Is the user trained? Assessing performance and cognitive resource demands in the Virtusphere

Virtual reality systems provide a convenient means of studying human cognition and performance on a wide range of tasks for which real-world testing is cost prohibitive or difficult to control. For the results of such studies to be valid, it is important to ensure that aspects of the virtual experience do not alter a participant's behavior or performance on the experimental tasks. This can be particularly difficult when using novel locomotion interfaces that require training. Training procedures should not be completed until movement tasks can be performed at a high level of ability and they do not interfere with concurrent cognitive tasks. A study is described in which subjects were trained to locomote in the Virtusphere, an interface resembling a “human-sized hamster ball.” The effectiveness of training is discussed in terms of both movement abilities and performance on a concurrent cognitive task. Movement performance was tracked as subjects learned to travel through a virtual environment. Additionally, subjects simultaneously completed cognitive tasks in a dual-task selective-interference paradigm. Results showed very rapid improvement on movement measures, including distance traveled and the ratio of collisions to distance traveled, with performance improvement becoming gradual within a few minutes. However, results also highlight persistent problems with concurrent spatial memory tasks, indicating that the training is not really done when performance on the movement metrics levels off.