Age-related increase in top-down activation of visual features

Previous research suggests that, during visual search and discrimination tasks, older adults place greater emphasis than younger adults on top-down attention. This experiment investigated the relative contribution of target activation and distractor inhibition to this age difference. Younger and older adults performed a singleton discrimination task in which either an E or an R target (colour singleton) was present among distractor letters. Relative to a baseline condition in which the colours of the targets and distractors remained constant, an age-related slowing of performance was evident when either the colour of the target or that of the distractors varied across trials. The age-related slowing was more pronounced in response to target colour variation, suggesting that older adults place relatively greater emphasis on the top-down activation of target features.     

Mind-wandering in younger and older adults: converging evidence from the Sustained Attention to Response Task and reading for comprehension

One mechanism that has been hypothesized to contribute to older adults' changes in cognitive performance is goal neglect or impairment in maintaining task set across time. Mind-wandering and task-unrelated thought may underlie these potential age-related changes. The present study investigated age-related changes in mind-wandering in three different versions of the Sustained Attention to Response Task (SART), along with self-reported mind-wandering during a reading for comprehension task. In the SART, both younger and older adults produced similar levels of faster reaction times before No-Go errors of commission, whereas, older adults produced disproportionate post-error slowing. Subjective self-reports of mind-wandering recorded during the SART and the reading task indicated that older adults were less likely to report mind-wandering than younger adults. Discussion focuses on cognitive and motivational mechanisms that may account for older adults' relatively low levels of reported mind-wandering.     

Age-related increase in top-down activation of visual features

Previous research suggests that, during visual search and discrimination tasks, older adults place greater emphasis than younger adults on top-down attention. This experiment investigated the relative contribution of target activation and distractor inhibition to this age difference. Younger and older adults performed a singleton discrimination task in which either an E or an R target (colour singleton) was present among distractor letters. Relative to a baseline condition in which the colours of the targets and distractors remained constant, an age-related slowing of performance was evident when either the colour of the target or that of the distractors varied across trials. The age-related slowing was more pronounced in response to target colour variation, suggesting that older adults place relatively greater emphasis on the top-down activation of target features.     

The attentional demands of encoding and retrieval in younger and older adults: 2. Evidence from secondary task reaction time distributions

Three studies examined the effects of encoding or retrieval on properties of secondary task reaction time (RT) distributions in younger and older adults. Relative to full attention conditions, encoding and retrieval increased secondary task RT medians and standard deviations more for older adults than for younger adults, and the age-related RT increase was most pronounced among the slowest RTs. Hierarchical regression analyses revealed two age-related mechanisms underlying these effects, which were interpreted as cognitive slowing and reductions in attentional resources. Cognitive slowing affects the entire RT distribution regardless of the memory task. By contrast, reduced attentional resources result in very long RTs, especially when the tasks require self-initiated encoding or retrieval operations.     

Age differences in Stroop interference: contributions of general slowing and task-specific deficits

This study examined the contributions of general slowing and task-specific deficits to age-related changes in Stroop interference. Nine hundred thirty-eight participants aged 20 to 89 years completed an abbreviated Stroop color-naming task and a subset of 281 participants also completed card-sorting, simple reaction time, and choice reaction time tasks. Age-related increases in incongruent color-naming latency and card-sorting perseverative errors were observed. Hierarchical regression analyses showed that the processing speed measures accounted for significant variance on both dependent measures, but that there was also a significant residual effect of age. An additional regression analysis showed that some of the variance in incongruent color-naming, after controlling for processing speed, was shared with the variance in perseverative errors. Overall, findings suggest that the age difference in Stroop interference is partially attributable to general slowing, but is also attributable to age-related changes in task-specific processes such as inhibitory control.     

Age Inequalities in Recognition Memory: Effects of Stimulus Presentation Time and List Repetitions

It has been suggested that age-related slowing in the execution of mental operations in time-limited visual information processing tasks can affect subsequent memory performance. To investigate this proposal, recognition memory for Chinese symbols displayed in rapid serial visual presentation (RSVP) was assessed in 30 young adults and 33 older adults. The effects of presentation times (500, 1000, 2000, 2500, 3000, and 6000 ms) on target recognition were examined across six study-test trials for each participant. Recognition accuracy was higher for young adults than for older adults, especially at the shorter stimulus durations. Analysis of the time-accuracy functions describing the stimulus durations and amount of repetitions required to equate the performance of younger and older adults indicated that a limited-time mechanism provided an incomplete account for age-related differences in memory for rapidly presented information.     

Age-related differences in the von restorff isolation effect

When one item is made distinct from the other items in a list, memory for the distinctive item is improved, a finding known as the isolation or von Restorff effect (after von Restorff, 1933). Although demonstrated numerous times with younger adults and children, this effect has not been found with older adults (Cimbalo & Brink, 1982). In contrast to the earlier study, we obtained a significant von Restorff effect for both younger and older adults using a physical manipulation of font colour. The effect size for older adults was smaller than that obtained for younger adults, confirming a prediction of Naveh-Benjamin's (2000) associative deficit hypothesis, which attributes age-related differences in memory performance to older adults' reduced ability to form associations. The findings are consistent with related research in which older adults demonstrate similar—but smaller—benefits for distinctive information to those for younger adults.     

Patterns and Predictors of Adult Age Differences in Mental Imagery

Adult age differences in, and predictors of, component imagery processes were examined across a broad elderly adult age range (65-86 years). Relative to younger adults, older adults were slower and less accurate on tasks of image generation, maintenance, scanning, and rotation. Ability to maintain mental images in particular was compromised by older age. Manipulations of stimulus complexity produced inconsistent differential age effects across tasks. Processing speed and sensorimotor functioning were prominent predictors of performance and age-related variance in all imagery components, with smaller contributions from working memory and executive function. These findings suggest that age-related decrements in individual imagery processes depend primarily on how quickly information can be processed and on the neurophysiological integrity of the ageing brain.     

Ageing, remembering, and executive function

This study was designed to investigate the relationship between executive functions and the age-related decline in episodic memory through the states-of-awareness approach. Following the presentation of a word list, a group of younger adults and a group of older adults undertook a recognition test in which they classified their responses according to the Remember-Know-Guess procedure (Gardiner & Richardson-Klavehn, 2000). In order to operationalise the executive function hypothesis, we investigated three specific executive functions (updating, shifting, and inhibition of a prepotent response) described in Miyake et al.'s (2000) theoretical model, and a complex executive task. The results revealed that fewer "R" responses were made during the recognition test by the older than the younger group, whereas there was no difference between the groups in the number of "K" responses. In addition, correlations indicated that remembering depended on executive function measures, whereas knowing did not. The hierarchical regression analyses showed that controlling for executive function, and particularly for the 2-back test, largely removed the age-related variance in remembering. These findings support the notion that executive dysfunction, and specifically updating decline, plays a central role in age-related memory loss.     

Adult age differences in visual search accuracy: attentional guidance and target detectability

Previous research, relying primarily on reaction time measures of highly accurate performance, suggests that both younger and older adults can increase the efficiency of visual search by guiding attention to a candidate subset of items. The authors investigated attentional guidance when accuracy was well below ceiling to focus more specifically on the role of perceptual processes. In the most difficult condition (conjunction search), the likelihood of missing a target was greater for older adults than for younger adults, and this effect was not attributable entirely to generalized slowing. Both age groups were able to improve search efficiency by attending to a distinct subset of display items, indicating that attentional guidance to perceptual features does not exhibit age-related decline. A signal-detection model of the conjunction search data demonstrated that the age difference represented an age-related decline in target detectability.     

Age-related change in visual information processing: Toward a unified theory of aging and visual memory

Memory for semantic information is relatively preserved through the normal aging process. Visuospatial memory remains less intact. In the present article a theory is proposed that links this processing difference to normal age-related generalized cognitive slowing, and to the appearance of specific age-related differences in memory performance. Evidence for these suggestions is presented from work in four areas: mental rotation, spatial memory, paired-associates learning, and free recall. Cognitive performance in young and older respondents is shown to vary predictably with systematic variation of visuospatial and semantic stimulus factors consistent with these hypotheses. A further test of these ideas derives from the development of a clinically useful mnemonic system for older adults that is based on these principles. Taken together, this research indicates that much of the deficit observed in the memory performance of older adults may derive not from memory problems per se, but rather from the action of generalized cognitive slowing, which contributes to diminished abilities to represent and process visual images. This series of findings may provide a framework for understanding a wide variety of the processes involved in aging and visual memory, and for the creation of applications to aid the memory of older adults.     

Speech comprehension difficulties in older adults: cognitive slowing or age-related changes in hearing?

Speech comprehension declines more rapidly in older adults than in younger adults as speech rate increases. This effect is usually attributed to a slowing of brain function with age. Alternatively, this Age X Speed interaction could reflect the inability of the older adult's auditory system to cope with speed-induced stimulus degradation. When the authors speeded speech in a way that produced minimal degradation, both age groups were equally affected. However, when speech was speeded using other methods, word identification declined more in older than in younger adults. Hence, auditory decline rather than cognitive slowing may be responsible for older adults' poorer performance in speeded conditions.     

Age-related differences in the von Restorff isolation effect

When one item is made distinct from the other items in a list, memory for the distinctive item is improved, a finding known as the isolation or von Restorff effect (after von Restorff, 1933). Although demonstrated numerous times with younger adults and children, this effect has not been found with older adults (Cimbalo & Brink, 1982). In contrast to the earlier study, we obtained a significant von Restorff effect for both younger and older adults using a physical manipulation of font colour. The effect size for older adults was smaller than that obtained for younger adults, confirming a prediction of Naveh-Benjamin's (2000) associative deficit hypothesis, which attributes age-related differences in memory performance to older adults' reduced ability to form associations. The findings are consistent with related research in which older adults demonstrate similar—but smaller—benefits for distinctive information to those for younger adults.     

Word-list-learning performance in younger and older adults: intra-individual performance variability and false memory

We investigated the word-list-learning performance of younger and older adults over 4 consecutive days at different times of day to study age-related differences in consistency of performance over time and the influence of circadian variation on performance. Eighteen younger (M age, 23.4 years) and 18 older (M age, 73.3 years) men and women participated. The start time of testing alternated between morning and early evening across the 4 days of testing. On each test day, participants learned a different list of 15 unrelated words over four learning trials. As expected, younger adults performed better than older adults on immediate recall, delayed recall, and recognition. Contrary to our expectations, time of day did not significantly influence recall or recognition performance in either the older or younger adults. Older adults did show a greater incidence of false memory (i.e., previously learned list intrusions in free recall and false alarms in recognition) than younger adults. Older adults also exhibited greater intra-individual performance variability on the measures of false memory across test days. This variability was not related to circadian variation. False memory and variability of performance have both been linked to frontal systems dysfunction. The findings presented here are consistent with the notion that changes in cognition with aging in part reflect age-related decline in frontal lobe function.     

Role of age in relation between two kinds of abilities and performance in acquisition of new motor skill

Better understanding of age-related differences in skilled performance was the focus of analyses of cognitive-performance scores-relationships in acquisition of a new motor skill. 31 younger adults and 33 older adults were tested on both a cognitive and a psychomotor test. Then, they were asked to learn a juggling task over 12 sessions of 20 min. Analysis indicated age-related differences in the rate of learning. Acquisition by the younger adult group was significantly faster than that by the older adult group. This difference was also reflected in the relationship of cognition and performance for the two age groups. Motor execution for the older adults seemed to require more psychomotor ability, especially at the end of the learning sessions, and was dependent on cognitive control. This trend is consistent with the perspective that cognitive predictors of performance are related to age.     

Age-related decline in executive function predicts better advice-giving in uncomfortable social contexts

Conventional wisdom suggests that older adults are more likely than young adults to speak their mind. Age-related executive function (EF) decline is believed to underlie this tendency by weakening older adults' capacity to inhibit responses. While age-related EF decline disrupts social and cognitive functioning in many domains, such degeneration may also carry the unforeseen benefit of improving communication in uncomfortable social contexts. We examined the performance of relatively low and high EF older adults and young adults on the socially distressing task of providing critical advice to a troubled obese teenager. Relative to higher EF older adults and younger adults, lower EF older adults were more open, provided more advice, and were seen as more empathic. Moreover, doctors specializing in obesity treatment rated lower EF older adults’ advice to the teen as having greater potential for prompting a lifestyle change. Our findings suggest a potential silver lining to age-related cognitive decline.     

Older age, traumatic brain injury, and cognitive slowing: some convergent and divergent findings

Reaction time (RT) meta-analyses of cognitive slowing indicate that all stages of processing slow equivalently and task independently among both older adults (J. Cerella & S. Hale, 1994) and adults who have suffered a traumatic brain injury (TBI; F. R. Ferraro, 1996). However, meta-analyses using both RT and P300 latency have revealed stage-specific and task-dependent changes among older individuals (T. R. Bashore, K. R. Ridderinkhof, & M. W. van der Molen, 1998). Presented in this article are a meta-analysis of the effect of TBI on processing speed, assessed using P300 latency and RT, and a qualitative review of the literature. They suggest that TBI induces differential slowing. Similarities in the effects of older age and TBI on processing speed are discussed and suggestions for future research on TBI-induced cognitive slowing are offered.     

The enhanced Simon effect for older adults is reduced when the irrelevant location information is conveyed by an accessory stimulus

The Simon effect, better performance when irrelevant stimulus location corresponds with the response location than when it does not, typically is larger for older than younger adults. However, Simon and Pouraghabagher [Simon, R. J., & Pouraghabagher, A. R. (1978). The effect of aging on the stages of processing in a choice reaction time task. Journal of Gerontology, 33, 553-561] found no age difference using an accessory-stimulus Simon task in which the relevant dimension was the color of a visual stimulus and the irrelevant dimension the location of a tone. Experiment 1 confirmed that older adults show a larger Simon effect than younger adults for the visual Simon task and that this age-related deficit is reduced or eliminated for the auditory-accessory task. Experiment 2 provided evidence suggesting that a small part of the age-related deficit in the visual Simon task is due to having to code the location of the relevant stimulus, but Experiment 3 showed that the majority of the deficit is due to the relevant and irrelevant information being conveyed by the same stimulus. Reaction-time distribution analyses show similar functions for younger and older adults, suggesting that the time course of activation is similar for both age groups.     

Word-List-Learning Performance in Younger and Older Adults: Intra-Individual Performance Variability and False Memory

ABSTRACT

We investigated the word-list-learning performance of younger and older adults over 4 consecutive days at different times of day to study age-related differences in consistency of performance over time and the influence of circadian variation on performance. Eighteen younger (M age, 23.4 years) and 18 older (M age, 73.3 years) men and women participated. The start time of testing alternated between morning and early evening across the 4 days of testing. On each test day, participants learned a different list of 15 unrelated words over four learning trials. As expected, younger adults performed better than older adults on immediate recall, delayed recall, and recognition. Contrary to our expectations, time of day did not significantly influence recall or recognition performance in either the older or younger adults. Older adults did show a greater incidence of false memory (i.e., previously learned list intrusions in free recall and false alarms in recognition) than younger adults. Older adults also exhibited greater intra-individual performance variability on the measures of false memory across test days. This variability was not related to circadian variation. False memory and variability of performance have both been linked to frontal systems dysfunction. The findings presented here are consistent with the notion that changes in cognition with aging in part reflect age-related decline in frontal lobe function.     

Aging, memory and visual search

Potential age-related differences in the memory processes that underlie visual search are examined in the present study. Using a dynamic, gaze-contingent search paradigm developed to assess memory for previously examined distractors, older adults demonstrated no memory deficit. Surprisingly, older adults made fewer refixations compared to their younger counterparts, indicating better memory for previously inspected objects. This improved memory was not the result of a speed-accuracy trade-off or larger Inhibition-of-Return effects for older than for younger adults. Additional analyses suggested that older adults may derive their benefit from finer spatial encoding of search items. These findings suggest that some of the memory processes that support visual search are relatively age invariant.