Search

Temporal and semantic associative processes during the acquisition of new verbal information undergo various changes across the life span. Temporal order clusters and subjective clusters were monitored during verbal learning trials using the Rey (Auditory Verbal Learning Task) for 1471 participants aged 8–91. Pairs, three-word, and four-word clusters were measured. Subjective clusters were generated at similar frequency across the whole life span. By contrast, a clear inverted-U curve across life span was indicated for temporal clusters. More words were subjectively clustered than clustered by temporal presentation order. The number of words clustered increased across trials, and cluster types showed a different increase profile across trials. The subjective cluster increment was faster and steeper than the temporal cluster increment in most of the age segments. Life span trajectory tendencies in the formation of temporal and semantic associations in recall were interpreted in relation to different frameworks of cognitive life span changes. [ABSTRACT FROM AUTHOR]

Context effects on recognition memory provide an important indirect assay of associative learning and source memory. Neuropsychological studies have indicated that such context effects may obtain even if the contexts themselves are not remembered--for example, in individuals impaired on direct tests of memory for contextual information. In contrast, a recent study indicated that the effects of temporal context reinstatement on visual recognition obtain only when the contextual information itself was explicitly recollected. Here we report that the effects of reinstatement of spatial-simultaneous context on visual object recognition memory obtain irrespective of whether those context stimuli are explicitly recognized. We suggest that spatial-simultaneous context effects might be based on ensemble unitization of target and context stimuli at encoding, whereas temporal context effects may require recollective processes. Keywords: Memory; Context; Binding; Recognition; Source memory; Association.

The authors describe a transient phase during training on a movement sequence wherein, after an initial improvement in speed and decrease in variability, individual participants' performance showed a significant increase in variability without change in mean performance speed. Subsequent to this phase, as practice continued, variability again decreased, performance significantly exceeded the gains predicted by extrapolation of the initial learning curve, the type of errors committed changed, and performance became more coherent. The transient phase of increased variability may reflect a mixture of 2 (or more) performance routines before the more effective one is set and mastered, presumably the setting up of a sequence-specific representation. Both group and individual analyses indicated a departure from the single process (e.g., power-law) model of learning. However, although similar phases appeared in the mean group data, there was little correspondence to individual participants' time courses, and the individuals' gains in the second low-variability phase were masked. Keywords: procedural learning, sequence learning, strategy change

We examined the hypothesis that older adults' deficits in contextual memory result from difficulties in contending with partial encoding-to-retrieval changes in the context. We measured effects of contextual change and constancy on recognition memory for words, in older and younger adults. We assessed the ability to adjust to partial contextual changes by manipulating encoding-retrieval context similarity: identical, new and unrelated, conceptually similar, or perceptually similar. For both older and younger adults, identical and conceptually similar contexts benefited recognition of target words, whereas perceptually similar contexts did not. Older adults did not make more false alarms. In contrast, older adults' direct recognition of contextual stimuli was at chance. These results indicate that retrieval processes, rather than encoding or rigidity in the use of contextual cues, are implicated in older adults' difficulties in memory for contextual information. Key Words: Aging--Context effect--Source memory--Recognition.

While effects of contextual change or constancy on memory are widely found when tested by free and cued recall, there is greater inconsistency in context effects on recognition. This study employed a paradigm maximizing target-context interactivity and specificity to reveal three levels of context effects on successful retrieval, as well as context effects on the generation of false alarms, thereby revealing separable contributions of target--context binding, additive familiarity, and configural constancy. The separability of these factors enables the use of memory context effects as tools for investigating associative memory.

The ability to generate associative representations and to retrieve them from long-term episodic memory generally declines in healthy aging. However, it is unclear whether healthy aging has differential effects on associative memory for identity, spatial configuration, and temporal order relationships. In the current study, we assessed how healthy aging impacts on associative memory for identity, spatial, or temporal relationships between pairs of visual objects via discrimination of intact and rearranged pairs. Accuracy and response time performance of healthy older adults (aged 65–80) were compared with young adults (ages 19–30). Age-related declines in associative memory were observed equally for all types of associations, but these declines differed by associative status: aging most strongly affected ability to discriminate rearranged pairs. These results suggest that associative memory for identity, spatial, and temporal relationships are equally affected by healthy aging, and may all depend on a shared set of basic associative mechanisms. [ABSTRACT FROM AUTHOR]

Twenty-five older and 25 younger adults were compared on declarative (i.e., Rey Auditory-Verbal Learning Test and Visual Pair Associations) and procedural (i.e., Tower of Hanoi puzzle and Porteus mazes) learning tasks. A dissociation between learning rate on declarative and procedural tasks was demonstrated for the elderly participants. The younger group showed a steeper learning rate than the older group on the declarative tasks. By contrast, the learning rate of both groups on the procedural tasks did not differ consistently, whether the measure was number of errors/moves or time elapsed (with one exception in which the older group showed a steeper learning rate than the younger group). The younger group's baseline performance was better than that of the older group on all tasks employed in this study. These results reinforce the importance of distinguishing between baseline performance and the rate of learning on procedural learning tasks.

Study of incidental learning of temporal order using the Rey Auditory Verbal Learning Test reveals that memory of temporal order is sensitive to age and gender. Temporal order is linked to retention and not acquisition. The scores obtained are too high to be attributed to chance. The test sample includes 190 healthy subjects from four age groups.

Objective: Previous research has shown that when individuals are asked questions referring to previously seen visual stimuli, their eye movements spontaneously return to the visual area where the stimuli were first seen. This recurring eye movement phenomenon has been shown to assist the memory retrieval of visual images. Individuals with moderate-to-severe traumatic brain injury (TBI) typically suffer from visual memory deficits as well as difficulty in spontaneously initiating mnemonic strategies. Perhaps TBI patients have trouble employing the eye movement reactivation strategy, thus further contributing to the visual memory deficits so prevalent among this population. Method: In this study, 27 healthy individuals and 27 patients with moderate-to-severe TBI from the Lowenstein Rehabilitation Hospital participated in a memory task. Participants were first exposed to stimuli and were then asked questions about the displayed stimuli. The testing session was conducted for each participant under two conditions: (1) while eyes were free to move over the screen; (2) while eyes were fixated. Results: Study findings show that the control group significantly benefitted from the free viewing in comparison to the fixed viewing condition, while this effect was absent among the TBI group. This was corroborated by eye tracking data showing that participants with TBI showed a minimal tendency to reactivate eye movements effectively, as occurs among the healthy group. Conclusions: The research findings expand our comprehension of visual memory among the TBI population, presenting rehabilitation health clinicians with new directions in understanding visual memory deficits. [ABSTRACT FROM AUTHOR]

Objectives: Anxiety and subjective memory complaints (SMC) are major risk factors for Mild Cognitive Impairment (MCI) and dementia. However, the association between anxiety, SMC and medical help-seeking due to complaints is not clear. Here, we assessed anxiety which rose specifically by memory examination and compared it between help-seekers in memory clinics (HS) and non-help seekers (NHS). Methods: Twenty HS (60% female) were recruited from a memory Clinic, and 55 NHS (63% female) were recruited from the community. Participants (aged 59–82) completed objective memory assessment, Subjective Memory questionnaire, depression questionnaire and State-Trait Anxiety questionnaire. State-anxiety was assessed immediately following memory testing (indicating anxiety triggered by testing memory). For statistical evaluation, we used non-parametric tests. Results: HS participants reported significantly higher levels of state-anxiety and had more SMC compared to the NHS. No differences in objective memory tests and trait-anxiety were found. Conclusions: People who are seeking help in memory clinics (even those who do not meet any criteria for memory decline) are liable to be at high risk for MCI and dementia. Clinical Implications: We recommend that HS with SMC should be treated as a high-risk group, even if they do not show objective memory deficits. [ABSTRACT FROM AUTHOR]