Leah L. Light - US grants

The proposed research is designed to increase our understanding of language comprehension and production in old age. Older adults have consistently been found to perform more poorly on memory tasks than young adults. This age-related difference in memory has been attributed to decreased ability to understand language. In our previous research, however, we have observed age invariance in language comprehension accompanied by memory deficits in old age. One goal of the proposed research is to further explore age-related changes in certain language comprehension processes that have implicated in memory deficits and to examine the relation between initial comprehension and subsequent retention. A second goal is to study cognitive processes fundamental to language comprehension which are also important for speech production. Given the potential for production data to inform our understanding of cognitive deficits in old age, it is surprising that very little research effort has been devoted to this topic. We investigate the roles of semantic processing and attentional capacity in both language comprehension and in speech production, using both laboratory experiments and more naturalistic methods. Thus, we are concerned with mental processes that are critical components of the everyday activities of producing, understanding, and remembering linguistic information. Seventeen experiments are proposed which explore processes involved in producing and understanding language. The experiments are designed to answer four broad questions. (1) Do young and older adults differ in their ability to use linguistic context to specify meanings of words and sentences during comprehension of language? (2) Are there age-related differences in the relation between semantic encoding and memory? (3) Do young and older adults differ in their ability to retrieve lexical or semantic information? (4) Are there age differences in the nature or frequency of speech errors and repairs?

DESCRIPTION (adapted from investigator's abstract): Contemporary accounts of memory distinguish between memory judgments based on a sense of familiarity and those based on recollection of associations between events experienced together or between events and the contexts in which they occur. In particular, familiarity has been posited to underlie repetition-priming phenomena, whereas recollection plays a more central role in recall and recognition. Healthy older adults score lower on recall and recognition and also remember fewer sensory and temporal-spatial details of their experiences. In contrast, age differences are small, and frequently statistically unreliable, on indirect measures of memory. Such findings suggest that familiarity is (relatively) spared in old age whereas recollection is impaired. The proposed research addresses three fundamental issues posed within this framework. (1) In studies using response-signal methodology, participants are required to respond as soon as a signal is given. Signal times are chosen such that at the shortest lags performance is at chance and at the longest it is asymptotically accurate. Different kinds of information become available at different points in the retrieval episode, with familiarity information available before information needed for recollection. Experiments 1-9 chart the availability of different kinds of information during retrieval in young and older adults. This research is intended to determine if the difference in the time course of availability for familiarity and recollection is exaggerated in old age. If so, this would suggest that older adults rely more on familiarity than recollection because the availability of contextual information is delayed. (2) Experiments 10-12 are intended to provide new data on the role of familiarity and recollection in recognition memory in older adults. Young adults use a variety of recall-like processes in recognition, especially in associative recognition tasks in which people must decide whether not two events were originally experienced together or separately. Studies of associative recognition in older adults are few in number and have not manipulated variables that permit a detailed picture of the contributions of different types of recollection. The proposed studies of recognition examine the effects of list length, word frequency, and test structure on recollective processes in recognition memory. (3) Recent meta-analyses suggest that older adults are more impaired on some indirect measures of memory than on others. Experiments 13-16 test the hypothesis that older adults exhibit less priming than young adults only on tasks that involve high response competition. These experiments also address the issue of whether age differences in priming are larger for accuracy than for latency measures.