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Biomedical subjects

L L Light

Publications and source records attributed to L L Light.

At least 19 recordsLinked to original sources
PubMed1996

Guessing strategies, aging, and bias effects in perceptual identification.

In the typical single-stimulus perceptual identification task, accuracy is improved by prior study of test words, a repetition priming benefit. There is also a cost, inasmuch as previously studied words are likely to be produced (incorrectly) as responses if the test word is orthographically similar but not identical to a studied word. In two-alternative forced-choice perceptual identification, a test word is flashed and followed by two alternatives, one of which is the correct response. When the two alternatives are orthographically similar, test words identical to previously studied items are identified more accurately than new words (a benefit) but tests words orthographically similar to studied words are identified less accurately than new words (a cost). Ratcliff and McKoon (in press) argue that these are bias effects that arise in the decision stage of word identification. We report five experiments that examined the alternative hypothesis that these bias effects arise from postperceptual guessing strategies. In single-stimulus perceptual identification, repetition priming benefits were equally great for young and older adults who claimed to use deliberate guessing strategies and those who did not (Experiment 1). In contrast, only groups of young and older people who claimed to deliberately guess studied words in a two-alternative forced-choice task (Experiments 2 and 5) showed reliable benefits and costs. Costs and benefits were abolished in the two-alternative forced-choice task when a very long study list was used, presumably because the increased retrieval burden made the use of deliberate guessing strategies less attractive (Experiment 3). Under conditions similar to those of Experiment 3, repetition priming was observed in single-stimulus perceptual identification (Experiment 4). These results are consistent with the view that costs and benefits in the forced-choice perceptual identification task arise from deliberate guessing strategies but that those in the single-stimulus task do not. The possibility that the observed relationship between strategy reports and priming effects reflects erroneous postexperimental assessments of strategies by participants is also considered.

Adolescent↗
PubMed1996

One-trial associative priming of nonwords in young and older adults.

In this article, three experiments in which single-trial associative priming for nonwords was investigated in young and older adults in a pronunciation task are reported. During an encoding task, associative priming was observed for young and older adults, although cued recall was near zero for both groups. Associative priming for young and older adults was found under full attention conditions, but when attention was divided at study, associative priming was observed in Experiment 3, but not in Experiment 2. Divided attention also disrupted recognition memory for new associations in young and older adults. The results limit the generality of findings of age-related decrements in associative priming by showing an absence of such decrements in tasks that do not require elaborative processing during encoding. They also argue against G. Musen and L. Squire's (1993) suggestion that formation of new connections in implicit memory requires multiple study opportunities, whereas declarative memory is specialized for rapid acquisition of new associations.

Adult↗
PubMed1995

Repetition priming of nonwords in young and older adults.

In 3 experiments, a pronunciation task was used to examine repetition priming of novel nonwords in young and older adults. The contributions of item and associative priming to the total repetition priming effect were assessed. In Experiment 1, age consistency was found in both components of repetition priming after 9 repetitions of nonwords. Experiment 2 established that young and older adults were similar in item and associative priming after as few as 2 repetitions of nonwords. Finally, Experiment 3 demonstrated that associative priming persists for at least 3 min and that it is dissociable from cued recall. The overall pattern of results strongly argues that elaborative processing is not necessary to obtain associative priming in indirect memory tasks and that young and older adults show similar magnitudes of associative priming.

Adolescent↗
PubMed1994

Adult age differences in repetition priming: a meta-analysis.

This article reports a meta-analysis comparing the size of repetition priming effects in young and older adults. The main analysis included 39 effect sizes. Of these, 23 effect sizes could be classified as involving item priming and 16 as involving associative priming. The weighted mean effect size for the age difference was .304, with a confidence interval from .217 to .392. Because the confidence interval did not include 0, the hypothesis of no age difference in repetition priming was rejected. Subsidiary analyses, however, revealed that the weighted mean effect size for repetition priming was smaller than those for recognition or recall measures from the set of experiments included in the effect-size meta-analysis. Difficulties in drawing conclusions about process dissociations in old age in the face of only a partial dissociation in experimental measures are considered.

Aged↗
PubMed1992

Direct and indirect measures of memory for modality in young and older adults.

In 2 experiments, young and older adults demonstrated modality effects of similar magnitude in perceptual identification tasks. That is, both young and older adults demonstrated more repetition priming when study and test modalities matched than when they were different, suggesting that contextual information was equally available across age. However, when asked explicitly to retrieve modality information, older adults were less accurate than young adults. These results constitute evidence for a dissociation between direct and indirect measures of memory for modality information. They call into question hypotheses that memory impairment in old age is due to deficient encoding of contextual information and challenge current accounts of modality effects in repetition priming.

Acoustic Stimulation↗
PubMed1991

Instantiation of general terms in young and older adults.

Instantiation of general terms in discourse requires inference from general world knowledge and use of linguistic context to particularize meaning. According to the semantic deficit hypothesis, older adults should be less likely than young adults to generate or to store such inferences. In Experiments 1 and 2 an indirect measure, relatedness judgment, was used to assess immediate comprehension and memory for inferences. In Experiment 3 a direct measure, cued recall, was used to tap memory for inferences. No age differences in immediate or delayed memory were observed in Experiments 1 or 2. In Experiment 3 older adults recalled fewer sentences, but there was no evidence for a specific decrement in storage of inferential material. Older adults are not impaired in ability to draw inferences based on general world knowledge, nor are they more likely than young adults to encode linguistic information in a general, stereotypic fashion.

Adult↗
PubMed1989

Direct and indirect tests of memory for category exemplars in young and older adults.

Young and older adults were compared on direct (cued recall) and indirect (exemplar generation) tests of memory for category members. Because category names served as cues in both tasks, amount of retrieval support was constant across tasks. Although older adults produced fewer category members in cued recall, priming of category exemplars in the generation task did not vary with age. These results suggest that age constancy in priming tasks does not depend on physical similarity between study materials and retrieval cues provided at test and point to the importance of deliberate recollection as a factor in determining the extent of age differences in memory.

Adolescent↗
PubMed1988

Young and older adults' use of context in spatial memory.

We evaluated the hypothesis that older adults remember spatial information less well than younger adults because they use contextual information less effectively. Young and older adults studied schematic town maps on which structures were presented either simultaneously or successively and on which a network of streets was either present or absent. However, age did not interact with either contextual variable. Thus, we conclude that age differences in spatial memory do not arise from differences in the use of context.

Adult↗
PubMed1987

Implicit and explicit memory in young and older adults.

In three experiments, young and older adults were compared on both implicit and explicit memory tasks. The size of repetition priming effects in word completion and in perceptual identification tasks did not differ reliably across ages. However, age-related decrements in performance were obtained in free recall, cued recall, and recognition. These results, similar to those observed in amnesics, suggest that older adults are impaired on tasks which require conscious recollection but that memory which depends on automatic activation processes in relatively unaffected by age.

Adult↗
PubMed1986

Dissociation of memory and awareness in young and older adults.

Young (mean age = 23.41 years) and older (mean age = 69.41 years) adults studied a list of 80 words. They were tested immediately and 7 days later for both yes/no recognition and for ability to complete fragments such as E D L M, with words, some of which had been studied previously. The fragment completion task was not described as a memory test and subjects were encouraged to respond to all word fragments. Younger adults scored higher on recognition than older adults but not on fragment completion. These results, similar to those obtained with amnesics, suggest that older adults are impaired on tasks which require a conscious effort to recognize an event but that memory without awareness is unaffected by age.

Adult↗
PubMed1985

Working-memory capacity, age, and memory for discourse.

Two experiments explored the issue of whether age-related differences in memory for discourse can be explained by age-related differences in working memory capacity. Young and older adults were given a series of tasks designed to measure working memory capacity and memory for paragraphs. Although age-related differences were observed on digit, word, and sentence spans as well as on recall (Experiment 1) and recognition (Experiment 2), retention was not predicted well by scores on any of the span measures for either young or older adults in either experiment. The implications of these findings for hypotheses that age-related declines in working memory are responsible for problems in memory for prose are considered.

Adult↗