The associative memory deficit of older adults: the role of strategy utilization

Past research has established an associative deficit hypothesis (e.g., M. Naveh-Benjamin, 2000) that attributes part of older adults' poor episodic memory performance to their difficulty in creating and retrieving cohesive episodes. Here, the authors evaluate the degree to which this deficit can be reduced by older adults' use of associative strategies. Young and older adults learned word pairs under either intentional-learning instructions or instructions eliciting associative strategies either at encoding or both at encoding and at retrieval, and they then took tests on their memory for both the components and the associations. Results replicated the associative deficit of older adults under intentional-learning instructions. In addition, they showed that instructions to use appropriate associative strategies during either encoding or, even more so, during encoding and retrieval resulted in a significant decrease in the associative deficit. The theoretical and applied implications of these results are discussed.     

Consolidation of novel word learning in native English-speaking adults

Sleep has been shown to improve the retention of newly learned words. However, most methodologies have used artificial or foreign language stimuli, with learning limited to word/novel word or word/image pairs. Such stimuli differ from many word-learning scenarios in which definition strings are learned with novel words. Thus, we examined sleep's benefit on learning new words within a native language by using very low-frequency words. Participants learned 45 low-frequency English words and, at subsequent recall, attempted to recall the words when given the corresponding definitions. Participants either learned in the morning with recall in the evening (wake group), or learned in the evening with recall the following morning (sleep group). Performance change across the delay was significantly better in the sleep than the wake group. Additionally, the Levenshtein distance, a measure of correctness of the typed word compared with the target word, became significantly worse following wake, whereas sleep protected correctness of recall. Polysomnographic data from a subsample of participants suggested that rapid eye movement (REM) sleep may be particularly important for this benefit. These results lend further support for sleep's function on semantic learning even for word/definition pairs within a native language.     

The differential effects of emotional salience on direct associative and relational memory during a nap

Relational memories are formed from shared components between directly learned memory associations, flexibly linking learned information to better inform future judgments. Sleep has been found to facilitate both direct associative and relational memories. However, the impact of incorporating emotionally salient information into learned material and the interaction of emotional salience and sleep in facilitating both types of memory is unknown. Participants encoded two sets of picture pairs, with either emotionally negative or neutral objects paired with neutral faces. The same objects were present in both sets, paired with two different faces across the sets. Baseline memory for these directly paired associates was tested immediately after encoding, followed by either a 90-min nap opportunity or wakefulness. Five hours after learning, a surprise test assessed relational memory, the indirect association between two faces paired with the same object during encoding, followed by a retest of direct associative memory. Overall, negative information was remembered better than neutral for directly learned pairs. A nap facilitated both preservation of direct associative memories and formation of relational memories, compared to remaining awake. Interestingly, however, this sleep benefit was observed specifically for neutral directly paired associates, while both neutral and negative relational associations benefitted from a nap. Finally, REM sleep played opposing roles in neutral direct and relational associative memory formation, with more REM sleep leading to forgetting of direct associations but promoting relational associations, suggesting that, while not benefitting memory consolidation for directly learned details, REM sleep may foster the memory reorganization needed for relational memory.     

Adult age differences in memory for name-face associations: The effects of intentional and incidental learning

Previous studies have indicated that older adults have a special deficit in the encoding and retrieval of associations. The current study assessed this deficit using ecologically valid name-face pairs. In two experiments, younger and older participants learned a series of name-face pairs under intentional and incidental learning instructions, respectively, and were then tested for their recognition of the faces, the names, and the associations between the names and faces. Under incidental encoding conditions older adults' performance was uniformly lower than younger adults in all three tests, indicating age-related impairments in episodic memory representations. An age-related deficit specific to associations was found under intentional but not under incidental learning conditions, highlighting the importance of strategic associative processes and their decline in older adults. Separate analyses of hits and false alarms indicate that older adults' associative deficit originated from high false alarm rates in the associative test. Older adults' high false alarm rates potentially reflect their reduced ability to recollect the study-phase name-face pairs in the presence of intact familiarity with individual names and faces.     

Discrimination and Reversal Learning by Toddlers Aged 15-23 Months

Few studies have investigated simple discrimination and discrimination reversal learning by children younger than 2 years. Extant research has shown that teaching discrimination reversals may be challenging with this population. We used social reinforcement and correction procedures to teach simple simultaneous discrimination and discrimination reversal tasks involving three pairs of animal pictures displayed in a paper notebook. Participants were eight typically developing toddlers aged 15-23 months. All learned at least one simple discrimination/discrimination reversal problem. Four children learned all problems and showed evidence of learning set formation. Perhaps surprisingly, discrimination reversals were sometimes learned more rapidly than original discriminations. The procedures suggest a potentially efficient methodology for investigating more complex aspects of relational learning in toddlers.

     

Can associative information be strategically separated from item information in word-pair recognition?

Subjects learned word pairs either once or three times but were instructed to ignore the association of the two words in each pair and only to memorize the individual words at study and recognize them at test. The test word pairs included intact pairs, rearranged pairs made up of old words exchanged among the studied pairs, and new pairs consisting of one old and one new word. Subjects were instructed to respond yes to both intact and rearranged pairs and no to new pairs. Results showed that the rearranged test pairs, as compared with intact pairs, produced longer reaction times, lower discrimination (d′), and lower remember judgments. In addition, more learning either did not reduce or actually increased the pairing effect. These results are difficult to reconcile with the notion that associative information is retrieved in a slow, controlled, and effortful process but are consistent with the encoding specificity principle and the global activation theory of recognition.     

Looking in the wrong direction correlates with more accurate word learning

Previous research on lexical development has aimed to identify the factors that enable accurate initial word-referent mappings based on the assumption that the accuracy of initial word-referent associations is critical for word learning. The present study challenges this assumption. Adult English speakers learned an artificial language within a cross-situational learning paradigm. Visual fixation data were used to assess the direction of visual attention. Participants whose longest fixations in the initial trials fell more often on distracter images performed significantly better at test than participants whose longest fixations fell more often on referent images. Thus, inaccurate initial word-referent mappings may actually benefit learning.     

Sleep's function in the spontaneous recovery and consolidation of memories

Building on 2 previous studies (B. R. Ekstrand, 1967; B. R. Ekstrand, M. J. Sullivan, D. F. Parker, & J. N. West, 1971), the authors present 2 experiments that were aimed at characterizing the role of retroactive interference in sleep-associated declarative memory consolidation. Using an A-B, A-C paradigm with lists of word pairs in Experiment 1, the authors showed that sleep provides recovery from retroactive interference induced at encoding, whereas no such recovery was seen in several wake control conditions. Noninterfering word-pair lists were used in Experiment 2 (A-B, C-D). Sleeping after learning, in comparison with waking after learning, enhanced retention of both lists to a similar extent when encoding was less intense because of less list repetition and briefer word-pair presentations. With intense encoding, sleep-associated improvements were not seen for either list. In combination, the results indicate that the benefit of sleep for declarative memory consolidation is greater for weaker associations, regardless of whether weak associations result from retroactive interference or poor encoding.     

Single and concurrent discrimination learning by monkeys after lesions of inferotemporal cortex

Three monkeys with bilateral lesions of inferotemporal cortex and three unoperated controls (all previously sophisticated at visual discriminations) learned 60 discriminations between pairs of multi-featured computer-generated patterns. They then learned 5 problem sets, each composed of 5 pairs of the same kind learned concurrently, and finally 20 more single discriminations.

Previous reports that inferotemporal lesions selectively impair concurrent learning were disconfirmed; given practice at learning pairs concurrently, the inferotemporals learned these at a similar rate to single pairs. Analysis of intra-problem learning supported the suggestion that the lesion affects visual identification (the ability to distinguish objects within a large population) rather than visual association or memory.     

The effects of divided attention on encoding processes under incidental and intentional learning instructions: Underlying mechanisms?

Divided attention (DA) at encoding has been shown to significantly disrupt later memory for the studied information. However, what type of processing gets disrupted during DA remains unresolved. In this study, we assessed the degree to which strategic effortful processes are affected under DA by comparing the effects of DA at encoding under intentional and pure incidental learning instructions. In three experiments, participants studied list of words or word pairs under either full or divided attention. Results of three experiments, which used different methodologies, converged to show that the effects of DA at encoding reduce memory performance to the same degree under incidental and intentional learning. Secondary task performance indicated that encoding under intentional learning instructions was more effortful than under incidental learning instructions. In addition, the results indicated enhanced attention to the initial appearance of the words under both types of learning instructions. Results are interpreted to imply that other processes, rather than only strategic effortful ones, might be affected by DA at encoding.     

睡眠学习的ERP研究

夜间用脑电监测被试睡眠状态,并反复播放英语单词和中文对译词,第二天用词汇决定任务检查学习效果,并记录ERP,结果发现：（1）与未学过的英—中词对相比,被试对学过的词对中中文词的反应时明显缩短;（2）学过的词对中中文词引发的N600的波幅比未学过的明显降低。以上结果表明睡眠学习效果在内隐记忆测验中明显。另外发现被试几乎不能在播放学过的英语词时说出中文对译词,与未学过的词对相比没有显著差别,提示睡眠学习效果在外显记忆测验中不明显。以上结果表明,在本实验条件下,间接测验比直接测验更敏感。     

When does feedback facilitate learning of words?

Some researchers have suggested that although feedback may enhance performance during associative learning, it does so at the expense of later retention. To examine this issue, subjects (N = 258) learned Luganda-English word pairs. After 2 initial exposures to the materials, subjects were tested on each item several times, with the presence and type of feedback varying between subjects. A final test followed after 1 week. Supplying the correct answer after an incorrect response not only improved performance during the initial learning session--it also increased final retention by 494%. On the other hand, feedback after correct responses made little difference either immediately or at a delay, regardless of whether the subject was confident in the response. Practical and theoretical implications are discussed.     

Implicit and explicit memory for new associations in normal and amnesic subjects

Two experiments examined whether repetition priming effects on a word completion task are influenced by new associations between unrelated word pairs that were established during a single study trial. On the word completion task, subjects were presented with the initial three letters of the response words from the study list pairs and they completed these fragments with the first words that came to mind. The fragments were shown either with the paired words from the study list (same context) or with other words (different context). Both experiments showed a larger priming effect in the same-context condition than in the different-context condition, but only with a study task that required elaborative processing of the word pairs. This effect was observed with college students and amnesic patients, suggesting that word completion performance is mediated by implicit memory for new associations that is independent of explicit recollection.     

Posthypnotic amnesia for recently learned material: Interactions with “episodic” and “semantic” memory

In two experiments, posthypnotic amnesia was suggested for a word list memorized during hypnosis. After an initial test of amnesia the subjects gave word associations (Experiment 1) or category instances (Experiment 2) to stimuli intended to elicit the critical (word list) items covered by the amnesia. The extent of initial amnesia observed was strongly associated with measured hypnotic susceptibility. Even among the most hypnotizable subjects, however, the dense amnesia did not prevent the critical items from being elicited by the semantic memory tasks, nor did it modulate the priming which these associations received by virtue of the prior learning experience. Moreover, production of the critical items did not, in general, remind the amnesic subjects of those items which they had previously learned, but could not now remember. Full memory was restored after the amnesia suggestion was canceled by a prearranged cue. Posthypnotic amnesia appears to represent a temporary dissociation of episodic features from memory traces, so that the subject has difficulty in reconstructing the context in which the target events occurred.     

The Influence of Learning Style and Cognitive Ability on Recall of Names and Faces in an Older Population

The present study examined whether, for older adults, a verbal or imagery cognitive style is associated with recall of names and faces learned in an experimental condition. Cognitive abilities that are represented in current models of face recognition and name recall were also examined. Those abilities included picture naming, verbal fluency (i.e., naming items within a given category), vocabulary comprehension, visual memory, and the learning of unassociated word pairs. Fifty older adults attempted to learn first and last names of 20 student actors and actresses pictured on videotapes (40 names total). On average, participants learned the most first names, followed by last names, and the fewest full names. The greater the number of responses on a questionnaire associated with an imagery cognitive style, the more the names of faces were correctly identified by participants. There was no significant relationship between a verbal cognitive style and the number of names and faces recalled. As for cognitive abilities, all of the abilities measured—with the exception of vocabulary comprehension—were significantly associated with the number of names and faces learned. A regression analysis indicated that the best predictor of successful name-face learning was the participants' ability to learn and recall 5 unrelated word pairs. When that cognitive measure was deleted from the regression analysis, delayed visual memory and verbal fluency were the next best predictors of the older adults' ability to learn names and faces.     

Word learning and individual differences in word learning reflected in event-related potentials

Adults learned the meanings of rare words (e.g., gloaming) and then made meaning judgments on pairs of words. The 1st word was a trained rare word, an untrained rare word, or an untrained familiar word. Event-related potentials distinguished trained rare words from both untrained rare and familiar words, first at 140 ms and again at 400-600 ms after onset of the 1st word. These results may point to an episodic memory effect. The 2nd word produced an N400 that distinguished trained and familiar word pairs that were related in meaning from unrelated word pairs. Skilled comprehenders learned more words than less skilled comprehenders and showed a stronger episodic memory effect at 400-600 ms on the 1st word and a stronger N400 effect on the 2nd word. These results suggest that superior word learning among skilled comprehenders may arise from a stronger episodic trace that includes orthographic and meaning information and illustrate, how an episodic theory of word identification can explain reading skill.     

Paired-associate learning and priming effects in amnesia: a neuropsychological study

Despite severe deficits of recall and recognition, amnesic patients can exhibit normal priming effects. Amnesic patients have also been reported to perform well on tests of paired-associate learning that involve related word pairs (e.g., table-chair). The present study investigated the role of priming effects in paired-associate learning. Experiment 1 illustrated the distinction between the memory impairment of amnesic patients and their intact priming ability. Amnesic patients were markedly deficient in learning unrelated word pairs, despite exhibiting normal priming as measured by a word-completion test involving the same words. In Experiment 2A, amnesic patients showed good paired-associate learning for related word pairs, though control subjects still performed significantly better. In addition, the good performance by amnesic patients was short-lived, and performance fell to baseline after a 2-hr delay. Control subjects performed well above baseline at all delay conditions. Experiment 2B showed that the forgetting of related word pairs by amnesic patients followed the same time course as the decay of word priming. Experiment 3 showed that amnesic patients were as good as control subjects at learning related word pairs when incidental learning and test procedures were used (a word-association test). The advantage of control subjects over amnesic patients in Experiments 2A and 2B could therefore be attributed to the explicit learning instructions that are standard in paired-associate tests. Finally, Experiment 4 showed that amnesic patients exhibited normal priming when they were asked to "free associate" to words (e.g., child) that were semantically related to previously presented words (e.g., baby). The results indicate that both priming effects and paired-associate learning of related word pairs depend on activation, a process that is preserved in amnesia. Activation can account for the findings of good performance by amnesic patients on tests of word priming (Experiments 1 and 2B), related paired associates (Experiments 2A and 2B), and word association (Experiments 3 and 4). Activation is a transient phenomenon presumed to operate on and facilitate access to preexisting representations. Control subjects can establish new associations and can strengthen preexisting associations by engaging processes that are impaired in amnesia. As a result, when explicit learning instructions are used to test paired-associate learning of related word pairs, control subjects can learn better and can remember longer than can amnesic patients (Experiments 2A and 2B).(ABSTRACT TRUNCATED AT 400 WORDS)     

The influence of learning style and cognitive ability on recall of names and faces in an older population

The present study examined whether, for older adults, a verbal or imagery cognitive style is associated with recall of names and faces learned in an experimental condition. Cognitive abilities that are represented in current models of face recognition and name recall were also examined. Those abilities included picture naming, verbal fluency (i.e., naming items within a given category), vocabulary comprehension, visual memory, and the learning of unassociated word pairs. Fifty older adults attempted to learn first and last names of 20 student actors and actresses pictured on videotapes (40 names total). On average, participants learned the most first names, followed by last names, and the fewest full names. The greater the number of responses on a questionnaire associated with an imagery cognitive style, the more the names of faces were correctly identified by participants. There was no significant relationship between a verbal cognitive style and the number of names and faces recalled. As for cognitive abilities, all of the abilities measured--with the exception of vocabulary comprehension--were significantly associated with the number of names and faces learned. A regression analysis indicated that the best predictor of successful name-face learning was the participants' ability to learn and recall 5 unrelated word pairs. When that cognitive measure was deleted from the regression analysis, delayed visual memory and verbal fluency were the next best predictors of the older adults' ability to learn names and faces.     

Stimulus-naming effects at different stages of motor paired-associate learning

In a combined verbal and motor paired-associate task, nonsense names and button-pushing responses were learned for three random shapes, with verbal training beginning after 3, 12, or 24 motor learning trials. Earlier studies indicated that concurrent verbal and motor learning produce a strong tendency for the naming and button-pushing responses to be learned in “consistent” pairs. According to the theoretical analysis presented, the verbal-motor consistency is explained by the development of name-button associations. It was predicted that these associations affect both motor errors and correct responses, that their effects are greater for correct responses, and that attenuation of the effects due to delay in verbal training is gr, eater for motor errors. The results are in good agreement with the predictions, and they suggest that name-button associations develop rapidly even under delayed verbal training.     

Judgments of learning reflect encoding fluency: conclusive evidence for the ease-of-processing hypothesis

According to the ease-of-processing hypothesis, judgments of learning (JOLs) rely on the ease with which items are committed to memory during encoding--that is, encoding fluency. Conclusive evidence for this hypothesis does not yet exist because encoding fluency and item difficulty have been confounded in all previous studies. To disentangle the effects of encoding fluency and item difficulty on JOLs, we used a variant of the learner-observer-judge method in which participants observed the study phase of another participant and indicated his or her JOLs. At the same time, the to-be-studied word pairs were concealed by strings of symbols. Our experiment revealed that participants use self-paced study time as a cue for JOLs when they themselves have studied and recalled word pairs before. This metacognitive monitoring of study time provides strong support for the ease-of-processing hypothesis.