On the Use of Reaction Time as a Measure of Intelligibility

This paper describes an automated intelligibility testing system developed at the RAF Institute of Aviation Medicine to assess aircrew microphones. The system is currently used to administer the Modified Rhyme Test and the Clarke Vowel Test, but may readily be altered to accommodate any multiple choice test. In addition to counting the percentage of words correctly identified, the system also computes a subject's reaction time.An experiment was performed whereby a reference microphone was assessed in turn with three experimental types. The reaction time scores enabled finer discrimination in the relative performance of the microphones to be made, compared with the percentage of words correctly identified.