A relatively simple architectural space was modeled and used to compare the effects of spatial training in simulations versus training in the real world. Thirty-five subjects were trained in one of the following conditions: real world (RW), virtual environment (VE), nonimmersive virtual environment (NVE), and model (Mod). The VE condition made use of a head-mounted display to view the simulated environment, while the NVE condition used a desktop monitor. In the Mod condition, the subject viewed and could manipulate a 3-D model of the space, viewed from a desktop display. The training-transfer tasks, performed after brief unstructured exposure to the actual space or to one of the simulations, consisted of estimating the bearing and range to various targets in the real space from various spatially distributed stations, each such pair of estimates constituting a subtask of the overall transfer task. Results obtained from each of the four training conditions proved to be roughly the same. Training in any one of the simulations was comparable to training in the real world. Independent of training condition, there was a strong tendency among subjects to underestimate range. Variability in range errors was dominated by differences among subjects, whereas variability in bearing errors was dominated by differences among subtasks. These results are discussed in the context of plans for future work.

Information-transfer (IT) rates in bits/sec were estimated for a variety of methods of human communication and modalities of reception. Using previously published data, a range of communication rates for which transmission is highly accurate was established for each method and modality. These communication rates were converted into a normalized unit of transmission (words/sec). The normalized units were then converted into estimates of IT rate (bits/sec) using Shannon's (1951) calculations of the information content of a single letter of the alphabet. Maximal estimates of IT rates of roughly 40 to 60 bits/sec are observed for speech (through audition) and for reading and sign language (through vision). Maximal rates roughly 50 percent lower are obtained for reading through the tactual sense. Estimates of IT rates for motor output tasks are also considered. A close correspondence is generally observed between IT rates for receiving a given display and IT rates for the motor output task required for producing the display. These results have implications for the design of synthetic-environment systems and the displays and controls to be used in these systems, by providing examples of communication rates that have been achieved by humans in the area of language communication.

Virtual reality technology is now being used to provide exposure and desensitization for a number of phobic conditions. In this paper, we first review these current applications and discuss the work needed to refine and expand these applications to phobias. We then comment briefly on some preliminary applications of VR technology to mental-health problems outside the domain of phobias. Finally, we consider ways in which VR might be used to further enhance psychotherapy and assist in the treatment of a wide variety of disorders. Various possible interventions are discussed, along with the technological developments needed to make them possible.