Recent technology allows Air traffic control (ATC) messages to be sent in textual format via data link, as well as via radio transmission. The purpose of this project is to investigate differences between auditory and textual transmission of information to better predict errors as a function of modality and to ultimately develop a set of guidelines for data link transmission of ATC messages. To this end, we will address three issues: working memory interference, message coherence, and workload.

     The first issue specifically regards whether different modes of interference (verbal or visual) are more detrimental for data link or radio transmission. We will also investigate differences between interference that occurs concurrently and subsequent to the target task.

     The second issue regards the effects of coherence of the ATC message.We will compare auditory and textual presentation of data-link messages that vary in coherence on two levels, the word (spelled out vs. abbreviated) and the idea (complete, incomplete).

     The third issue regards the differential effects of workload on text and speech communications. Moderate workload will involve performing the data-link activities simultaneously with the monitoring task. High workload will involve data-link activities performed simultaneously with monitoring, tracking, and resource management tasks. A high-workload/unpredictable condition will additionally include unexpected failures in the resource management task. Within each of these areas we also investigate effects of message length, urgency, and expectancy. This project will provide valuable information concerning the effects of interference, message coherence, and workload on task completion and comprehension in the ATC environment.