Associative symmetry versus independent associations in the memory for object-location associations.

The formation of associations between objects and locations is a vital aspect of episodic memory. More specifically, remembering the location where one experienced an object and, vice versa, the object one encountered at a specific location are both important elements for the memory of an event. Whether episodic associations are holistic representations of individual components or whether there are unidirectional, separately modifiable connections between them has been investigated nearly exclusively using verbal stimuli. A preliminary conclusion concerning this controversy is that verbal associations are, at least, highly correlated (M. J. Kahana, 2002). This theoretical debate, which in the past has undergone a major empirical effort, is still of relevance for the concurrent global matching models of associative memory (S. E. Clark & S. D. Gronlund, 1996). The authors used variations of a novel object-location learning paradigm to complement the accumulated evidence regarding the nature of episodic associations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Free associations with EPS and memory

In celebrating 50 years of EPS involvement in memory, I have taken a personal line rather than trying to achieve even coverage. Accordingly, the paper is in three parts. In the first, some early papers that have resonance for today's debates are described. Their framework was Bartlettian, with versions of schema theory as the guiding principles, and they were formative in my undergraduate education. This phase ended in the 1950s. From then, there was an explosion of work in memory in the U.K., the most important parts of which saw light at the EPS. This requires a proper history, which requires a proper space. In the second part, then, rather than show favourites or sample at random, my own involvement in EPS and memory is fallibly revisited, to give some flavour of the excitement, as well as some of the ideas. In the final part, some current work is described, and the Current State Buffer is introduced, in the hope of anticipating a little of the next 50 years.     

The effect of voluntary eye movements on associations and mood

OBJECTIVE: Our aim was to compare the outcome of esophageal resection for carcinoma in elderly patients (aged over 70 and over 80 years) with that of younger patients managed within a single specialist thoracic surgery unit. PATIENTS AND METHODS: Between January 1987 and November 1997, 523 patients underwent esophagectomy for carcinoma in the Nottingham City Hospital Thoracic Surgery Unit. The patients were divided into 3 groups by age: group I, under 70 years (n = 337); group II, 70 to 79 years (n = 150), and group III, 80 to 86 years (n = 36). These groups were compared with regard to preoperative medical status, operability and resectability, complications, operative mortality, and longterm survival. RESULTS: Patients in groups II (6.0%) and III (2.8%) had fewer preexisting respiratory problems than patients in group I (12.5%), and the patients in group III had fewer preexisting cardiovascular problems (16.7%) than patients in groups I (25.2%) and II (32.7 %). Although patients in group III were generally less likely to have operable lesions (64.3%), no significant differences in resectability rate were detected among the 3 groups (80.8%, 77.7%, and 80%). Elderly patients (groups II and III) had a higher incidence of overall (34% and 36.1%), respiratory (24.7% and 19.4%), and cardiovascular (7.3% and 11.1%) complications than those aged under 70 years (24.6%, 16.3%, and 2.1%, respectively). However, operative mortality (4.7%, 6.7%, and 5.6%) and 5-year survivals inclusive of operative mortality (25.1%, 21.2%, and 19.8%) were similar among the 3 groups. CONCLUSIONS: Accumulated experience in all aspects of perioperative management may account for a low hospital mortality in elderly patients despite a greater operative risk. The survival benefit is similar to that in the younger age groups, enforcing the view that esophagectomy within specialist thoracic units can be safely offered (in appropriately selected patients) with acceptable long-term survival in all age groups.     

The modality-match effect in recognition memory.

The modality-match effect in recognition refers to superior memory for words presented in the same modality at study and test. Prior research on this effect is ambiguous and inconsistent. The present study demonstrates that the modality-match effect is found when modality is rendered salient at either encoding or retrieval. Specifically, in Experiment 1, visual and auditory study trials were either randomly intermixed or presented in blocks, followed by a standard (old–new) recognition test. The modality-match effect was observed for the mixed but not the blocked condition. Experiment 2 used a modality-judgment test (requiring a seen, heard, or new judgment). The resulting measure of recognition memory exhibited the modality-match effect for both list conditions. These results imply (a) that the modality-match effect is a consistent finding when modality is salient and (b) that the effect arises at retrieval rather than encoding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unitization and grouping mediate dissociations in memory for new associations.

Previous research has demonstrated performance dissociations between explicit and implicit memory for newly acquired associations between unrelated words. The present article accounts for this finding in terms of two factors: unitization and grouping. Unitization involves representing previously separate items as a single unit, and grouping involves forming associations among separate representations. We propose that grouping facilitates primarily explicit remembering by providing the routes for accessing encoded word pairs via the cues available during testing; in contrast, unitization affects primarily implicit remembering by enabling the reintegration of studied items in response to partial cues. Consistent with this view, the results from two experiments show that by focusing processing on the relation between target word pairs, explicit remembering can be manipulated independently of implicit remembering. Two further experiments reveal that a material manipulation (concreteness of words) affects both implicit and explicit remembering. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential TCR signaling and the generation of memory T cells

PURPOSE: Serum soluble interleukin-2 receptor level is a sensitive and quantitative marker of lymphocyte activation. We determined levels of serum soluble interleukin-2 receptor in children with reflux nephropathy to evaluate its clinical significance in the prediction for the progression of renal injuries. MATERIALS AND METHODS: Serum soluble interleukin-2 receptor values were determined in 63 children with reflux nephropathy. The group consisted of 37 boys and 26 girls 10 to 18 years old. T cells (naive and memory), B cells and macrophages were evaluated immunohistochemically in the scarred kidneys of 4 other patients (3 boys and 1 girl 5 to 16 years old) who underwent nephrectomy due to severe reflux nephropathy with little function seen on (99m)technetium-dimercapto-succinic acid (DMSA) renal scan. Levels of serum soluble interleukin-2 receptor were measured by an enzyme-linked immunosorbent assay. We simultaneously determined serum levels of creatinine and beta2-microglobulin, and urinary levels of alpha1-microglobulin and microalbumin. Individual functions of the right and left kidneys were estimated by renal dimercaptosuccinic acid uptake. RESULTS: Levels of serum soluble interleukin-2 receptor in the patients who had low total uptake of DMSA (right uptake plus left uptake) were significantly higher than those from patients with normal total uptake. Levels of serum soluble interleukin-2 receptor correlated significantly with levels of creatinine (r=0.616, p <0.0001) and beta2-microglobulin (r=0.803, p <0.0001), and levels of urinary alpha1-microglobulin (r=0.753, p <0.0001) and microalbumin (r=0.673, p <0.0001). A significant negative correlation was observed between levels of serum soluble interleukin-2 receptor and total DMSA uptake values (right uptake plus left uptake r=-0.678, p <0.0001). In the scarred kidneys leukocyte infiltrates were markedly increased in fibrosed spaces. The predominant cell type in these lesions was memory T cells. CONCLUSIONS: These results suggest that elevated levels of serum soluble interleukin-2 receptor are likely to reflect activated T cells in the kidneys of patients with reflux nephropathy and may be a useful predictor of progression of renal injury in these children.     

The effect of induced stress on free associations.

"The purpose of the present paper was to investigate the influence of stress on the common responses in free associations. On the basis of a dedifferentiation theory, it was predicted that stress would reduce the frequency of common responses. On the basis of a drive theory, one might anticipate an increase in frequency of common responses. Stress was operationally defined as a situation in which subjects had just taken a difficult course examination and were waiting to be told their grades. Results indicated highly significant decrements in common responses as a function of stress. There was no tendency toward 'novel' responses (responses not given to a stimulus in the Russell and Jenkins standardization [1954])." From Psyc Abstracts 36:01:3HJ61S. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The memory enhancement effect of emotion is absent in conceptual implicit memory.

Memory for emotional stimuli is superior to memory for neutral stimuli. This study investigated whether this memory advantage is present in implicit memory. Memory was tested with a test of explicit memory (associate cued recall) and a test of conceptual implicit memory (free association) identical in all respects apart from the retrieval instructions. After studying emotional and neutral paired associates, participants saw the first member of the pair, the cue; in the test of explicit memory participants were instructed to recall the associate; in the test of implicit memory participants were instructed to generate the first word coming to mind associated to the word. Depth of study processing dissociated performance in the tests, confirming that the free-association test was not contaminated by an intentional retrieval strategy. Emotional pairs were better recalled than neutral pairs in the test of explicit memory but not in the equivalent test of implicit memory. The absence of an emotion effect in implicit memory implies that emotional material does not have a privileged global mnemonic status; intentional retrieval is necessary for observing the emotion-related memory advantage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modality specificity of implicit memory for new associations.

In previous research we demonstrated that newly acquired associations between unrelated word pairs influence the magnitude of priming effects on word-completion tests. This phenomenon of implicit memory for new associations is observed only following semantic study elaboration. The present experiments reveal that implicit memory for new associations, though elaboration dependent, is also modality specific: Associative effects on a visual word-completion test were consistently reduced by study-test modality shifts. In contrast, explicit memory for new associations, as indexed by cued-recall performance, was uninfluenced by modality shifts. The modality effect on completion performance was eliminated when subjects were given brief visual preexposures to, or were required to construct visual images of, word pairs presented in auditory study conditions. The results pose a theoretical puzzle insofar as they indicate that within the domain of implicit memory, access to the products of elaborative processing depends on modality-specific, sensory-perceptual processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Explicit contamination in "implicit" memory for new associations

In one view of implicit memory, priming arises from modification of preexisting representations; however, the role of such representations is currently in doubt following findings of implicit memory for newly formed associations. Closer consideration of studies reporting this effect, and of others that have failed to obtain it, suggests that such priming might results from the employment of explicit memory strategies. With measures designed to permit exclusion of such strategies, three experiments using lexical decision and stem-completion tasks found no evidence of truly implicit memory for unrelated pairs. Instead, priming was found only in those subjects (50% of the total in one experiment) who reported using explicit memory in stem completion. Contrary to previous conclusions, the results indicate a role for established representations in explaining implicit memory.     

Individual differences in memory associations involving the positive and negative outcomes of alcohol use.

In previous studies of memory association and alcohol use, the authors found that positive outcomes of drinking were associated in memory with alcohol concepts among heavier drinkers. The present study examined whether previous alcohol use predicted associative memory responses to negative, as well as positive, outcomes of drinking. It also examined whether the normative frequency of positive and negative outcomes affected responses. In the present sample of 609 students, previous alcohol use, normative frequency of outcome, and the number of outcomes listed strongly predicted alcohol-related associative responses to positive outcomes and, to a lesser extent, negative outcomes. The results suggest that repetitive alcohol use strengthens the association in memory between alcohol concepts and both positive and negative outcomes. However, thoughts about potential positive outcomes may be more readily cued by situational factors and events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Separating consciously controlled and automatic influences in memory for new associations.

The process dissociation paradigm was applied to investigate the contributions of automatic and consciously controlled processes to the repetition priming effect for new associations, under elaborative encoding (Experiments 1 and 2) and copy instructions (Experiment 3). Semantically unrelated context–target word pairs were presented during study, and context words and stems were presented during test. Target word stems were paired with the same context words as at study (intact), paired with different context words from study (recombined), or were the stems of unstudied words (control). Participants had to complete stems with the first word that came to mind (indirect), with studied words (inclusion), or with new, unstudied words (exclusion). Results indicated that consciously controlled processes mediated the associative repetition effect under elaborative encoding, whereas automatic processes were implicated under copy instructions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The generation effect with nonwords.

This article challenges the view that the generation effects occur only for items represented in semantic memory. We obtained generation effects regardless of the lexical status of the cue used to generate the target and regardless of the lexical status of the target. Generation effects were comparable for wordlike and unwordlike nonwords. The effect for nonwords depended on displaying the target at the end of each generate trial. We argue that such feedback gives subjects appropriate visual experience with nonwords; otherwise, the disadvantage of never seeing the generated nonwords could overwhelm any memorial advantage conferred by generating. Generated items also suffer when study and test formats differ more for generated than for read items; we demonstrated that changing format reduces recognition for nonwords. We conclude that previous failures to demonstrate generation effects with nonwords reflect confoundings with such familiarity factors and that the generation effect does exist for nonwords. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bidirectional associations in multiplication memory: Conditions of negative and positive transfer.

A variety of experimental evidence indicates that the memory representation for multiplication facts (e.g., 6 × 9 = 54) incorporates bidirectional links with a forward association from factors to product and a reverse association from product to factors. Surprisingly, the authors did not find evidence in Experiment 1 of facilitative transfer-of-practice from multiplication (6 × 9 = ?) to factoring (54 = ? × ?); in fact, multiplication practice produced item-specific interference with factoring. Similarly, the authors found no evidence in Experiment 2 that repetition of specific factoring problems (54 = ? × ?) facilitated performance of corresponding multiplication problems (6 × 9 = ?). In Experiment 3, participants practiced both multiplication and factoring and presented facilitative transfer in both directions. Thus, bidirectional facilitation occurred if both operations were practiced, but interference occurred when only one operation was practiced. We propose that this seemingly paradoxical behavior occurs because it is adaptive for the bidirectional retrieval structure to retain operational flexibility in the context of practicing both operations, whereas it is adaptive to specialize the memory representation for the practiced operation (i.e., factoring or multiplication) when only one operation is practiced. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The shape memory effect and pseudoelasticity in polycrystalline Cu-Zn alloys

The shape memory effect associated with the reverse transformation of deformed martensite, pseudoelastic behavior involved in stress-induced martensite formation and the reversion of strained martensite after an applied stress is relaxed aboveA _f have been studied. Grain size and specimen geometry effects have been related to the above phenomena. Although recoverable strains as high as 10.85 pct were observed in coarse-grained (“bamboo” type) specimens, the shape memory effect is restricted in fine-grained specimens because of permanent grain boundary deformation and intergranular fracture which occurs at relatively low strains. A fine grain size also acts to suppress pseudoelastic behavior because permanent, localized deformation is generated concurrent with the formation of stress-induced martensite which inhibits reversion of the latter upon release of stress. The apparent plastic deformation of martensite belowM _f can be restored by transforming back to the original parent phase by heating toA _f (shape memory) or alternatively, can be recovered belowM _f by applying a small stress of opposite sign. Martensite deformed belowM _f with the same stress maintained while heating persists aboveA _f, but reverts to the parent phase in a pseudoelastic manner when the stress is relieved. The athermal thermoelastic martensite, which forms in groups composed of four martensite plate variants, undergoes several morphology changes under deformation. One of the variants within a plate group cluster may grow with respect to the others, and eventually form a single crystalline martensitic region. At a later stage pink colored deformation bands form in the same area and join up with increasing stress, resulting in thermally irreversible kinks. The clusters of plate groups may expand like grain growth or contract as a whole during deformation, or act as immobile “subgrains” which lead to permanent deformation at their boundaries. Stress-induced martensite usually forms as one variant of parallel plates which join up with increasing stress to form single crystalline regions. Further stress leads to pink colored deformation bands, similar to those in the deformed athermal martensite. Other similarities and differences between the stress-induced and athermal martensite have been investigated and are discussed.     

The shape memory effect and pseudoelasticity in polycrystalline Cu-Zn alloys

The shape memory effect associated with the reverse transformation of deformed martensite, pseudoelastic behavior involved in stress-induced martensite formation and the reversion of strained martensite after an applied stress is relaxed aboveA _f have been studied. Grain size and specimen geometry effects have been related to the above phenomena. Although recoverable strains as high as 10.85 pct were observed in coarse-grained (“bamboo” type) specimens, the shape memory effect is restricted in fine-grained specimens because of permanent grain boundary deformation and intergranular fracture which occurs at relatively low strains. A fine grain size also acts to suppress pseudoelastic behavior because permanent, localized deformation is generated concurrent with the formation of stress-induced martensite which inhibits reversion of the latter upon release of stress. The apparent plastic deformation of martensite belowM _f can be restored by transforming back to the original parent phase by heating toA _f (shape memory) or alternatively, can be recovered belowM _f by applying a small stress of opposite sign. Martensite deformed belowM _f with the same stress maintained while heating persists aboveA _f, but reverts to the parent phase in a pseudoelastic manner when the stress is relieved. The athermal thermoelastic martensite, which forms in groups composed of four martensite plate variants, undergoes several morphology changes under deformation. One of the variants within a plate group cluster may grow with respect to the others, and eventually form a single crystalline martensitic region. At a later stage pink colored deformation bands form in the same area and join up with increasing stress, resulting in thermally irreversible kinks. The clusters of plate groups may expand like grain growth or contract as a whole during deformation, or act as immobile “subgrains” which lead to permanent deformation at their boundaries. Stress-induced martensite usually forms as one variant of parallel plates which join up with increasing stress to form single crystalline regions. Further stress leads to pink colored deformation bands, similar to those in the deformed athermal martensite. Other similarities and differences between the stress-induced and athermal martensite have been investigated and are discussed. Formerly with the University of Illinois at Urbana-Champaign     

Cholinomimetics and memory. The effect of choline chloride

Young normal subjects received 16 g of choline chloride in a double-blind A-B-A design. Short- and long-term memory function was evaluated. Comparison of group means indicated that choline chloride did not significantly affect short-term memory or long-term memory. However, individual subjects may have had some aspects of long-term memory affected by choline chloride treatments. The results suggest that the effect of lower doses of choline on long-term memory should be evaluated.     

The emergent generation effect and hypermnesia: Influences of semantic and nonsemantic generation tasks.

The generation effect is moderated by experimental design, affecting recall in within-subjects designs but typically not in between-subjects designs. However, N. W. Mulligan (2001) found that the generation effect emerged over repeated recall tests in a between-subjects design, calling into question the generality of this limiting condition. In addition, the generate condition but not the read condition produced hypermnesia (increased recall over tests). The present experiments demonstrate that semantic-based (semantic-associate and category-associate) generation tasks produce this pattern of results whereas nonsemantic (letter transposition, rhyme, word fragment) generation tasks do not. Thus, the emergent generation effect appears to be a byproduct of semantic elaboration rather than a direct product of generation. In addition, high- and low-imagery words produced equivalent hypermnesia and emergent generation effects, arguing against a mediating role for imagistic encoding. Finally, there is no evidence of an emergent generation effect for nonwords, another traditional limiting condition of the generation effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The self-reference effect in memory: A meta-analysis.

In this review, the authors examine the basis for the mnemonic superiority that results from relating material to the self. A meta-analysis confirms the expected self-reference effect (SRE) in memory, with self-referent encoding strategies yielding superior memory relative to both semantic and other referent encoding strategies. Consistent with theory and research that suggest self-reference (SR) produces both organized and elaborate processing, the SRE was smaller (a) when SR is compared with other-reference (OR) rather than semantic encoding and (b) when the comparison tasks promote both organization and elaboration. Thus, the SRE appears to result primarily because the self is a well-developed and often-used construct that promotes elaboration and organization of encoded information. The authors discuss the implications of these and other findings for theories of the SRE and for future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)