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Biomedical subjects

R R Hunt

Publications and source records attributed to R R Hunt.

12 recordsLinked to original sources
PubMed1992

Affective valence and memory in depression: dissociation of recall and fragment completion.

Depressed (n = 16) and nondepressed (n = 16) subjects' memory for affectively valenced words was assessed by an explicit test (free recall) and an implicit test (word fragment completion). Under free-recall instructions, depressed subjects recalled significantly more negatively valenced than positively valenced words, whereas the opposite pattern was observed in nondepressed control subjects. These results replicate those previously reported in the literature. The differential effect of word valence was absent, however, when memory was tested implicitly: Depressed and nondepressed subjects exhibited equivalent priming of positive and negative words. These data are discussed in terms of Williams, Watts, MacLeod, and Mathews's (1988) model of depression.

Adult↗
PubMed1990

Perceptual identification, fragment completion, and free recall: concepts and data.

The effects of orthographically distinctive and orthographically common words were compared on tests of free recall, fragment completion, perceptual identification, and lexical decision. Orthographic distinctiveness is argued to effect data-driven processing and, in light of recent theory, should have little effect upon free recall but substantial effects upon fragment completion and perceptual identification. The results showed superior recall and fragment completion of orthographically distinctive words but more accurate perceptual identification of orthographically common words. Latency of lexical decision was longer for orthographically distinctive than for orthographically common words. The visual complexity of orthographically distinctive words may require more extensive sensory processing than is possible within the temporal constraints of perceptual identification tests. The effect of orthographic distinctiveness upon free recall reveals a certain inadequacy in the notion of transfer-appropriate processing.

Cues↗
PubMed1989

A reexamination of the role of imagery in learning and memory.

Five experiments were conducted to examine whether the superior recall of concrete over abstract words might be better accounted for in terms of relative differences in the processing of relational and distinctive information rather than redundant verbal and imaginal memory codes. Concrete and abstract word pairs were presented in the standard paired-associated learning task or under conditions intended to affect the nature and extent of relational processing between pair members. Concreteness effects were attenuated or eliminated when relational processing was prevented at encoding (Experiments 3, 4, and 5) or when the use of encoded relations within pairs was prevented at recall (Experiments 1, 2, and 3). The results indicated the viability of an account of concreteness effects in paired-associate learning based on the joint functions of distinctive and relational information. They also remove theoretical constraints imposed on imagery theories by the incorrect assumption of a uniform presence of concreteness effects in memory for word lists.

Adult↗
PubMed1989

How much "effort" should be devoted to memory?

We focus on the issue of whether cognitive effort is causally related to memory. We begin with a discussion of the concept of cognitive effort as derived from capacity models of attention. We then suggest that the theoretical analysis of memory may involve concepts from different levels of psychological analysis, and we draw a distinction between concepts that represent boundary conditions and sufficient cause. When applied to memory phenomena, attentional concepts serve only as a boundary--or limiting--function in memory theory. In contrast, concepts that represent memorial processes serve as a sufficient cause function. In some instances, cognitive effort appears to have been used as a sufficient cause concept, resulting in some confusion. A review of the literature reveals a haphazard correlation between indexes of cognitive effort and of memory performance. Alternatively, the application of cognitive effort or capacity to the memory performance of certain populations (clinical, children, and elderly) illustrates a potentially more appropriate use of the concept.

Aged↗
PubMed1988

Adult age differences in memory for imagined and performed actions.

Young and older adults were presented a list of 24 descriptions of simple actions. For each list item, subjects were either instructed to perform the action or else were instructed to imagine themselves performing the action. On a surprise recall test, age differences were found for both performed and imagined actions as well as for source judgments (remembering which actions had been performed and which imagined). The latter effect, however, resulted from the near chance level of performance of a minority of the older adults; the performance of the majority of the older adults overlapped with that of the young adults on the source judgment task.

Adolescent↗
PubMed1986

The generation effect and reality monitoring: evidence from dementia and normal aging.

The role of semantic memory activation in accounting for generation effects and reality monitoring was investigated in young and old normal adults and in patients with dementia of the Alzheimer's type (DAT). Both young and old normal adults demonstrated higher recall for internally generated information than for externally presented information, whereas the DAT patients failed to demonstrate a generation effect. Similarly, reality monitoring scores (discrimination between internal and external items) were high for both age groups of normals, but near chance levels for the DAT group. These results implicate semantic memory as an important factor in generation effects.

Adult↗
PubMed1969

The synthesis and pharmacology of some 1,4,5,6-tetrahydropyrimidines.

1. Several 1- and 2-substituted, and 1,2-disubstituted, 1,4,5,6-tetrahydropyrimidines have been prepared and their toxicological and pharmacological properties have been investigated.2. In general the compounds were neuromuscular blocking agents with the monosubstituted members of the series showing a depolarizing type of activity and the disubstituted compounds a non-depolarizing type.3. The toxicity to mice of some of the monosubstituted compounds was increased by pretreatment of the animals with SKF 525A, but the toxicity of the disubstituted compounds was unaffected.4. The results obtained with these compounds are not at variance with a suggestion made previously that nicotinic action at the neuromuscular junction can result from an interaction between drug and receptor at two points separated by about 4 A.

Animals↗