Dual Tasks Costs to Adults' Language Production

描述（由申请人提供）：拟建的实验将通过使用双任务程序来评估年轻人和老年人语言产生的成本，从而加深我们对衰老如何影响语言产生的理解。跟踪-转子跟踪的实时精度将作为语言生成的实时处理需求的指标进行研究。实验1将建立跟踪准确性的基线，并比较年轻人和老年人在口头回答发人深省的问题时从事转子跟踪的任务优先级。在实验2中，当年轻人和老年人参与各种语言生成任务时，他们的跟踪准确性将被监测，这些任务包括死记硬背字母表、倒数、阅读句子和散文，以及自发演讲（回答发人深省的问题）。为了对语言产生的每时每刻的认知成本进行更细致的评估，在实验3和实验4中，跟踪准确性的连续记录将被同步和时间锁定在年轻人和老年人大声说话或朗读时的语言产生的连续记录上。语音信号将被分割以标记句子和分句的起始/偏移。然后将计算这些片段的平均跟踪精度，从而产生对应于关键语音“事件”（如不同类型的嵌入子句）的跟踪精度的任务时间测量。平均跟踪精度随着句子和分句的复杂性而降低。在实验5中，跟踪准确性将被监测，同时参与者参与一个受控的生产任务，该任务将句子计划与计划实施和句子生产分开。核心假设是，语言产生对老年人来说是昂贵的，他们必须利用认知储备能力来应对双重任务需求。在要求较高的情况下，如造一个复杂的句子，老年人的认知储备会不足。因此，他们对跟踪的控制将会恶化，导致准确性下降。随着语言任务要求的增加，老年人的语言会逐渐退化，首先表现为语速下降，然后更普遍地丧失流畅性，最后是语法复杂性和命题内容的丧失。

DESCRIPTION (provided by applicant): The proposed experiments will advance our understanding of how aging affects language production by using dual task procedures to assess the costs of language production to young and older adults. Moment-to-moment accuracy of pursuit-rotor tracking will be studied as an indicator of moment-to-moment processing demands of language production. Experiment 1 will establish baselines for tracking accuracy and compare task priorities of young and older adults engaged in rotor tracking while orally responding to thought-provoking questions. In Experiment 2, young and older adults' tracking accuracy will be monitored as they engage in a variety of language production tasks ranging from rote repetition of the alphabet, to counting backwards, to reading sentences and prose, and spontaneous speech (responding to thought-provoking questions). In order to provide a more fine grained assessment of the moment-to-moment cognitive costs of language production, in Experiments 3 and 4, continuous records of tracking accuracy will be synchronized and time-locked to a continuous record of language production while young and older adults speak or read aloud. The speech signal will be segmented to mark the onset/offset of sentences and clauses. Average tracking accuracy, will then be computed for these segments, yielding time-on-task measurement of tracking accuracy that correspond to critical speech "events" such as different types of embedded clauses. Average tracking accuracy is expected to decrease with sentence and clause complexity. In Experiment 5, tracking accuracy will be monitored while participants engage in a controlled production task that separates sentence planning from plan implementation and sentence production. The central hypothesis is that language production is costly to older adults who must draw upon cognitive reserve capacity in order to respond to dual task demands. In demanding situations, e.g., producing a complex sentence, older adults' cognitive reserve will be insufficient. As a result, their control over tracking will deteriorate, resulting in decreased accuracy. As linguistic task demands increase, older adults' speech will erode, first showing a reduction in speed, then a loss of fluency more generally, and finally a loss of grammatical complexity and propositional content.