AgentSheets®: an Interactive Simulation Environment
with End-User Programmable Agents
AgentSheets Inc., Gunpark Drive 6560, Boulder, Colorado, 80301, email: email@example.com
Center for LifeLong Learning and Design, Department of Computer Science, University of Colorado at
Boulder, Campus Box 430, Boulder, Colorado 80309-0430, email: firstname.lastname@example.org
Current Information Technology is mostly focused on
With the dawn of the new millennium we are reflecting on
information and provides little support for
the relatively short history of the information age. Yes, we
information. An exponentially growing amount
have come a long way from the early beginnings. The
of information becomes increasingly unmanageable with
Internet has matured from being a peculiar playground of a
today's information technology approaches. Through web
handful of researchers to a rapidly growing network
portals, emails, chat rooms, and news lists all kinds of
connecting people, resources and services all over the
information can be accessed everywhere, all the time.
planet. The rate of adoption is truly astonishing. In just 7
Often embedded in rapidly flashing animations the
years the Internet has attained a market share of 25%. It
information glut is fighting for our attention and we are
took telephone 35 years to achieve the same penetration.
fighting to locate relevant information. The ability to
access information is a crucial first step but now we need
In a technological context, reflection is often accompanied
to explore new means of processing
information. How can
by prediction. What is next with information technology?
we keep up with frequently updated website content and
What will we be able to do with technology, what will
setup autonomous computation helping us to process
technology do to us? On an analytical level we have tools
such as Moore's law helping us to capture technological
growth as mathematical functions. According to Moore's
End-user programmable agents are a means to give people
law the speed of computer chips doubles every 18 months.
autonomous information-processing power. Simulation is a
Despite earlier calls for caution this has been true for many
form of information processing. Agents can be used to
years. Even growth limitations attributed to physical
build interactive simulations. AgentSheets® is an agent-
constraints such as molecular limitations regularly have
based simulation-authoring tool that allows end-users to
been overcome with new innovations. Maybe as soon as
build interactive simulations and publish them as Java
this or the next year we will see the first consumer PCs
applets on the web. Interactive simulations can help people
featuring 1 Giga Hertz clocked CPUs. Soon thereafter we
to explore complex issues and communicate them to other
will forget that there ever were CPUs operating at non-
people effectively. Interactive simulations are more
Giga Hertz speeds. Mega Hertz measurements will no
engaging than static text, images and even video.
longer be associated with computers at all. Instead all we
Moreover, people can define the behavior of end-user
will associate with Mega Hertz measure will the frequency
programmable agents to access existing information such
of FM radio stations.
as stock ticker symbols and to process that information by
analyzing and synthesizing it.
Another kind of growth equally astonishing as the growth
of computing speed is the growth of information spaces.
Just like the speed of CPUs the number of websites on the
Internet is growing exponentially. Since we are running
content. Interactive content such as
out of valid internet IP numbers, soon we need to replace
simulations cannot be captured on a static, paper-based,
the current internet addressing scheme with a new one
medium. By now, the computational power of personal
capable to deal with this kind of growth. Plotting the
computers has reached the necessary levels to run
amount of information accessible via the Internet and the
sophisticated simulations that would have required a
computing speed versus time we cannot react any other
supercomputer only a couple of years ago. Using
way than being genuinely impressed with information
technologies such as Java and Flash, interactive content
technology. No other technology ever has changed our
can be embedded in web pages and made accessible to
lives so rapidly, so profoundly.
everybody on the planet with a web browser.
How do we benefit from increasing information volume
By now the idea of featuring interactive content on the
and computing speed? A loaded question to be sure. It is
Internet is not all that new anymore. However, the
not clear what the exact shape of the curve would be if we
applications of interactive content discussed here are
were to plot the average Intelligence Quotient (IQ) or – if
different in the sense that people who are not programmers
there would be such as thing – the Creativity Quotient over
or web designers have built this interactive content. The
time. My fear is that IQ and CQ would look remarkably
quest is the exploration of new tools that will enable
flat next to CPU speed and information volume. Maybe
computer end-users to build interactive content very much
this is not terribly surprising but it still raises a number of
in the same spirit as tools – now called word processors –
essential issues. Just how it is possible that with more
have enabled end-users to build static content on their
information accessible and with more computation power
computers. The specific tool discussed here called
available we still fail to experience any kind of profound
AgentSheets is only one instance of a more general
impact on the qualitative aspects of live such as education?
framework of end-user tools to author interactive content.
The average degree of understanding of the world (science,
No detailed description of AgentSheets can be given here.
politics, nature, etc.) appears not to have changed much
Following a quick overview of the AgentSheets authoring
despite the fact that most answers to complex questions
tool is a description of how people have used AgentSheets
may be just one web search away.
to build simulations which, in turn, have been used to
communicate complex ideas or to further their own
ECommerce has become the most celebrated application of
understanding in ways impossible with static media.
the Internet. Jeff Bezos, CEO of Amazon.com was just
selected to be "1999 Person of the Year" by Time
AgentSheets: A Simulation Authoring Tool
magazine for his pioneering success with eCommerce. I do
not wish to attack these efforts in any way – I order most
Combining Java authoring, end-user programmable agents
of my books from Amazon – but really hope that as a
and spreadsheet technology, AgentSheets [Repenning and
society we can push the internet beyond the aspiration of
Sumner 1995] [Repenning, et al. 1998]
turning the web into a gigantic virtual shopping mall.
(http://www.agentsheets.com) is an authoring tool that
Despite the rapid, again exponential, growth of shopping
empowers casual computer users with no formal
transaction on the web it is unlikely that in the end more
programming training to build and publish web-based
people are reading books. There simply have to be
information technology applications that have the potential
to truly enrich life and not just to serve as a commodity.
Today's Internet killer apps (email, and eCommerce) push
old types of content such as text, images and videos,
through new media. What kind of other content types
could there be and how can people use them to do what?
In the remainder of this paper some scenarios are presented
in which information technology is used as medium
have used AgentSheets and VAT to create interactive
simulations and games in a variety of disciplines including
computer science, environmental design, fine art, robotics,
music, history, and biology. In an elementary school
science class, students created ecosystem simulations to
explore food webs and sustainability issues. In a high
school history class, students created social and historical
simulations. Scientists working with NASA created
simulations of E.coli bacteria fermenting in zero gravity.
Figure 1. AgentSheets combines Agent, Spreadsheet and
Java Authoring technology
AgentSheets enables users to create such simulations,
using its end-user programming language
Visual AgenTalk® (VAT). Users design agents' looks by
drawing icons and create agents' behaviors by composing
VAT conditions and actions from command palettes into
rules. Conditions and actions allow agents to do a variety
of operations including:
compute spreadsheet-like formulas
react to mouse clicks and key strokes
Figure 2: SimProzac: Simulation running in a webpage
sense other agents
explaining how Serotonin works in the Synapse and how
send messages to agents
Antidepressants affect the system.
play sampled sounds and MIDI instruments
Figure 2 above shows an interactive simulation explaining
the effects of Prozac to patients by modeling a serotonin
gather information from web pages
synapse in the brain. The simulation was built by a
psychiatrist for his patients. For this particular simulation,
Visual AgenTalk employs a new approach to end-user
a suite of agents (Table 1) was created by specifying their
programming called Tactile Programming. Tactile
look and their behavior using the Visual AgenTalk
Programming primitives and programs not only have
language. Figure 3 illustrates two VAT rules from the
enhanced visual representations to help program
behavior of the Serotonin molecule defining animation and
readability, but also have interactive interfaces to assist
interaction with membranes.
with program writability. Tactile Programming is well
suited for collaborative use since it eases program
Ambach 1996] of behaviors.
A wide spectrum of users, ranging from elementary school
students with no programming background to scientists,
at the center of the sense-making process and suggest that
students learn by actively building their own understanding
of a topic. One promising approach to meaningful learning
and robust understanding of science centers on the creation
and use of computer simulations as representations of how
and why things work [Papert and Harel 1993]. Activities
with simulations have the potential to help children
organize, develop, test, and refine their ideas about
Figure 3: Part of the serotonin behavior which specifies that if
the serotonin looks like
, it will change to
, or with 15%
chance if the serotonin sees a membrane to its right, it will
move to the right.
The specific point of building the SimProzac simulation
was to communicate complex chemical interactions to
patients. The web serves as an ideal platform to harness the
communicative power of interactive simulations such as
SimProzac. Entire AgentSheets simulations can be
exported as Java applets and JavaBeans, using the
Ristretto™ Agent-to-Java-Byte-Code generator
[Repenning and Ioannidou 1997]. This allows simulations
Figure 4. A simulation world populated with animal agents
to be published on the web making them accessible to a
designed by kids
larger community of users. Using Ristretto™ the serotonin
simulation was turned into a Java applet (Figure 2).
The Science Theater/Teatro de Ciencias (sTc) project has
developed a number of activities with simulations for
elementary school students [Rader, et al. 1998]. The
Using Simulations in Lifelong Learning
EcoWorlds curriculum for 4th and 5th graders focuses on a
AgentSheets appeals to an unusually wide range of users.
number of content areas, including characteristics of
This general applicability makes AgentSheets an ideal tool
organisms, structure and function in living systems,
for lifelong learning including K-12 education, University
populations and ecosystems, and diversity and adaptations
level education and workplace training [Gina Cherry, et al.
of organisms. The EcoWorlds unit addresses these issues
1999]. Justin Martin [Martin 1998] put the market
by having students work in small groups to create
potential of lifelong learning into numbers: "The
computer simulations of ecosystems in different
Knowledge-based economy is in full bloom. America's
environments such as the arctic or a desert. Activities with
investment in lifelong learning—everything from teaching
simulations are integrated into a curriculum, which
kids in the schools to training adults in the work
incorporates hands-on activities, research activities, and
force—runs to $665 billion a year, more than is spent on
In the Science Theater activity kids collaboratively design
The following sections provide a sense of the applicability
animals and exchange them through the Behavior
of AgentSheets by presenting example projects.
Exchange. The Behavior Exchange is a web-based
repository of agents allowing AgentSheets users to share
useful agents with each other
Elementary Schools: EcoWorlds
Current reform efforts in science education emphasize
constructivist pedagogies - approaches that place students
present their own thoughts and ideas for their final
One of the groups that chose to do a final project using
AgentSheets selected the topic of the California Grape
Boycott in the context of the Chicano/a, Latino/a Civil
Rights movement. The project, as the students defined it,
consisted of building a Web page with a boycott
simulation which they had created, as well as links to
related Web sites. In fact, these students' Web site served
as a small virtual library on the subject.
Figure 5. The Behavior Exchange is a web-based repository of
agents. Users can share their agents with other users.
The process of designing animals and exchanging them to
build a joint simulation is new, engaging way to learn
about complex system collaboratively. The motivation of
building simulations was so high that student were found
to return early from their lunch breaks in order to tweak
their simulations. The same students had never returned
early from their lunch breaks to read books.
Figure 6. A student produced webpage containing a
In this example information agents capture information
simulation of the Californian Grape Boycot
processing. These agents are built and distributed as a form
In order to build the simulation, the students realized that
of collaboration between computer end-users.
they needed to find out about the history of the boycott and
High Schools: The Grape Boycott
of the United Farm Workers movement. The students did
some initial research in the library and on the Web to learn
At the high school level, simulations were used in John
the basic historical facts, and found relevant information in
Zola's "Protest and Reform" history class at New Vista
Web pages, which they could reference on their own Web
High School [Ioannidou, et al. 1998]. In this class, students
had the opportunity to study protest movements throughout
U.S. history (e.g. the Civil Rights movement and the anti-
Vietnam war movement), and to learn about theories of
In modeling applications simulations are used to explore
protest and social change. Initially, simulations were used
complex causalities between a set of interacting variables.
in this context to present some of the concepts of protest
The reasons why people build models include issues such
and reform through "Segregation" and "Protest March"
the price of running a physical experiment (for instance it
simulations created by the researchers using the
is very expensive to explore the effects of micro gravity by
AgentSheets system. Students also created simulations to
putting an experiment aboard a Space Shuttle), and the
danger of operating an experiment (for instance an
experiment melting the core of a nuclear power plant).
The use of simulation technology is not limited to
Modeling is most beneficial to simulation builders. The
traditional screen-with-mouse interaction approaches. New
model becomes an instrument of the explorative thinking
display and interaction techniques when combined with
process allowing the builder to test new hypothesis leading
simulations result in a new kind of tangible interactive
to new insight and understanding. An example of an
medium. Professor Ernesto Arias from the University of
interactive simulation model created by scientists at the
Colorado school of Architecture & Design is concerned
BioServe Space Technologies center is shown below
with decision making as a public process. He has been
(Figure 7). The simulation models the behavior of E.Coli
using AgentSheets in many of his courses, and is now
bacteria in microgravity and explores its implications for
working with the Center of LifeLong Learning & Design
fermentation biotechnology [Klaus 1998].The goal of the
on new interface technologies that bring the power of
model is to explain why E.Coli bacteria behave
simulations to the public. He envisions information kiosks
fundamentally different in microgravity situations such as
located in public buildings such as libraries. Using a
aboard the Space Shuttle orbiting around the earth. The
display technology called SmartBoard, he is building
process of building this model has helped the BioServe
simulations that combine the physical world with the
scientists to better understand complex molecular
virtual world. Physical objects such as LEGO blocks can
interactions involving bacteria cell sedimentation cell
be placed onto a vertical version of the SmartBoard (see
diffusion, byproduct diffusion and nutrient uptake.
Figure 8). The virtual world is an AgentSheets simulationof the Boulder bus system. Along with members of the
healthy community initiative, Professor Arias is exploring
issues such as public transportation and pollution.
Community members experience public transportation
scenarios either personally, by interacting with the
physical virtual simulation, or over the web.
Figure 7. E.Coli bacteria are situated in a low-gravity
environment and are slowly sinking toward the bottom of the
cell. Glucose is absorbed and converted into waste products.
From a learning perspective modeling is useful because it
helps simulation builders to explore new ground. The
Figure 8. A Physical + Virtual Simulation running AgentSheets
on SmartBoard (horizontal in front and vertical in back)
physical experiments that have been in the MIR space
station and were part of the 5 Space Shuttle missions are
Connecting Simulation to other Components
costly and need extensive preparation. The simulation, in
contrast, can be varied at any time and run in parameter
Interactive simulations could be turned into a richer
ranges that cannot be replicated with the physical
learning activity if they could be connected to other
educational components such as plotters, databases, and
spreadsheets. Addressing these kinds of issues the National
Science Foundation is supporting the Educational Software
Ioannidou, A., Repenning, A. and Zola, J. 1998.
Components of Tomorrow [ESCOT] project with the goal
Posterboards or Java Applets? InInternational Conference
of exploring the use of Java-based component technology
of the Learning Sciences 1998
(Atlanta, GA). Association
in education [Roschelle, et al. 1999]. To this end ESCOT
of the Advancement of Computing in Education, 152-159.
brings together researchers, practitioners, developers,
curriculum designers, publishers and content experts.
Klaus, D. M. 1998. Microgravity and its implications for
Along with SimCalc and Geometer's Sketchpad®,
fermentation biotechnology. Trends in Biotechnology 16
AgentSheets is one of the cornerstone ESCOT tools to
generate educational components and build math activities.
Martin, J. 1998. Lifelong Learning Spells Earnings.
In Figure 8 an AgentSheets simulation called the Virus
, 1, 197-200.
Attack simulation is connected to the SimCalc graphing
component to plot the number to infected people while the
Papert, S. and Harel, I. (Ed.). 1993. Constructionism.
simulation is running. This allows users to track the
Norwood, NJ: Ablex Publishing Corporation.
spreading of the virus through graphical and numeric data,
Rader, C., Cherry, G., Brand, C., Repenning, A. and
as well as simulated visual data.
Lewis, C. 1998. Designing Mixed Textual and Iconic
Programming Languages for Novice Users. InProceedings
of the 1998 IEEE Symposium of Visual Languages
Scotia, Canada). Computer Society, 187-194.
Repenning, A. and Ambach, J. 1996. Tactile
Programming: A Unified Manipulation Paradigm
Supporting Program Comprehension, Composition and
Sharing. InProceedings of the 1996 IEEE Symposium of
(Boulder, CO). Computer Society, 102-
Repenning, A. and Ioannidou, A. 1997. Behavior
Processors: Layers between End-Users and Java Virtual
Figure 9. ESCOT Connected Math activity combining
Machines. InProceedings of the 1997 IEEE Symposium of
AgentSheets Virus Attack simulation component (left) with
(Capri, Italy). Computer Society, 402-
SimCalc plotting component (right).
Repenning, A., Ioannidou, A. and Ambach, J. 1998. Learn
to Communicate, and Communicate to Learn. submitted to
AgentSheets research and AgentSheets Inc. are supported
Journal of Interactive Media in Education
by the National Science Foundation (DMI 9761360, REC
9804930, REC-9631396, RED 9253425, CDA-940860).
Repenning, A. and Sumner, T. 1995. Agentsheets: A
Medium for Creating Domain-Oriented Visual Languages.
IEEE Computer 28
, 3, 17-25.
Gina Cherry, Andri Ioannidou, Cyndi Rader, Cathy Brand
Roschelle, J., DiGiano, C., Koutlis, M., Repenning, A.,
and Repenning, A. 1999. Simulations for Lifelong
Phillips, J., Jackiw, N. and Suthers, D. 1999. Developing
Learning. In National Educational Computing Conference,
Educational Software Components. IEEE Computer 32
(Atlantic City, NJ).
Table 1: Application Domains for Interactive Simulations
K-12 Education: High School
How does a TV work?
This simulation illustrates how a picture
is scanned in by a camera (left), transmitted to a TV set and
converted back in to a picture (right). Users can paint their own
Interactive Story Telling
: History students create interactive
pictures and play with TV signal processing parameters.
stories of historical events such as the Montgomery bus boycott.
Learning by visualization and modeling
: The effects of
Learning by taking apart
: What makes a bridge stable? The
microgravity onto E.coli bacteria are modelled by NASA. This is
goal presented to the users of this simulation is to remove as
a simulation of an experiment that was aboard the Space Shuttle
many elements of the bridge as possible without making the
with John Glenn. This simulaton requires several thousand
bridge collapse. A number of connected issues are revealed
including forces, architecture, and geometric perspective. This
simulation was featured on the PBS Mathline.
Learning through simulation use
: This simple voting
Learning through design
: Even if the finished simulation/game
simulation explains concepts such as clustering, migration and
is not directly related to educational goals, the process of
stability of two party systems. Can it predict the outcome of the
building the simulation may be very educational. The Ultimate
election in 2000?
Pacman is a complete game based on complex Artificial
Intelligence algorithms and the non-trivial math of diffusion
The White Horse Press Brown, Karen. "Poisonous Plants, Pastoral Knowledge and Perceptions of Environmental Change in South Africa, c. 1880–1940." Environment and History 13, no. 3 (Aug, 2007): 307–32. http://www.environmentandsociety.org/node/3303. All rights reserved. © The White Horse Press 2007. Except for the quotation of short passages for the purpose of criticism or review, no part of this article may be reprinted or reproduced or utilised in any form or by any electronic, mechanical or other means, including photocopying or recording, or in any information storage or retrieval system, without permission from the publishers. For further information please see http://www.whpress.co.uk.
Investigation of Selected Signalling System Genes in Pathological Gambling Final Report Principal Investigator and the Project Contact Person: James L. Kennedy, M.D., Director, Neuroscience Research, CAMH 250 College St., R-31 – Toronto, ON – M5T 1R8 – Phone: 416- 979-4987 FAX: 416- 979-4666. James_Kennedy@camh.net