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Biomedical subjects

J S Freund

Publications and source records attributed to J S Freund.

9 recordsLinked to original sources
PubMed1990

Age differences in free recall and subjective organization.

Previous studies concerned with subjective organization occurring during free-recall learning have not provided consistent evidence for a hypothesis of organizational deficiency in the elderly. To assess the role of recall conditions in this discrepancy, the free-recall learning of younger and older adults was examined under conditions where the recalled words were either visible or not visible. Also, 5 measures of subjective organization, including measures used in earlier studies, were used to assess the role of measurement factors in producing the inconsistent findings. Younger adults, regardless of recall condition, recalled more words and showed more subjective organization than did the older adults with each of the measures. List length, rather than type of recall trial or measure of subjective organization, seems to be responsible for the conflicting findings obtained by other investigators.

Adolescent↗
PubMed1986

Activity duration and adult age differences in memory for activity performance.

Young and elderly subjects performed a series of activities that varied in the duration of their performances (45 s, 90 s, and 180 s). Duration was found to have a negligible effect on the subsequent recall of the activities and on the magnitude of the age deficit in recall. Operationalization of the program for performing an activity seems essential for establishing a memory trace of that activity's performance, but the duration of performing that activity seems to yield no further enhancement of that trace.

Adolescent↗
PubMed1986

Recognition and frequency judgments in young and elderly adults.

Three experiments examined frequency judgments and recognition memory in young and elderly adults. Subjects were presented a long list of words at either a 5-s rate (Experiments 1 & 3) or a 1-s rate (Experiment 2), after which frequency-judgment and recognition memory tasks were administered. Either an absolute (Experiments 1 & 2) or a relative (Experiment 3) frequency-judgment task was used. The recognition test, which involved repeated tests of some items, involved either one incorrect item paired with each correct item (Experiments 1 & 2), or four incorrect items (Experiment 3). Age-related differences in frequency judgments, for the more frequently presented items, were found in all three experiments. For the recognition scores, the predicted interaction between age and successive tests was found only in Experiment 3. The results were interpreted within the framework of age-related differences in elaborative encoding and in distractibility to irrelevant stimuli.

Adolescent↗
PubMed1976

Paired-associate learning in young and old adults as related to stimulus concreteness and presentation method.

This study investigated the learning of young and old adults as related to two variables, stimulus concreteness (low vs. high) and presentation method (recall vs. multiple choice vs. associate matching). The main findings were: (a) the elderly did not perform as well as the young adults, (b) for both age groups performance was better for the pairs with concrete stimuli than for the pairs with abstract stimuli, and (c) for both age groups performance was best with the associative matching method and poorest with the recall method. The paired-associate performance of the elderly is characterized by deficiencies in both response learning and associative learning.

Adult↗
PubMed1975

Scanning electron microscopy of glucocrticoid-treated hepatocytes and hepatoma cells in culture.

The morphological effects of exposure to hydrocortisone have been examined in two cell lines of liver origin by scanning electon microscopy. In one of these, an aneuploid line derived from a Morris hepatoma, the presence of hormone results not only in a suppression of cell proliferation, but in a marked flattening of the cells and loss of surface microvilli; in the other cell line, a diploid line derived from adult rat liver, the suppression of cell division is less marked, and the morphological effects of the hormone are far less striking. While the suppression of cell division in both of these cell lines is known to be rapidly reversible upon the removal of hormone, the presence of hormone causes the hepatoma cells to assume both monolayer growth characteristics and a morphology resembling those of cells derived from normal liver.

Animals↗