Age differences in memory as a function of depth of processing

Variations in Age-Related Deficits among Episodic Memory Tasks: An Archival Study

Craik (1986) has proposed that age-related deficits on memory tasks are proportional to the extent to which these tasks require the use of self-initiated operations. Because the number of required self-initiated operations vary among traditional episodic memory tasks, these tasks should display a gradation of age-related deficits. The objective of this study was to test this hypothesis. A secondary analysis (i.e. based on the results of previous studies) was performed on 22 studies in which verbal stimuli were used as targets on more than one episodic memory task. Of the 24 comparisons provided by the studies, 21 supported the gradation concept. This result suggests that the self-initiated operation hypothesis is valid.

A study of remote spatial memory in aged rats

The effect of aging on remote spatial memory was tested in a group of 2-year-old rats (VR-O) that, as young adults, were reared for 3 months in a complex 'village' environment. The VR-O rats exhibited significant savings in finding the locations of specific reward compartments within the village, relative to a group of old rats (VNR-O) experiencing the village for the first time. The VNR-O rats were also impaired, relative to naive young rats, in learning the reward locations. Probe tests indicated that the VR-O rats retained allocentric spatial memory for the environment and were not using sensory or other non-spatial cues to guide behaviour. Overall, the results indicate that the aged rats experienced a decline in the ability to learn and remember detailed spatial relationships and that the VR-O group's successful performance on the remote spatial memory test was guided by a form of schematic memory that captured the essential features of the village environment. The potential contribution of the hippocampus to the pattern of lost and spared learning and memory observed in the aged rats was discussed.

The benefit of deep processing and high educational level for verbal learning in young and middle-aged adults

BACKGROUND AND AIMS

The aim of the present study was to examine whether deeper processing of words during encoding in middle-aged adults leads to a smaller increase in word-learning performance and a smaller decrease in retrieval effort than in young adults. It was also assessed whether high education attenuates age-related differences in performance.

METHODS

Accuracy of recall and recognition, and reaction times of recognition, after performing incidental and intentional learning tasks were compared between 40 young (25-35) and 40 middle-aged (50-60) adults with low and high educational levels.

RESULTS

Age differences in recall increased with depth of processing, whereas age differences in accuracy and reaction times of recognition did not differ across levels. High education does not moderate age-related differences in performance.

CONCLUSIONS

These findings suggest a smaller benefit of deep processing in middle age, when no retrieval cues are available.

Cognitive operations in the generation effect on a recall test: role of aging and divided attention

Generation effect (generated words are better memorized than read words) of anagrams, rhymes, and associates of target words was examined in young, elderly, and very old subjects. Experiments 1 and 2 showed that only young subjects benefit from the generation effect in a free-recall test when the rule is of a phonological nature. Experiments 3, 4, and 5 showed that the generation effect of rhymes was due to a resources-dependent self-initiated process. Experiments 4 and 5 showed that in a divided-attention situation, generation effect of rhymes is not significant in young subjects, but that the generation effect of semantic associates remains significant for both groups (Experiment 5). The results are discussed within the environmental support framework and the transfer-appropriate processing framework.

Correlation of functional MR imaging activation data with simple reaction times

PURPOSE

To determine the relationship between subject reaction times (RTs) and activation volume in the brain during visuomotor functional magnetic resonance (MR) imaging.

MATERIALS AND METHODS

Twenty-four subjects performed a simple RT task during single-event functional MR imaging, and RTs were recorded. The six subjects with the fastest RTs were designated the fast RT group, and the six subjects with the slowest RTs were designated the slow RT group. The data were processed with noncorrected height threshold (P <.001) for individual comparisons and corrected height threshold (P <.05) for group comparisons (t tests). The activation volumes in both occipital lobes, the left sensorimotor cortex, and the supplemental motor cortices were compared for the two groups.

RESULTS

The mean RT +/- SD was 342 msec +/- 20.15 for the fast RT group and 475 msec +/- 36.17 for the slow RT group (P <.0001). More voxels of activation were seen in the fast RT group than in the slow RT group in the occipital lobes, left sensorimotor cortices, and supplemental motor cortices on individual and group maps. This difference was statistically significant in the left sensorimotor (P =.03) and left visual (P =.05) cortices. In the right visual cortex, a trend toward more activation in the fast RT group was noted (P =.15). There was a negative correlation between RTs and activation volume in the left sensorimotor cortex (P =.048).

CONCLUSION

There was a greater activation volume in motor and visual cortices in the fast RT group than in the slow RT group.

Using encoding and retrieval strategies to improve 24-hour dietary recalls among older adults

OBJECTIVE

To examine whether using an encoding strategy and/or providing more support at the time of retrieval improves the accuracy of 24-hour dietary recalls among the elderly.

DESIGN

Posttest-only control group design.

SETTING

The sample was recruited through advertisements and at senior centers and a low-income apartment building in rural central Pennsylvania.

SUBJECTS

Study participants were 21 men and 73 women aged 58 years old and older. Everyone completed the study.

INTERVENTION

The treatment group was unobtrusively guided in use of an encoding strategy before consuming the prepared meal.

MAIN OUTCOME MEASURES

A 24-hour dietary recall and recognition tests were administered the next day for the foods consumed at the meal and for serving sizes of 5 of the foods. Memory tests were also administered.

STATISTICAL ANALYSES PERFORMED

Linear regression was used to examine differences between the treatment and control groups and to identify variables that explained variation in the number of foods correctly recalled or recognized. The Chi 2 test was used to examine correct vs incorrect recall or recognition of the serving sizes of the 5 foods between the groups and to identify explanatory variables for this task.

RESULTS

Subjects remembered more foods when they used an encoding strategy and when recognition replaced free recall; they performed best when both strategies were used. Use of this encoding strategy did not improve accurate recall or recognition of serving sizes of 5 foods; however, performances did improve when recognition replaced free recall.

CONCLUSIONS

Among older adults, use of an encoding strategy and provision of support at the time of retrieval enhances memory of foods consumed but not of amounts consumed. To strengthen memory of foods consumed, older adults need to perform effortful memory tasks when they are eating.

Enhancing the self-report of alcohol consumption in the community: two questionnaire formats

Two questionnaire formats for assessing alcohol consumption in a community sample were compared. Subjects completed the Semi-Quantitative Food Frequency Questionnaire and a questionnaire specifically targeting alcohol use. Across all alcoholic beverages, subjects reported lower consumption on the alcohol questionnaire than on the food frequency questionnaire. The results suggest that food frequency questionnaires may provide a better means for enhancing self-report of alcohol use than questionnaires that target solely alcohol intake.

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.

Age differences in the effects of contextual framework and word- familiarity on episodic memory

The effect of contextual framework on episodic memory for words was investigated by asking young and older adults either to study a list of words for intentional recall, or to place the words into a story context, with subsequent incidental recall. The story context orienting task was no more beneficial for recall than the study task, and this was true for both young and old. Providing the story at both encoding and retrieval, however, was beneficial, but equally so for both age groups. Pre-experimental familiarity with word items in terms of cohort relevance was an important determinant of recall for both age groups.

The systematic use of semantic and acoustic processing by younger and older adults

To examine age differences in semantic and acoustic processing, 80 older and 80 younger adults participated in an incidental learning study. The study compared free recall and semantic and acoustic cued recall performance after five orienting conditions. The younger adults performed better than the older adults, especially after acoustic orienting. Encoding specificity effects occurred at both age levels. The results indicated that both age groups performed better with semantic processing than acoustic processing, but that older adults relied on the semantic information far more than the younger adults.

Memory function and brain biochemistry in normal aging and in senile dementia

One might argue that the decrease in the number of brain cells as a function of age could be the source of the functional age deficits in memory performance. However, this possibility seems less likely since the actual loss of neurons up to advanced age is relatively small. There are no good estimates of the loss of synapses. Golgi staining of cortical neurons would indicate that there is a loss with higher age. So far, however, the most convincing data of marked loss with age appear at the biochemical level. Most human data fail to demonstrate a decrease in cholinergic and serotonergic activity as a function of normal aging, although there is a loss of corresponding receptors. In AD/SDAT, however, there is a marked damage to these systems. Conceivably, acetylcholine may be providing informational rather than tone setting or balancing influence on memory function. This may explain the failure of cholinomimetic drugs to improve memory in AD/SDAT due to their inability to supply the informational properties of normal neuronal transmission. The catecholamines, noradrenaline and dopamine are both lost in normal aging and to a much higher degree in AD/SDAT. Animal data show that noradrenaline deficiency results in scattered attention. Such a pattern might also exist in the intact aged and through guidance by means of instructions, contextual cues, and a richer TBR information, the elderly are being forced to attend. This may promote and supersede the normal functions of the noradrenaline system by directions from external rather than internal influences, conceivably by potentiating the remaining noradrenaline neurons. The cortical motor areas are relatively spared from neuro-degenerative changes in normal aging and in AD/SDAT and this might provide a neuroanatomical basis for the elderly's and mildly to moderately demented patients' success in memory performance when motor action is involved. The role of dopamine in motor function and its stability with age in hippocampus may also provide a neurochemical basis for the preservation of memory when the subjects are allowed to act physically during encoding.

Age differences in the effect of encoding congruence on incidental free and cued recall

The effect of encoding congruence on incidental free and cured recall was investigated by presenting young and older adults with a list of 24 words, one from each of 24 taxonomic categories. half the subjects from each age group received a congruent orienting task, in which category questions were matched with relevant word instances; the other half from each age group received a non-congruent orienting task, in which category questions were not matched with relevant instances. The age x orienting task x memory interaction indicated that the free recall performance of the young was higher following the congruent orienting, but that of the old was no different following congruent and non-congruent orienting. On cued recall, both age groups performed at the same high level following congruent orienting. The young had a marginally higher level of cued recall than the old following non-congruent orienting. The implications of these findings for processing and production deficiency hypotheses of age-related memory differences were discussed.

Aging and recognition memory: methodological and interpretive problems

The recognition memory and aging literature has been reviewed with the purpose of evaluating the notion that the elderly encode semantic information in a more variable manner than the young. Because of methodological, as well as interpretive problems, only a handful of the investigations may be given serious consideration. It is recommended that future investigators report hits, false alarms, sensitivity and response-bias measures. It is also recommended that a concerted effort be made to equate age groups for response bias, that complete details of experimental procedures be reported and that appropriate statistical tests be made.

Age differences in cued recall and recognition under varying encoding and retrieval conditions

This experiment investigated the role of the encoding-retrieval relationship in adult age differences in memory. To determine the optimal encoding-retrieval conditions for adults of different ages, young, middle-aged, and older adults were given a semantic or acoustic orienting task, followed by semantic and acoustic recognition tests or semantic and acoustic cued recall tests. As predicted, the results demonstrated the importance of similar encoding and retrieval conditions at all ages, especially with semantic processing. Age differences were reduced on the recognition test and when semantic encoding was combined with a semantic cue test at retrieval. It was concluded that acoustic processing is not as effective as semantic processing for older or younger adults, and that effective use of semantic processing by older adults depends on constrained task conditions. These conditions include congruent semantic orienting questions that specify precise meanings for each target item, and retrieval cues that match the information in the orienting questions.

The effects of orienting tasks on adult age differences in recall and recognition

This research examined the type of recognition errors made following orienting task instructions in order to investigate possible age differences in the depth of processing of information to be learned. Eighteen young, 18 middle-aged, and 18 elderly adults viewed 48 words, each of which was accompanied by learning instructions or a phonological or semantic orienting task. Subjects were then presented previously-seen items paired with a synonym, rhyme, or unrelated word. Analyses revealed no age differences in the number or pattern of recognition errors. Middle-aged and elderly adults recalled fewer items than young adults and their recall scores were less affected by orienting task instructions. Results are discussed in the context of possible age differences in the depth and elaboration of processing during study.

What is the evidence for retrieval problems in the elderly?

To determine whether older adults experience particular problems with retrieval, groups of young and elderly adults were given free recall and recognition tests of supraspan lists of unrelated words. Analysis of number of words correctly recalled and recognized yielded a significant age by retention test interaction: greater age differences were observed for recall than for recognition. In a second analysis of words recalled and recognized, corrected for guessing, the interaction disappeared. It was concluded that previous interpretations that age by retention test interactions are indicative of retrieval problems of the elderly may have been confounded by methodological problems. Furthermore, it was suggested that researchers in aging and memory need to be explicit in identifying their underlying models of error processes when analyzing recognition scores: different error models may lead to different results and interpretations.