Chris: To me, a “game” has a scoring system with winners and losers, but a game doesn’t need to model anything in the real world. It can be completely based on fantasy without any correlate in reality. A “simulation,” in contrast, would not have winners and losers, but would represent something in the real world or a scientific abstraction such as mathematical logic. Of course the distinction between games and simulations is a continuum rather than a dichotomy, so we can find lots of designs that are in between the two pure extremes of games and simulations.

	The distinction between games and simulations is a continuum rather than a dichotomy...

simSchool: On the simulation side, you can still have goals and purposes that are somewhat like games - the role that the user plays to reach a goal, to find something out or to experiment.

Chris: That is exactly right. One of the things game designers know, but simulation designers sometimes forget is that simulations are created with a purpose in mind. Both explicitly and tacitly that purpose is conveyed to the participant. Even a relatively open-ended simulation has controls to shape what happens; instructions; limits created by the underlying rules, and implicit analogies to real world phenomena, all of which convey a sense of purpose.

simSchool: How would you define virtual reality (VR)?

Chris: My definition of “virtual reality” is more precise than common parlance. To me, VR means full physical immersion. The participant is wearing a head-mounted display or is inside a CAVE (Computer Assisted Virtual Environment) in which four surfaces of the room are graphically active - three walls and either the floor or the ceiling -- or in some other way the senses are immersed inside of the environment. For example, if I am looking at a two and half dimensional simulation on a computer monitor, and I turn my head away from the monitor, the illusion of sensory immersion is destroyed because I am not looking at the monitor anymore. But if I am sensorially immersed with a VR head mounted display or CAVE and I turn my head, the illusion is not destroyed because the world changes in response.

“Virtual environments” as described earlier are a much looser construct. In the early days, people thought of text based MUDs (Multiple User Dimension) as virtual environments, but -- when people use that term now

-- they generally mean graphical representations of a digital context. Technically, a purely two-dimensional representation within just the frame of the monitor is a virtual environment. But what designers like myself mean by a virtual environment is a two and a half dimensional representation that allows participants to move their avatars so as to change point of view.

simSchool: In Virtual environments are there elements of simulations and games?

Chris: Simulations, games and virtual environments can fuse in very interesting ways. Andy van Dam at Brown in his CAVE has a virtual painting program; participants can create three-dimensional virtual art by moving a paintbrush through space, selecting from palettes of colors and paintbrush characteristics. In contrast, the virtual reality “worlds” I and my colleagues built with National Science Foundation sponsorship, Newton’s World and Maxwell’s World, were game-like simulations modeling the causal relationships that underlie real-world phenomena. More information about our Project ScienceSpace, including a streaming video of our VR worlds, is available at http://www.gse.harvard.edu/~dedech/. Our simulations were meant to help learners understand abstract “laws” of physics, as opposed to an open ended, aesthetic painting simulation for personal expression.

My current design-based research involves a Multi-user Virtual Environment Experiential Simulator (MUVEES). My colleagues and I have designed River City, a simulation on a number of different levels. River City simultaneously models historical, physical, and social phenomena. Readers may wish to visit our MUVEEs project webpage to learn more about our research and to vicariously experience being in River City.

simSchool: Mark Prensky and Clark Aldrich and others keep using the phrase “video game” as a genre title of all these complex highly immersive worlds, some of which use game devices. What is your thought about what is happening in bridging the kind of work that you and I do and the entertainment world?

Chris: In any rapidly evolving field, terminology gets confused. I always bristle when people call River City a “video game,” since it was deliberately designed to go well beyond videogames. A nuanced common terminology with many distinctions among types of games and simulations is better than a simplistic terminology with only few descriptors to label a wide spectrum of designs.  ...continue