness. ìPlato banned the
art of drama from his republic because he thought that humans
were in danger of confusing art and life.î [Laurel 1990]
People are notoriously suspicious of ìalternateî
realities; the very name Virtual Reality is enough to raise the
hackles of those who fear that other people canít make
distinctions between different kinds of experience. Sometimes
we just donít give people enough credit for common sense.
I think children are far more likely to mistake Disneyland for
the real world than they are to confuse VR and reality.
Summary
New technology obviously needs thoughtful introduction
into classrooms. Technology does not, by itself, improve education,
and even the most promising educational innovation needs skillful
application to be effective. But, there is clearly the potential
that VR learning environments can be powerful educational experiences.
The significance of VR to education may be
wider than particular learning applications. VR provides a testbed
for exploring the very foundations of education. What we teach
our children springs from our assumptions about how the world
works and what is valuable. Our methods of teaching are based
on our understanding of the role of the mind in learning. Educators
are re-examining the philosophical foundations of education [Goodman
1984] by comparing the implications of Objectivism to those of
Constructivism:
ìObjectivism and Constructivism represent
alternative conceptions of learning and thinking...Objectivism
assumes that the role of mental activities is to represent the
real world...and that the role of education is to help students
learn about the world and replicate its content and structure
in their thinking. Constructivism, on the other hand, claims
that we construct our own reality through interpreting perceptual
experiences...that reality is in the mind of the knower rather
than in the object of our knowing. Constructivists, rather than
prescribing learning outcomes, focus on tools and environments
for helping learners interpret the multiple perspectives of the
world in creating their own.î [Jonassen 1990]
By making VR tools and environments available
to educators, we may discover more about the very process of learning.
By participating in the development of VR, educators can guide
the growth of the technology, and perhaps influence the course
of educational change. As we test and refine this unique learning
environment together, we might even hope that VR really will help
us to teach more effectively, and that we will see more often
that bright light of understanding in our studentsí eyes.
References:
Belkin, G.S., Gray, J.L. Educational Psychology. Dubuque, Iowa: Wm.C.Brown 1977
Bricken, W. VEOS Preliminary Functional Design. Technical Report, Human Interface Technology Laboratory, U. of Washington, Seattle: 1991
Bricken, M. No Interface to Design. Cyberspace: The First Steps. MIT Press, Cambridge, MA: 1991
Bricken, M. A Description of the Human Interface Technology Laboratoryís Virtual Worlds. Technical Report, Human Interface Technology Laboratory, U. of Washington, Seattle: 1990
Bruner, J. On Knowing: Essays for the Left Hand. Cambridge, Ma: Harvard University Press 1962
Bruner, J. Actual Minds, Possible Worlds. Cambridge, Ma: Harvard University Press: 1986
Clark, R.E. Reconsidering Research on Learning from Media. Review of Educational Research, Winter 1983, Vol. 53, No. 4, pp. 445-459
Elias, Jim (Executive Director, US West Communications). Tele-Virtuality and the Potential Role for Communications. presentation, Industry Symposium on Virtual Worlds Technology, Seattle, WA; Feb. 1991
Furness, T. Visually Coupled Information Systems. ARPA Conference on Biocybernetic Applications for Military Systems, Chicago, IL, April 1978
Furness, T. Harnessing Virtual Space. SID International Symposium, May 1988
Furness, T. Retinal Scanners for Head-Mounted Display. Washington Technology Center Presentation, Seattle WA, 1991.
Goodman, N. Of Mind and Other Matters. Cambridge, MA: Harvard University Press, 1984
Gardner, Booth (Governor, WA). in, A New Learning Enterprise. Business Week, Dec. 10, 1990
Gore, Al (Senator, TN). The Digitization of Schools. Business Week, Dec. 10, 1990
Harrow, A. A Taxonomy of the Psychomotor Domain. New York
James, W. Talks to Teachers. New York: W.W. Norton, 1958. (originally published, 1892)
Johnson, D.W. & Johnson, R.T. Interdependence and Interpersonal Attraction Among Heterogeneous Individuals: A Theoretical Formulation and a Meta-Analysis of the Research. Review of Educational Research, Spring 1983
Jonassen, D.H. Objectivism vs. Constructivism: Do We Need a New Philosophical Paradigm? University of Colorado (unpublished)
Kohlberg, L. Early Education: A cognitive-Developmental View. Child Development, 1968 Vol. 39, pp.1013-1062
Laurel, B. The Art of Human-Computer Interface Design. Addison-Wesley, 1990 pp. 481-482
Leonard, G.B. Education and Ecstasy. New York: Dell 1968
Papert, S. Mindstorms. New York: Basic Books 1980
Perelman, L.J. A New Learning Enterprise. Business Week, Dec. 10, 1990
Rogers, C. Freedom to Learn. Columbus, Ohio: Charles E. Merrill, 1969
Silberman, C. Crisis in the Classroom. New York: Random House, 1970
Sturman, D.J., Zeltzer, D., Piper, S. Hands-on Interaction with Virtual Environments. Proceedings ACM SIGGRAPH Symposium on User Interface Software and Technology, Williamsburg, VA: Nov. 1989, pp. 19-24
Vygotsky, L. Mind in Society: The Development of Higher Psychological Processes. Cambridge: Harvard University Press, 1978
Zeltzer, D. Virtual Environments: Where Are We Going? Proceedings 12th International IDATE (Institut de líAudiovisuel Telecommunications en Europe) Conference, Nov. 1990, Montpellier, France