年老化与文本理解

年老化与文本理解的研究表明,老年人在表层形式和文本基础两个低水平表征上的理解和记忆能力下降,而在情境模型的建构和提取、更新等加工过程中都没有发现由于年老化引起的能力下降。在介绍这些研究的基础上,从情境模型与另两个低水平加工的不同特点和老年人自身的特殊性两个方面分析了老年人在不同层次表征水平加工能力差异的原因。对情境模型水平加工能力保持的潜在机制及相关的影响因素,以及如何弥补在低水平加工中认知能力因年龄而产生的下降等问题还需要进行探讨     

Age-differential effects on updating cue information: Evidence from event-related potentials

Recent models on cognitive aging consider the ability to maintain and update context information to be a key source of age-related impairments in various cognitive tasks (Braver & Barch in Neuroscience & Biobehavioral Reviews, 26: 809–817, 2002). Context updating has been investigated with a modified AX-continuous-performance task by comparing performance and brain activity between context-dependent trials (i.e., correct responses require updating of the preceding cue information) and context-independent trials (i.e., correct responses are independent of cue information). We used an event-related potential (ERP) approach to identify sources of age differences in context processing in the early and late processing of cue information. Our behavioral data showed longer latencies and higher error rates on context-dependent than on context-independent trials for older than for younger adults, suggesting age-related impairments in context updating. The ERP data revealed larger P3b amplitudes for context-dependent than for context-independent trials only in younger adults. In contrast, in older adults, P3b amplitudes were more evenly distributed across the scalp and did not differ between context conditions. Interestingly, older but not younger adults were sensitive to changes of cue identity, as indicated by larger P3b amplitudes on cue-change than on cue-repeat trials, irrespective of the actual context condition. We also found a larger CNV on context-dependent than on context-independent trials, reflecting active maintenance of context information and response preparation. The age-differential effects in the P3b suggest that both younger and older adults were engaged in updating task-relevant information, but relied on different information: Whereas younger participants indeed relied on context cues to update and reconfigure the task settings, older adults relied on changes in cue identity, irrespective of context information.     

Instantiation of general terms in young and older adults

Instantiation of general terms in discourse requires inference from general world knowledge and use of linguistic context to particularize meaning. According to the semantic deficit hypothesis, older adults should be less likely than young adults to generate or to store such inferences. In Experiments 1 and 2 an indirect measure, relatedness judgment, was used to assess immediate comprehension and memory for inferences. In Experiment 3 a direct measure, cued recall, was used to tap memory for inferences. No age differences in immediate or delayed memory were observed in Experiments 1 or 2. In Experiment 3 older adults recalled fewer sentences, but there was no evidence for a specific decrement in storage of inferential material. Older adults are not impaired in ability to draw inferences based on general world knowledge, nor are they more likely than young adults to encode linguistic information in a general, stereotypic fashion.     

Accounting for age differences on the Wisconsin Card Sorting Test: decreased working memory, not inflexibility

Two experiments examined the role of cognitive inflexibility and reduced working memory in age-related declines on the Wisconsin Card Sorting Test. Both standard scoring procedures and newly developed scores were used to measure each construct, and modifications of the test further evaluated the role of working memory. Results indicated that age differences are not due to cognitive inflexibility but that for a subset of older adults errors are associated with a reduction in the amount of information that can be stored or processed in working memory. These age differences disappear, however, when visual cues provide information about the immediately preceding sort. The authors conclude by proposing a decline in updating working memory as the explanation that can best account for the entire pattern of age differences on this test.     

Adult age differences in explanations and memory for behavioral information

Age differences in the effects of knowledge-based expectations on both the use of integrative memory processes and recall were examined. In the context of an impression-formation task, young and older adults were presented with lists containing behaviors that varied in consistency with attributed personality traits. Younger adults recalled trait-inconsistent behaviors better than consistent ones, but older adults exhibited no such consistency effect. The age difference in performance was related to the younger adults' spontaneously producing more explanations for inconsistent behaviors. Explanations are assumed to facilitate access to such information by establishing associations with other behavioral information residing in memory. When age differences in the use of explanation-based processing were controlled, the age differences in the effects of consistency on memory were eliminated.     

老年人情景记忆更新的改变：竞争记忆的回溯性干扰

记忆更新是获取新知识的一种重要能力。大量研究显示老年人情景记忆受损,但鲜有研究探讨老年人情景记忆更新模式的改变。研究在匹配了老年人和年轻人编码程度的前提下,探讨情景记忆更新的老化效应及其潜在的认知机制。我们对AB-AC记忆更新范式进行了创新,同时考察了在项目改变和位置改变条件下的老化效应,并在测试阶段纳入诱饵选项,进一步排除编码程度带来的影响。研究结果显示年轻人能对A-B和A-C记忆分离存储,而老年人更多地受到回溯性记忆干扰,即在A-B测试中出现C的闯入,并且该干扰效应显著地大于诱饵刺激带来的影响。研究结果表明,在年轻人和老年人编码程度匹配的情况下,年轻人的记忆更新通过记忆分化来实现,而老年人更多地受到竞争记忆的回溯性干扰。     

Adult Age Differences in the Access and Deletion Functions of Inhibition

ABSTRACT

This study examined age differences in working memory using a delayed-matching-to-sample (DMTS) task. Based on the inhibitory decline hypothesis, which posits that older adults are more susceptible to interference, age differences were expected to be greater for older adults when irrelevant information was present during encoding. Two experiments tested both the access and deletion functions of inhibition. In both experiments, performance was equated for older and younger participants on a no-interference version of the DMTS task to control for age differences in encoding information into working memory. Results consistently showed equivalent effects of distraction for older and younger adults regardless of the difficulty of the perceptual discrimination of targets and distractors, the degree of processing of the distractors, or the semantic relationship between targets and distractors. These results support theories that propose age differences in encoding to explain age differences in working memory, and are inconsistent with theories that propose that older adults are more susceptible to interference than younger adults.     

Age differences in verbal and visuo-spatial working memory updating: evidence from analysis of serial position curves

Memory updating is the ability to select and update relevant information and suppress no-longer-relevant data. The few studies in this area, targeting mainly the verbal domain, have investigated and confirmed an age-related decline in working memory updating ability (De Beni & Palladino, 2004; Van der Linden, Bredart, & Beerten, 1994). The present research examines the ability of younger and older adults to update information in verbal and visuo-spatial running memory tasks. Results showed that the participants' performance was higher in the verbal than in the visuo-spatial task. Nonetheless, independently of the task domain, an age-related decline in updating performance was found. Moreover, analysis of serial positions suggested that, in the updating procedure, the participants were not attempting to actively maintain items, preferring to adopt a low-effort, "recency-based" strategy. The use of this type of strategy is more evident in older participants, as shown in both the accuracy performance and the proportion of intrusion errors.     

Younger and older adults’ associative memory for medication interactions of varying severity

While older adults face various deficits in binding items in memory, they are often able to remember information that is deemed important. In Experiment 1, we examined how younger and older adults remember medication interactions of varying severity. There were no age differences in overall memory accuracy, but older adults’ performance depended on the severity of the interactions (such that the interactions associated with the most severe health outcomes were remembered most accurately) while younger adults’ did not. In Experiment 2, a similar task was designed to create interference in memory. Even with this more difficult task there were no age differences in recall accuracy, and both age groups remembered the interactions with the severe outcomes most accurately. These findings suggest that, under certain circumstances, older adults do not face deficits in associative recognition accuracy of information that varies in importance.     

Spatial updating of multiple targets: Comparison of younger and older adults

When walking without vision, people mentally keep track of the directions and distances of previously viewed objects, a process called spatial updating. The current experiment indicates that while people across a large age range are able to update multiple targets in memory without perceptual support, aging negatively affects accuracy, precision, and decision time. Participants (20 to 80 years of age) viewed one, three, or six targets (colored lights) on the floor of a dimly lit room. Then, without vision, they walked to a target designated by color, either directly or indirectly (via a forward turning point). The younger adults’ final stopping points were both accurate (near target) and precise (narrowly dispersed), but updating performance did degrade slightly with the number of targets. Older adults’ performance was consistently worse than the younger group, but the lack of interaction between age and memory load indicates that the effect of age on performance was not further exacerbated by a greater number of targets. The number of targets also significantly increased the latency required to turn toward the designated target for both age groups. Taken together, results extend previous work showing impressive updating performance by younger adults, with novel findings showing that older adults manifest small but consistent degradation of updating performance of multitarget arrays.     

Situation models and aging

Younger and older adults were tested for their ability to process and retrieve information from texts. The authors focused on the construction and retrieval of situation models relative to other types of text representations. The results showed that during memory retrieval, younger adults showed superior memory for surface form and textbase knowledge (what the text was), whereas older adults had equivalent or superior memory for situation model information (what the text was about). The results also showed that during reading, older and younger adults were similar in their sensitivity to various aspects of the texts. Overall, these findings suggest that although there are age-related declines in the processing and memory for text-based information, for higher level representations, these abilities appear to be preserved. Several possibilities for why this is the case are discussed, including an in-depth consideration of one possibility that involves W. Kintsch's (1988) construction-integration model.     

Patterns of resource allocation are reliable among younger and older readers

Younger and older adults read short expository passages across 2 times of measurement for subsequent comprehension or recall. Regression analysis was used to decompose word-by-word reading times into resources allocated to word- and textbase-level processes. Readers were more sensitive to these demands when reading for recall than when reading for comprehension. Patterns of resource allocation showed good test-retest reliabilities and were predictive of memory performance. Within age group, resource allocation parameters were not systematically correlated with other individual-difference measures, suggesting that strategies of on-line resource allocation may be a unique source of individual differences in determining comprehension of and memory for text. Age differences in allocation patterns appeared to reflect general slowing among the older adults. Because older adults showed equivalent memory performance to that of younger readers, the reading time data may represent the on-line resource allocation needed for comparable outcomes among older and younger readers.     

Eye movements of young and older adults while reading with distraction

The authors used eye-tracking technology to examine young and older adults' online performance in the reading in distraction paradigm. Participants read target sentences and answered comprehension questions following each sentence. In some sentences, single-word distracters were presented in either italic or red font. Distracters could be related or unrelated to the target text. Online measures, including probability of fixation, fixation duration, and number of fixations to distracting text, revealed no age differences in text processing. However, young adults did have an advantage over older adults in overall reading time and text comprehension. These results provide no support for an inhibition deficit account of age differences in the reading in distraction paradigm, but are consistent with J. Dywan and W. E. Murphy's (1996) suggestion that older adults are less able than the young to distinguish target and distracter information held in working memory.     

Dopaminergic and cholinergic modulations of visual-spatial attention and working memory: insights from molecular genetic research and implications for adult cognitive development

Attention and working memory are fundamental for selecting and maintaining behaviorally relevant information. Not only do both processes closely intertwine at the cognitive level, but they implicate similar functional brain circuitries, namely the frontoparietal and the frontostriatal networks, which are innervated by cholinergic and dopaminergic pathways. Here we review the literature on cholinergic and dopaminergic modulations of visual-spatial attention and visual working memory processes to gain insights on aging-related changes in these processes. Some extant findings have suggested that the cholinergic system plays a role in the orienting of attention to enable the detection and discrimination of visual information, whereas the dopaminergic system has mainly been associated with working memory processes such as updating and stabilizing representations. However, since visual-spatial attention and working memory processes are not fully dissociable, there is also evidence of interacting cholinergic and dopaminergic modulations of both processes. We further review gene-cognition association studies that have shown that individual differences in visual-spatial attention and visual working memory are associated with acetylcholine- and dopamine-relevant genes. The efficiency of these 2 transmitter systems declines substantially during healthy aging. These declines, in part, contribute to age-related deficits in attention and working memory functions. We report novel data showing an effect of dopamine COMT gene on spatial updating processes in older but not in younger adults, indicating potential magnification of genetic effects in old age.     

Lifespan aging and belief reasoning: Influences of executive function and social cue decoding

Older adults often perform poorly on Theory of Mind (ToM) tests that require understanding of others’ beliefs and intentions. The course and specificity of age changes in belief reasoning across the adult lifespan is unclear, as is the cause of the age effects. Cognitive and neuropsychological models predict that two types of processing might influence age differences in belief reasoning: executive functioning and social cue detection. In the current study we assessed 129 adults aged between 18 and 86 on novel measures of ToM (video clips and verbal vignettes), which manipulated whether true or false belief reasoning was required. On both video and verbal tasks, older adults (aged 65–88) had specific impairments in false belief reasoning, but showed no such problem in performing true belief tasks. Middle-aged adults (aged 40–64) generally performed as well as the younger adults (aged 18–39). Difficulties in updating information in working memory (but not inhibitory problems) partially mediated the age differences in false belief reasoning. Also, the ability to decode biological motion, indexing social cue detection, partially mediated age-related variance in the ability to interpret false beliefs. These results indicate that age differences in decoding social cues and updating information in memory may be important influences on the specific problems encountered when reasoning about false beliefs in old age.     

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.     

Effects of Domain,Retention Interval,and Information Load on Young and Older Adults’ Visuospatial Working Memory

Age-related differences in visuospatial working memory were examined in 69 young adults and 49 older adults exposed to three pairs of tasks. Each pair consisted of one task involving information about the form or appearance of items and another task involving information about item locations. The first pair of tasks manipulated retention interval and required maintaining information about one item. The second pair also manipulated retention interval and required maintaining information about multiple items presented simultaneously. The third pair manipulated the number of sequentially presented items. Analyses of the first two pairs of tasks revealed significant age deficits in working memory for spatial locations but not in working memory for visual features. Notably, there were no age differences in the effect of retention interval on any of the four tasks, suggesting that visuospatial information is lost at similar rates in older and young adults. Analyses of the third pair of tasks revealed that, regardless of domain, increasing the amount of information impaired older adults’ memory performance to a greater extent than young adults’ performance. Thus, the present results suggest differences in basic working memory capacity in both domains, but a lack of age differences in rates of forgetting from working memory, and greater age-related deficits in the spatial domain than in the object domain.     

Using eye movement measures to investigate effects of age on memory for objects in a scene

We examined whether there were age-related differences in eye movements during intentional encoding of a photographed scene that might account for age-related differences in memory of objects in the scene. Younger and older adults exhibited similar scan path patterns, and visited each region of interest in the scene with similar frequency and duration. Despite the similarity in viewing, there were fundamental differences in the viewing-memory relationship. Although overall recognition was poorer in the older than younger adults, there was no age effect on recognition probability for objects visited only once. More importantly, re-visits to objects brought gain in recognition probability for the younger adults, but not for the older adults. These results suggest that the age-related differences in object recognition performance are in part due to inefficient integration of information from working memory to longer-term memory.     

语言能力的老化机制：语言特异性与非特异性因素的共同作用

语言能力的衰退是由于一般认知能力衰退引起的, 还是由于语言加工系统的衰退引起的, 抑或是两者的共同作用?研究中测量了青年组和老年组的一般认知能力(加工速度、工作记忆和抑制能力), 以及在词汇、句子和语篇三个水平上的语言理解能力和语言产生能力。结果发现, 一般认知能力、语言理解和语言产生能力都存在年老化现象。分层回归分析表明, 一般认知能力对语言能力的贡献, 以及语言理解能力和产生能力之间的相互贡献在青年组和老年组中是不同的, 且存在词汇、句子和语篇水平上的差异。在词汇水平上, 青年人的成绩能够被一般认知能力和另一种语言能力所显著预测, 而老年人的成绩却不受一般认知因素影响; 在句子水平上, 青年人的成绩仍能被一般认知能力或另一种语言能力所解释, 但这两类变量都无法预测老年人的任务成绩; 在语篇水平上, 青年人理解任务的成绩显著地受到产生能力影响, 而老年人的理解和产生任务成绩则分别可以被一般认知能力和语言理解能力所解释。对组间差异的回归分析表明, 一般认知能力和另一种语言能力对组间差异都有显著贡献, 且前者的贡献大于后者。上述研究结果表明, 语言能力的老化是语言特异性因素和非特异性因素共同作用的结果。     

Decline in working memory updating through ageing: intrusion error analyses

The present research examines the decline in working memory updating through age. Two experiments compared groups of participants in different age ranges (young-old, 55-65 years, old, 66-75 years and old-old, more than 75 years and, in Experiment 2 only, young, 20-30 years). Memory updating tasks were administered, which required participants to remember the smallest items in each list. To perform the task correctly, participants had to update information efficiently, reducing interference from items no longer relevant. Intrusion errors were computed and in the first experiment these were described as "intrusions of irrelevant items" (immediate exclusion) and "intrusions of once relevant items" (delayed exclusion). The oldest adults performed worse in memory updating and made a greater number of intrusion errors of once relevant information. In the second experiment results showed that increases in memory load (number of items that had to be remembered) and updating demand (number of potentially relevant items) impaired performance. The oldest adults had greater difficulty when the task demand was increased. Furthermore, they produced a higher number of intrusion errors, particularly when the updating demand was increased. It therefore appears that elderly people have specific difficulty in updating information in working memory by excluding irrelevant information.