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Biomedical subjects

S Hashtroudi

Publications and source records attributed to S Hashtroudi.

6 recordsLinked to original sources

Age differences in using source-relevant cues.

Subjects heard words originating from 2 speakers and later decided which of the 2 speakers said the words. Older adults had difficulty with source monitoring when perceptual cues from 2 sources were similar (2 female speakers), but this difficulty was overcome when perceptual cues were distinctive (a male and a female speaker) and were the only salient cues to source. Older adults also benefited from distinctive spatial cues when these were the only salient cues to source. Older adults, however, experienced difficulties in using multiple cues (both perceptual and spatial) to source effectively, whereas younger adults were able to use multiple cues to enhance their source-monitoring performance. It is suggested that age differences in source monitoring result from differential cue utilization.

Adult

The effects of milacemide on item and source memory.

Prior research has shown that memory for facts and items (item memory) and memory for where one has learned these items (source memory) can be dissociated under certain conditions. In this study, we examined the effects of milacemide, a derivative of glycine, on memory for item and source information in healthy young and older adults. These results pointed to a dissociation between source memory and item memory: Milacemide administration seemed to facilitate memory for source information but did not affect recognition memory.

Acetamides

Does organization improve priming?

In five experiments, the effects of organization on implicit memory or priming tests were compared with its effects on the explicit memory tests of free and cued recall. Organization was manipulated by varying list structure (blocked vs. random presentation of categorized items) and by instructions. The results showed that organization had parallel effects on the category-production priming test and free- and cued-recall tests; performance was enhanced by organization on both types of tests. It was also demonstrated that the effect of organization on priming was limited to the category-production test and was not obtained with the word-identification priming test. These results suggest that performance on implicit and explicit memory tests is similarly affected by experimental manipulations when both types of tests rely on conceptually driven processing. In addition, performance on two implicit tests is dissociated when one test relies on conceptually driven processing and the other on data-driven processing.

Adult

Priming is independent of skill learning.

This study examined the relation between repetition priming and skill learning. Priming refers to facilitation in processing a specific item as a result of previous exposure to that item. Skill learning refers to general improvement in task performance as a function of practice. In Experiment 1 (N = 60), skill acquisition occurred in partial-word identification and inverted reading tasks but not in a word-fragment completion task. However, the amount of priming was the same in all three tasks. In Experiment 2 (N = 52), priming effects in partial-word identification did not vary as a function of practice with degraded words. In Experiment 3 (N = 40), skill learning was greater with high- than with low-frequency words, whereas priming was unaffected by word frequency. Experiment 4 (N = 20) ruled out the possibility that explicit retrieval was involved in the implicit memory tasks. These results suggest that priming can be independent of skill learning.

Humans

Effects of aging on priming and skill learning.

This study examined the effects of aging on 2 kinds of implicit memory; repetition priming and skill learning. In Experiment 1, older adults showed less improvement in the skill of reading inverted words than did young adults, but priming performance did not differ for the 2 age groups. Similarly, in Experiment 2, in a partial-word identification task, skill learning was observed only for young adults, whereas there was no age difference in priming. Experiments 1a and 2a, however, showed that when older adults were presented with more perceptual information than were young adults, the age deficit in skill learning was eliminated. These results indicate that skill learning is impaired under data-limited conditions, whereas priming is unaffected under these conditions. It is proposed that the age deficit in skill learning is related to a deficit in perceptual organization and reorganization.

Adolescent

Glycine prodrug facilitates memory retrieval in humans.

Modulation of glycine concentrations in the brain influences learning and memory functions in experimental animals. We administered milacemide, a glycine prodrug, or placebo to young and older healthy adults, who performed a word-retrieval task. Milacemide administration increased the number of words retrieved and decreased the latency with which these words were retrieved for both young and older adults.

Acetamides