Integrating working memory capacity and context-processing views of cognitive control

Individuals low in working memory capacity (WMC) exhibit impaired performance on a variety of cognitive control tasks. The executive-attention theory of WMC (Engle & Kane, 2004) accounts for these findings as failures of goal maintenance and response conflict resolution. Similarly, the context-processing view (Braver et al., 2001) provides an explanation of cognitive control deficits observed in schizophrenia patients and older adults that is based on the ability to maintain context information. Instead of maintenance deficits, the inhibition view (Hasher, Lustig, & Zacks, 2007) states that older adults and individuals low in WMC primarily have an impairment in the ability to inhibit information. In the current experiment, we explored the relationships among these theories. Individuals differing in performance on complex span measures of WMC performed the AX-Continuous Performance Test to measure context-processing performance. High-WMC individuals were predicted to maintain the context afforded by the cue, whereas low-WMC individuals were predicted to fail to maintain the context information. Low-WMC individuals made more errors on AX and BX trials and were slower to respond correctly on AX, BX, and BY trials. The overall pattern of results is most consistent with both the executive-attention and context-processing theories of cognitive control.     

Cognitive control in context: Working memory capacity and proactive control

Working memory is important for maintaining critical information in an active state to guide future behavior. The executive-attention theory of working memory capacity (WMC; Engle & Kane, 2004) argues that goal maintenance is important for response selection when stimuli are associated with competing responses. Braver, Burgess, and Gray (2007) have labeled this type of preparatory activity proactive control. Previous WMC studies have not allowed individuals to use goal information to prepare a specific response in advance of the stimulus. The current experiment used different versions of a cue-probe task to examine the relationship between individual differences in WMC and proactive control. Across three versions of the AX version of the Continuous Performance Test, the proportion of targets was manipulated to affect both the predictive validity of the A cue and the prepotency of the target response to X probes. The results indicated that the high-WMC individuals used the cue information to prepare responses in advance only when a specific probe was likely to occur. In contrast, the performance of the low-WMC individuals was less dependent upon the cue and more contingent upon overall response frequencies. The results indicate that individual differences in WMC are related to proactive control and anticipation, and important for translating cognition into action.     

Context-processing deficits in schizophrenia: diagnostic specificity, 4-week course,and relationships to clinical symptoms

Previous research on schizophrenia suggests that context-processing disturbances are one of the core cognitive deficits present in schizophia. However, it is not clear whether such deficits are specific to schizophrenia as compared with other psychotic disorders. To address this question, the authors administered a version of the AX Continuous Performance Test designed to assess context processing in a sample of healthy controls, patients with schizophrenia, and patients with other psychotic disorders. Participants were tested at index (when medication naive and experiencing their first contact with psychiatric services) and 4 weeks later, following medication treatment. At index, patients with schizophrenia and the psychotic comparison group demonstrated similar impairments in context processing. However, context-processing deficits improved in the psychotic comparison group at 4 weeks but did not improve in patients with schizophrenia.     

Stereotype Threat Impairs Older Adult Driving

Stereotypes can harm human performance, especially when activated in individuals with diminished working memory capacity (WMC). Performance implications for the stereotype of poor driving in older adults were investigated. Using a sample of older adults, WMC (the ability to maintain task goals and ignore distractions) and driving performance [brake reaction time (RT), following distance, and crashes] were assessed, the latter using a high‐fidelity simulator. Elderly participants under stereotype threat with reduced WMC exhibited slower brake RTs and longer following distances compared with a control condition that was not threatened. This driving profile was characteristic of cognitive distraction. Stereotype threat has clear consequences for human performance in a common real‐world task—driving—that is critical to public safety. Furthermore, these findings suggest caution in how the media and public policy communicate information about older adult driving.Copyright © 2015 John Wiley & Sons, Ltd.     

Context-processing deficits in schizotypal personality disorder

Research suggests that schizotypal personality disorder (SPD) is a part of the spectrum of schizophrenia-related illnesses. This article hypothesizes that a deficit in the representation and maintenance of context is a core cognitive disturbance in schizophrenia and that SPD individuals should demonstrate context-processing deficits. To test this hypothesis, the authors administered 3 versions of their AX-CPT task, designed to assess context processing, to 35 healthy controls and 26 individuals with DSM-IV SPD. They also administered working memory and selective attention tasks. SPD individuals displayed context representation deficits similar to those found in schizophrenia but did not show the same additional deficits in context maintenance. Context processing was strongly associated with working memory and selective attention performance in the SPD individuals.     

The role of prefrontal cortex in working-memory capacity,executive attention,and general fluid intelligence: an individual-differences perspective

We provide an "executive-attention" framework for organizing the cognitive neuroscience research on the constructs of working-memory capacity (WMC), general fluid intelligence, and prefrontal cortex (PFC) function. Rather than provide a novel theory of PFC function, we synthesize a wealth of single-cell, brain-imaging, and neuropsychological research through the lens of our theory of normal individual differences in WMC and attention control (Engle, Kane, & Tuholski, 1999; Engle, Tuholski, Laughlin, & Conway, 1999). Our critical review confirms the prevalent view that dorsolateral PFC circuitry is critical to executive-attention functions. Moreover, although the dorsolateral PFC is but one critical structure in a network of anterior and posterior "attention control" areas, it does have a unique executive-attention role in actively maintaining access to stimulus representations and goals in interference-rich contexts. Our review suggests the utility of an executive-attention framework for guiding future research on both PFC function and cognitive control.     

Why does working memory capacity predict variation in reading comprehension? On the influence of mind wandering and executive attention

Some people are better readers than others, and this variation in comprehension ability is predicted by measures of working memory capacity (WMC). The primary goal of this study was to investigate the mediating role of mind-wandering experiences in the association between WMC and normal individual differences in reading comprehension, as predicted by the executive-attention theory of WMC (e.g., Engle & Kane, 2004). We used a latent-variable, structural-equation-model approach, testing skilled adult readers on 3 WMC span tasks, 7 varied reading-comprehension tasks, and 3 attention-control tasks. Mind wandering was assessed using experimenter-scheduled thought probes during 4 different tasks (2 reading, 2 attention-control). The results support the executive-attention theory of WMC. Mind wandering across the 4 tasks loaded onto a single latent factor, reflecting a stable individual difference. Most important, mind wandering was a significant mediator in the relationship between WMC and reading comprehension, suggesting that the WMC-comprehension correlation is driven, in part, by attention control over intruding thoughts. We discuss implications for theories of WMC, attention control, and reading comprehension.     

Working memory capacity in generalized social phobia

Research suggests that understanding complex social cues depends on the availability of cognitive resources (e.g., Phillips, Channon, Tunstall, Hedenstrom, & Lyons, 2008). In spite of evidence suggesting that executive control functioning may impact anxiety (e.g., Eysenck, Derakshan, Santos, & Calvo, 2007), relatively few studies have examined working memory in individuals with generalized social phobia. Moreover, few studies have examined the role of threat-relevant content in working memory performance in clinically anxious populations. To this end, the present study assessed working memory capacity (WMC) in individuals with generalized social phobia and nonanxious controls using an operation span task with threat-relevant and neutral stimuli. Results revealed that nonanxious individuals demonstrated better WMC than individuals with generalized social phobia for neutral words but not for social threat words. Individuals with generalized social phobia demonstrated better WMC performance for threat words relative to neutral words. These results suggest that individuals with generalized social phobia may have relatively enhanced working memory performance for salient, socially relevant information. This enhanced working memory capacity for threat-relevant information may be the result of practice with this information in generalized social phobia.     

Context-processing deficits in schizophrenia: converging evidence from three theoretically motivated cognitive tasks

To test the hypothesis that the ability to actively represent and maintain context information in a central function of working memory and that a disturbance in this function contributes to cognitive deficits in schizophrenia, the authors modified 3 tasks--the AX version of the Continuous Performance Test, Stroop, and a lexical disambiguation task--and administered them to patients with schizophrenia as well as to depressed and healthy controls. The results suggest an accentuation of deficits in patients with schizophrenia in context-sensitive conditions and cross-task correlations of performance in these conditions. However, the results do not definitively eliminate the possibility of a generalized deficit. The significance of these findings is discussed with regard to the specificity of deficits in schizophrenia and the hypothesis concerning the neural and cognitive mechanisms that underlie these deficits.     

Impaired context maintenance in mild to moderately depressed students

We test the hypothesis that people with depression experience difficulties in maintaining task-relevant context information over longer periods of time using the AX version of the continuous performance task (AX-CPT). The AX-CPT requires that participants maintain a context cue (A) in an active state in order to respond correctly to a target cue (X) presented after a short delay. A total of 40 nondepressed and mild to moderately depressed students completed versions of the task with short (1-s) or long (10-s) interstimulus intervals (ISIs). Mildly depressed participants made significantly more context-dependent (BX) errors, unlike controls who made more errors on trials where good context processing would impair performance (AY). This pattern of errors was only evident in the long ISI condition, suggesting poor maintenance of contextual information.     

Individual differences in susceptibility to false memory in the Deese-Roediger-McDermott paradigm

The authors addressed whether individual differences in the working memory capacity (WMC) of young adults influence susceptibility to false memories for nonpresented critical words in the Deese-Roediger-McDermott associative list paradigm. The results of 2 experiments indicated that individuals with greater WMC recalled fewer critical words than individuals with reduced WMC when participants were forewarned about the tendency of associative lists (e.g., bed, rest, . . .) to elicit illusory memories for critical words (e.g., sleep). In contrast, both high and low WMC participants used repeated study-test trials to reduce recall of critical words. These findings suggest that individual differences in WMC influence cognitive control and the ability to actively maintain task goals in the face of interfering information or habit.     

Accounting for cognitive aging: context processing, inhibition or processing speed?

Age-related deficits in context processing were examined in relationship to two predominant theories of cognitive aging (the Inhibitory Deficit and Processing Speed Models). Older and younger adults completed a measure of context processing (AX Continuous Performance Test (CPT) task) as well as a computerized battery of inhibitory tasks: Stroop, garden path sentences, go no-go, and the stop-signal paradigm. Participants also completed a simple processing speed task. After controlling for baseline differences in processing speed, age effects were detected on the AX-CPT. Smaller, but significant age effects were noted on the Stroop and stop-signal tasks, but no significant age effects were found on the garden path sentence and go no-go tasks. Intertask correlations were weak, providing little evidence for a homogenous or uniform construct of inhibition. The sensitivity of the AX-CPT to cognitive aging is discussed in the context of existing theories of cognitive aging. The authors suggest that deficits in context processing and utilization may underlie cognitive aging phenomena.     

Individual differences in working memory capacity predict visual attention allocation

To the extent that individual differences in working memory capacity (WMC) reflect differences in attention (Baddeley, 1993; Engle, Kane, & Tuholski, 1999), differences in WMC should predict performance on visual attention tasks. Individuals who scored in the upper and lower quartiles on the OSPAN working memory test performed a modification of Egly and Homa’s (1984) selective attention task. In this task, the participants identified a central letter and localized a displaced letter flashed somewhere on one of three concentric rings. When the displaced letter occurred closer to fixation than the cue implied, high-WMC, but not low-WMC, individuals showed a cost in the letter localization task. This suggests that low-WMC participants allocated attention as a spotlight, whereas those with high WMC showed flexible allocation.     

Need for closure and dealing with uncertainty in decision making context: The role of the behavioral inhibition system and working memory capacity

The aim of the present study was to investigate the moderated mediation model of the relationship between the behavioral inhibition system (BIS), need for closure (NFC) and working memory capacity (WMC) in the decision making process. It was assumed that NFC works as a motivational mechanism that enables individuals high in BIS to deal with uncertainty; therefore, NFC mediates the effect of BIS on behavior in a decision-making situation. Moreover, as uncertainty management requires cognitive resources, we expected WMC to moderate this relationship. In line with our hypothesis, we found that NFC mediated the relationship between BIS and the information search about the job candidates, and this effect occurred only for individuals high in WMC. We discuss these results in the context of effective self-regulation, as well as motivational and cognitive determinants of effort.     

Accounting for Cognitive Aging: Context Processing,Inhibition or Processing Speed?

ABSTRACT

Age-related deficits in context processing were examined in relationship to two predominant theories of cognitive aging (the Inhibitory Deficit and Processing Speed Models). Older and younger adults completed a measure of context processing (AX Continuous Performance Test (CPT) task) as well as a computerized battery of inhibitory tasks: Stroop, garden path sentences, go no-go, and the stop-signal paradigm. Participants also completed a simple processing speed task. After controlling for baseline differences in processing speed, age effects were detected on the AX-CPT. Smaller, but significant age effects were noted on the Stroop and stop-signal tasks, but no significant age effects were found on the garden path sentence and go no-go tasks. Intertask correlations were weak, providing little evidence for a homogenous or uniform construct of inhibition. The sensitivity of the AX-CPT to cognitive aging is discussed in the context of existing theories of cognitive aging. The authors suggest that deficits in context processing and utilization may underlie cognitive aging phenomena.     

COMT val158Met and executive control: a test of the benefit of specific deficits to translational research

The role of catechol-O-methyltransferase (COMT) val158met in prefrontal cortical deficits associated with the liability to schizophrenia remains controversial. This study evaluated 464 healthy adult participants using three measures of executive functions in working memory: a 3-back version of the N-back continuous performance task (CPT) and two variants of the AX-CPT. The interpretability of N-back performance was confounded by possible generalized deficits, whereas the AX variants included internal controls for uncovering specific deficits. There was no relationship between the COMT genotype and N-back performance, whereas val/val individuals had a specific deficit on a dot-pattern version of the AX-CPT. In this case, a specific executive function known as context processing appeared to be compromised. These data suggest that the interpretability gained by including task manipulations to uncover specific deficits can enhance associations between cognitive and genetic levels of analysis.     

Working memory capacity and go/no-go task performance: selective effects of updating, maintenance, and inhibition

The ability to temporarily maintain information in order to successfully perform a task is important in many daily activities. However, the ability to quickly and accurately update existing mental representations in distracting situations is also imperative in many of these same circumstances. In the current studies, individuals varying in working memory capacity (WMC) performed different varieties of go/no-go tasks that have been hypothesized to measure inhibitory ability. The results indicated that low-WMC individuals relative to high-WMC individuals showed worse performance specifically in certain conditions of the conditional go/no-go task. Further analyses showed that increasing the temporal lag/number of intervening items between the previous target and the current lure had a deleterious effect on the performance of the low-WMC group only. The results indicate a relationship between WMC and the ability to selectively update, maintain, and retrieve information, especially in interference-rich conditions.     

Working memory capacity modulates task performance but has little influence on task choice

Variation in the ability to maintain internal goals while resolving competition from multiple information streams has been related to individual differences in working memory capacity (WMC). In a multitask environment, task choice and task performance are influenced by internal goals, prior behavior within the environment, and the availability of relevant and irrelevant information in the environment. Using the voluntary task-switching procedure, task performance, as measured by switch costs, was related to WMC, but only at short preparation intervals. Task choice processes were only weakly related to WMC. These findings are consistent with models of cognitive control that separate task choice processes from the processes of activating and maintaining task readiness. WMC is related to regulation of specific task parameters but not to choice processes integral to the coordination of multiple sources of information.     

Context processing and cognitive control in children and young adults

T. S. Braver and colleagues (e.g., T. S. Braver, J. D. Cohen, & D. M. Barch, 2002) have provided a theory of cognitive control that focuses on the role of context processing. According to their theory, an underlying context-processing mechanism is responsible for the cognitive control functions of attention, inhibition, and working memory. In the present study, the authors examined whether T. S. Braver et al.'s theory can account for developmental differences in cognitive control. The authors compared the performance of children (M age = 11.9 years, SD = 0.43 years) with that of young adults (M age = 21.7 years, SD = 3.61 years) on a continuous performance task (AX-CPT) that placed demands on context processing. The results suggest that developmental differences in the cognitive control functions of attention, inhibition, and working memory may be based on age-related changes in an underlying context-processing mechanism.     

Working memory capacity and spontaneous emotion regulation in generalised anxiety disorder

Researchers have postulated that deficits in cognitive control are associated with, and thus may underlie, the perseverative thinking that characterises generalised anxiety disorder (GAD). We examined associations between cognitive control and levels of spontaneous state rumination following a stressor in a sample of healthy control participants (CTL; n?=?27) and participants with GAD (n?=?21). We assessed cognitive control by measuring working memory capacity (WMC), defined as the ability to maintain task-relevant information by ignoring task-irrelevant information. To this end, we used an affective version of the reading span task with valenced (negative or neutral) distractors. Lower WMC in the presence of negative distractors was associated with greater state rumination in the GAD group, but not in the CTL group. These findings suggest that difficulty maintaining task-relevant information due to interference from negative distractors contributes to perseverative thinking in GAD.