Binding and strategic selection in working memory: A lifespan dissociation.

Working memory (WM) shows a gradual increase during childhood, followed by accelerating decline from adulthood to old age. To examine these lifespan differences more closely, we asked 34 children (10–12 years), 40 younger adults (20–25 years), and 39 older adults (70–75 years) to perform a color change detection task. Load levels and encoding durations were varied for displays including targets only (Experiment 1) or targets plus distracters (Experiment 2, investigating a subsample of Experiment 1). WM performance was lower in older adults and children than in younger adults. Longer presentation times were associated with better performance in all age groups, presumably reflecting increasing effects of strategic selection mechanisms on WM performance. Children outperformed older adults when encoding times were short, and distracter effects were larger in children and older adults than in younger adults. We conclude that strategic selection in WM develops more slowly during childhood than basic binding operations, presumably reflecting the delay in maturation of frontal versus medio-temporal brain networks. In old age, both sets of mechanisms decline, reflecting senescent change in both networks. We discuss similarities to episodic memory development and address open questions for future research. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Interference, aging, and visuospatial working memory: The role of similarity.

Objective: Older adults' performance on working memory (WM) span tasks is known to be negatively affected by the buildup of proactive interference (PI) across trials. PI has been reduced in verbal tasks and performance increased by presenting distinctive items across trials. In addition, reversing the order of trial presentation (i.e., starting with the longest sets first) has been shown to reduce PI in both verbal and visuospatial WM span tasks. We considered whether making each trial visually distinct would improve older adults' visuospatial WM performance, and whether combining the 2 PI-reducing manipulations, distinct trials and reversed order of presentation, would prove additive, thus providing even greater benefit. Method: Forty-eight healthy older adults (age range = 60–77 years) completed 1 of 3 versions of a computerized Corsi block test. For 2 versions of the task, trials were either all visually similar or all visually distinct, and were presented in the standard ascending format (shortest set size first). In the third version, visually distinct trials were presented in a reverse order of presentation (longest set size first). Results: Span scores were reliably higher in the ascending version for visually distinct compared with visually similar trials, F(1, 30) = 4.96, p = .03, η2 = .14. However, combining distinct trials and a descending format proved no more beneficial than administering the descending format alone. Conclusions: Our findings suggest that a more accurate measurement of the visuospatial WM span scores of older adults (and possibly neuropsychological patients) might be obtained by reducing within-test interference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Explaining age differences in temporal working memory.

To determine the cognitive mechanisms underlying age differences in temporal working memory (WM), the authors examined the contributions of item memory, associative memory, simple order memory, and multiple item memory, using parallel versions of the delayed-matching-to-sample task. Older adults performed more poorly than younger adults on tests of temporal memory, but there were no age differences in nonassociative item memory, regardless of the amount of information to be learned. In contrast, a combination of associative and simple order memory, both of which were reduced in older adults, completely accounted for age-related declines in temporal memory. The authors conclude that 2 mechanisms may underlie age differences in temporal WM, namely, a generalized decline in associative ability and a specific difficulty with order information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interference and facilitation in spatial working memory: Age-associated differences in lure effects in the n-back paradigm.

Working memory (WM) declines prominently during normal aging. The mechanisms underlying this decline are not fully understood. The authors analyzed performance on 2 versions of a 2-back spatial WM task to assess younger and older adults' responses to lures (i.e., nontarget items that match an item earlier in the sequence but not at the current target lag). Results demonstrate lure interference effects that are particularly pronounced among older adults. At the same time, however, older adults showed facilitation for targets. Taken together, these findings suggest that the contribution of familiarity signals to WM performance increases during normal aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in proactive interference, working memory, and abstract reasoning.

[Correction Notice: An erratum for this article was reported in Vol 23(4) of Psychology and Aging (see record 2008-19072-007). The original article contained an incorrect DOI. The correct DOI is as follows: 10.1037/a0012577.] It has been hypothesized that older adults are especially susceptible to proactive interference (PI) and that this may contribute to age differences in working memory performance. In young adults, individual differences in PI affect both working memory and reasoning ability, but the relations between PI, working memory, and reasoning in older adults have not been examined. In the current study, young, old, and very old adults performed a modified operation span task that induced several cycles of PI buildup and release as well as two tests of abstract reasoning ability. Age differences in working memory scores increased as PI built up, consistent with the hypothesis that older adults are more susceptible to PI, but both young and older adults showed complete release from PI. Young adults' reasoning ability was best predicted by working memory performance under high PI conditions, replicating M. Bunting (2006). In contrast, older adults' reasoning ability was best predicted by their working memory performance under low PI conditions, thereby raising questions regarding the general role of susceptibility to PI in differences in higher cognitive function among older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correction to Emery, Hale, and Myerson (2008).

Reports an error in "Age differences in proactive interference, working memory, and abstract reasoning" by Lisa Emery, Sandra Hale and Joel Myerson (Psychology and Aging, 2008[Sep], Vol 23[3], 634-645). The original article contained an incorrect DOI. The correct DOI is as follows: 10.1037/a0012577. (The following abstract of the original article appeared in record 2008-13050-014.) It has been hypothesized that older adults are especially susceptible to proactive interference (PI) and that this may contribute to age differences in working memory performance. In young adults, individual differences in PI affect both working memory and reasoning ability, but the relations between PI, working memory, and reasoning in older adults have not been examined. In the current study, young, old, and very old adults performed a modified operation span task that induced several cycles of PI buildup and release as well as two tests of abstract reasoning ability. Age differences in working memory scores increased as PI built up, consistent with the hypothesis that older adults are more susceptible to PI, but both young and older adults showed complete release from PI. Young adults' reasoning ability was best predicted by working memory performance under high PI conditions, replicating M. Bunting (2006). In contrast, older adults' reasoning ability was best predicted by their working memory performance under low PI conditions, thereby raising questions regarding the general role of susceptibility to PI in differences in higher cognitive function among older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Breaking the waves: Age differences in electrical brain activity when reading text with distractors.

The authors tested whether older adults have greater difficulty than younger adults in ignoring task-irrelevant information during reading as a result of age-related decline in inhibitory processes. Participants were shown target sentences containing distractor words. They were instructed to read aloud each sentence and ignore distractors. The N400 event-related potential (ERP) was used to measure the extent of semantic processing of target and distracting information. It showed that younger adults semantically processed both target and distracting material, whereas online processing of target sentences in older adults was disrupted by the distractors. In older adults, memory for target information related to their susceptibility to distraction and inhibition efficiency. Implications for age-differences in inhibitory control, working memory, and resource capacity are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Longitudinal change in language production: Effects of aging and dementia on grammatical complexity and propositional content.

Mixed modeling was used to examine longitudinal changes in linguistic ability in healthy older adults and older adults with dementia. Language samples, vocabulary scores, and digit span scores were collected annually from healthy older adults and semiannually from older adults with dementia. The language samples were scored for grammatical complexity and propositional content. For the healthy group, age-related declines in grammatical complexity and propositional content were observed. The declines were most rapid in the mid 70s. For the group with dementia, grammatical complexity and propositional content also declined over time, regardless of age. Rates of decline were uniform across individuals. These analyses reveal how both grammatical complexity and proposition content are related to late-life changes in cognition in healthy older adults as well as those with dementia. Alzheimer's disease accelerates this decline, regardless of age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and Input Processing in Dual-Task Situations.

The psychological refractory period (PRP) paradigm was used to test whether older participants suffer from input interference in dual-task situations. Young (24 years) and older (57 years) adults gave speeded responses to 2 successively presented stimuli. The results showed increased susceptibility of older participants to input interference. Further experiments revealed that this input interference is related to the salience of the 2nd stimulus and that it is specific to older participants. Our findings indicate that parallel processing at the input stages of dual-task performance requires cognitive control. An age-related decline in the control of input processes should be considered as one source of age effects in dual-task performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in the use of distractor homogeneity during visual search.

Previous research has suggested that an age-related decline may exist in the ability to inhibit distracting information during visual search. The present experiments used a conjunction search task in which the within-item features of the target (an upright L) and the distractors (rotated Ls) were identical. In each of 2 experiments, both young and older adults searched the display significantly more rapidly when the distractors were all rotated in the same direction (homogeneous) than when the distractors were rotated in different directions (heterogeneous). The concept of a generalized, age-related slowing was able to account for many aspects of the data, although the degree of relative improvement associated with distractor homogeneity was greater for young adults than for older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The structural organization of the mental lexicon and its contribution to age-related declines in spoken-word recognition.

Three experiments were conducted within the framework of the Neighborhood Activation Model of spoken-word recognition to study how the structural organization of the mental lexicon may contribute to age-related declines in spoken-language processing. Experiment 1 showed that the number and frequency of words that are phonetically similar to a target word had differential effects on perceptual identification in older and younger adults, with older adults being particularly disadvantaged in identifying hard words (words phonetically similar to many other high-frequency words). Experiment 2 showed that age-related deficits in the ability to identify hard words remained under conditions in which performance for a set of easy words (items phonetically similar to relatively few other low-frequency words) was the same for older and younger adults. In Experiment 3, reducing the resources available for identification by changing from single to multiple talkers reduced word recognition more among older than younger adults. Diminished cognitive resources, impaired inhibitory control, and increased general slowing are discussed as explanations for the results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging minds and twisting attitudes: An fMRI investigation of age differences in inhibiting prejudice.

Cognitive capacity is believed to decline with age, but it is not known whether this decline extends to tasks involving social cognition. In the current study, social neuroscience methodologies were used to examine the effects of age-related cognitive decline on older adults’ abilities to engage regulatory mechanisms (which are typically impaired by normal aging) to inhibit negative reactions to stigmatized individuals. Older and young adults were presented with images of stigmatized individuals (e.g., individuals with amputations, substance abusers) and of normal controls while they underwent functional magnetic resonance imaging. All participants were also given a battery of tests to assess their executive function capacity. Young adults showed more activity in areas associated with empathy (i.e., medial prefrontal cortex) than did older adults when viewing stigmatized faces. By contrast, older adults with relatively preserved levels of executive function had heightened activity in areas previously implicated in emotion regulation (i.e., lateral prefrontal cortex) as compared to other groups. These results suggest that although cognitive decline may interfere with older adults’ attitudes toward stigmatized individuals, older adults with relatively preserved cognitive function may utilize different strategies to compensate for these deficits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of 42 hr of total sleep deprivation on component processes of verbal working memory.

The current investigation examined changes in working memory (WM) component processes following total sleep deprivation (TSD) in a sample of healthy young persons. Forty subjects were administered a verbal form of a continuous recognition test (CRT) before and after 42 hr of TSD. Parameters of a computational model of the CRT reflecting attention, WM span, and rate of episodic memory encoding were estimated for each individual. Subjects made more errors on the test following sleep deprivation. Analysis of model parameters revealed statistically independent declines in both the attention and WM span parameters, with a larger effect observed for the decline in WM span. Examination of individual profiles suggested that the effects of TSD on verbal WM component processes vary from person to person. Declines in global verbal WM functioning appear to be primarily driven by reduced WM span and attention; however, these effects may be individual-specific. Further applications of the computational model for examining WM component processes with sleep deprivation and other clinical populations are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in executive control across the life span: Examination of task-switching performance.

A study was conducted to examine changes in executive control processes over the life span. More specifically, changes in processes responsible for preparation and interference control that underlie the ability to flexibly alternate between two different tasks were examined. Individuals (N?=?152) ranging in age from 7 to 82 years participated in the study. A U-shaped function was obtained for switch costs (i.e., the time required to switch between tasks compared with a repeated-task baseline), with larger costs found for young children and older adults. Switch costs were reduced with practice, particularly for children. All age groups benefited from increased preparation time, with larger benefits observed for children and older adults. Adults benefited to a greater extent than children when the interval between the response to one task and the cue indicating which task to perform next was lengthened, which suggested faster decay of interference from the old task set for adults than for children. A series of hierarchical analyses indicated that the age-related variance in task-switching performance is independent, at least in part, from the age-related variance in other cognitive processes such as perceptual speed and working memory. The results are discussed in terms of the development and decline of executive control processes across the life span. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Older adults' decoding of emotions: Role of dynamic versus static cues and age-related cognitive decline.

Although age-related deficits in emotion recognition have been widely explored, the nature and scope of these deficits remain poorly understood. We conducted two experiments to examine whether these deficits are less pronounced when older adults evaluate dynamic compared with static images, and second, whether age-related cognitive decline exacerbates these deficits. Our results suggest that age-related cognitive decline exacerbates older adults' deficits in detecting anger, but only from static faces. Furthermore, older adults do not show emotion recognition deficits when evaluating global emotions from dynamic images of faces. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-differential motivational consequences of optimization versus compensation focus in younger and older adults.

Four studies investigated age-related differences in goal focus in younger and older adults. Studies 1 and 2 confirmed the hypothesis that younger adults are more persistent when the same sensorimotor task offers possibility for optimizing performance than when the task requires counteracting a loss in performance (compensation). In contrast, older adults were more persistent in the compensation than in the optimization condition. Study 3 showed that the age-differential effects of goal focus on persistence were not simply due to perceiving the 2 conditions as easy versus difficult. Study 4 ruled out that the age differences were due to differences in the 2 tasks themselves. Taken together, the studies underscore the importance of situating motivational research into a life span context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related practice effects across longitudinal neuropsychological assessments in older people with schizophrenia.

Objective: The relationship between aging and practice effects on longitudinal neuropsychological assessments was investigated in middle-aged and older people with schizophrenia and healthy controls. Method: Older people with schizophrenia (n = 107; M age = 56.1) and age-comparable nonpsychiatric controls (n = 107; M age = 57.7) were scheduled to receive annual assessments on a comprehensive battery of neuropsychological tests for an average of 2.5 years (range 11 months to 4 years). Mixed-model analyses were used to separately examine the effects of practice and age on test performance. Results: Number of prior assessments (practice) was associated with significant performance improvement across assessments, whereas older age was associated with significant decline in performance. The groups did not differ significantly in extent of age-related cognitive decline, but a three-way interaction among group, age, and practice was found, such that greater age-related decline in practice effects were found for older people with schizophrenia relative to nonpsychiatric participants. Conclusions: This study did not find any evidence of neurodegenerative age-related decline in neuropsychological abilities in middle-aged and older people with schizophrenia, but older age was associated with diminished ability to benefit from repeated exposure to cognitive tasks in people with schizophrenia. Cognitive impairment in schizophrenia may combine with cognitive decline associated with normal aging to reduce practice effects in older patients. These findings have important implications for the design of studies examining the longitudinal trajectory of cognitive functioning across the life span of people with schizophrenia, as well as clinical trials that attempt to demonstrate cognitive enhancement in these individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in reading with distraction: Sensory or inhibitory deficits?

Two experiments examined how sensory acuity affects age differences in susceptibility to interference in the reading-with-distraction task. In both experiments, older and younger adults read texts in an italic font and were required to ignore distractor words in an upright font. Experiment 1 examined whether the age-related increase in distractibility can be simulated in younger adults by reducing their visual acuity. Experiment 2 investigated whether the age differences in distractibility disappear if visual acuity is equated across all participants in both age groups. Both experiments showed that an impairment in visual acuity leads to increased interference in the reading-with-distraction task. However, older adults were much more impaired by the distractor material than younger adults with reduced visual acuity (Experiment 1). The age differences in the reading-with-distraction task persisted when visual acuity was equated between older and younger adults (Experiment 2). We conclude that the age-related increase in susceptibility to interference in the reading-with-distraction task is not solely due to perceptual deficits of older adults but arises from a deficit in higher cognitive processes such as inhibitory attention. Nevertheless, sensory acuity has to be taken into account as a potential confounding factor in perceptually demanding visual attention tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in recollection: Three patterns of enhanced encoding.

Memory encoding conditions can be manipulated in a variety of ways, and many of these methods result in improved recollection for both younger and older adults relative to baseline conditions. Previous results have shown differential age-related patterns of improvement, however, with some manipulations giving equal improvement to young and old participants, some benefiting older adults more, and others benefiting younger adults more. In 2 experiments, the authors show that presenting pictures with words benefited older more than younger participants, word generation benefited both groups equally, and an encoding condition requiring novel integrative processing benefited younger more than older adults. The authors discuss these results in terms of the enhanced elaboration afforded and processing demanded by differential combinations of age groups and encoding conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)