title: Message comprehension as a function of intelligibility and advance knowledge of the topic.
abstract: The relationship was investigated between estimated intelligibility (EI) and message comprehension (ability to answer questions presented at various levels of intelligibility). In Exper. I, 10 young adults identified the S/N ratio they associated with 0, 25, 50, 75, and 100% intelligibility for easy story material in speech-shaped noise at a constant 75 db SPL; subsequently, at the S/N's thus determined, comprehension was measured with easy short-answer questions. There was a very strong relationship between EI and comprehension, suggesting that the two were more or less synonomous. In Exper. II, comprehension with easy short-answer questions was measured at EI's of 25, 50, and 75% when each question was preceded by relevant, irrelevant, or no cues to the general topic of the question. Relevant cues had a positive effect which was significant at the 25 and 75% EI levels. The suggestion from Exper. I on the identity of EI and comprehension was modified to show that EI levels are a psychoacoustic variable which can be used to identify a regular decrease in comprehension when the speech signal is progressively masked by speech-shaped noise, but that the actual level and rate of decrease in intelligibility is a function of other factors, including psycholinguistic features of the message itself.
mesh_terms: D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D010470:Perceptual Masking; D012107:Research Design; D013065:Speech Intelligibility