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Biomedical subjects

T M Hess

Publications and source records attributed to T M Hess.

25 records · Page 2Linked to original sources
PubMed1986

Adult age differences in memory for explicit and implicit sentence information.

Adult age differences in the processing of implicit sentence information were examined by testing recognition memory for stated and implied information. The effects of organization on such processing also were examined by presenting test sentences in a structured (story) or unstructured (unrelated sentences) format. No age differences were observed in memory for implied instruments-suggesting that aging has little effect on the processing and storage of such implicational information. In addition, structure had little effect on memory for implied information but interacted with age in determining memory for explicity stated instruments: Young adults remembered more explicit information in the structured condition.

Adult↗
PubMed1986

Aging effects on prototype abstraction and concept identification.

The hypotheses that prototype abstraction is an automatic process unaffected by aging and that different aging effects associated with different types of concept learning can be accounted for by differential effortful memory process involvement were examined. Young and old adults were compared on tests of prototype abstraction and concept identification, and relationships between performance measures derived from these tasks and backward memory span were assessed. In the abstraction task, both age groups used prototypical organizational processes to structure incoming information, but age differences did exist in the specificity of the information used in prototype construction. Concept identification performance, however, declined with age, and the poorer performance of the old adults was related to their poorer memory skills. The results suggest that the different aging effects associated with different tests of conceptual skills are dependent upon the nature of the underlying processes.

Adult↗
PubMed1984

Effects of semantically related and unrelated contexts on recognition memory of different-aged adults.

Two experiments were conducted to examine adult age differences in the use of context information. In Experiment 1, the encoding of contextually influenced semantic features was examined, and the encodings of target words by both young and old adults were observed to be influenced by semantic information provided by the context. Older adults did make more semantic confusion errors, however, suggesting less distinctive encoding. Verbal ability also influenced performance, with the difference between ability groups being similar to that between age groups. In Experiment 2, target words were presented in semantically unrelated contexts, and older adults were found not to encode contextual information in this situation. It is hypothesized that the older adults' context effects in Experiment 1 were due to automatic activation of nonspecific word meaning features due to the relation between target and context. When no such familiar context existed, the older adults were less likely to use context information.

Adult↗
PubMed1983

Context utilization in young and old adults.

Two experiments examined adult age differences in the spontaneous use of context to study and retrieve information. Young and old adults were presented with a series of homographs (targets) that were paired with two context words which biased a specific meaning of the target. Recognition memory for targets was then tested by presenting them in the same context or removing or varying the context. In general, recognition decreased in both groups as the retrieval context became more dissimilar to the study context, suggesting that both young and old adults utilize context and that congruent study and retrieval information facilitates retrieval. However, it appeared that older primarily encoded general semantic information relating to the association between target and context, whereas younger adults encoded distinctive information about individual targets. Such encoding differences could account for observed age differences in false recognitions for lures in old contexts and correct recognitions for targets in new contexts.

Adolescent↗
PubMedDate not supplied

Aging-related changes in the processing and retention of script information.

Adult age differences in the processing of script-related information were examined in two separate experiments. In both studies, no age differences were observed in the pattern of reading times across different types of script actions, with all groups reading relevant actions faster than irrelevant ones. In addition, script structure had similar effects across age groups on both recall and recognition performance, with relevant actions being recalled better than irrelevant ones, and atypical actions recognized better than typical ones. In both cases, however, the younger adults exhibited better memory than the older adults for all types of actions, but the age differences in performance decreased as the relevance and typicality of the target information increased. It is suggested that aging is associated with greater dependence upon scripts in the encoding of scripted events.

Adolescent↗
PubMedDate not supplied

The selective removal of phosphorus from soil: is event size important?

Data from the Woburn Erosion Reference Experiment (Bedfordshire, UK) were used to test the hypothesis that losses of phosphorus (P) in small erosion events are as great as those in infrequent large events, and to examine the effect of storm characteristics on the selective enrichment of P in eroded sediment. For almost every plot event in the period 1988 to 1994, the clay-sized fraction of the sediment was enriched compared with the soil of the plots. There was more variation in clay enrichment for smaller erosion events than for larger ones. The clay and P contents of the sediment were strongly correlated (p < 0.01), and there was a wider range of P concentrations in the sediment derived from small events than in that from large events. However, individual events resulting in small soil losses (< 100 kg) did not account for greater P losses than larger events (> 100 kg). The greater frequency of smaller events, combined with the likelihood of higher P concentrations in the sediment, therefore accounted for a greater proportion of the P lost over the 6-yr period than the infrequent large events. Phosphorus concentrations generally increased with increasing peak discharge and decreased with increasing event duration. For the same return period, P losses were generally greater from plots cultivated up and down the slope than from those cultivated across the slope. Overall, our results suggest that small erosion events should be controlled to prevent P contamination of surface waters and that the most effective means of doing this are by the introduction of minimal tillage techniques and across-slope cultivations.

Agriculture↗