Adult age differences in short-term memory for serial order: Data and a model.

Age-related deficits in short-term memory have been widely reported, but reduced overall scores could reflect increased order errors, increased omissions, or increased intrusions. Different explanations for reduced short-term memory with aging lead to different predictions. In this study, young (n?=?68; M age?=?20 years) and older (n?=?99; M age?=?65 years) adults were presented with lists of letters and were asked to recall each list immediately in the correct order. Age differences in error patterns were similar for auditory and visual presentation. For example, older adults made more errors of every type, and a greater proportion of the older adults' errors were omissions. An additional condition, in which older adults were encouraged to guess, ruled out an age increase in response threshold as a full explanation for the results. The data were modeled by an oscillator-based computational model of memory for serial order. A good fit to the aging data was achieved by simultaneously altering two parameters that were interpreted as corresponding to frontal decline and response slowing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trial-to-trial carryover in auditory short-term memory.

Using a short-term recognition memory task, the authors evaluated the carryover across trials of 2 types of auditory information: the characteristics of individual study sounds (item information) and the relationships between the study sounds (study set homogeneity). On each trial, subjects heard 2 successive broadband study sounds and then decided whether a subsequently presented probe sound had been in the study set. On some trials, the similarity of the probe item to stimuli presented on the preceding trial was manipulated. This item information interfered with recognition, and false alarms increased from 0.4% to 4.4%. Moreover, the interference was tuned so that only stimuli that were very similar to each other interfered. On other trials, the relationship among stimuli was manipulated to alter the criterion subjects used in making recognition judgments. The effect of this manipulation was confined to the trial on which the criterion change was generated and did not affect the subsequent trial. These results demonstrate the existence of a sharply tuned carryover of auditory item information but no carryover of the effects of study set homogeneity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of age on item and associative measures of memory: A meta-analysis.

In this meta-analysis, the authors evaluated recent suggestions that older adults' episodic memory impairments are partially due to a reduced ability to encode and retrieve associated/bound units of information. Results of 90 studies of episodic memory for both item and associative information in 3,197 young and 3,192 older adults provided support for the age-related associative/binding deficit suggestion, indicating a larger effect of age on memory for associative information than for item information. Moderators assessed included the type of associations, encoding instructions, materials, and test format. Results indicated an age-related associative deficit in memory for source, context, temporal order, spatial location, and item pairings, in both verbal and nonverbal material. An age-related associative deficit was quite pronounced under intentional learning instructions but was not clearly evident under incidental learning instructions. Finally, test format was also found to moderate the associative deficit, with older adults showing an associative/binding deficit when item memory was evaluated via recognition tests but not when item memory was evaluated via recall tests, in which case the age-related deficits were similar for item and associative information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Meeting Mr. Farmer Versus Meeting a Farmer: Specific Effects of Aging on Learning Proper Names.

Previous research testing age-related learning and memory problems specific to proper names has yielded mixed results. In the present experiments, young and older participants saw faces of previously unknown people identified by name and occupation. On subsequent presentations of each picture, participants attempted to recall the pictured person's name and occupation. Young and older adults made more name errors (the occupation was recalled but not the correct name) than occupation errors (the name was recalled but not the correct occupation), and older adults made relatively more name but not occupation errors than young adults. This specific age-related deficit in proper-name learning is explained within an interactive-activation model of memory and language that has been extensively applied to cognitive aging and proper-name retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Primacy, Recency, and Suffix Effects in Auditory Short-Term Memory for Pure Tones: Evidence From a Probe Recognition Paradigm.

The present study was designed to explore serial position and suffix effects in the short-term retention of nonverbal sounds. In contrast with previous studies of these effects, a probe recognition paradigm was used to minimize the possibility that participants would use a verbal labelling strategy. On each trial, participants heard a memory set consisting of three pure tones, followed five seconds later by a probe tone. Participants were required to indicate whether or not the probe tone had been a member of the memory set. On most trials, a suffix sound was presented 1 second following the third sound in the memory set. Results revealed that tones presented in the first and last positions of the memory set were recognized more accurately than were tones presented in the middle position. Furthermore, recognition of sounds presented in the last position was compromised when the memory set was followed by a postlist suffix of similar pitch, spectral composition, and spatial location. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serial order in spatial immediate memory

Serial order effects in spatial memory are investigated in three experiments. In the first an analysis of errors in recall data suggested that immediate transpositions were the most common error and that order errors over 2 or 3 adjacent items accounted for the majority of errors in recall. The first and last serial positions are less error-prone than is the middle position in sets of six and seven items. A second experiment investigated recognition of transpositions and found that immediate transpositions were hardest to recognize but that a traditional serial position effect was not found. This may be due to the difficulty of maintaining one set of spatial items when another set is presented for comparison. A probe experiment, in which subjects were asked to recognize whether a single item came from a memory set and then to assign it to its position in the set indicated that the first and last positions were remembered more accurately than were central positions. The combination of serial order data in recall and position data suggests that there are similarities between serial order and position effects in the verbal and spatial domains and that serial order in spatial sequences is position-based.     

Short-term memory in autism spectrum disorder.

Three experiments examined verbal short-term memory in comparison and autism spectrum disorder (ASD) participants. Experiment 1 involved forward and backward digit recall. Experiment 2 used a standard immediate serial recall task where, contrary to the digit-span task, items (words) were not repeated from list to list. Hence, this task called more heavily on item memory. Experiment 3 tested short-term order memory with an order recognition test: Each word list was repeated with or without the position of 2 adjacent items swapped. The ASD group showed poorer performance in all 3 experiments. Experiments 1 and 2 showed that group differences were due to memory for the order of the items, not to memory for the items themselves. Confirming these findings, the results of Experiment 3 showed that the ASD group had more difficulty detecting a change in the temporal sequence of the items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in temporal and item memory.

Three experiments tested whether the relationship between age differences in temporal and item memory depends on the degree to which the item memory measure relies on memory for context. The authors predicted a stronger relationship of temporal memory to free recall than to recognition memory. Results showed that age differences in temporal memory could be eliminated after controlling for free recall but not recognition memory performance. Under some conditions recognition memory accounted for a significant portion of age-related variance in temporal memory. These results challenge past research that has interpreted age differences in temporal and item memory as independent and suggest that a generalized decline in context memory may underlie reduced performance in older adults on all types of memory tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neural basis for recognition confidence in younger and older adults.

Although several studies have examined the neural basis for age-related changes in objective memory performance, less is known about how the process of memory monitoring changes with aging. The authors used functional magnetic resonance imaging to examine retrospective confidence in memory performance in aging. During low confidence, both younger and older adults showed behavioral evidence that they were guessing during recognition and that they were aware they were guessing when making confidence judgments. Similarly, both younger and older adults showed increased neural activity during low- compared to high-confidence responses in the lateral prefrontal cortex, anterior cingulate cortex, and left intraparietal sulcus. In contrast, older adults showed more high-confidence errors than younger adults. Younger adults showed greater activity for high compared to low confidence in medial temporal lobe structures, but older adults did not show this pattern. Taken together, these findings may suggest that impairments in the confidence–accuracy relationship for memory in older adults, which are often driven by high-confidence errors, may be primarily related to altered neural signals associated with greater activity for high-confidence responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Explaining age differences in temporal working memory.

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

Age-related associative deficits are absent with nonwords.

Words and nonwords were used as stimuli to assess item and associative recognition memory performance in young and older adults. Participants were presented with pairs of items and then tested on both item memory (old/new items) and associative memory (intact/recombined pairs). For words, older participants performed worse than young participants on item and associative tests but to a greater extent on the latter. In contrast, for nonwords, older participants performed equally worse than young participants on item and associative tests. This is the first study to demonstrate that a manipulation of stimulus novelty can alter age-related associative deficits. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Do young and older adults rely on different processes in source memory tasks? A neuropsychological study.

Source memory has consistently been associated with prefrontal function in both normal and clinical populations. Nevertheless, the exact contribution of this brain region to source memory remains uncertain, and evidence suggests that processes used by young and older adults may differ. The authors explored the extent to which scores on composite measures of neuropsychological tests of frontal and medial temporal function differentially predicted the performance of young and older adults on source memory tasks. Results indicated that a frontal composite measure, consistently associated with source memory performance in older adults, was unrelated to source memory in young adults, although it was sensitive to a demanding working memory task. The memory composite score, however, predicted performance in the young group. In addition, item and source memory were correlated in young but not older people. Findings are discussed in terms of age-related differences in working memory and executive functions, and differential binding processes necessary for item and source memory. The requirement to integrate item and source information at encoding appears to place greater demands on executive or working memory processes in older adults than in younger adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Effects of Aging and Divided Attention on Memory for Item and Associative Information.

The present study examined how aging and divided attention influence memory for item and associative information. Older adults and younger adults working under full-attention conditions and younger adults working under divided-attention conditions studied unrelated word pairs. Memory for item information was measured by later recognition of the 2nd word in the pair, and associative information was measured by recognition of the entire pair. Both older adults in the full-attention condition and younger adults in the divided-attention condition performed more poorly than younger adults in the full-attention condition, with the deficit in associative information being greater than the deficit in item information. In addition, a differentially greater associative decrement was found for the older adults, as shown by their heightened tendency to make false-alarm responses to re-paired (conjunction) distractors. The results are discussed in terms of an age-related reduction in processing resources compounded by an age-related increase in older adults' reliance on familiarity in associative recognition memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-referencing enhances memory specificity with age.

Self-referencing has been identified as an advantageous mnemonic strategy for young and older adults. However, little research has investigated the ways in which self-referencing may influence older adults' memory for details, which is typically impaired with age, beyond memory for the item itself. Experiment 1 assessed the effects of self- and other-referencing on memory for visually detailed pictures of objects in thirty-two young and thirty-two older adults. Results indicate that self- and close other-referencing similarly enhance general (item) and specific (detail) recognition for both young and older adults relative to the distant other condition. Experiment 2 extended these findings to source memory, with young and older adults encoding verbal information in self-referent, semantic, and structural conditions. Findings suggest that self-referencing provides an age-equivalent boost in general memory and specific memory for specific source details. We conclude that the mnemonic benefits of referencing the self extend to specific memory for visual and verbal information across the lifespan. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Serial position and set size in short-term memory: The time course of recognition.

Subjects viewed sequentially presented lists of 3–6 words, which were followed by a recognition probe. Memory retrieval speed (dynamics) and strength were measured in an interruption speed–accuracy trade-off (SAT) procedure and a collateral reaction time (RT) procedure. In SAT, item strengths depended on serial position, but only two retrieval speeds were observed: a fast rate for the last item in the study list (a case of immediate repetition between study and test) and a slow rate for all other items that was independent of serial position and set size. Serial-position-dependent strengths and set-size-dependent criterion shifts accounted for standard RT patterns that have been taken as evidence for serial scanning in short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The benefits and costs of repeated memory tests for young and older adults.

Repeated and prolonged searches of memory can lead to an increase in how much is recalled, but they can also lead to memory errors. These 3 experiments addressed the costs and benefits of repeated and prolonged memory tests for both young and older adults. Participants saw and imagined pictures of objects, some of which were physically or conceptually similar, and then took a series of repeated or prolonged recall tests. Both young and older adults recalled more on later tests than on earlier ones, though the increase was less marked for older adults. In addition, despite recalling less than did young adults, older adults made more similarity-based source misattributions (i.e., claiming an imagined item was seen if it was physically or conceptually similar to a seen item). Similar patterns of fewer benefits and more costs for older adults were seen on both free and forced recall tests and on timed and self-paced tests. Findings are interpreted in terms of age-related differences in binding processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of pure pair repetition on younger and older adults' associative memory.

Although aging causes relatively minor impairment in recognition memory for components, older adults' ability to remember associations between components is typically significantly compromised, relative to that of younger adults. This pattern could be associated with older adults' relatively intact familiarity, which helps preserve component memory, coupled with a marked decline in recollection, which leads to a decline in associative memory. The purpose of the current study is to explore possible methods that allow older adults to rely on pair familiarity in order to improve their associative memory performance. Participants in 2 experiments were repeatedly presented with either single items or pairings of items prior to a study list so that the items and the pairs were already familiar during the study phase. Pure pair repetition (the effects of pair repetition after the effects of item repetition are taken into account) increased associative memory for older and younger adults. Findings based on remember and know judgments suggest that familiarity but not recollection is involved in mediating the repetition effect. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Serial retrieval processes in the recovery of order information.

The retrieval of temporal order and item information from short-term memory (STM) are examined with the cued-response speed–accuracy trade-off (CR-SAT) procedure and a complementary reaction time (RT) task. The retrieval of order information was examined with a 2-alternative forced-choice (2AFC), relative judgment of recency (JOR) task. Analyses of the pattern of mean RT, RT accuracy, and the overall shape of the RT distribution for correct JORs suggest that order information is retrieved by a serial retrieval mechanism. Analyses of SAT retrieval functions confirm that order information is retrieved by a recency-based, serial retrieval process. These results contrast with previous SAT analyses of STM item recognition (B. McElree and B. A. Dosher, see record 1990-09049-001), which indicate that item information is retrieved by a parallel or direct-access mechanism. The dissociation between item and order information retrieval was further documented in a 2AFC item recognition SAT study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of emotional valence and arousal upon memory trade-offs with aging.

Attention can be attracted faster by emotional relative to neutral information, and memory also can be strengthened for that emotional information. However, within visual scenes, often there is an advantage in memory for central emotional portions at the expense of memory for peripheral background information, called an emotion-induced memory trade-off. The authors examined how aging impacts the trade-off by manipulating valence (positive, negative) and arousal (low, high) of a central emotional item within a neutral background scene and testing memory for item and background components separately. They also assessed memory after 2 study–test delay intervals, to investigate age differences in the trade-off over time. Results revealed similar patterns of performance between groups after a short study–test delay, with both age groups showing robust memory trade-offs. After a longer delay, young and older adults showed enhanced memory for emotional items but at a cost to memory for background information only for young adults in negative arousing scenes. These results emphasize that attention and consolidation stage processes interact to shape how emotional memory is constructed in young and older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and fluency-based illusions in recognition memory.

We examined age-related differences in susceptibility to fluency-based memory illusions. The results from 2 experiments, in which 2 different methods were used to enhance the fluency of recognition test items, revealed that older and young adults did not differ significantly in terms of their overall susceptibility to this type of memory illusion. Older and young adults were also similar in that perceptual fluency did not influence recognition memory responses when there was a mismatch in the sensory modality of the study and test phases. Likewise, a more conceptual fluency manipulation influenced recognition memory responses in both older and young adults regardless of the match in modality. Overall, the results indicate that older adults may not be more vulnerable than young adults to fluency-based illusions of recognition memory. Moreover, young and older adults appear to be comparable in their sensitivity to factors that modulate the influence of fluency on recognition decisions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)