Familiarity,Cued and Free Odor Identification and Their Association with Cognitive Functioning in Middle Aged and Older Adults

ABSTRACT

The aim of the present study was to examine the association between familiarity of odors, cued and free odor identification performance and cognitive function in elderly adults. It was further investigated how age affects performance on the various odor tasks. A third aim was to investigate the role of familiarity in explaining performance on the free identification task. One hundred and thirty-six participants (aged 45–79 years) with normal olfactory sensitivity were assessed with the Scandinavian Odor Identification Test (SOIT) and standardized tests of cognitive function. Familiarity did not correlate with any measure of cognitive function, while verbal identification performance was associated with several cognitive measures, although correlations were modest. In this sample, free odor identification was affected by increasing age to a marginally larger extent than cued identification performance and familiarity ratings. The results suggest that the different olfactory tasks involve different levels of cognitive processing.     

Age benefits in everyday prospective memory: the influence of personal task importance, use of reminders and everyday stress

The present diary study examined everyday prospective memory tasks in younger and old adults and explored the role of personal task importance, use of reminders and everyday stress as possible correlates of age-related prospective memory performance in everyday life. Results revealed an age benefit in everyday prospective memory tasks. In addition, task importance was identified as a critical moderator of age-related prospective memory performance. More frequent use of reminders and lower levels of stress, however, were associated with better prospective memory performance in general but did not contribute to age-related prospective memory performance. Exploring further possible correlates of prospective memory revealed that the strategy to reprioritize initially planned intentions was associated with age benefits in everyday prospective memory. Results suggest that the age-related benefit observed in experimenter-given tasks transfers to everyday prospective memory and varies in dependence of motivational and cognitive factors. Implications for theoretical models of prospective memory and aging are discussed.     

Binding and inhibition in working memory: individual and age differences in short-term recognition

Two studies investigated the relationship between working memory capacity (WMC), adult age, and the resolution of conflict between familiarity and recollection in short-term recognition tasks. Experiment 1 showed a specific deficit of young adults with low WMC in rejecting intrusion probes (i.e., highly familiar probes) in a modified Sternberg task, which was similar to the deficit found in old adults in a parallel experiment (K. Oberauer, 2001). Experiment 2 generalized these results to 3 recognition paradigms (modified Sternberg, local recognition, and n back tasks). Old adults showed disproportional performance deficits on intrusion probes only in terms of reaction times, whereas young adults with low WMC showed them only in terms of errors. The generality of the effect across paradigms is more compatible with a deficit in content-context bindings subserving recollection than with a deficit in inhibition of irrelevant information in working memory. Structural equation models showed that WMC is related to the efficiency of recollection but not of familiarity.     

Central executive involvement in children's spatial memory

Previous research with adults found that spatial short-term and working memory tasks impose similar demands on executive resources. We administered spatial short-term and working memory tasks to 8- and 11-year-olds in three separate experiments. In Experiments 1 and 2 an executive suppression task (random number generation) was found to impair performances on a short-term memory task (Corsi blocks), a working memory task (letter rotation), and a spatial visualisation task (paper folding). In Experiment 3 an articulatory suppression task only impaired performance on the working memory task. These results suggest that short-term and working memory performances are dependent on executive resources. The degree to which the short-term memory task was dependent on executive resources was expected to be related to the amount of experience children have had with such tasks. Yet we found no significant age-related suppression effects. This was attributed to differences in employment of cognitive strategies by the older children.     

Central executive involvement in children's spatial memory

Previous research with adults found that spatial short-term and working memory tasks impose similar demands on executive resources. We administered spatial short-term and working memory tasks to 8- and 11-year-olds in three separate experiments. In Experiments 1 and 2 an executive suppression task (random number generation) was found to impair performances on a short-term memory task (Corsi blocks), a working memory task (letter rotation), and a spatial visualisation task (paper folding). In Experiment 3 an articulatory suppression task only impaired performance on the working memory task. These results suggest that short-term and working memory performances are dependent on executive resources. The degree to which the short-term memory task was dependent on executive resources was expected to be related to the amount of experience children have had with such tasks. Yet we found no significant age-related suppression effects. This was attributed to differences in employment of cognitive strategies by the older children.     

Effects of adult age and working memory on reasoning and spatial abilities

Three predictions were derived from the hypothesis that adult age differences in certain measures of cognitive functioning are attributable to age-related reductions in a processing resource such as working-memory capacity. Each prediction received at least some degree of empirical support in a study involving 120 males ranging between 20 and 79 years of age. First, older adults exhibited greater impairments of performance than did young adults when task complexity increased and more demands were placed on the limited processing resources; second, the magnitudes of these complexity effects were highly correlated across verbal (reasoning) and spatial (paper folding) tasks. Finally, statistical control of an index of a working-memory processing resource attenuated the effects of age on the measures of cognitive performance. It was concluded that further progress in understanding the mechanisms of the relation between age and cognitive functioning will require improved conceptualizations of the nature of working memory or other hypothesized mediating constructs.     

Visual function and cognitive aging: differential role of contrast sensitivity in verbal versus spatial tasks

Cognitive and sensory function are correlated in older adults. Sensory function may provide an index of neurological integrity (common-cause hypothesis). Declining sensory input may also directly impair cognition (direct-cause hypothesis). Accordingly, sensory function should more strongly predict cognitive performance and should account for more age-related variability in tasks with higher sensory demands. In a cross-sectional adult life span sample, visual contrast sensitivity was a better predictor and accounted for more of the age-related variability in high sensory-demand tasks, compared with low sensory-demand tasks, consistent with the direct-cause hypothesis. The results suggest a direct role for sensory function in cognitive aging when task conditions place heavy demands on sensory processing.     

Age differences in response selection for pure and mixed stimulus-response mappings and tasks

Two experiments examined effects of mixed stimulus-response mappings and tasks for older and younger adults. In Experiment 1, participants performed two-choice spatial reaction tasks with blocks of pure and mixed compatible and incompatible mappings. In Experiment 2, a compatible or incompatible mapping was mixed with a Simon task for which the mapping of stimulus color to location was relevant and stimulus location was irrelevant. In both experiments, older adults showed larger mixing costs than younger adults and larger compatibility effects, with the differences particularly pronounced in Experiment 1 when location mappings were mixed. In mixed conditions, when stimulus location was relevant, older adults benefited more than younger adults from complete repetition of the task and stimulus from the preceding trial. When stimulus location was irrelevant, the benefit of complete repetition did not differ reliably between age groups. The results suggest that the age-related deficit associated with mixing mappings and tasks is primarily due to older adults having more difficulty separating task sets that activate conflicting response codes.     

Differential age-related effects on conjunctive and relational visual short-term memory binding

An age-related associative deficit has been described in visual short-term binding memory tasks. However, separate studies have suggested that ageing disrupts relational binding (to associate distinct items or item and context) more than conjunctive binding (to integrate features within an object). The current study directly compared relational and conjunctive binding with a short-term memory task for object–colour associations in 30 young and 30 older adults. Participants studied a number of object–colour associations corresponding to their individual object span level in a relational task in which objects were associated to colour patches and a conjunctive task where colour was integrated into the object. Memory for individual items and for associations was tested with a recognition memory test. Evidence for an age-related associative deficit was observed in the relational binding task, but not in the conjunctive binding task. This differential impact of ageing on relational and conjunctive short-term binding is discussed by reference to two underlying age-related cognitive difficulties: diminished hippocampally dependent binding and attentional resources.     

Environmental topography and postural control demands shape aging-associated decrements in spatial navigation performance

This study tests the hypothesis that aging-induced cognitive permeation of sensorimotor functions contributes to adult age differences in spatial navigation performance. Virtual maze-like museums were projected in front of a treadmill. Sixteen 20-30-year-old men and sixteen 60-70-year-old men performed a way-finding task in city-block or variable topographies while walking with or without support. Walking support attenuated age-related decrements in navigational learning. Navigation load increased trunk-angle variability for older adults only. Age differences in spatial knowledge persisted despite perfect place-finding performance. City-block topography was easier than variable topography for younger adults only, indicating age-related differences in reliance on spatial relational learning. Attempts at supporting older adults' navigation performance should consider sensorimotor/cognitive interactions and qualitative differences in navigational activity.     

Focus of attention and automaticity in handwriting

This study investigated the nature of automaticity in everyday tasks by testing handwriting performance under single and dual-task conditions. Item familiarity and hand dominance were also manipulated to understand both cognitive and motor components of the task. In line with previous literature, performance was superior in an extraneous focus of attention condition compared to two different skill focus conditions. This effect was found only when writing with the dominant hand. In addition, performance was superior for high familiarity compared to low familiarity items. These findings indicate that motor and cognitive familiarity are related to the degree of automaticity of motor skills and can be manipulated to produce different performance outcomes. The findings also imply that the progression of skill acquisition from novel to novice to expert levels can be traced using different dual-task conditions. The separation of motor and cognitive familiarity is a new approach in the handwriting domain, and provides insight into the nature of attentional demands during performance.     

增龄性联结记忆损伤及其影响因素

老年人的联结记忆随年龄增长而出现普遍损伤, 这种增龄性联结记忆损伤究竟是因捆绑功能受损导致的特定损伤还是因整体认知机能受损导致的信息表征能力的整体损伤, 还存有争论。以Naveh-Benjamin (2000)的联结损伤假说(ADH)为代表的特定损伤观认为, 增龄性联结记忆损伤与老年人捆绑不同项目和提取这些捆绑的特定加工过程的损伤有关; 而以Benjamin (2010)的DRYAD模型为代表的整体损伤观则认为, 增龄性联结记忆损伤与老年人因老化而导致的记忆保持精度的整体损伤有关。二者在基本观点、实验支持及存在问题上各有侧重。此外, 影响增龄性联结损伤的因素还可大致分为刺激信息特性、被试主体特点两方面。同时强调未来研究不仅要关注老年人联结损伤的认知机制和影响因素, 更应关注其实际应用和临床指导价值。     

Aging and time-sharing aspects of executive control

A particularly important aspect of executive functioning involves the ability to coordinate two simultaneous activities. The role of this aspect of executive functioning in adult-age differences in cognitive performance was examined in a study involving 150 adults between 20 and 91 years of age who performed the same visual-motor tracking task with three different primary tasks. The participants also performed several additional cognitive tasks that allowed examination of the relation of time-sharing efficiency to other types of cognitive functioning The results were consistent with the existence of a distinct time-sharing ability because the time-sharing costs in the three dual-task combinations were significantly correlated with one another but only weakly correlated with other cognitive variables. Increased age was associated with reductions in time-sharing ability, and greater efficiency in performing two tasks at once was associated with better performance on tasks assessing spatial, reasoning, and memory abilities. Although this pattern is what one would expect if executive processes contribute to age differences in cognitive functioning, the effects were smaller than those associated with a perceptual speed construct.     

Language, space, and the development of cognitive flexibility in humans: the case of two spatial memory tasks

Prior experiments have shown that young children, like adult rats, rely mainly on information about the macroscopic shape of the environment to reorient themselves, whereas human adults rely more flexibly on combinations of spatial and non-spatial landmark information. Adult rats have also been shown to exhibit a striking limitation in another spatial memory task, movable object search, again a limitation not shown by human adults. The present experiments explored the developmental change in humans leading to more flexible, human adult-like performance on these two tasks. Experiment 1 identified the age range of 5-7 years as the time the developmental change for reorientation occurs. Experiment 2 employed a multiple regression approach to determine that among several candidate measures, only a specific language production measure, the production of phrases specifying exactly the information needed to solve the task like adults, correlated with the reorientation performance of children in this age range. Experiment 3 revealed that similar language production abilities were associated with more flexible moving object search task performance. These results, in combination with findings with human adults, suggest that language production skills play a causal role in allowing older humans to construct novel representations rapidly, which can then be used to transcend the limits of phylogenetically older cognitive processes.     

The effects of attention on age-related relational memory deficits: evidence from a novel attentional manipulation

Healthy aging is often accompanied by episodic memory decline. Prior studies have consistently demonstrated that older adults show disproportionate deficits in relational memory (RM) relative to item memory (IM). Despite rich evidence of an age-related RM deficit, the source of this deficit remains unspecified. One of the most widely investigated factors of age-related RM impairment is a reduction in attentional resources. However, no prior studies have demonstrated that reduced attentional resources are the critical source of age-related RM deficits. Here, we used qualitatively different attention tasks and tested whether reduced attention for relational processing underlies the RM deficit observed in aging. In Experiment 1, we imposed either item-detection or relation-detection attention tasks on young adults during episodic memory encoding and found that only the concurrent attention task that involves relational processing disproportionately impaired RM performance in young adults. Moreover, by ruling out the possible confound of task difficulty on the disproportionate RM impairment, we further demonstrated that reduced relational attention is a key factor for the age-related RM deficit. In Experiment 2, we replicated the results from Experiment 1 by using different materials of stimuli and found that the effect of relational attention on RM is material general. The results of Experiment 2 also showed that reducing attentional resources for relational processing in young adults strikingly equated their RM performance to that of older adults. Thus, this study documents the first evidence that reduced attentional resources for relational processing are a critical factor for the relational memory impairment observed in aging.     

Age-related differences in concurrent-task performance of normal adults: evidence for a decline in processing resources.

A concurrent-task paradigm was used to investigate age-related differences in the attentional capacity of 92 right-handed adults. Young, middle-aged, and elderly Ss were compared as they performed speeded, unimanual finger tapping with and without concurrent silent reading, speaking, and maze completion. There were 2 levels of difficulty for each cognitive task. The decrement in tapping rate from the single- to dual-task condition increased linearly with age. Concurrent-task tapping was slowed more by difficult than by easy tasks, and difficult tasks had a disproportionately disruptive effect on the concurrent performance of elderly Ss. The heightened vulnerability of the elderly to concurrent-task effects cannot be attributed parsimoniously to either general slowing or diminution of a specific resource. Instead the results suggest a reduction in a general-purpose processing resource with increasing age.     

Normal aging and the dissociable prototype learning systems

Dissociable prototype learning systems have been demonstrated behaviorally and with neuroimaging in younger adults as well as with patient populations. In A/not-A (AN) prototype learning, participants are shown members of category A during training, and during test are asked to decide whether novel items are in category A or are not in category A. Research suggests that AN learning is mediated by a perceptual learning system. In A/B (AB) prototype learning, participants are shown members of category A and B during training, and during test are asked to decide whether novel items are in category A or category B. In contrast to AN, research suggests that AB learning is mediated by a declarative memory system. The current study examined the effects of normal aging on AN and AB prototype learning. We observed an age-related deficit in AB learning, but an age-related advantage in AN learning. Computational modeling supports one possible interpretation based on narrower selective attentional focus in older adults in the AB task and broader selective attention in the AN task. Neuropsychological testing in older participants suggested that executive functioning and attentional control were associated with better performance in both tasks. However, nonverbal memory was associated with better AN performance, while visual attention was associated with worse AB performance. The results support an interactive memory systems approach and suggest that age-related declines in one memory system can lead to deficits in some tasks, but to enhanced performance in others.     

Aging and perception of visual form from temporal structure

In this study, the authors examined age-related changes in participants' ability to perceive global spatial structure defined by temporal fine structure among elements undergoing rapid, irregular change. Participants were also tested on a task involving form recognition from luminance contrast and on a task dependent on perception of 3-dimensional shape from motion. Compared with young adults, older individuals were less sensitive to spatial form defined by temporal structure. In contrast, older observers performed as well as young adults on the other two tasks that were not dependent on temporal sensitivity, ruling out nonsensory factors as the cause of the deficits on the temporal structure task. This selective deficit may reveal reduced sensitivity within the temporal impulse response of the aging visual system, a deficit that could be related to reduced effectiveness of neural inhibition.     

Susceptibility of spatial and verbal working memory to demands of the central executive

We used a dual-task paradigm to examine the degree to which domain-specific spatial and verbal subsystems depend on the domain-general central executive. Forty participants were asked to retain spatial or verbal information while performing a concurrent secondary task related to simple arithmetic. The secondary tasks consisted of three cognitive processes: single-digit addition, a digit-carrying operation, and digit reading. The single-digit addition and carry operation include central executive functioning, while digit reading relies solely on the phonological loop. The single-digit addition caused a performance decrement on the spatial working memory task, while the digit reading impaired performance on the verbal working memory task. The carry operation interfered with recall accuracy on both working memory tasks. The spatial working memory task was significantly correlated with the verbal working memory task only when the secondary task was more demanding on the central executive. Our results suggest that spatial working memory rather than verbal working memory is susceptible to failure of central executive functioning and that the central executive plays an important role in regulating the cognitive demands of different domains.     

Age-related similarities and differences in monitoring spatial cognition

Spatial cognitive performance is impaired in later adulthood but it is unclear whether the metacognitive processes involved in monitoring spatial cognitive performance are also compromised. Inaccurate monitoring could affect whether people choose to engage in tasks that require spatial thinking and also the strategies they use in spatial domains such as navigation. The current experiment examined potential age differences in monitoring spatial cognitive performance in a variety of spatial domains including visual–spatial working memory, spatial orientation, spatial visualization, navigation, and place learning. Younger and older adults completed a 2D mental rotation test, 3D mental rotation test, paper folding test, spatial memory span test, two virtual navigation tasks, and a cognitive mapping test. Participants also made metacognitive judgments of performance (confidence judgments, judgments of learning, or navigation time estimates) on each trial for all spatial tasks. Preference for allocentric or egocentric navigation strategies was also measured. Overall, performance was poorer and confidence in performance was lower for older adults than younger adults. In most spatial domains, the absolute and relative accuracy of metacognitive judgments was equivalent for both age groups. However, age differences in monitoring accuracy (specifically relative accuracy) emerged in spatial tasks involving navigation. Confidence in navigating for a target location also mediated age differences in allocentric navigation strategy use. These findings suggest that with the possible exception of navigation monitoring, spatial cognition may be spared from age-related decline even though spatial cognition itself is impaired in older age.