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L W Poon

Publications and source records attributed to L W Poon.

At least 55 records · Page 3Linked to original sources
PubMed1985

Speed of processing in normal aging: effects of speech rate, linguistic structure, and processing time.

Young and elderly adults heard three types of speech materials varying in both length and degree of semantic and syntactic constraints. Time compression was used to vary speech rates systematically to test a speed of processing hypothesis as one explanation of performance deficits associated with normal aging. In addition to segment length effects, the elderly participants showed significantly steeper rates of performance decline with increasing speech rate, with slope constants dependent on the structural constraints of the speech materials. The results are discussed in terms of processing rate hypotheses and context utilization.

Adolescent↗
PubMed1984

On subject selection in cognitive aging research.

This paper surveys the recent practices of subject selection in cognitive aging research and provides examples of how the magnitude of age differences in the overall population could be under- or over-estimated given different sample distributions of gender, health, education and intellectual functioning. Some guidelines are suggested for consideration in future research.

Adult↗
PubMed1983

On the use of word association norms in aging research.

The word associations of young, middle-aged, and older adults were compared to cohort matched normative word associations. Cohort differences in most common response were observed for a subset of stimulus words which did not have strong primary responses in the norms. For those stimulus words assumed to be free of cohort differences, there were no significant differences between the three age groups in amount of agreement with the normative responses. It is concluded that standard word association norms are as reliable for older individuals as for the young provided that words with strong associates are selected.

Adult↗
PubMed1982

Age and iconic read-out.

Letter recognition was investigated in 16 young adults (mean age = 21) and in 16 older men (mean age =64) by exposing seven-letter strings for brief periods followed by a mask. Young adults were able to identify three letters at a rate of 27 msec per letter, a value which is typical of other reports. Any additional letters were identified at a much slower rate. In contrast, older adults were able to identify only two letters, at a rate of 35 msec per letter. Older men thus showed a decline in both the amount of and rate at which information was encoded from the icon within a fixation period. These findings have implications for experiments involving visual arrays.

Adolescent↗
PubMed1982

An analysis of the effect of aging on recognition memory.

The effect of aging on recognition memory processing is analyzed in terms of a stimulus-sampling model of recognition memory with parameters representing encoding effectiveness and stimulus overlap or interference. A standard study-test paradigm with a 2-alternative-forced-choice test was used with older and younger adults. While no significant difference in accuracy between groups was observed, it was found that the distribution of recognition scores for older adults was bimodal with an upper mode which did not differ from the younger group and a lower mode representing a large decrement in performance. For those adults who showed recognition deficity with aging, analysis in terms of the model revealed reduced encoding effectiveness. Recognition performance of the older adults was strongly related to verbal ability as measured by the WAIS vocabulary subtest. Disparate results of recognition studies in the aging literature are discussed in terms of variations in verbal ability among the groups studied.

Adult↗
PubMed1981

Effects of bizarre and interacting imagery on learning and retrieval of the aged.

The effects of bizarre and interacting imagery on the acquisition and retrieval of 20 paired associates (PA) were examined using 30 young and 27 (out of 38) elderly who successfully learned the PAs to criterion. Interaction imagery facilitated acquisition, especially for the elderly, but did not benefit retrieval. There was no evidence that bizarre imageries were superior than logical one in facilitating acquisition or retrieval. Furthermore, the elderly tended to resist using bizarre imagery, and both young and elderly subjects tended to use imagery that was more congruent with non-bizarre life experiences and events.

Adult↗
PubMed1981

Age, imagery, and practice in paired-associate learning.

Elder and college-aged subjects performed a series of paired-associate tasks designed to investigate age differences in the use of mnemonic imagery as a strategy in verbal learning. Subjects were tested on three occasions at two-week intervals. Two ten-pair lists of concrete-noun paired associates were learned at each session. Standard (no-imagery), self-generated, and experimenter-provided imagery instructions were used. Results indicated that imagery instructions are quite beneficial for elders in the short run. However, elders tended not to use the strategy effectively after a two-week interval unless reminded to do so. Results also indicated that elders were capable of generating useful learning strategies on their own when given sufficient experience with the task.

Adolescent↗
PubMed1981

The effect of age on speed of lexical access.

The present study concerns the effect of aging on speed of lexical access. Normative word-frequency was manipulated in a lexical decision task with older and younger adults. Three methods of comparing processing time in the lexical access stage across age groups were evaluated: the subtraction method, the analysis of covariance, and the additive-factor method. The adequacy of the subtraction method was questioned because of the difficulty of finding a control task identical to the experimental task in all processing stages except lexical access. The analysis of covariance was considered to be inconclusive in this kind of application because of the correlation between the covariate and the independent variable, age. The additive-factor method appeared to be a viable alternative to these two analyses. Within this framework, the lack of an interaction between the two variables, age and word-frequency, indicates that the factors affected different stages of processing. Since word-frequency has been shown to affect the lexical access stage, the present result was taken to suggest that aging does not affect speed of lexical access.

Aged↗
PubMed1981

Mental rotation and age reconsidered.

Research has established that subjects required to identify tilted patterns do so by first rotating them mentally into an upright position. Gaylord and Marsh (1975) found that the rate of mental rotation of elderly subjects was 84% slower than young subjects. Using simpler patterns and college-enrolled "elderly," Jacewicz and Hartley (1979) found no age difference in rotation rates. Using Jacewicz and Hartley's patterns, and a subject sample more similar to Gaylord and Marsh's, the present study found that although absolute rates were increased, an age-decline of 96% was still in evidence.

Adult↗
PubMed1980

Age and word frequency effects in continuous recognition memory.

Fifty-seven males representing groups with median ages of 20, 52, and 63 years were presented with a long sequence of words. Using a four point scale, they judged whether each word was presented for the first ("new") or second ("old") time in the sequence. High and low frequency words and separations of 0 to 64 words between the two presentations of a given word were employed. Analyses of errors confidence judgments and decision times revealed minimal or no age difference when the number of words intervening between successive presentations did not exceed the span of immediate memory. Older subjects' performance declined more rapidly than younger subjects from 3 to 12 second retention intervals, but declined at about the same rate from 12 to 192 second retention intervals. Low frequency words were better remembered by all age groups and there was no interaction between the effects of age and word frequency in any dependent measure.

Adult↗
PubMed1979

A questionnaire assessment of age differences in retention of recent and remote events.

Age-related differences in memory for recently and remotely dated events have been evaluated through questionnaire assessment. Results from previous studies employing the technique differ in the analysis of retrieval of recent and remote events. In attempting to reconcile extant results from the literature, the following study employed a group of healthy males ranging in age from 26 to 69. The results showed: 1. The elderly exhibited no impairment of the ability to remember recent colloquial events. 2. The elderly's surprisingly accurate recall of remote events was not a product of selective and frequent rehearsal.

Adult↗
PubMed1978

Toward applying cognitive skill training to memory problems.

Four elements of a successful program of cognitive skill training for the elderly include: (a) the use of mnemonic aids for the memorization of new information; (b) the development of motivational techniques to enhance attention to materials and maintenance of cognitive skills acquired through training; (c) the design of techniques which utilize individual differences in abilities, personality, and cognitive style to enhance individual programs of cognitive skill training; and (d) the use of appropriate medical and/or psychiatric care when necessary.

Aged↗
PubMed1978

Speed of retrieval from long-term memory in relation to age, familiarity, and datedness of information.

The time required to name four groups of pictures was measured in 83 community dwelling males (18-70 years of age). One group consisted of objects used 50 to 70 years ago (unique dated exemplars), and another consisted of objects unique to contemporary times (unique contemporary exemplars). For comparison, other pictures of contemporary and dated objects commonly used in both periods were employed. There were three major findings. One, the familiarity of the pictured object is the major determinant of the time required to retrieve its name. Older subjects named the dated unique objects that were relatively more familiar to them more rapidly than did younger adults, while the reverse was true for contemporary unique objects. No age difference in the speed of naming common contemporary objects was found. Two, the overall age-related difference in naming latency was attributed to perceptual-motor aspects of the task. Three, the physical features as well as the familiarity of the object contributed to the speed of retrieval of the object's name.

Adolescent↗
PubMed1975

Changes in alpha rhythm asymmetry during learning of verbal and visuospatial tasks.

Alpha activity in the two cortical hemispheres was examined during learning and overlearning of a verbal and a visuospatial task. Compared to a pretask baseline condition, the amount of alpha activity during the tasks was decreased. An increase in alpha activity was found from learning to overlearning in both tasks. A greater amount of alpha was found in the right hemisphere for both tasks. In addition, no difference in the degree of alpha asymmetry was found between the tasks. This was discussed in light of prior contrary findings. A significant positive correlation was found between change in learning rate and change in alpha asymmetry during the verbal task. An interpretation of this finding was offered in terms of the level of hemispheric activation reflecting the degree of task engagement.

Alpha Rhythm↗