Compatibility and Resource Competition between Modalities of Input, Central Processing, and Output

Synthesized auditory displays and speech recognizers were used in two experiments to develop guidelines for their implementation in military aircraft. In the first experiment, the competition between encoding and response modalities of concurrent tasks was examined. The memory search task was more susceptible to competition for visual encoding, whereas the tracking task bore the greater impact from shared manual responding. The second experiment examined competition between tasks for encoding and response modalities and the optimum assignment of modalities to a given task. A simulated flight task was performed concurrently with either a spatial task (target acquisition) or a verbal task (memory). Best performance and least interference with the flight task were obtained when the spatial task was displayed visually and responded to manually and also when the verbal task was displayed auditorily and responded to with speech.