Effects of noise and workload on a communication task

Communication is of vital importance in the cockpit today. It is essential for pilots to be able to understand the messages sent to them. A major requirement of any aircraft voice communication system is the ability to deliver intelligible speech. In a loose sense, intelligibility may be defined as the understanding of spoken words (Webster, 1979). Several language factors affect intelligibility including vocabulary size, word frequency (familiarity) effects, number of response alternatives, number of syllables, phonetic elements and context (Webster, 1972). Other external considerations include equipment or design features and environment (Webster and Allen, 1972). With such a wide range of sources of influence, it is easy to understand the need for a reliable intelligibility test. One such test found to be particularly useful in studying the effects of aircraft noise has been the Modified Rhyme Test (MRT).