ABSTRACT
This chapter describes various methods for eliciting perceptions of body acceleration. The focus of discussion is on the “user’s requirements” for perceiving acceleration in a virtual environment (VE). The most direct means for eliciting an acceleration perception in a VE is by using a real acceleration stimulus that is meant to mimic critical aspects of the “virtual acceleration” perception being conveyed. A rudimentary understanding of human vestibular function is necessary in order to employ physical acceleration effectively as part of a virtual environment. This chapter provides an introduction to the “vestibular channel” of the VE stimulus and details different methods for exploiting knowledge about the vestibular modality to elicit perceptions of self-motion, self-tilt, and self-entry into unusual force environments. The authors compare physical acceleration of the user to other methods, such as visually induced illusions of self-motion or illusions of self-motion induced by locomotion without displacement (as occurs on treadmills). The authors conclude that the most compelling perceptions of body acceleration in VEs will be achieved through mutually enhancing combinations of vestibular, visual, and somesthetic stimuli. A particularly effective approach will be to use acceleration stimuli that duplicate the real acceleration profiles being simulated, but to do so in a different environment from the (virtual) environment where the user perceives himself to be located.
