Working memory capacity for spoken sentences decreases with adult ageing: recall of fewer but not smaller chunks in older adults

Previous studies show that older adults have poorer immediate recall for language but the reason is unknown. Older adults may recall fewer chunks from working memory, or may have difficulty binding words together to form multi-unit chunks. We examined these two hypotheses by presenting four types of spoken sentences for immediate free recall, differing in the number and length of chunks per trial: four short, simple sentences; eight such sentences; four compound sentences, each incorporating two meaningful, short sentences; and four random word lists, each under a sentence-like intonation. Older adults recalled words from (accessed) fewer clauses than young adults, but there was no ageing deficit in the degree of completion of clauses that were accessed. An age-related decline in working memory capacity measured in chunks appears to account for deficits in memory for spoken language.     

Word frequency influences on the list length effect and associative memory in young and older adults

Many studies show that age deficits in memory are smaller for information supported by pre-experimental experience. Many studies also find dissociations in memory tasks between words that occur with high and low frequencies in language, but the literature is mixed regarding the extent of word frequency effects in normal ageing. We examined whether age deficits in episodic memory could be influenced by manipulations of word frequency. In Experiment 1, young and older adults studied short and long lists of high- and low-frequency words for free recall. The list length effect (the drop in proportion recalled for longer lists) was larger in young compared to older adults and for high- compared to low-frequency words. In Experiment 2, young and older adults completed item and associative recognition memory tests with high- and low-frequency words. Age deficits were greater for associative memory than for item memory, demonstrating an age-related associative deficit. High-frequency words led to better associative memory performance whilst low-frequency words resulted in better item memory performance. In neither experiment was there any evidence for age deficits to be smaller for high- relative to low-frequency words, suggesting that word frequency effects on memory operate independently from effects due to cognitive ageing.     

Semantic binding,not attentional control,generates coherent global structure in children's narrative memory

Encoding and retrieving global narrative structure influences children's narrative recall. The influence of age and attentional/executive resources on binding processes during sentence list recall was examined in 5- to 6- and 8- to 9-year-old children. Older and younger children showed superior recall of lists, and achieved higher scores on two metrics of chunking; access to different sentences (i.e., number of chunks) and sentence completion (i.e., chunk size), when lists were presented within a coherent global structure. Children's list recall and sentence access, but not their sentence completion scores, were affected by a concurrent self-paced attention-demanding task. Children, unlike adults, engage in active storage of verbal information in thematically related sentence lists. The coherence-advantage effect was stable across age groups and insensitive to the secondary task. Overall, findings imply that semantic binding generates stronger memory representations and superior recall for sentences within a story context than for sentence sets that lack global narrative structure.     

Searching for the Trace: The Influence of Age, Lexical Activation and Working Memory on Sentence Processing

To investigate the stability of trace reactivation in healthy older adults, 22 older volunteers with no significant neurological history participated in a cross-modal priming task. Whilst both object relative center embedded (ORC) and object relative right branching (ORR) sentences were employed, working memory load was reduced by limiting the number of words separating the antecedent from the gap for both sentence types. Analysis of the results did not reveal any significant trace reactivation for the ORC or ORR sentences. The results did reveal, however, a positive correlation between age and semantic priming at the pre-gap position and a negative correlation between age and semantic priming at the gap position for ORC sentences. In contrast, there was no correlation between age and priming effects for the ORR sentences. These results indicated that trace reactivation may be sensitive to a variety of age related factors, including lexical activation and working memory. The implications of these results for sentence processing in the older population are discussed.     

Episodic intertrial learning of younger and older participants: Effects of age of acquisition

There is clear evidence of a deficit in episodic memory for older adults compared to younger adults. Using an intertrial technique previous research has investigated whether this deficit can be attributed to a decline in encoding or consolidation. On standard memory tests, these two aspects of memory function can be measured by examining the items forgotten or acquired across multiple learning trials. The present study assessed whether age deficits in episodic memory were affected by stimulus characteristics, specifically age of acquisition (AoA). A standard intertrial design was implemented whereby participants studied word lists over several study-test trials. The stimulus characteristics of AoA were manipulated using a pure-list technique. Our findings showed that older adults demonstrate an overall recall deficit which appeared to be a consequence of both an encoding deficit and consolidation weakness. Earlier-acquired words were recalled significantly better than later-acquired words and this was apparently due to both enhanced encoding and consolidation of earlier- over later-acquired words. The key finding is that older adults show a recall advantage for earlier- compared to later-acquired words over the entire experiment to a greater degree than younger adults.     

Evidence for language recoding in autistic, retarded and normal children: a re-examination

In a replication and extension of earlier studies by Hermelin & O'Connor, language recoding abilities in autistic, retarded and normal children matched for mental age and digit span, were compared in a verbal recall task. Random word lists, sentences, and anomalous sentences, eight or 12 items in length (for high and low memory span subgroups) were presented and the number of words recalled from each type of input was scored. All low span children recalled sentences better than random lists with normal children superior to retarded and autistic children and the latter group poorer than the retarded group. Autistic children showed a recency effect with both types of input. There were no group differences amongst high span children and sentences were again better recalled than random lists. In Expt II sentences were better recalled than anomalous sentences, with autistic and retarded children equivalent in performance and poorer than normal children. Although low span autistic children were clearly deficient in recall of sentence material when compared with the two control groups, the effect of conditions showed that they were able to use structure to improve recall. Since high span autistic children did not perform differently from controls it is suggested that results from this kind of study may not be generalizable, and that claims for a specific coding deficit in autistic children need further substantiation.     

Age deficits in recall under optimal study conditions

Young and older adults studied lists of words under both standard and optimal study conditions for subsequent free recall. Under optimal conditions, the participants studied each word for as long as they wished, were allowed to take notes, and were encouraged to actively use whatever strategies they thought would maximize recall. Both age groups recalled more words under optimal study conditions than under standard conditions, but the improvement was greater for the young adults. This increase in the age-related recall deficit was not due to differences in study time. The results suggest that standard laboratory memory tasks do not overestimate the memory deficits of older adults because of a failure to provide either optimal learning conditions or sufficient study time.     

A developmental comparison of the effectiveness of encoding tasks.

In Experiment 1, the free-recall performance of young children, college students, and older adults was examined. Subjects encoded words by simply learning them, by studying them in either base or elaborate sentence frames, or by constructing sentences. Overall recall was better for the college students than for the children or for the older adults, and the college students recalled best in the simple learning condition. The young children recalled best in the sentence construction condition; recall by older adults did not vary as a function of the encoding tasks. In Experiment 2, college students and older adults recalled a categorized list, encoding the words by simply learning them, by studying them in elaborate sentence frames, or by completing word fragments. For both age groups, simple learning produced the highest level of recall. These results suggest that organization provides the most effective encoding system and that older adults may need a more obvious basis for organization than do younger adults. Younger and older adults recalled equally well only when organization was discouraged by conceptual processing.     

Aging and the Deletion Function of Inhibition

The present study was adapted from the sentence completion task of Hartman and Hasher (1991). We addressed the question raised by Burke (1997): are the age-related differences in priming effects found in that task better explained by deficits in explicit memory or by inefficient inhibitory mechanisms? In the study phase, older and younger adults read high cloze sentences ending with an expected or an unexpected final word. In the second phase, participants were asked to complete sentence frames with either the final word presented during the study phase (inclusion condition) or with another, new word (exclusion condition). The third phase was an indirect memory test of perceptual identification. Finally, we compared explicit memory for recalled and inhibited words in a recognition test. In perceptual identification by older adults, priming was equivalent for recalled and inhibited words, whereas in younger adults priming was higher for recalled than for inhibited words. In the explicit memory test, recognition scores were lower for inhibited words in both age groups. These results are consistent with the view of Hasher and Zacks (1988), who assume an age-related decline in the ability to suppress no-longer-relevant information     

Effects of saccadic bilateral eye movements on memory in children and adults: an exploratory study

The effects of saccadic bilateral (horizontal) eye movements on true and false memory in adults and children were investigated. Both adults and children encoded lists of associated words in the Deese-Roediger-McDermott paradigm followed by a test of recognition memory. Just prior to retrieval, participants were asked to engage in 30s of bilateral vs. vertical vs. no eye movements. For studied information, the results for adults replicated previous work; bilateral eye movements were demonstrated to increase the accuracy of memory by increasing the hit rate and reducing the false alarm rate for related and unrelated recognition test lures. The results for children also indicated an improvement in memory accuracy, and like adults, was due to both an increase in the hit rate and a reduction in the false alarm rate. In spite of these similarities, the effects of bilateral eye movements differed between adults and children for critical unstudied words; i.e., those associated with the theme of the list. Only in adults did, bilateral eye movements reduce associative false memories; children did not show a reduction in false memory for critical associates. This produced a dissociation between the effects of eye movements on associative false memory as a function of age. The results are discussed from a developmental perspective in terms of potential mechanisms underlying true and false memory.     

Working memory affects older adults’ use of context in spoken-word recognition

Many older listeners report difficulties in understanding speech in noisy situations. Working memory and other cognitive skills may modulate older listeners’ ability to use context information to alleviate the effects of noise on spoken-word recognition. In the present study, we investigated whether verbal working memory predicts older adults’ ability to immediately use context information in the recognition of words embedded in sentences, presented in different listening conditions. In a phoneme-monitoring task, older adults were asked to detect as fast and as accurately as possible target phonemes in sentences spoken by a target speaker. Target speech was presented without noise, with fluctuating speech-shaped noise, or with competing speech from a single distractor speaker. The gradient measure of contextual probability (derived from a separate offline rating study) affected the speed of recognition. Contextual facilitation was modulated by older listeners’ verbal working memory (measured with a backward digit span task) and age across listening conditions. Working memory and age, as well as hearing loss, were also the most consistent predictors of overall listening performance. Older listeners’ immediate benefit from context in spoken-word recognition thus relates to their ability to keep and update a semantic representation of the sentence content in working memory.     

Aging,imagery, and the bizarreness effect

ABSTRACT

This study examined the bizarre imagery effect in young and older adults, under incidental and intentional conditions. Intentionality was manipulated across experiments, with participants receiving an incidental free recall test in Experiment 1 and an intentional test in Experiment 2. This study also examined the relation between working memory resources and the bizarreness effect. In Experiment 1 young and older adults were presented with common and bizarre sentences; they later received an incidental recall test. There were no age differences in sensitivity to the bizarreness effect in Experiment 1 when ANOVAs were used to analyze the data. However, when the bizarreness effect was examined in terms of effect size, there was evidence that younger adults produced larger bizarreness effect sizes than younger adults. Experiment 2 further explored age differences in sensitivity to the bizarreness effect by presenting young and older adults with bizarre and common sentences under intentional learning conditions. Experiment 2 failed to yield age differences as a function of item type (bizarre vs. common). In addition, Experiment 2 failed to yield significant evidence that the bizarreness effect is modulated by working memory resources. The results of this study are most consistent with the distinctiveness account of the bizarreness effect.     

Let's pretend: The role of motoric imagery in memory for sentences and words

A number of theories suggest that for young children, concepts should have an important motoric (or sensory-motor) component. A levels-of-processing theory is proposed which predicts that processing on motoric imagery should facilitate memory for both isolated words and for sentences. Experiment 1 examined the effects of motoric enactment (viz., pretend play) of sentences on memory for the sentences. Motoric imagery facilitated memory for both children (5 to 7 years of age) and adults, though, contrary to expectations, the effects were weaker for the children than for the adults. Further, it was found that motoric imagery affected the initial acquisition, but was not important as a retreival cue. Experiment 2 examined the effects of motoric imagery on free recall of lists of unrelated words. Under these conditions, motoric imagery facilitated memory for both children (7 to 9 years of age) and adults equally; in contrast, visual imagery instructions had no effect on memory. These results indicate that motoric imagery may facilitate memory under conditions in which visual imagery has no effect. Theoretical implications are explored for previous experiments on pretend play which suggest that training for pretent enactment can facilitate cognitive development.     

记忆的前向测试效应对老年人学习新事物的作用

为检验前置测试是否可以有效地提升老年人学习新事物的能力,参与实验的老年人被随机分为有前置测试的实验组和无前置测试的对照组,在实验1中学习了5列单词,在实验2中记忆了5列日用品,在实验3中学习了4段讲座视频。结果表明,实验组老年人对新事物的记忆成绩均高于对照组的老年人。结论认为,前置测试能够显著提升老年人学习新事物的能力,干扰降低与学习参与相结合的“加减”理论能更好地解释提升老年人记忆的前向测试效应。     

Age-related differences in immediate serial recall: Dissociating chunk formation and capacity

We assessed the contribution of two hypothesized mechanisms to impaired memory performance of older adults in an immediate serial recall task: decreased temporary information storage in a capacity-limited mechanism, such as the focus of attention, and a deficit in binding together different components into cohesive chunks. Using a method in which paired associations between words were taught at varying levels to allow an identification of multiword chunks (Cowan, Chen, & Rouder, 2004), we found that older adults recalled considerably fewer chunks and, on average, smaller chunks than did young adults. Their performance was fairly well simulated by dividing attention in younger adults, unlike what has been found for long-term associative learning. Paired-associate knowledge may be used in an implicit manner in serial recall, given that younger adults under divided attention and older adults use it well despite the relatively small chunk capacities displayed by these groups.     

Process and strategy in memory for speech among younger and older adults

Younger and older adults listened to and immediately recalled short passages of speech that varied in the rate of presentation and in the degree of linguistic and prosodic curing. Although older adults showed a differential decrease in recall performance as a function of increasing speech rate, age differences in recall were reduced by the presence of linguistic and prosodic cues. Under conditions of optimum linguistic redundancy, older adults were also found to add more words and to make more meaning-producing reconstructions in recall. Differences in overall performance are accounted for in terms of age-related changes in working memory processing and strategy utilization.     

Emotional working memory capacity in posttraumatic stress disorder (PTSD)

Participants with a lifetime history of posttraumatic stress disorder (PTSD) and trauma-exposed controls with no PTSD history completed an emotional working memory capacity (eWMC) task. The task required them to remember lists of neutral words over short intervals while simultaneously processing sentences describing dysfunctional trauma-related thoughts (relative to neutral control sentences). The task was designed to operationalise an everyday cognitive challenge for those with mental health problems such as PTSD; namely, the ability to carry out simple, routine tasks with emotionally benign material, while at the same time tackling emotional laden intrusive thoughts and feelings. eWMC performance, indexed as the ability to remember the word lists in the context of trauma sentences, relative to neutral sentences, was poorer overall in the PTSD group compared with controls, suggestive of a particular difficulty employing working memory in emotion-related contexts in those with a history of PTSD. The possible implications for developing affective working memory training as an adjunctive treatment for PTSD are explored.     

工作记忆中汉语反词长效应机制

工作记忆中的反词长效应(reverse word-length effect)指在对长词和短词混合的词表进行即时序列回忆时, 独立长词回忆成绩优于独立短词的现象。以汉字词语为材料通过3个实验探讨反词长效应的机制。实验1采用纯粹词表和长短词混合词表, 既得到纯粹词词长效应, 也得到独立词反词长效应。实验2削弱了长短词之间的词长差异, 结果独立词反词长效应消失, 且独立词回忆成绩优于纯粹词。实验3设计了视觉延迟条件, 得到与实验1类似的结果, 只是独立词反词长效应有所削弱。三个实验的结果并不一致, 无法用现有的语音回路理论或SIMPLE理论进行很好地解释, 理论的整合与创新显得非常重要。因此, 提出多重编码以既相互竞争又相互补充方式进行平行加工的观点进行更完整地解释。     

Verbal learning across the lifespan: an analysis of the components of the learning curve

Previous studies on the acquisition process of verbal material, conducted separately on child and adult populations, reveal that the lifespan is characterized by an inverted-U performance curve with similar achievements at its two poles. To clarify the acquisition mechanism across the entire lifespan, the learning curve for the Rey Auditory Verbal Learning Test was reproduced for participants aged 8–91. The study utilized typical trial summary scores and a more refined analysis of trial-by-trial single-word recalls, including omissions (missed words that were previously recalled), additions (recalled words previously missed), and touched words (a count for the first recall time only, for each word during the five learning trial). A clear age effect was shown for the number of words recalled – symmetrically increases during childhood and decreases in adulthood. Similarly, increased turnover of words omitted and added characterized both incremental and decremental age differences. Measurement patterns differed for the age segments on the two sides of the lifespan, despite the similar total number of words recalled by the two sides. Acquisition pattern in children was characterized by a higher number of touched words and higher turnover than for adult groups. In contrast, older adults achieved fewer touched words and lower turnover than the child groups. This study shows that it is possible to reach the same quantitative results via different cognitive processes. The results are interpreted in terms of specific mechanisms of maturational characteristics.     

Pictorial superiority effects in oldest-old people

We examined memory for pictures and words in middle-age (45–59 years), young-old (60–74 years), old-old (75–89 years), and the oldest-old adults (90–97 years) in the Louisiana Healthy Aging Study. Stimulus items were presented and retention was tested in a blocked order where half of the participants studied 16 simple line drawings and the other half studied matching words during acquisition. Free recall and recognition followed. In the next acquisition/test block a new set of items was used where the stimulus format was changed relative to the first block. Results yielded pictorial superiority effects in both retention measures for all age groups. Follow-up analyses of clustering in free recall revealed that a greater number of categories were accessed (which reflects participants’ retrieval plan) and more items were recalled per category (which reflects participants’ encoding strategy) when pictures served as stimuli compared to words. Cognitive status and working memory span were correlated with picture and word recall. Regression analyses confirmed that these individual difference variables accounted for significant age-related variance in recall. These data strongly suggest that the oldest-old can utilise nonverbal memory codes to support long-term retention as effectively as do younger adults.