2.2.3. Immersive Virtual Environments
In contrast to the virtual learning environments described above, immersive educational environments are being developed using high-end equipment. They are consequently limited to situations with special funding, such as academic and research environments. Most of the projects are developed especially for head-mounted display systems (HMD).
A large part of this educational research has been focused on science education, as in the ScienceSpace projects developed by Dede and his colleagues \cite {Dede96}, which set out to explore motion, electrostatic forces and other physics concepts. The initial formative evaluation reports on learners' engagement, surprise and understanding of the alternative representations of the concepts provided in the ScienceSpace worlds \cite {Dede96}.
The Human Interface Technology Laboratory (HITL) at the University of Washington has been one of the early educational seedbeds for VR, with projects such as the Virtual Reality Roving Vehicle (VRRV) \cite{Rose95,Winn93}, Water on Tap \cite{Byrne96}, and summer camp programs in VR for students \cite{Bricken93}. The VRRV and summer camp projects focus on "world-building" activity, where students conceive and create the objects of their own virtual worlds, by using 3D modeling software on desktop computers. Although this gives the opportunity for students to understand the process involved in creating a virtual setting, the actual immersive experience is limited to a short visit of the pre-designed virtual worlds (4 to 10-minute VR experiences). The concept that virtual reality is a process and not a product is important \cite {Bricken91}, but does not take advantage of the potential educational benefits of the technology and does not justify its use. One of the reasons students are not more actively involved with the actual virtual experience within the virtual reality system is the fact that the systems used by these projects (HMDs) are not flexible enough to allow more than one participant at a time. The VRRV project attempts to overcome such restrictions in an interesting way, by travelling to schools and giving students (of grades 4-12) the possibility of experiencing VR, although still one at a time and for a short time.
Virtual reality technologies such as the CAVE \cite{CruzNeira93} and the ImmersaDesk, are freed from the limitations of HMDs (unwieldy hardware, single-user participation, short and infreqent immersive experiences), but not the limitations of size and cost. Although these systems have been used successfully in the area of scientific visualization, the development of CAVE applications for education has been almost non-existent. CitySpace, a learning project where children build virtual cities, has been demonstrated in the CAVE, but not in an educational context. This project, as with HITL's projects, emphasized the children's modeling activity prior to incorporating the models in a virtual city. The more natural physical setup of the CAVE (a 10x10x10 ft. room rather than a device), the relatively non-intrusive interface hardware (no helmets to wear), and its multi-user support (more than one learner can share the experience at once) show promise as a VR tool for the development of learning environments. The NICE project, described in the next chapter, seeks to explore this potential.
Finally, a study performed in a non-academic setting is worth mentioning. The Computer Museum in Boston set out to compare the immersive VR, two-dimensional desktop, and video instruction of cell biology. The subject population was large and varied, consisting of randomly chosen museum visitors \cite{Gay94}. The study reports that the VR users scored higher on the factual post-tests than the video users, but lower than the monitor users. However, the immersive users enjoyed their experience the most and reported the most desire to continue learning about the subject after the experience. A very similar but limited study was also performed with Water on Tap \cite {Byrne96}, a chemistry application developed at the HITL, but the quantitative approach to this study produced results of questionable value.