Sustained-attention capacity in young and older adults

The sustained-attention capacity of young (21-29 years) and older (65-78 years) adults was examined using a high-event rate digit-discrimination vigilance task presented at three levels of stimulus degradation. Increased stimulus degradation led to a reduction in the hit rate and to a greater decline in hit rate over blocks (increased vigilance decrement). Sensitivity (d') declined over blocks only at the highest level of stimulus degradation. Older adults had a lower hit rate and showed greater vigilance decrement than young adults, particularly when stimuli were highly degraded. However, both age groups showed the same pattern of stability in sensitivity when stimulus degradation was moderate, and sensitivity decrement over time when stimulus degradation was high. The results suggest that the process of sustained allocation of capacity--as reflected in temporal changes in sensitivity--operates similarly in young and older adults.     

Semantic satiation in healthy young and older adults

In four experiments, semantic satiation was investigated in young and old adults. In the first two experiments, subjects were repeatedly presented a word (e.g.,dog) and then were presented a pair of words (e.g.,dog-cat ordog-chair) for a relatedness decision. The results of both experiments indicated that for the young adults, the relatedness effect (the difference between response latency on related and unrelated trials) decreased as a function of the number of times the satiated word was repeated, whereas for the older adults, there was no evidence of a decrease in the relatedness effect across repetitions of the satiated word. In the third experiment, we investigated whether phonological codes are also susceptible to satiation. This experiment was similar to the first two experiments with the exception that subjects made rhyme decisions (same-claim vs.same-dime) instead of semantic relatedness decisions. The results of this experiment did not yield any evidence of satiation for either the young adults or the older adults. The final experiment eliminated a simple decrease in attentional alertness or fatigue account of the semantic satiation effects found in the first two experiments. In this experiment, the repeated word was always unrelated to the pair of words presented for the relatedness decision. The results of this experiment did not yield any evidence of semantic satiation for either the young or the older adults. The discussion focuses on the mechanisms underlying semantic satiation and the implications of age-related changes in these mechanisms.     

Self-initiated object-location memory in young and older adults

The present study explored self-initiated object-location memory in ecological contexts, as aspect of memory that is largely absent from the research literature. Young and older adults memorized objects-location associations they selected themselves or object-location associations provided to them, and elaborated on the strategy they used when selecting the locations themselves. Retrieval took place 30 min and 1 month after encoding. The results showed an age-related decline in self-initiated and provided object-location memory. Older adults benefited from self-initiation more than young adults when tested after 30 min, while the benefit was equal when tested after 1 month. Furthermore, elaboration enhanced memory only in older adults, and only after 30 min. Both age groups used deep encoding strategies on the majority of the trials, but their percentage was lower in older adults. Overall, the study demonstrated the processes involved in self-initiated object-location memory, which is an essential part of everyday functioning.     

Antimnemonic effects of schemas in young and older adults

Schema-consistent material that is aligned with an individual’s knowledge and experience is typically more memorable than abstract material. This effect is often more extreme in older adults and schema use can alleviate age deficits in memory. In three experiments, young and older adults completed memory tasks where the availability of schematic information was manipulated. Specifying nonobvious relations between to-be-remembered word pairs paradoxically hindered memory (Experiment 1). Highlighting relations within mixed lists of related and unrelated word pairs had no effect on memory for those pairs (Experiment 2). This occurred even though related word pairs were recalled better than unrelated word pairs, particularly for older adults. Revealing a schematic context in a memory task with abstract image segments also hindered memory performance, particularly for older adults (Experiment 3). The data show that processing schematic information can come with costs that offset mnemonic benefits associated with schema-consistent stimuli.     

Feature memory and binding in young and older adults

Intact memory for complex events requires not only memory for particular features (e.g., item, location, color, size), but also intact cognitive processes for binding the features together. Binding provides the memorial experience that certain features belong together. The experiments presented here were designed to explicate these as potentially separable sources of age-associated changes in complex memory—namely, to investigate the possibility that age-related changes in memory for complex events arise from deficits in (1) memory for the kinds of information that comprise complex memories, (2) the processes necessary for binding this information into complex memories, or (3) both of these components. Young and older adults were presented with colored items located within an array. Relative to young adults, older adults had a specific and disproportionate deficit in recognition memory for location, but not for item or for color. Also, older adults consistently demonstrated poorer recognition memory for bound information, especially when all features were acquired intentionally. These feature and binding deficits separately contribute to what have been described as older adults’ context and source memory impairments.     

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.     

Relational frameworks for recall in young and older adults

Recent research indicates the presence of an age-related visual processing deficit, for which the elderly may attempt to compensate through the use of relational information. This hypothesis was tested, using the category superiority effect as a model system. In studies of young adults, the category superiority effect has been shown to be confined to relatively abstract stimulus materials, such as verbal items, and to be absent for pictures. However, it was predicted that a category superiority effect would be present in elderly adults both for verbal and for pictorial stimuli, since the elderly would be expected to utilize category information to compensate for imagerie deficits. This prediction was confirmed, consistent with the hypothesis advanced above. It was further suggested that the establishment of a prior framework for recall, based on relational information, would reduce this effect significantly. This prediction was also confirmed. This research was supported by Grant AGI 1605, National Institute on Aging, and by a grant from the School of Natural Sciences, California State University, Fresno.     

Self-initiated spatial working memory in young and older adults

The age-related decline in working memory (WM) has been studied extensively. Yet, research has focused mainly on one aspect of memory, in which older adults memorised information provided to them, neglecting the frequent everyday behaviour in which memory is self-initiated (SI), meaning that individuals memorise information they selected themselves. The present study used a modified spatial span task in which young and older adults memorised spatial sequences they constructed themselves, or random sequences provided to them. The results revealed that young and older adults carefully planned and constructed structured spatial sequences, by minimising distances between successive locations, and by selecting sequences with fewer path crossings and with more linear shapes. Older adults constructed sequences that were even more structured in some aspects. Young and older adults benefited from self-initiation to the same extent, showing similar age-related declines in SI and provided spatial WM. Overall, the study shows that older adults have access to metacognitive knowledge on the structure of efficient WM representations that benefit accuracy, and shows that older adults can use strategic encoding processes efficiently when encoding is SI. More generally, SI WM explores an important aspect of behaviour, demonstrating how older adults shape their environment to facilitate cognitive functioning.     

Self-reference enhances relational memory in young and older adults

The present study investigated the influence of self-reference on two kinds of relational memory, internal source memory and associative memory, in young and older adults. Participants encoded object–location word pairs using the strategies of imagination and sentence generation, either with reference to themselves or to a famous other (i.e., George Clooney or Oprah Winfrey). Both young and older adults showed memory benefits in the self-reference conditions compared to other-reference conditions on both tests, and the self-referential effects in older adults were not limited by low memory or executive functioning. These results suggest that self-reference can benefit relational memory in older adults relatively independently of basic memory and executive functions.     

Self-referencing enhances recollection in both young and older adults

Processing information in relation to the self enhances subsequent item recognition in both young and older adults and further enhances recollection at least in the young. Because older adults experience recollection memory deficits, it is unknown whether self-referencing improves recollection in older adults. We examined recollection benefits from self-referential encoding in older and younger adults and further examined the quality and quantity of episodic details facilitated by self-referencing. We further investigated the influence of valence on recollection, given prior findings of age group differences in emotional memory (i.e., “positivity effects”). Across the two experiments, young and older adults processed positive and negative adjectives either for self-relevance or for semantic meaning. We found that self-referencing, relative to semantic encoding, increased recollection memory in both age groups. In Experiment 1, both groups remembered proportionally more negative than positive items when adjectives were processed semantically; however, when adjectives were processed self-referentially, both groups exhibited evidence of better recollection for the positive items, inconsistent with a positivity effect in aging. In Experiment 2, both groups reported more episodic details associated with recollected items, as measured by a memory characteristic questionnaire, for the self-reference relative to the semantic condition. Overall, these data suggest that self-referencing leads to detail-rich memory representations reflected in higher rates of recollection across age.     

Relational frameworks for recall in young and older adults

Recent research indicates the presence of an age-related visual processing deficit, for which the elderly may attempt to compensate through the use of relational information. This hypothesis was tested, using the category superiority effect as a model system. In studies of young adults, the category superiority effect has been shown to be confined to relatively abstract stimulus materials, such as verbal items, and to be absent for pictures. However, it was predicted that a category superiority effect would be present in elderly adults both for verbal and for pictorial stimuli, since the elderly would be expected to utilize category information to compensate for imagerie deficits. This prediction was confirmed, consistent with the hypothesis advanced above. It was further suggested that the establishment of a prior framework for recall, based on relational information, would reduce this effect significantly. This prediction was also confirmed. This research was supported by Grant AGI 1605, National Institute on Aging, and by a grant from the School of Natural Sciences, California State University, Fresno.     

Both young and older adults discount suggestions from older adults on a social memory test

In the present study, we examined the impacts of participant age and confederate age on social memory processes. During a collaborative recall phase, young and older adult participants were exposed to the erroneous memory reports of a young or an older adult confederate. On a subsequent individual recall test, young and older adult participants were equally likely to incorporate the confederates’ erroneous suggestions into their memory reports, suggesting that participant age had a minimal effect on social memory processes. However, confederate age did have a marked effect: Young adult participants were less likely to incorporate misleading suggestions from older adult confederates and less likely to report “remembering” items suggested by older adult confederates. Critically, older adult participants were also less likely to incorporate misleading information from fellow older adult confederates. Both young and older adult participants discounted older adult confederates’ contributions to a memory test.     

The structure of verbal abilities in young and older adults

Four language sample measures as well as measures of vocabulary, verbal fluency, and memory span were obtained from a sample of young adults and a sample of older adults. Factor analysis was used to analyze the structure of the vocabulary, fluency, and span measures for each age group. Then an "extension" analysis was performed by using structural modeling techniques to determine how the language sample measures were related to the other measures. The measure of grammatical complexity was associated with measures of working memory including reading span and digit span. Two measures, sentence length in words and a measure of lexical diversity, were associated with the vocabulary measures. The fourth measure, propositional density, was associated with the fluency measures as a measure of processing efficiency. The structure of verbal abilities in young and older adults is somewhat different, suggesting age differences in processing efficiency.     

Metamemorial predictors of memory performance in young and older adults

The relationship between aspects of knowledge about memory and immediate and delayed recall on prose and word-list tasks was examined. Ss were 100 young and 100 older adults. Vocabulary ability was screened. Memory knowledge was assessed by the Metamemory in Adulthood (MIA) scale and the Short Inventory of Memory Experiences (SIME). Capacity and change measures of the MIA correlated with most dimensions of the SIME for both age groups. The anxiety measure of the MIA correlated with SIME measures only for the young. Regression analyses showed that strategy (MIA) predicted performance only for young adults, change (MIA) predicted performance only for older adults, and capacity (MIA) predicted performance for both age groups. Metamemory variables accounted for equivalent amounts of variance in both prose and word-list tasks, although there was an indication that prediction was slightly better for prose. Future researchers need to address the apparent increase in affect-related predictors of memory performance.     

Working-memory capacity and reading comprehension in young and older adults

Summary This study investigates the role of working-memory capacity in reading comprehension in young and older subjects. A task yielding separate measures for processing and storage components was used to assess working-memory capacity. A French version of the Nelson-Denny test was administered as a measure of abilities that underlie reading comprehension. In the working-memory task, recall performances were lower in older subjects. Nevertheless, the intercorrelations suggested that the age-related impairment was probably linked to the processing component. Mean scores on the reading-comprehension test did not differ between groups. However, scores were correlated with processing time on the working-memory task in younger subjects, but with storage capacity in older subjects.     

Repetition blindness and homophone blindness in young and older adults

We tested age effects on repetition blindness (RB), defined as the reduced probability of reporting a target word following presentation of the same word in a rapidly presented list. We also tested age effects on homophone blindness (HB), in which the first word is a homophone of the target word rather than a repeated word. Thirty young and 28 older adults viewed rapidly presented lists of words containing repeated, homophone, or unrepeated word pairs and reported all of the words immediately after each list. Older adults exhibited a greater degree of RB and HB than young adults using a conditional scoring method that provides certainty that blindness has occurred. The existence of RB and HB for both age groups, and increased blindness for older compared to young adults, supports predictions of a binding theory that has successfully accounted for a wide range of phenomena in cognitive aging.     

Eye movements of young and older adults during reading

The eye movements of young and older adults were tracked as they read sentences varying in syntactic complexity. In Experiment 1, cleft object and object relative clause sentences were more difficult to process than cleft subject and subject relative clause sentences; however, older adults made many more regressions, resulting in increased regression path fixation times and total fixation times, than young adults while processing cleft object and object relative clause sentences. In Experiment 2, older adults experienced more difficulty than young adults while reading cleft and relative clause sentences with temporary syntactic ambiguities created by deleting the that complementizers. Regression analyses indicated that readers with smaller working memories need more regressions and longer fixation times to process cleft object and object relative clause sentences. These results suggest that age-associated declines in working memory do affect syntactic processing.     

Judgments of blame and forgiveness: A comparison of young adults,older adults,and older adults with dementia

IntroductionAlzheimer's disease may modify moral judgment.ObjectiveIn two studies, we assessed the impact of dementia on blame and forgiveness. Study 1 compared the ways in which young adults, older adults, and older adults with dementia cognitively integrated two factors. Study 2 assessed the number of different factors that older adults with dementia were able to integrate during these moral judgments.MethodThe participants recorded their moral judgements in a blame task and in a forgiveness task. In study 1, the two questionnaires contained scenarios built from the combination of two factors. In study 2, the participants were confronted with the same tasks under three different conditions with scenarios that combined three, four or five factors.ResultsThe data from study 1 showed that the older adults with dementia did not combine the two factors in the same way as young adults did: the combination depended on the type of moral judgment. Study 2 revealed differences in moral judgment between older adults with dementia and adults without dementia in all tasks (i.e. with three, four or five factors combined).ConclusionDementia has an impact on moral judgments. Moral judgment among people with dementia is both task- and condition-dependant.     

Automatic and voluntary control of attention in young and older adults

Young and older adults searched for a target character in a 3-item display. On each trial, both a symbolic cue (arrow at fixation) and a spatial cue (abrupt onset of one item) could indicate the target's position. Participants were told to use the central arrow cue on all trials because it had 75% validity. The onset cue also had 75% validity for half the participants and 25% validity for the other half. Both age groups showed about the same cost and benefit effects for the central arrow cues, but the abrupt onsets had much larger cuing effects for older adults. Young adults were able to suppress at least partially an automatic attentional response to an abrupt onset item when the arrow cue preceded the onset and had a higher validity than the onset cue. Older adults appeared to be less able to inhibit their responses to abrupt onsets and to disengage their attention from invalid onset cues than were the young adults.