Comprehension of spoken language involves rapid construction of meaning from a transitory acoustic signal, the complexity of which can easily be overlooked. In ordinary conversation, speech rates may average between 100 and 180 words per minute (wpm), and a speaker reading aloud can easily average over 200 wpm. In addition, the words in spoken discourse often are unclear or garbled (Pollack & Pickett, 1963). In spite of these challenges, phonemic and syntactic structures interact with semantic and contextual contraints to produce the perception of an intelligible message in “real time” (Marslen-Wilson & Tyler, 1980). That is, unlike reading, in which the viewer may backtrack and proceed at a comfortable rate, speech is heard at the rate produced by the speaker. Not only must this complex acoustic signal be understood phonologically at this extraordinary rate, but also the utterances must be further analyzed into the sentences and propositional representations that give rise to meaning.

Whereas older adults often suffer from deficits in auditory processing (Olsho, Harkins, & Lenhardt, 1985), it has also been argued that they have particular difficulty with tasks requiring “deeper,” more effortful processing operations (Craik & Simon, 1980) and are slower in performing many cognitive operations (Salthouse, 1980, 1982). For these reasons, it might seem surprising that older adults are not more often noticed to have trouble in understanding everyday speech (e.g., in conversation, from television or radio).