Binding facilitates attention switching within working memory.

The authors investigated the units of selective attention within working memory. In Experiment 1, a group of participants kept 1 count and 1 location in working memory and updated them repeatedly in random order. Another group of participants were instructed to achieve the same goal by memorizing the verbal and spatial information in an integrative way as a moving digit. The behavioral data showed that switching attention between properties of an integrated working-memory item was faster than switching between respective properties of different items. Experiment 2 demonstrated that this switching facilitation cannot be simply ascribed to the different amount of working-memory items maintained by the two groups of participants. Finally, by adopting a pure verbal task in Experiment 3, the authors observed the same binding facilitation, with the possibility of "location-based selection" excluded. They summarize the observations of all 3 experiments in the study and suggest both a location- and object-based mechanism for attention selection in working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

From poor performance to success under stress: Working memory, strategy selection, and mathematical problem solving under pressure.

Two experiments demonstrate how individual differences in working memory (WM) impact the strategies used to solve complex math problems and how consequential testing situations alter strategy use. In Experiment 1, individuals performed multistep math problems under low- or high-pressure conditions and reported their problem-solving strategies. Under low-pressure conditions, the higher individuals' WM, the more likely they were to use computationally demanding algorithms (vs. simpler shortcuts) to solve the problems, and the more accurate their math performance. Under high-pressure conditions, higher WM individuals used simpler (and less efficacious) problem-solving strategies, and their performance accuracy suffered. Experiment 2 turned the tables by using a math task for which a simpler strategy was optimal (produced accurate performance in few problem steps). Now, under low-pressure conditions, the lower individuals' WM, the better their performance (the more likely they relied on a simple, but accurate, problem strategy). And, under pressure, higher WM individuals performed optimally by using the simpler strategies lower WM individuals employed. WM availability influences how individuals approach math problems, with the nature of the task performed and the performance environment dictating skill success or failure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of age, speed of processing, and working memory on comprehension of sentences with relative clauses.

Two hundred participants, 50 in each of four age ranges (19–29, 30–49, 50–69, 70–90) were tested for working memory, speed of processing, and the processing of sentences with relative clauses. In Experiment 1, participants read four sentence types (cleft subject, cleft object, subject-subject, subject-object) in a word-by-word, non-cumulative, self-paced reading task and made speeded plausibility judgments about them. In Experiment 2, participants read two types of sentences, one of which contained a doubly center embedded relative clause. Older participants' comprehension was less accurate and there was age-related slowing of online processing times in all but the simplest sentences, which increased in syntactically complex sentences in Experiment 1. This pattern suggests an age-related decrease in the efficiency of parsing and interpretation. Slower speed of processing and lower working memory were associated with longer online processing times only in Experiment 2, suggesting that task-related operations are related to general speed of processing and working memory. Lower working memory was not associated with longer reading times in more complex sentences, consistent with the view that general working memory is not critically involved in online syntactic processing. Longer online processing at the most demanding point in the most demanding sentence was associated with better comprehension, indicating that it reflects effective processing under some certain circumstances. However, the poorer comprehension performance of older individuals indicates that their slower online processing reflects inefficient processing even at these points. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Age differences in item manipulation span: The case of letter-number sequencing.

The authors report 2 experiments in which they examined age differences in working memory tasks involving complex item manipulation (i.e., letter-number sequencing). In Experiment 1, age differences on tasks involving item manipulation were not greater than age differences on tasks requiring recall of items in the order in which they appeared, suggesting that older adults do not have difficulty with item manipulation per se. In Experiment 2, slower presentation rates increased age differences in item manipulation spans, although age differences at the fastest rate may be attributed to differences in strategy use. In both experiments, age differences were largest when participants were most likely to be remembering familiar sequences, suggesting that older adults may have difficulties dampening the representations of such sequences once they are activated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Take The Best versus simultaneous feature matching: Probabilistic inferences from memory and effects of reprensentation format.

In 4 experiments, the tendency to use the simple heuristic Take The Best (TTB; G. Gigerenzer & D. Goldstein, 1996) was explored for probabilistic multiattribute inferences from memory. In a newly developed procedure, participants first learned attribute patterns that formed the basis for inferences in a second phase. A Bayesian method classified strategies as TTB, compensatory, or guessing. Experiment 1 had a high rate (64%) of participants classified as TTB users when inferences were made from memory. Experiment 2 showed that this was no mere materials effect. In Experiments 3 and 4, the authors examined effects of the representational format of the attribute information. Experiment 4 showed that the representational format may be an important moderating variable for strategy use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does differential strategy use account for age-related deficits in working-memory performance?

The strategy-deficit hypothesis states that age differences in the use of effective strategies contribute to age-related deficits in working memory span performance. To evaluate this hypothesis, strategy use was measured with set-by-set strategy reports during the Reading Span task (Experiments 1 and 2) and the Operation Span task (Experiment 2). Individual differences in the reported use of effective strategies accounted for substantial variance in span performance. In contrast to the strategy-deficit hypothesis, however, young and older adults reported using the same proportion of normatively effective strategies on both span tasks. Measures of processing speed accounted for a substantial proportion of the age-related variance in span performance. Thus, although use of normatively effective strategies accounts for individual differences in span performance, age differences in effective strategy use cannot explain the age-related variance in that performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How prior knowledge, WMC, and relevance of information affect eye fixations in expository text.

This study examined how prior knowledge and working memory capacity (WMC) influence the effect of a reading perspective on online text processing. In Experiment 1, 47 participants read and recalled 2 texts of different familiarity from a given perspective while their eye movements were recorded. The participants' WMC was assessed with the reading span test. The results suggest that if the reader has prior knowledge related to text contents and a high WMC, relevant text information can be encoded into memory without extra processing time. In Experiment 2, baseline processing times showed whether readers slow down their processing of relevant information or read faster through the irrelevant information. The results are discussed in the light of different working memory theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Control of the Contents of Working Memory--A Comparison of Two Paradigms and Two Age Groups.

Two experiments investigated whether young and old adults can temporarily remove information from a capacity-limited central component of working memory (WM) into another component, the activated part of long-term memory (LTM). Experiment 1 used a modified Sternberg recognition task (S. Sternberg, 1969); Experiment 2 used an arithmetic memory-updating task. In both paradigms, participants memorized 2 lists, one of which was cued as temporarily irrelevant. Removal of the irrelevant list from capacity-limited WM was indexed by the disappearance of list-length effects of that list on latencies for concurrent processing tasks. Young adults could outsource the irrelevant list within 2-3 s and retrieve it back into the central part of WM later. Old adults showed the same flexibility in the arithmetic updating task but seemed somewhat less able or inclined to temporarily move information into the activated part of LTM in the modified Sternberg task. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The role of working memory in decoding emotions.

Decoding facial expressions of emotion is an important aspect of social communication that is often impaired following psychiatric or neurological illness. However, little is known of the cognitive components involved in perceiving emotional expressions. Three dual task studies explored the role of verbal working memory in decoding emotions. Concurrent working memory load substantially interfered with choosing which emotional label described a facial expression (Experiment 1). A key factor in the magnitude of interference was the number of emotion labels from which to choose (Experiment 2). In contrast the ability to decide that two faces represented the same emotion in a discrimination task was relatively unaffected by concurrent working memory load (Experiment 3). Different methods of assessing emotion perception make substantially different demands on working memory. Implications for clinical disorders which affect both working memory and emotion perception are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Clearing the mind: A working memory model of distraction from negative mood.

The present research examined whether and how loading working memory can attenuate negative mood. In three experiments, participants were exposed to neutral, weakly negative, or strongly negative pictures followed by a task and a mood scale. Working memory demands were varied by manipulating task presence (Study 1), complexity (Study 2), and predictability (Study 3). Participants in all three experiments reported less negative moods in negative trials with high compared to low working memory demand. Working memory demands did not affect mood in the neutral trials. When working memory demands were high, participants no longer reported more negative moods in response to strongly negative pictures than to weakly negative pictures. These findings suggest that loading working memory prevents mood-congruent processing, and thereby promotes distraction from negative moods. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simultaneous Cognitive Operations in Working Memory After Dual-Task Practice.

The authors tested the hypothesis that with adequate practice, people can execute 2 cognitive operations in working memory simultaneously. In Experiment 1, 6 students practiced updating 2 items in working memory through 2 sequences of operations (1 numerical, 1 spatial). In different blocks, imperative stimuli for the 2 sequences of operations were presented either simultaneously or sequentially. Initially, most participants experienced substantial dual-task costs. After 24 sessions of practice, operation latencies for simultaneous presentation were equal to the maximum of times for the 2 operations in the sequential condition, suggesting perfect timesharing. Experiment 2 showed that a reduction of dual-task costs requires practice on the combination of the 2 updating tasks, not just practice on each individual task. Hence, the reduction of dual-task costs cannot be explained by shortening or automatization of individual operations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention control, memory updating, and emotion regulation temporarily reduce the capacity for executive control.

This research tested the hypothesis that initial efforts at executive control temporarily undermine subsequent efforts at executive control. Four experiments revealed that controlling the focus of visual attention (Experiment 1), inhibiting predominant writing tendencies (Experiment 2), taking a working memory test (Experiment 3), or exaggerating emotional expressions (Experiment 4) undermined performance on subsequent tests of working memory span, reverse digit span, and response inhibition, respectively. The results supported a limited resource model of executive control and cast doubt on competing accounts based on mood, motivation, or task difficulty. Prior efforts at executive control are a significant contextual determinant of the operation of executive processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is There a Specific Executive Capacity for Dual Task Coordination? Evidence From Alzheimer's Disease.

Three experiments compared groups of Alzheimer's disease (AD) patients and healthy older and younger participants on visuospatial tracking and digit sequence recall, as single tasks and performed concurrently. In Experiment 1, tasks were performed concurrently with very low demand relative to span. Only the AD patients showed a dual task deficit. In Experiment 2, single task demand was manipulated on each task from below span to above span for each individual. All groups showed the same performance reductions with increasing demand. In Experiment 3, demand on 1 task was constant, whereas demand on the concurrent task was varied. AD patients showed a clear dual task deficit but were no more sensitive than control groups to varying demand. Results suggest an identifiable cognitive resource for dual task coordination within a multiple component working memory system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional Stimuli, Divided Attention, and Memory.

The emotion-memory literature has shown that negative emotional arousal enhances memory. S. A. Christianson (1992) proposed that preattentive processing could account for this emotion-memory relationship. Two experiments were conducted to test Christianson's theory. In Experiment 1, participants were exposed to neutral and negative arousing slides. In Experiment 2, participants were exposed to neutral, negative arousing, and positive arousing slides. In both experiments, the aforementioned variable was factorially combined with a divided-attention or non-divided-attention condition. The authors predicted that, in contrast to the nondivided condition, dividing attention would adversely impact neutral and positive stimuli more than negative stimuli. The hypothesis was supported; participants recalled more high negative-arousal slides than positive or neutral slides when their attention was divided rather than nondivided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimation strategies and the judgment of event frequency.

Processes underlying judgments of absolute event frequency were investigated in 3 experiments. In all 3, word pairs consisting of a target (a category label, e.g., CITY) and context (a category exemplar, e.g., LONDON) were presented in a different or same-context study list. In the different context condition, each target was paired with a new context on each presentation; in the same-context condition, a target always appeared with the same context. Verbal protocols (Experiment 1) and response times (Experiments 2 and 3) indicate that multiple estimation strategies were used and that strategy selection was related to memory contents. In particular, different-context participants often enumerated, and same-context participants did not. Also, because range information only affected same-context estimates (Experiment 3), it appears that a numerical conversion process was necessary when nonenumeration strategies were used. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visuospatial cues for reinstating mental models in working memory during interrupted reading.

Reading involves constructing a mental representation in long-term working memory of the world described by the text. Disrupting short-term working memory can interfere with the maintenance of mental models (sets of retrieval cues) needed to access these representations, producing detrimental effects on reading time. In two experiments, subjects read passages that included pairs of coreferential sentences interrupted by unrelated text. As in previous research, reading times increased for the first sentence after the interruption, likely reflecting a reinstatement process for mental models in working memory. In the present research, pictures were provided as visuospatial cues to aid the reinstatement process. The interruption effect was found to be smaller with pictures related to the passages than with unrelated pictures (Experiment 1) or titles (Experiment 2); however, both of these effects occurred only for slow readers. The authors hypothesize that slow readers take the time needed to integrate visuospatial information into their mental models, providing more resilient access to long-term working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distinguishing Age Differences in Knowledge, Strategy Use, and Confidence During Strategic Skill Acquisition.

The authors examined how age differences in strategy selection are related to associative learning deficits and metacognitive variables, including memory ability confidence. In Experiment 1, increases in memory reliance for performance of the noun-pair lookup task were compared with increases in noun-pair memory ability. In Experiment 2, memory reliance was assessed for noun pairs memorized prior to the task. In each experiment, older adults manifested a substantial delay in transition to a retrieval-based strategy despite comparable noun-pair knowledge. In Experiment 3, young and older adults reported comparable confidence ratings for the accuracy of each memory probe response. However, older adults reported lower confidence in their general ability to use the memory retrieval strategy, which correlated with avoidance of the retrieval strategy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual and spatial working memory are not that dissociated after all: A time-based resource-sharing account.

Examinations of interference between visual and spatial materials in working memory have suggested domain- and process-based fractionations of visuo-spatial working memory. The present study examined the role of central time-based resource sharing in visuo-spatial working memory and assessed its role in obtained interference patterns. Visual and spatial storage were combined with both visual and spatial on-line processing components in computer-paced working memory span tasks (Experiment 1) and in a selective interference paradigm (Experiment 2). The cognitive load of the processing components was manipulated to investigate its impact on concurrent maintenance for both within-domain and between-domain combinations of processing and storage components. In contrast to both domain- and process-based fractionations of visuo-spatial working memory, the results revealed that recall performance was determined by the cognitive load induced by the processing of items, rather than by the domain to which those items pertained. These findings are interpreted as evidence for a time-based resource-sharing mechanism in visuo-spatial working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental change in working memory strategies: From passive maintenance to active refreshing.

Change in strategies is often mentioned as a source of memory development. However, though performance in working memory tasks steadily improves during childhood, theories differ in linking this development to strategy changes. Whereas some theories, such as the time-based resource-sharing model, invoke the age-related increase in use and efficiency of a strategy of active maintenance of memory traces, other theories, such as the task-switching model, do not mention strategy change. According to these models, either the cognitive load of the task or the duration of maintenance would account for recall performance. In the present study, we varied orthogonally these 2 factors. The results revealed that a different and unique factor affected recall performance at different ages: the duration of maintenance at age 6 and the cognitive load at age 7. As described by the task-switching model, younger children would not implement any maintenance activities while performing a concurrent task, their memory traces suffering from a time-based decay. This suggests that an increasing capacity of cognitive monitoring allows children to shift from this passive maintenance of memory traces to the active refreshing thereof at around the age of 7, reunifying the 2 current accounts of working memory development as 2 developmental stages. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Control of interference during working memory updating.

The current study examined the nature of the processes underlying working memory updating. In 4 experiments using the n-back paradigm, the authors demonstrate that continuous updating of items in working memory prevents strong binding of those items to their contexts in working memory, and hence leads to an increased susceptibility to proactive interference. Results of Experiments 1 and 2 show that this interference reflects a competition between a process that reveals the degree of familiarity of an item and a context-sensitive recollection process that depends on the strength of bindings in working memory. Experiment 3 further clarifies the origins of interference during updating by demonstrating that even items that are semantically related to the updated working memory contents but that have not been maintained in working memory before cause proactive interference. Finally, the results of Experiment 4 indicate that the occurrence of interference leads to top-down behavioral adjustments that prioritize recollection over familiarity assessment. The implications of these findings for the construct validity of the n-back task, for the control processes involved in working memory updating, and for the concept of executive control more generally are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)