Tracking sentence planning and production.

OBJECTIVE To assess age differences in the costs of language planning and production. METHODS A controlled sentence production task was combined with digital pursuit rotor tracking. Participants were asked to track a moving target while formulating a sentence using specified nouns and verbs and to continue to track the moving target while producing their response. The length of the critical noun phrase (NP) as well as the type of verb provided were manipulated. RESULTS The analysis indicated that sentence planning was more costly than sentence production, and sentence planning costs increased when participants had to incorporate a long NP into their sentence. The long NPs also tended to be shifted to the end of the sentence, whereas short NPs tended to be positioned after the verb. Planning or producing responses with long NPs was especially difficult for older adults, although verb type and NP shift had similar costs for young and older adults. DISCUSSION Pursuit rotor tracking during controlled sentence production reveals the effects of aging on sentence planning and production.