Individual differences in executive processing predict susceptibility to interference in verbal working memory.

Recent theories have suggested that resistance to interference is a unifying principle of executive function and that individual differences in interference may be explained by executive function (M. J. Kane & R. W. Engle, 2002). Measures of executive function, memory, and perceptual speed were obtained from 121 older adults (ages 63-82). We used structural equation modeling to investigate the relationships of these constructs with interference in a working memory task. Executive function was best described as two related subcomponent processes: shifting and updating goal-relevant representations and inhibition of proactive interference. These subcomponents were distinct from verbal and visual memory and speed. Individual differences in interference susceptibility and recollection were best predicted by shifting and updating and by resistance to proactive interference, and variability in familiarity was predicted by resistance to proactive interference and speed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pigs in space: spatial memory and its susceptibility to interference

This study provided basic information about spatial memory in the domestic pig, Sus scrofa and examined how susceptible it is to disruption by environmental stimuli. Eight male pigs were tested individually in a foraging arena. Each day, they entered the arena to search for food randomly located in one of 10 enclosed areas (search trial). After finding and eating the food, they were removed from the arena for a retention interval, and then allowed back in to relocate the food in the same area as previously (relocation trial). Once pigs had achieved a criterion level of performance in relocation trials, 'disturbances' (e.g. isolation, novel food source, novel spatial environment) were presented during the retention interval. Disturbance days were separated by control days on which no disturbance was presented. During search trials, pigs did not use food-related cues to locate food, but appeared to use memory to search systematically and avoid revisits to empty areas. During relocation trials, they found food using fewer area visits than expected by chance, indicating that they could remember the location of food across both 10-min and 2-h retention intervals. Disturbances administered during 10-min retention intervals resulted in more relocation errors than on corresponding control days, indicating that spatial memory in pigs is susceptible to interference by relatively mild environmental stimuli, in contrast to that in rats, Rattus norvegicus and pigeons, Columba livia which appears to be highly resistant to retroactive interference even when potent stimuli are used. Analysis of error locations suggested that disturbances probably acted to increase the general area in which the pig remembered the food to be located, and so reduced accuracy of memory without eradicating it. There was no evidence that errors made during relocation trials represented sampling of areas not visited during the preceding search trial.Copyright 1997 The Association for the Study of Animal Behaviour     

Individual differences in spatial working memory in relation to schizotypy.

With a delayed-response task, spatial working memory function was assessed in normal students who were selected for schizotypy. The Wisconsin Card Sorting Test was also administered. Twenty-eight undergraduate students who scored high on the Perceptual Aberration Scale (PerAb) and 23 who scored low on this scale participated in this study. High PerAb students performed less accurately compared with the low PerAb controls on the delayed-response task, and they were more than twice as likely as low PerAb students to be impaired. The groups did not differ in the number of perseverative errors or number of categories achieved on the Wisconsin Card Sorting Test, but, as predicted, high PerAb students were less able to maintain set than were the low PerAb students. Neuropsychological implications of these data are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional neuroanatomy of spatial working memory in children.

Functional magnetic resonance imaging (fMRI) was used to examine spatial working memory in 8- to 11-year-old children tested under three conditions. In the visual condition, children were asked to examine the location of a dot on a screen. In the motor condition, children were instructed to push a button that corresponded to the location of a dot presented on a screen. In the memory condition, children were asked to remember the location of a dot presented 1 or 2 trials previously. Subtracting the activation of the motor condition from the memory condition revealed activity in the dorsal aspects of the prefrontal cortex and in the posterior parietal and anterior cingulate cortex. These findings were also obtained in the analysis of the memory minus visual conditions except that motor cortex activation was also observed. These findings parallel those reported in comparable studies of adults and suggest that fMRI may be a useful means of examining function–structure relations in developmental populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in proactive interference, working memory, and abstract reasoning.

[Correction Notice: An erratum for this article was reported in Vol 23(4) of Psychology and Aging (see record 2008-19072-007). The original article contained an incorrect DOI. The correct DOI is as follows: 10.1037/a0012577.] It has been hypothesized that older adults are especially susceptible to proactive interference (PI) and that this may contribute to age differences in working memory performance. In young adults, individual differences in PI affect both working memory and reasoning ability, but the relations between PI, working memory, and reasoning in older adults have not been examined. In the current study, young, old, and very old adults performed a modified operation span task that induced several cycles of PI buildup and release as well as two tests of abstract reasoning ability. Age differences in working memory scores increased as PI built up, consistent with the hypothesis that older adults are more susceptible to PI, but both young and older adults showed complete release from PI. Young adults' reasoning ability was best predicted by working memory performance under high PI conditions, replicating M. Bunting (2006). In contrast, older adults' reasoning ability was best predicted by their working memory performance under low PI conditions, thereby raising questions regarding the general role of susceptibility to PI in differences in higher cognitive function among older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and interference in verbal working memory.

According to inhibitory views of working memory, old adults should have particular problems deleting irrelevant information from working memory, leading to greater interference effects compared with young adults. The authors investigated this hypothesis by using variations of an A-B, C-D retroactive interference paradigm in working memory with young and old adults. They used a recognition measure of memory, assessing both accuracy and reaction time. The primary finding was that senior adults consistently exhibited proportionally greater retroactive interference effects compared with young adults when interfering word pairs that had been read aloud had to be rejected. Patterns of recognition and reaction time data suggested that old adults' activation of target material is similar to young adults, but they experience sustained activation of irrelevation material that has entered working memory. Theoretical implications of these findings for inhibitory deficit (R.T. Zacks & L. Hasher, 1998) and source memory deficit accounts of cognitive aging are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal working memory and sentence comprehension: A multiple-components view.

Semantic and syntactic aspects of sentence comprehension were investigated for 3 patients (aged 61, 65, and 72 yrs) who showed different patterns of performance on short-term memory tasks. On a sentence anomaly judgment task assessing the retention of semantic information, only patient A. B. showed a detrimental effect on comprehension with increases in the number of words to be held in an unintegrated fashion. On judgments of grammatical acceptability, only patient M. W. demonstrated a detrimental effect of increasing the number of words intervening between the words signaling that a sentence was ungrammatical. The results suggest that semantic and syntactic components must be postulated in addition to the phonological and articulatory components of A. D. Baddeley's (1986, 1990) working memory model. Although the phonological, semantic, and syntactic components may be differentially affected by brain damage, the components interact and support each other in normal comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hippocampal and amygdaloid involvement in nonspatial and spatial working memory in rats: Effects of delay and interference.

Parametric manipulations of the task demand were used to examine the role of the hippocampus and amygdala in nonspatial and spatial working memory in male rats. Hippocampal lesions produced an immediate and long-lasting impairment of nonspatial working memory in an operant task. The memory deficits increased as the delay interval and the amount of proactive interference increased. Hippocampal lesions severely impaired spatial working memory in spatial alternation. Extensive postoperative testing reduced the magnitude of impairment of nonspatial but not spatial working memory. Amygdaloid lesions did not impair any aspect of performance in 2 tasks. The results suggest that the hippocampus, but not the amygdala, is involved in working memory and the task demand is a critical determinant for observing impairments of nonspatial working memory following hippocampal lesions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in visuospatial working memory.

In two visuospatial working memory (VSWM) span experiments, older and young participants were tested under conditions of either high or low interference, using two different displays: computerized versions of a 3 × 3 matrix or the standard (randomly arrayed) Corsi block task (P. M. Corsi, 1972). Older adults' VSWM estimates were increased in the low-interference, compared with the high-interference, condition, replicating findings with verbal memory span studies. Young adults showed the opposite pattern, and together the findings suggest that typical VSWM span tasks include opposing components (interference and practice) that differentially affect young and older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in working memory.

Two experiments were conducted to determine whether adult age differences in working memory should be attributed to less efficient processing, a smaller working memory storage capacity, or both. In Experiment 1, young, middle-age, and older adults solved 3 additional problems before giving the answers to any. Older adults added as well as young and middle-age adults but showed a more pronounced serial position curve across the 3 problem positions. In Experiment 2, young and older adults constructed linear orderings (e.g., ABCD) from pairwise information presented in sentences (e.g., BC). Manipulations involving processing (e.g., type of sentence) did not interact with age differences, but those involving storage capacity (e.g., ordering length) did. All main effects and interactions support the hypothesis of a smaller storage capacity but do not rule out some processing deficit in older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Proactive interference and item similarity in working memory.

Proactive interference (PI) may influence the predictive utility of working memory span tasks. Participants in one experiment (N=70) completed Ravens Advanced Progressive Matrices (RAPM) and multiple versions of operation span and probed recall, modified for the type of memoranda (digits or words). Changing memoranda within- or across-trials released PI, but not doing so permitted PI buildup. Scores from PI-build trials, but not PI-release trials, correlated with RAPM and accounted for as much variance in RAPM as unmodified tasks. These results are consistent with controlled attention and inhibition accounts of working memory, and they elucidate a fundamental component of working memory span tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in working memory.

Active and passive measures of short-term memory over a large segment of the adult life span were compared. Two hundred twenty-eight volunteers, aged 30 to 99 years, performed the digit span forward and backward task, the Peterson-Peterson task, and a new working memory task in which active manipulation of information is emphasized. Age differences were slight for passive tasks. For the working memory task, significant declines were found between the ages of 60 to 69 and 70+ years. It is suggested that the age differences may be due to a decrease in the flexibility with which processing changes are made. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in working memory: Introduction to the special section.

This special section includes a set of 5 articles that examine the nature of inter- and intraindividual differences in working memory, using working memory span tasks as the main research tools. These span tasks are different from traditional short-term memory spans (e.g., digit or word span) in that they require participants to maintain some target memory items (e.g., words) while simultaneously performing some other tasks (e.g., reading sentences). In this introduction, a brief discussion of these working memory span tasks and their characteristics is provided first. This is followed by an overview of 2 major theoretic issues that are addressed by the subsequent articles—(a) the factors influencing the inter- and intraindividual differences in working memory performance and (b) the domain generality versus domain specificity of working memory—and also of some important issues that must be kept in mind when readers try to evaluate the claims regarding these 2 theoretical issues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal and spatial interference effects in congenitally blind and sighted subjects.

Compared 8 congenitally blind, 8 sighted, and 8 blindfolded sighted female school students (mean age 16 yrs) using a selective interference technique. Ss categorized the words of sentences and the corners of figures while responding either spatially (by typing), verbally, or while tapping. Spatial responding slowed RTs more than tapping or verbal responding in the figure condition, and verbal and spatial responding were slower than tapping in the sentence categorization. No major differences were found between the response patterns of the 3 groups. It is argued that many imagery tasks involve a heavy dependence on spatial information processing, and to the extent that the blind and the sighted perform similarly in such situations, it follows that they are using similar spatial representations. Implications for studies of imagery and the representational skills of the blind are discussed. (French abstract) (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exploring developmental differences in visual short-term memory and working memory.

Although visuospatial short-term memory tasks have been found to engage more executive resources than do their phonological counterparts, it remains unclear whether this is due to intrinsic differences between the tasks or differences in participants’ experience with them. The authors found 11-year-olds’ performances on both visual short-term and working memory tasks to be more greatly impaired by an executive suppression task (random number generation) than were those of 8-year-olds. Similar findings with adults (e.g., Kane & Engle, 2000) suggest that the imposition of a suppression task may have overloaded the older children’s executive resources, which would otherwise be used for deploying strategies for performing the primary tasks. Conversely, the younger children, who probably never had the capacity or know-how to engage these facilitative strategies in the first place, performed more poorly in the single task condition but were less affected in the dual task condition. These findings suggest that differences in the children’s ability to deploy task-relevant strategy are likely to account for at least part of the executive resource requirements of visual memory tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal working memory and solvent exposure: A positron emission tomography study.

Neuropsychological studies have documented frontal dysfunction in patients with a history of exposure to organic solvents. The deficits typically observed in these patients appear to be related to working memory (WM). This study used [1?O] water positron emission tomography (PET) to examine the pattern of neural activation during verbal working memory in patients with a history of exposure to solvents. Six individuals with solvent exposure were compared with 6 age- and education-matched controls. On the 2 WM tasks examined with PET, with equivalent task performance, participants with solvent exposure demonstrated frontal peaks that were atypical for the tasks, whereas the posterior peaks were typical for the tasks. The results support frontal dysfunction and compensatory use within anterior regions of the WM system in patients with solvent exposure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The complexities of complex span: Explaining individual differences in working memory in children and adults.

Two studies are presented that investigated the constraints underlying working memory performance in children and adults. In each case, independent measures of processing efficiency and storage capacity are assessed to determine their relative importance in predicting performance on complex span tasks, which measure working memory capacity. Results show that complex span performance was independently constrained by individual differences in dornain-general processing efficiency and domain-specific storage capacity. Residual variance, which may reflect the ability to coordinate storage and processing, also predicted academic achievement. These results challenge the view that complex span taps, a limited-capacity resource pool shared between processing and storage operations. Rather, they are consistent with a multiple-component model in which separate resource pools support the processing and storage functions of working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rehearsal in spatial working memory

This article reports 3 experiments that tested a hypothesis regarding the nature of rehearsal in spatial working memory, one in which discrete shifts of spatial selective attention mediate the maintenance of location-specific representations. Experiment 1 demonstrated increases in visual processing efficiency for locations held in working memory, which suggested that attention was oriented toward these locations. Experiment 2 eliminated key alternative explanations for Experiment 1 by using an identical stimulus display with a nonspatial memory task, and little or no facilitation of processing at memorized locations was found under these conditions. Finally, Experiment 3 showed that spatial working memory was impaired when participants were hindered in their ability to attend to memorized locations. It is argued that these results implicate selective spatial attention as a rehearsal mechanism for spatial working memory.     

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)     

Individual differences in working memory and complex cognition.

The relations among assessments of working memory (WM) and a range of complex cognitive abilities were examined. In 2 experiments participants completed 2 WM tasks designed to assess verbal and nonverbal WM, as well as assessments of verbal intelligence, nonverbal intelligence, and academic achievement. Verbal WM had no relationship with nonverbal intelligence, whereas nonverbal WM had no relationship with verbal intelligence and academic achievement. A reanalysis of P. C. Kyllonen & R. E. Christal (see PA, Vol 78:32248; Experiment 1) is reported in which multiple indicators of WM were used to identify verbal and nonverbal WM factors; both of these WM factors were heavily saturated with a second-order factor, g (61% and 69%, respectively). Convergent and discriminant validation of the multidimensionality of WM was found in the patterns of correlations among the first-order Working Memory, General Knowledge, and Speed factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)