New age-linked asymmetries: aging and the processing of familiar versus novel language on the input versus output side.

This research demonstrates 3 new age-linked asymmetries between identifying versus retrieving phonological information. Young and older adults read aloud familiar isolated words (e.g., mind) and novel pseudowords (e.g., mond) in a production task and identified lexical status for identical stimuli in a comprehension task. Young adults made fewer errors than older adults in production but not comprehension (an age-related input-output asymmetry), and they produced pseudowords but not words with fewer errors than older adults (a lexical-status asymmetry). The lexical-status asymmetry also occurred for response onset times but not for output durations (an onset-output asymmetry). All 3 asymmetries were predicted under the transmission deficit hypothesis (D. G. MacKay & D. M. Burke, 1990) but contradict theories such as general slowing that cannot explain why aging affects some types of information processing more than others.