Age-related differences in executive control of working memory

In two experiments, we used dual-task methodology to assess the effect of aging on executive control of working memory. We hypothesized that (1) age-related dual-task costs would be observed even when individual tasks represent different perceptual modalities; (2) age would modulate the effect of increased temporal overlap on dual-task performance; and (3) the vulnerability of specific memory mechanisms to interference would be age related. We found that aging was associated with disproportionate dual-task costs that increased when extending the overlap between individual tasks. The effect of interference with encoding, and arguably output, was disproportionately larger in old than in young individuals. Ensuring that individual tasks represent different perceptual modalities is important but insufficient when using dual-task methodology to assess the effect of aging on executive function. The degree of temporal overlap between individual tasks and the sensitivity of specific memory operations to interference should be considered, as well.     

Happiness increases verbal and spatial working memory capacity where sadness does not: Emotion,working memory and executive control

The effects of emotion on working memory and executive control are often studied in isolation. Positive mood enhances verbal and impairs spatial working memory, whereas negative mood enhances spatial and impairs verbal working memory. Moreover, positive mood enhances executive control, whereas negative mood has little influence. We examined how emotion influences verbal and spatial working memory capacity, which requires executive control to coordinate between holding information in working memory and completing a secondary task. We predicted that positive mood would improve both verbal and spatial working memory capacity because of its influence on executive control. Positive, negative and neutral moods were induced followed by completing a verbal (Experiment 1) or spatial (Experiment 2) working memory operation span task to assess working memory capacity. Positive mood enhanced working memory capacity irrespective of the working memory domain, whereas negative mood had no influence on performance. Thus, positive mood was more successful holding information in working memory while processing task-irrelevant information, suggesting that the influence mood has on executive control supersedes the independent effects mood has on domain-specific working memory.     

Fluid intelligence, working memory and executive functioning

The causes underlying the correlation between working memory and fluid intelligence remain unknown. There are some researchers who argue that the answer can be found on the presumed executive component of working memory. However, the available empirical evidence is far from conclusive. The present study tested a sample of 229 participants. Intelligence, working memory, and executive functioning were measured by one analytic reasoning test (TRASI), a dual task combining a primary task of deductive reasoning with a secondary task of counting, and the Tower of Hanoi task, respectively. All the 3 measures were computer administered. The results indicate that the shared variance between executive functioning and working memory do not account for the relationship between intelligence and working memory. Some theoretical implications are discussed.     

Drifting from slow to "D'oh!": working memory capacity and mind wandering predict extreme reaction times and executive control errors

A combined experimental, individual-differences, and thought-sampling study tested the predictions of executive attention (e.g., Engle & Kane, 2004) and coordinative binding (e.g., Oberauer, Süβ, Wilhelm, & Sander, 2007) theories of working memory capacity (WMC). We assessed 288 subjects' WMC and their performance and mind-wandering rates during a sustained-attention task; subjects completed either a go/no-go version requiring executive control over habit or a vigilance version that did not. We further combined the data with those from McVay and Kane (2009) to (1) gauge the contributions of WMC and attentional lapses to the worst performance rule and the tail, or τ parameter, of reaction time (RT) distributions; (2) assess which parameters from a quantitative evidence-accumulation RT model were predicted by WMC and mind-wandering reports; and (3) consider intrasubject RT patterns--particularly, speeding--as potential objective markers of mind wandering. We found that WMC predicted action and thought control in only some conditions, that attentional lapses (indicated by task-unrelated-thought reports and drift-rate variability in evidence accumulation) contributed to τ, performance accuracy, and WMC's association with them and that mind-wandering experiences were not predicted by trial-to-trial RT changes, and so they cannot always be inferred from objective performance measures.     

The more your mind wanders,the smaller your attentional blink: An individual differences study

The present studies investigate the hypothesis that individuals who frequently report experiencing episodes of mind wandering do so because they under-invest attentional/executive resources in the external environment. Here we examined whether self-reported instances of mind wandering predict the magnitude of the “attentional blink” (AB) in a rapid serial visual presentation (RSVP) task, since a prominent view is that the AB derives from an over-investment of attention in the information stream. Study 1 demonstrates that subjective reports of mind wandering in a sustained attention task have a negative predictive relation with respect to the magnitude of the AB measured in a subsequent RSVP task. In addition, using the Spontaneous and Deliberate Mind Wandering Questionnaire in Study 2, we were again able to show that trait-level mind wandering in everyday life negatively predicts AB magnitude. We suggest that mind wandering may be the behavioural outcome of an adaptive cognitive style intended to maximize the efficient processing of dynamic and temporally unpredictable events.     

Pre-frontal executive committee for perception,working memory,attention, long-term memory,motor control,and thinking: a tutorial review

As an explicit organizing metaphor, memory aid, and conceptual framework, the prefrontal cortex may be viewed as a five-member 'Executive Committee,' as the prefrontal-control extensions of five sub-and-posterior-cortical systems: (1) the 'Perceiver' (dominant-right-hemisphere ventral-lateral prefrontal cortex--VL/PERC-PFC) is the frontal extension of the ventral perceptual stream (the VL/PERC system) which represents the world and self in object coordinates; (2) the 'Verbalizer' (dominant-left-hemisphere ventral-lateral prefrontal cortex system--VL/VERB-PFC) is the frontal extension of the language stream (the VL/VERB system) which represents the world and self in language coordinates; (3) the 'Motivator' (ventral/medial-orbital pre-frontal cortex--VMO-PFC) is the frontal cortical extension of a subcortical extended-amygdala stream (the VMO system) which represents the world and self in motivational/emotional coordinates; (4) the 'Attender' (dorsal-medial/anterior cingulate--DM/AC-PFC) is the frontal cortical extension of a subcortical extended-hippocampal stream (the DM/AC system) which represents the world and self in spatiotemporal coordinates and directs attention to internal and external events; and (5) the 'Coordinator' (the dorsolateral prefrontal cortex--DL-PFC) is the frontal extension of the dorsal perceptual stream (the DL system) which represents the world and self in body- and eye-coordinates and controls willed action and working memory. This tutorial review examines the interacting roles of these five systems in perception, working memory, attention, long-term memory, motor control, and thinking.     

Predicting eye-movement characteristics across multiple tasks from working memory and executive control

Individual differences in working memory (WM) and executive control are stable, related to cognitive task performance, and clinically predictive. Between-participant differences in eye movements are also highly reliable (Carter & Luke, Journal of Experimental Psychology: Human Perception and Performance, 2018; Henderson & Luke, Journal of Experimental Psychology: Human Perception and Performance, 40(4), 1390–1400, 2014). However, little is known about how higher order individual differences in cognition are related to these eye-movement characteristics. In the present study, healthy college-age participants performed several individual difference tasks to measure WM span and executive control. Participants also performed three eye-movement tasks: reading, visual search, and scene viewing. Across all tasks, higher WM scores were related to reduced skewness in fixation duration distributions. In reading, higher WM scores predicted longer saccades. In scene viewing, higher WM scores predicted longer fixations. Theoretical and clinical implications of these findings are discussed.     

Tracking the train of thought from the laboratory into everyday life: An experience-sampling study of mind wandering across controlled and ecological contexts

In an experience-sampling study that bridged laboratory, ecological, and individual-differences approaches to mind-wandering research, 72 subjects completed an executive-control task with periodic thought probes (reported by McVay & Kane, 2009) and then carried PDAs for a week that signaled them eight times daily to report immediately whether their thoughts were off task. Subjects who reported more mind wandering during the laboratory task endorsed more mind-wandering experiences during everyday life (and were more likely to report worries as off-task thought content). We also conceptually replicated laboratory findings that mind wandering predicts task performance: Subjects rated their daily-life performance to be impaired when they reported off-task thoughts, with greatest impairment when subjects’ mind wandering lacked metaconsciousness. The propensity to mind wander appears to be a stable cognitive characteristic and seems to predict performance difficulties in daily life, just as it does in the laboratory     

Updating information in verbal working memory and executive functioning

50 older adults (M age=77.9 yr., SD=7.3; 35 women and 15 men) were tested using the updating working-memory task. They were also given the neuropsychological Wisconsin Card Sorting Test, assumed to evaluate executive functioning and the frontal cortex. A factor analysis with age, education, and verbal ability partialled out was computed on the updating task outcomes and resulted in a two-factor solution, indicating that this task requires two independent processes, interpreted as reflecting a storage component and an updating component. Partial correlations with age, education, and verbal ability partialled out indicated that Wisconsin Card Sorting Test measures were significantly associated with the factor supposed to reflect the updating process. Such results appeared consistent with the model of working memory with a central executive system involved in the updating process and related to the executive-frontal functioning, and a phonological loop system involved in the storage of verbal information and not linked to executive-frontal functions.     

Age differences in working memory tasks: The role of secondary memory and the central executive system

Two experiments are reported in which age differences in working memory performance are explored. In the first study, young and older adults held 2, 3, 4, or 5 unrelated words in mind while verifying a single or complex sentence. An age-related decrement was found in subsequent serial recall of the words, and this decrement was larger with longer word lists. Experiment 2 confirmed the interaction between age and list length, using list lengths of 4, 6, and 8 words and a free-recall procedure. There was no interaction between age and divided attention in either experiment. Surprisingly, sentence complexity had a greater detrimental effect on recall in the younger group. The results are discussed in terms of articulatory rehearsal being augmented by using secondary memory in the case of younger subjects.     

Individual differences in working memory capacity and dual-process theories of the mind

Dual-process theories of the mind are ubiquitous in psychology. A central principle of these theories is that behavior is determined by the interplay of automatic and controlled processing. In this article, the authors examine individual differences in the capacity to control attention as a major contributor to differences in working memory capacity (WMC). The authors discuss the enormous implications of this individual difference for a host of dual-process theories in social, personality, cognitive, and clinical psychology. In addition, the authors propose several new areas of investigation that derive directly from applying the concept of WMC to dual-process theories of the mind.     

Individual differences in young children's suggestibility: Relations to event memory,language abilities,working memory,and executive functioning

In this paper, two empirical studies are presented in which an attempt was made to explain individual differences in two different aspects of 4-year-olds’ suggestibility, that is, their ability to resist false suggestions and memory impairments due to prior misinformation. As sources of individual differences cognitive skills along the information processing pathways were chosen: executive functioning (Study 1) and working memory (Study 2). Additionally, memory for the observed event and language proficiency were included in the studies. The results revealed that overall individual differences in language skills made a significant and consistent contribution to individual differences in the included measures of children's susceptibility to suggestions. Executive function and working memory skills were not directly related to children's tendency to yield false suggestions and their memory impairments in a recognition test after being misled. However, both executive function and working memory were related to children's language proficiency pointing to a possible indirect effect and underlining the importance of language competencies in early childhood.     

Understanding the role of mind wandering in stress-related working memory impairments

Mind wandering has been identified as a possible cause for stress-related working memory (WM) task impairments following laboratory stressors. The current study attempted to induce mind wandering regarding negative, positive, or neutral events using an expressive writing task and examined the impact on WM task performance. We examined the role of mind wandering in understanding the impact of life stress on WM. Additionally, we explored the role of thought suppression on the relationship between mind wandering and WM. One hundred and fifty participants completed WM measures before (Time 1) and after (Time 2) the writing manipulation. The writing manipulation did not alter mind wandering or WM task performance. Time 1 WM predicted mind wandering during the Time 2 WM task, which subsequently predicted poorer Time 2 WM task performance. The impact of daily life stress on WM was mediated by mind wandering. Trait levels of thought suppression moderated the impact of mind wandering on WM. Specifically, higher levels of suppression resulted in stronger negative impact of mind wandering on WM task performance. Findings are discussed in terms of the impact of mind wandering on WM task performance.     

One executive function never comes alone: monitoring and its relation to working memory,reasoning, and different executive functions

Monitoring is involved in many daily tasks and is described in several theoretical approaches of executive functioning. This study investigated the relative relationship of cognitive processes that are theoretically relevant to monitoring, such as concept formation, reasoning, working memory, and general cognitive control functions. Data from 699 participants who performed the Balanced Switching Task, aiming at capturing monitoring, were used. Subsamples also performed standard tasks assessing the processes assumed to be related to monitoring. Structural equation modeling revealed that general cognitive control processes are particularly relevant. They mediate the relationship between working memory, reasoning, and monitoring. Updating and maintaining information, as well as concluding from information which strategies can guide behavior toward predefined goals, is required for the ability to exert general cognitive control, which again may be relevant for implementing strategies in a goal-directed way. Together, these processes seem to be necessary to adequately monitor behavior in complex tasks.     

White matter hyperintensities and working memory: an explorative study

White matter hyperintensities (WMH) are commonly observed in elderly people and may have the most profound effect on executive functions, including working memory. Surprisingly, the Digit Span backward, a frequently employed working memory task, reveals no association with WMH. In the present study, it was investigated whether more detailed analyses of WMH variables and study sample selection are important when establishing a possible relationship between the Digit Span backward and WMH. To accomplish this, the Digit Span backward and additional working memory tests, WMH subscores, and cardiovascular risk factors were examined. The results revealed that performance on the Digit Span backward test is unrelated to WMH, whereas a relationship between other working memory tests and WMH was confirmed. Furthermore, a division between several white matter regions seems important; hyperintensities in the frontal deep white matter regions were the strongest predictor of working memory performance.     

Aging ebbs the flow of thought: Adult age differences in mind wandering,executive control,and self-evaluation

Two experiments examined the relations among adult aging, mind wandering, and executive-task performance, following from surprising laboratory findings that older adults report fewer task-unrelated thoughts (TUTs) than do younger adults (e.g., Giambra, 1989, Jackson and Balota, 2012). Because older adults may experience more ability- and performance-related worry during cognitive tasks in the laboratory, and because these evaluative thoughts (known as task-related interference, “TRI”) might be sometimes misclassified by subjects as task-related, we asked subjects to distinguish task-related thoughts from TRI and TUTs when probed during ongoing tasks. In Experiment 1, younger and older adults completed either a go/no-go or a vigilance version of a sustained attention to response task (SART). Older adults reported more TRI and fewer TUTs than did younger adults while also performing more accurately. In Experiment 2, subjects completed either a 1- or a 2-back version of the n-back task. Older adults again reported more TRI and fewer TUTs than younger adults in both versions, while performing better than younger adults in the 1-back and worse in the 2-back. Across experiments, older adults' reduced TUT rates were independent of performance relative to younger adults. And, although older adults consistently reported more TRI and less mind wandering than did younger adults, overall they reported more on-task thoughts. TRI cannot, therefore, account completely for prior reports of decreasing TUTs with aging. We discuss the implications of these results for various theoretical approaches to mind-wandering.     

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.     

Coherence and recurrency: maintenance,control and integration in working memory

Working memory (WM), including a ‘central executive’, is used to guide behavior by internal goals or intentions. We suggest that WM is best described as a set of three interdependent functions which are implemented in the prefrontal cortex (PFC). These functions are maintenance, control of attention and integration. A model for the maintenance function is presented, and we will argue that this model can be extended to incorporate the other functions as well. Maintenance is the capacity to briefly maintain information in the absence of corresponding input, and even in the face of distracting information. We will argue that maintenance is based on recurrent loops between PFC and posterior parts of the brain, and probably within PFC as well. In these loops information can be held temporarily in an active form. We show that a model based on these structural ideas is capable of maintaining a limited number of neural patterns. Not the size, but the coherence of patterns (i.e., a chunking principle based on synchronous firing of interconnected cell assemblies) determines the maintenance capacity. A mechanism that optimizes coherent pattern segregation, also poses a limit to the number of assemblies (about four) that can concurrently reverberate. Top-down attentional control (in perception, action and memory retrieval) can be modelled by the modulation and re-entry of top-down information to posterior parts of the brain. Hierarchically organized modules in PFC create the possibility for information integration. We argue that large-scale multimodal integration of information creates an ‘episodic buffer’, and may even suffice for implementing a central executive.     

The neurotic wandering mind: An individual differences investigation of neuroticism,mind-wandering,and executive control

Cognitive psychology and cognitive neuroscience have recently developed a keen interest in the phenomenon of mind-wandering. People mind-wander frequently, and mind-wandering is associated with decreased cognitive performance. But why do people mind-wander so much? Previous investigations have focused on cognitive abilities like working memory capacity and attention control. But an individual's tendency to worry, feel anxious, and entertain personal concerns also influences mind-wandering. The Control Failure?×?Concerns model of mind-wandering. Psychological Bulletin, 136, 188–197] argues that individual differences in the propensity to mind-wander are jointly determined by cognitive abilities and by the presence of personally salient concerns that intrude on task focus. In order to test this model, we investigated individual differences in mind-wandering, executive attention, and personality with a focus on neuroticism. The results showed that neurotic individuals tended to report more mind-wandering during cognitive tasks, lower working memory capacity, and poorer attention control. Thus the trait of neuroticism adds an additional source of variance in the tendency to mind-wander, which offers support for the Control Failure?×?Concerns model. The results help bridge the fields of clinical psychology, cognitive psychology, affective neuroscience, and cognitive neuroscience as a means of developing a more complete understanding of the complex relationship between cognition, personality, and emotion.