The effects of word co-occurance on short-term memory: Associative links in long-term memory affect short-term memory performance.

In immediate serial recall tasks, high-frequency words are recalled better than low-frequency words. This has been attributed to high-frequency words' being better represented and providing more effective support to a redintegration process at retrieval (C. Hulme et al., 1997). In studies of free recall, there is evidence that frequency of word co-occurrence, rather than word frequency per se, may explain the recall advantage enjoyed by high-frequency words (J. Deese, 1960). The authors present evidence that preexposing pairs of low-frequency words, so as to create associative links between them, has substantial beneficial effects on immediate serial recall performance. These benefits, which are not attributable to simple familiarization with the words per se, do not occur for high-frequency words. These findings indicate that associative links between items in long-term memory have important effects on short-term memory performance and suggest that the effects of word frequency in short-term memory tasks are related to differences in interitern associations in long-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modality effects in short-term verbal memory.

Argues that for short-term memory, auditory presentation is consistently superior to visual presentation, with the difference restricted to recently presented items. A review of the literature indicates that recall increases with fast presentation rates when auditory presentation is used in a serial recall task; otherwise, recall decreases as presentation rate increases. Some puzzling findings on dichotic and bisensory split-span memory are shown to be related to aspects of the modality difference, notably the strong sequential associations in auditory memory. (116 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interference effects in schizophrenic short-term memory.

Presented 35 lists of 7 digits to 24 16-41 yr old schizophrenic patients and 24 16-39 yr old matched normal controls. Items in the different serial positions were probed randomly in a series of 7 recall trials for each list. Input interference resulting from interpolation of items between presentation and recall of the probed item was the same for both groups. Output interference resulting from interpolation of responses between presentation and recall was greater for schizophrenics than for normals. Significant differences in error patterns were also found. It is concluded that output interference is a major causative factor in the schizophrenic recall deficit. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Word-frequency and phonological-neighborhood effects on verbal short-term memory.

Immediate memory span and maximal articulation rate were assessed for word sets differing in frequency, word-neighborhood size, and average word-neighborhood frequency. Memory span was greater for high- than low-frequency words, greater for words from large than small phonological neighborhoods, and greater for words from high- than low-frequency phonological neighborhoods. Maximal articulation rate was also facilitated by word frequency, phonological-neighborhood size, and neighborhood frequency. In a final study all 3 lexical variables were found to influence the recall outcome for individual words. These effects of phonological-word neighborhood on memory performance suggest that phonological information in long-term memory plays an active role in recall in short-term-memory tasks, and they present a challenge to current theories of short-term memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ability correlates of memory performance in adulthood and aging.

The predictive relationships between an array of cognitive process and intellectual ability variables and text- and word-recall performance were examined. A sample of 584 men and women from 3 age groups (19–36, 55–69, and 70–86 years) completed a battery of 23 tasks marking 2 latent criterion variables and 10 latent predictor variables. The results indicated that (a) individual differences in process and ability variables predict performance on text and word recall, accounting for approximately half of the variance; (b) the pattern of predictors is quite similar for text and word recall; (c) age-related differences in text and word recall can be substantially accounted for by individual differences in constituent abilities, particularly indicators of verbal speed and working memory; and (d) there is some evidence to suggest that the pattern of ability–performance relationships varies across age, but such interactions appear to be relatively small. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual noise and aging.

Presents evidence pertaining to the hypothesis that aging is characterized by a decrement in the ability to suppress irrelevant stimuli (perceptual noise). Although studies in the various sensory modalities generally support a perceptual noise hypothesis of aging, most of the evidence is marred by serious structural weaknesses. It is concluded that the heuristic value of such a unifying hypothesis seems, however, to justify further investigation aimed at correcting these flaws. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of sleep loss on short-term recognition memory.

Compared the performance of 20 sleep-deprived undergraduates on a probe-recognition memory task with that of 20 nondeprived controls over periods up to 55 hrs. Recognition was either immediate or delayed by 20 sec. Results show that the sleep-deprived group made significantly more errors in the perception of the material, and under the delay condition retained less adequately those items correctly perceived. It is argued that these findings are consistent with the notion that sleep loss causes a deficit in attention, leading to misperception and a failure to rehearse adequately material presented for memorization. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory and aging: Separating the effects of content and context.

In 3 experiments, we investigated the hypothesis that age-related differences in working memory might be due to the inability to bind content with context. Participants were required to find a repeating stimulus within a single series (no context memory required) or within multiple series (necessitating memory for context). Response time and accuracy were examined in 2 task domains: verbal and visuospatial. Binding content with context led to longer processing time and poorer accuracy in both age groups, even when working memory load was held constant. Although older adults were overall slower and less accurate than young adults, the need for context memory did not differentially affect their performance. It is therefore unlikely that age differences in working memory are due to specific age-related problems with content-with-context binding. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contextual effects on the short-term memory retrieval of schizophrenic young adults.

Two experiments were performed to determine if the dysfunction in mnemonic organization often found in schizophrenic free-recall performance is the result of an organizational deficit in short-term memory processing. In Exp I, which tested 16 schizophrenics, 16 nonschizophrenic psychiatric patients, and 16 nonpatient controls, categorical cues (letters and digits) were introduced into a Sternberg item recognition task. Schizophrenics utilized the categorical cue to reduce their latencies for search and retrieval as well as did both normals and nonschizophrenic psychiatric patients. In Exp II, which used a Sternberg context-recall task and tested the same number and type of Ss (31 also served in Exp I), latencies for both forward and backward sequential retrieval were measured. Schizophrenics again performed as well as controls. Data also suggest that the retrieval strategies adopted by schizophrenics were comparable to those of controls in both experiments. It is concluded that schizophrenics' short-term memory processes for categorical and sequential materials are adequate and therefore are not responsible for the organizational dysfunction in their free-recall performance. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Facilitative effects of the ampakine CX516 on short-term memory in rats: enhancement of delayed-nonmatch-to-sample performance

In the companion article (Hampson et al., 1998), the ampakine CX516 (Cortex Pharmaceuticals) was shown to produce a marked facilitation of performance of a spatial delayed-nonmatch-to-sample (DNMS) task in rats. Injections of the drug before each daily session produced a marked and progressive improvement in performance at longer delays (>5 sec) that persisted for 7 d after drug treatment was terminated. In most animals (n = 9) the increase in performance carried over to the intervening vehicle for days, whereas in others (n = 3) the effects dissipated within the session according to the pharmacological half-life of CX516. In this article we report firing correlates of simultaneously recorded cells in the CA1 and CA3 fields of the hippocampus over the period in which DNMS performance was facilitated by CX516. Sample and Delay period firing was enhanced by 100-350% under CX516 and increased progressively over days as did DNMS performance. The firing increases were restricted to correct trials only and were largest on trials with long delays. Firing in the intertrial interval was also altered, but in a manner consistent with a previously demonstrated reduction in between-trial proactive interference by CX516. Finally, in animals in which the effects of CX516 were restricted to when the drug was actually present (i.e., no carryover effects), increased cell firing also paralleled the time course of the performance increase. Results are discussed with respect to the actions of ampakines on hippocampal cellular and synaptic processes that underlie DNMS performance.     

Verbal encoding effects on the visual short-term memory of learning disabled and normal readers.

Investigated the hypothesis that reading difficulties of learning disabled children are attributable to deficiencies in verbal encoding. Adopting a probe-type serial memory task, 60 normal and learning disabled readers matched on CA (9 yrs old), IQ, and sex were compared on recall performance after pretraining of named and unnamed stimulus conditions. The named condition for normal readers was superior in terms of recall performance. Consistent with the findings of F. Vellutino et al (1972, 1973, 1975), no difference was found in recall of nonverbal stimuli between normal and learning disabled readers. These data suggest that primary reading deficits in learning disabled children are related to verbal encoding deficiencies (visual–verbal integration) and not to deficiencies of visual memory, as suggested by the perceptual deficit hypothesis. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual short-term memory in the first year of life: Capacity and recency effects.

A span task was developed to assess the amount of information infants could hold in short-term memory. In this task, infants were presented with up to 4 items in succession and then tested for recognition by successively pairing each item with a novel one. A large sample of full-terms and low-birth-weight preterms (     

Proactive interference effects on short-term memory in rats: I. Basic parameters and drug effects.

An operant delayed-matching task was used to assess the role of proactive interference (PI) effects on short-term memory capacity of rats. Task performance was analyzed in terms of the influence of the sample positions and response choices on previous trials. PI was predominantly attributable to the influence of the immediately previous trial but not preceding trials and was abolished by increasing the intertrial intervals from 5 to 15 sec. Nicotine induced a decline in choice accuracy only on trials in which the previous response had been to the side opposite the current sample and correct response, suggesting an increased susceptibility to PI. Physostigmine induced a mild, relatively nonspecific decline in response accuracy. Clonidine induced delay-dependent impairments irrespective of responses on previous trials. None of these drugs enhanced choice accuracy at any dose tested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Normal aging and prospective memory.

We develop a laboratory paradigm for studying prospective memory and examine whether or not this type of memory is especially difficult for the elderly. In two experiments, young and old subjects were given a prospective memory test (they were asked to perform an action when a target event occurred) and three tests of retrospective memory (short-term memory, free recall, and recognition). From the perspective that aging disrupts mainly self-initiated retrieval processes, large age-related decrements in prospective memory were anticipated. However, despite showing reliable age differences on retrospective memory tests, both experiments showed no age deficits in prospective memory. Moreover, regression analyses produced no reliable relation between the prospective and retrospective memory tasks. Also, the experiments showed that external aids and unfamiliar target events benefit prospective memory performance. These results suggest some basic differences between prospective and retrospective memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of aging on directional and absolute errors in visuospatial memory.

Studied memory for visuospatial arrays in 28 male and 34 female healthy dextral adults (aged 20–90 yrs). 10 abstract figures were presented in each hemispace over a series of learning trials, and then delayed free recall of figure placement was obtained. Figures were misplaced significantly downward and leftward in both hemispaces. Both vertical and horizontal absolute error increased significanty with age, but no age effects on directional errors were observed. The increase in absolute error over age is consistent with decreased anterograde memory and visuospatial skills in the elderly. The directional errors are believed to result from an attentional shift toward proximal peripersonal space, in combination with attentional shifts from differential left vs right cerebral activation. Gender effects were also observed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Organization of visual short-term memory.

The authors examined the organization of visual short-term memory (VSTM). Using a change-detection task, they reported that VSTM stores relational information between individual items. This relational processing is mediated by the organization of items into spatial configurations. The spatial configuration of visual objects is important for VSTM of spatial locations, colors, and shapes. When color VSTM is compared with location VSTM, spatial configuration plays an integral role because configuration is important for color VSTM, whereas color is not important for location VSTM. The authors also examined the role of attention and found that the formation of configuration is modulated by both top-down and bottom-up attentional factors. In summary, the authors proposed that VSTM stores the relational information of individual visual items on the basis of global spatial configuration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory, short-term memory, and speech rate as predictors of children's reading performance at different ages.

This study explored the contribution of 2 working memory (WM) systems (the phonological loop and the central executive) to reading performance in younger (9-year-old) and older (14-year-old) children. The results showed that (a) significant age-related differences in verbal and visual-spatial WM performance were maintained when articulation speed and short-term memory (the phonological system) were partialed from the analysis and (b) WM predicted age-related differences in word recognition and comprehension performance independent of the contribution of a short-term memory and articulatory rate. The results were interpreted as support for the notion that both the phonological and the executive systems are important predictors of age-related changes in reading but that these processes operate independent of each other in predicting fluent reading. Several implications of the results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of aging and Alzheimer's disease on conceptual implicit and explicit memory.

The effects of aging and Alzheimer's disease (AD) on conceptual explicit and implicit memory were examined. Three groups of participants patients with AD; age-matched, older control participants; and younger control participants made deep (semantic) or shallow (nonsemantic) judgments about low-dominant category exemplars. Explicit memory was measured by category cued recall and implicit memory was measured by priming on a category-exemplar generation task. Younger participants had enhanced cued recall and priming following deep, relative to shallow, encoding; this indicated that both memory measures were conceptually driven. Aging reduced explicit, but not implicit, test performance, and it did not reduce conceptually driven processes for either test. In contrast, AD reduced explicit and implicit test performance, and it impaired conceptually driven memory processes for both tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual short-term memory in the hearing and the deaf.

Tested 9 deaf and 9 normal 15-27 yr olds on their ability to report letters, shapes, and nonsense figures from a tachistoscopic presentation. Deaf Ss performed worse than hearing Ss on recall of figural information, thereby supporting a linguistic coding hypothesis. However, there was no difference between the groups on position information, and letter confusions were primarily visual in both groups. Findings suggest that more attention should be given to visual short-term memory in theoretical models of memory. Formation of the icon was apparently not affected by a linguistic deficit, since effects of stimulus duration and type of viewing (continuous vs interrupted) were similar in both hearing and deaf Ss. Significant positive correlations which were found between deaf Ss' school reading scores and their tachistoscopic scores were not interpreted as support for a linguistic coding hypothesis, but rather as support for the notion that the memory skills tested in the experiment may underlie reading ability. (French summary) (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Slope analysis in short-term memory.

Presents procedures for transforming dichotomously scored data from short-term memory experiments into slope measures for evaluation by analysis of variance techniques. (PsycINFO Database Record (c) 2010 APA, all rights reserved)