Influences of item organizability and semantic retrieval cues on word recall in very old age

Abstract

This research investigated the influence of organizational structure in the materials and category cues at retrieval on episodic memory performance in very old age. A community-based sample of healthy, very old adults (N = 224) between 75 and 96 years was presented with two lists of words: a list of semantically unrelated words and a list of words from four taxonomic categories randomly intermixed. Free recall was assessed for both tasks and, for the organizable list, subjects received a cued recall test as well. Results showed an overall age-related deterioration of memory performance, although the ability to utilize item organizability and retrieval cues remained intact across age. Evidence from data on memory performance, as well as analyses of the nature of organizable free recall, suggests that problems at both encoding and retrieval may underlie the age-related performance deficit. In addition, there were age-related increases in (a) forgetting between free and cued recall, and (b) intrusion errors. Finally, regression analyses indicated that, in addition to age, level of schooling as well as markers of general cognitive status (the Mini-Mental State Examination) and fluid intelligence (Block Design) accounted for performance variation across all memory tasks.     

Memory for age-face associations in younger and older adults: the role of generation and schematic support

Memory for ages of unfamiliar faces was examined in an associative memory task to determine whether generation as well as schematic support (cues from faces) would enhance later cued recall of the age information and reduce older adults' associative deficit. Participants studied faces and were either presented with the age or first had to guess before being shown the correct age. Later, participants were given a cued-recall test. Both younger and older adults exhibited associative memory enhancements from first generating the ages at encoding (a generation effect) despite the fact the initial generation was often inaccurate. Although older adults recalled fewer ages overall compared with younger adults, older adults were able to remember the age information for older faces equally as well as younger adults. However, when errors committed during generation were large and when schematic support was not available to support encoding and retrieval (when the age information was inconsistent given the cues from the face), generating was no longer beneficial for either older or younger adults. Thus, although older adults display an associative deficit when remembering specific age-face associations, this can be reduced through the use of prior knowledge and generation at encoding.     

Aging affects word-stem completion and recognition but not category generation

In this study, we investigated the effect of aging on two implicit memory tasks, word-stem completion and category generation, and on explicit recognition. We compared the performance of young and older adults on these implicit memory tasks with those of explicit recognition. We expected better performance of young than older adults in the explicit memory task and similar priming in both implicit memory tasks. The results showed that young adults performed better than older adults in the recognition task. Moreover, both age groups showed priming in the implicit memory tasks, although priming was greater in young adults compared to older adults in the word-stem completion memory task, whereas both age groups showed similar levels of priming in the category generation task. The present results showed dissociations as a function of age not only between the explicit and the implicit tasks but also between the implicit tasks.     

Contributions of processing ability and knowledge to verbal memory tasks across the adult life-span

This study investigated the relationships of processing capacity and knowledge to memory measures that varied in retrieval difficulty and reliance on verbal knowledge in an adult life-span sample (N = 341). It was hypothesized that processing ability (speed and working memory) would have the strongest relationship to tasks requiring active retrieval and that knowledge (vocabulary ability) would be related to verbal fluency and cued recall, as participants relied upon verbal knowledge to retrieve category items (fluency) or develop associations (cued recall). Measurement and structural equation models were developed for the entire sample and separately for younger (aged 20-54 years, n = 168) and older (aged 55-92 years, n = 173) subgroups. In accordance with the hypotheses, processing ability was found to be most highly related to free recall, with additional significant relationships to cued recall, verbal fluency, and recognition. Knowledge was found to be significantly related only to verbal fluency and to cued recall. Moreover, knowledge was more important for older than for younger adults in mediating variance in cued recall, suggesting that older adults may use age-related increases in knowledge to partially compensate for processing declines when environmental support is available in memory tasks.     

Implicit and explicit memory in young and older adults

In three experiments, young and older adults were compared on both implicit and explicit memory tasks. The size of repetition priming effects in word completion and in perceptual identification tasks did not differ reliably across ages. However, age-related decrements in performance were obtained in free recall, cued recall, and recognition. These results, similar to those observed in amnesics, suggest that older adults are impaired on tasks which require conscious recollection but that memory which depends on automatic activation processes in relatively unaffected by age.     

Adult age differences in implicit and explicit memory: time course and encoding effects

Young and older adults were tested at three delays on word-stem completion or cued recall following semantic or structural word judgments. Identical three-letter stems were present at retrieval for both implicit (completion) and explicit (cued recall) tasks; only the intention to recall list words differed. The young adults outperformed the older adults on both implicit and explicit tasks at all test delays. Under some conditions, the older but not the young adults performed more poorly on cued recall than on stem completion, suggesting a possible failure to use implicitly available information to support explicit remembering. These results suggest that some forms of implicit memory decline with normal aging.     

Effects of depth-of-processing and ageing on word-stem and word-fragment implicit memory tasks: Test of the lexical-processing hypothesis

The joint effects of depth-of-processing and age on repetition priming in implicit memory tests of word-fragment completion (WFC) and word-stem completion (WSC) were investigated. The experiment consisted of three study tasks (perceptual, lexical, and semantic) and four memory conditions: implicit (WSC and WFC) and explicit (WS cued recall and WF cued recall). In the WSC condition, semantic and lexical study processing produced equal priming, both superior to the perceptual study processing, whereas the WFC test showed equal priming for these three study conditions. This finding provides clear evidence, consistent with the lexical-processing hypothesis, that depth-of-processing in WSC priming reflects a lexical rather than a semantic process. It also provides support for the view that WSC and WFC involve different processes. However, there was no evidence of an age effect on either of these two implicit tasks. The data also revealed an overall significant effect of age and depth-of-processing, and an interaction between these variables on explicit cued recall tasks, indicating that older adults benefited less than younger ones from a deep encoding condition.     

Evidence for disproportionate dual-task costs in older adults for episodic but not semantic memory

Previous research demonstrates that older adults are poor at dual tasking, but there is less agreement on whether their decrement is worse than that predicted from single-task performance. This study investigated whether task domain moderates dual-task costs in old age. In two experiments, young and older adults retrieved either previously learned associates (episodic retrieval) or overlearned category members (semantic retrieval) under single or working-memory load conditions, using cued recall (Experiment 1) and recognition (Experiment 2) procedures. In both experiments the proportional costs of dual tasking were age invariant for semantic retrieval but were particularly marked for episodic retrieval, although the size of the age effect was reduced in recognition compared to cued recall. The data suggest that age effects in dual tasking may be domain specific.     

Autobiographical memory specificity predicts social problem-solving ability in old and young adults

Based on recent research with young, depressed adults, age-related cognitive declines and decreased autobiographical specificity were hypothesized to predict poorer social problem-solving ability in older than in younger healthy adults. Priming autobiographical memory (ABM) was hypothesized to improve social problem-solving performance for older adults. Subsequent to cognitive tests, old and young participants' specific ABMs were tested using a cued recall task, followed by a social problem-solving task. The order of the tasks was counterbalanced to test for a priming effect. Autobiographical specificity was related to cognitive ability and predicted social problem-solving ability for both age groups. However, priming of ABM did not improve social problem-solving ability for older or younger adults. This study provides support for the hypothesis that autobiographical memory serves a directive function across the life-span.     

Autobiographical memory specificity predicts social problem-solving ability in old and young adults

Based on recent research with young, depressed adults, age-related cognitive declines and decreased autobiographical specificity were hypothesized to predict poorer social problem-solving ability in older than in younger healthy adults. Priming autobiographical memory (ABM) was hypothesized to improve social problem-solving performance for older adults. Subsequent to cognitive tests, old and young participants' specific ABMs were tested using a cued recall task, followed by a social problem-solving task. The order of the tasks was counterbalanced to test for a priming effect. Autobiographical specificity was related to cognitive ability and predicted social problem-solving ability for both age groups. However, priming of ABM did not improve social problem-solving ability for older or younger adults. This study provides support for the hypothesis that autobiographical memory serves a directive function across the life-span.     

Part set cuing in older adults: further evidence of intact forgetting in aging

The aim of this study was to look at the effect of aging on part set cuing while equating for baseline performance in episodic memory. Younger and older participants listened to three different word lists, each containing 24 words relating to a particular category. During recall, 0, 33, or 66% of the items presented in the learning phase were re-presented as cues. The results showed that recall of the never cued items was equally impaired by the presence of cues in younger and older adults, thus showing equivalent part set cuing effects in both groups. These results parallel previous findings showing equivalent inhibitory effects in younger and older adults with tasks that do not require executive control and provide additional support to previous studies challenging the view that frontal/executive processes play a major role in part set cuing.     

Constraints on retrieval search for episodic information in children and adults

The hypothesis that a lack of structural constraint limits children's ability to use context and category cues to search associative memory for episodic information is examined in this study. Second and fifth graders and college adults were shown word triplets at acquisition and asked to recall the final target member of each triplet in a cued recall task. The manipulations concerned sources of associative structure that could constrain retrieval search. The degree to which the members of the triplets were associated was varied, as well as the kind of association, and the kind and amount of retrieval support provided in the cue, and encoding was constrained by orienting questions or was unconstrained. The results showed that children's effective use of retrieval cues was more dependent on episodic associative structure, retrieval support, and the constrained encoding of associative information than was adults'. Differences in the associative structure of information in permanent memory seemed to contribute to the results.     

Dissociation of implicit and explicit memory tests: Effect of age and divided attention on category exemplar generation and cued recall

In this article, we report an experiment that provides further evidence concerning the differences between explicit and implicit measures of memory. The effects of age and divided attention on the implicit conceptual test of category exemplar generation (CEG) were compared with their effects on the explicit test of cued recall, where the category names served as cues in both tasks. Four age groups (20–35, 40–55, 60–75, and 76–90) were compared. Half of the subjects were also required to carry out a secondary letter-detection task during the learning phase. Cued recall performance was significantly impaired by increased age and imposition of the secondary task. In contrast, the CEG task was unaffected by these two factors. These results suggest that implicit conceptual tasks and explicit memory tasks are mediated by different processes. This conclusion opposes those of previous studies that showed that experimental manipulations (level of processing, generation, organization) influenced these two kinds of memory tests in a similar way.     

Reflections of distraction in memory: transfer of previous distraction improves recall in younger and older adults

Three studies explored whether younger and older adults' free recall performance can benefit from prior exposure to distraction that becomes relevant in a memory task. Participants initially read stories that included distracting text. Later, they studied a list of words for free recall, with half of the list consisting of previously distracting words. When the memory task was indirect in its use of distraction (Study 1), only older adults showed transfer, with better recall of previously distracting compared with new words, which increased their recall to match that of younger adults. However, younger adults showed transfer when cued about the relevance of previous distraction both before studying the words (Study 2) and before recalling the words (Study 3) in the memory test. Results suggest that both younger and older adults encode distraction, but younger adults require explicit cueing to use their knowledge of distraction. In contrast, older adults transfer knowledge of distraction in both explicitly cued and indirect memory tasks. Results are discussed in terms of age differences in inhibition and source-constrained retrieval.     

Dissociating word stem completion and cued recall as a function of divided attention at retrieval

The aim of this study was to investigate the widely held, but largely untested, view that implicit memory (repetition priming) reflects an automatic form of retrieval. Specifically, in Experiment 1 we explored whether a secondary task (syllable monitoring), performed during retrieval, would disrupt performance on explicit (cued recall) and implicit (stem completion) memory tasks equally. Surprisingly, despite substantial memory and secondary costs to cued recall when performed with a syllable-monitoring task, the same manipulation had no effect on stem completion priming or on secondary task performance. In Experiment 2 we demonstrated that even when using a particularly demanding version of the stem completion task that incurred secondary task costs, the corresponding disruption to implicit memory performance was minimal. Collectively, the results are consistent with the view that implicit memory retrieval requires little or no processing capacity and is not seemingly susceptible to the effects of dividing attention at retrieval.     

Age-related differences in the specificity of verbal encoding

A communication paradigm was used as an analogue to cued recall to separate age-related differences in encoding and retrieval. Younger and older adults (senders) generated a series of one-word clues that would enable other subjects (receivers) to generate a designated target word. Clue and target generation tasks, analogous to the encoding and retrieval components of cued recall, were conducted in the context of either a strong or a weak associate of the target. Clues generated by older senders were less effective than clues generated by younger senders in enabling receivers to generate targets, especially when clues or targets were generated in the context of a weak associate. A deficit among older receivers was also obtained, especially when a weak-rather than a strong-associate context word was given to the receiver. Older adults experience difficulty with encoding and retrieval tasks that require processing of context-specific information that is not part of the generic information typically associated with a stimulus.     

Dissociating word stem completion and cued recall as a function of divided attention at retrieval

The aim of this study was to investigate the widely held, but largely untested, view that implicit memory (repetition priming) reflects an automatic form of retrieval. Specifically, in Experiment 1 we explored whether a secondary task (syllable monitoring), performed during retrieval, would disrupt performance on explicit (cued recall) and implicit (stem completion) memory tasks equally. Surprisingly, despite substantial memory and secondary costs to cued recall when performed with a syllable-monitoring task, the same manipulation had no effect on stem completion priming or on secondary task performance. In Experiment 2 we demonstrated that even when using a particularly demanding version of the stem completion task that incurred secondary task costs, the corresponding disruption to implicit memory performance was minimal. Collectively, the results are consistent with the view that implicit memory retrieval requires little or no processing capacity and is not seemingly susceptible to the effects of dividing attention at retrieval.     

Effects of age and divided attention on memory components derived for the category exemplar generation task

Age differences in memory performances on a conceptually driven task, the category exemplar generation (CEG) test, were investigated. Thirty-six younger adults and 36 healthy older adults studied word lists in full and divided attention conditions. Recall was tested with category names. The process-dissociation procedure was used to derive estimates of controlled and automatic memory. Old-old adults (70-84 years) exhibited poorer conscious recollection than both younger (18-24) and young-old adults (59-69). In contrast, no age differences were found in estimates of automatic memory. For the younger and older adults, the divided encoding manipulation reduced both the consciously controlled and automatic estimates of memory. The results suggest that the few prior findings of age deficits in priming on the CEG may have been an artifact of contamination from conscious retrieval processes. They also indicate that the opportunity for greater semantic processing enhances the conceptual priming of both younger and older adults.     

Integrative and semantic relations equally alleviate age-related associative memory deficits

Two experiments compared effects of integrative and semantic relations between pairs of words on lexical and memory processes in old age. Integrative relations occur when two dissimilar and unassociated words are linked together to form a coherent phrase (e.g., horse-doctor). In Experiment 1, older adults completed a lexical-decision task where prime and target words were related either integratively or semantically. The two types of relation both facilitated responses compared to a baseline condition, demonstrating that priming can occur in older adults with minimal preexisting associations between primes and targets. In Experiment 2, young and older adults completed a cued recall task with integrative, semantic, and unrelated word pairs. Both integrative and semantic pairs showed significantly smaller age differences in associative memory compared to unrelated pairs. Integrative relations facilitated older adults' memory to a similar extent as semantic relations despite having few preexisting associations in memory. Integratability of stimuli is therefore a new factor that reduces associative deficits in older adults, most likely by supporting encoding and retrieval mechanisms.