Executive control processes of working memory predict attentional blink magnitude over and above storage capacity

When two masked, to-be-attended targets are presented within approximately half a second of each other, performance on the second target (T2) suffers, relative to when the targets are presented further apart in time or when the first target (T1) can be ignored. This phenomenon is known as the attentional blink (AB). Colzato et al. (Psychon Bull Rev 14:1051–1057, 2007) used an individual differences approach to examine whether individual AB magnitude was predicted by individual differences in working memory (WM), using the operation span paradigm (OSPAN). They found that OSPAN score was inversely related to AB magnitude even when a fluid intelligence measure (Raven’s SPM) was partialled out. However, it is not clear from this study whether it was the executive control aspect of working memory, the capacity aspect of short-term memory, (or both), that related to AB magnitude. In the present study we used a variety of WM measures that required varying degrees of executive control. OSPAN was negatively related to AB magnitude with Raven’s SPM, reading comprehension, reading rate, and digit forward and backward partialled out. Backward and forward digit span did not predict AB magnitude. These results support the conclusion that a “working” executive component of WM predicts temporal limitations of selective attention beyond static STM capacity and general cognitive ability.     

Visual selective attention is equally functional for individuals with low and high working memory capacity: Evidence from accuracy and eye movements

Selective attention and working memory capacity (WMC) are related constructs, but debate about the manner in which they are related remains active. One elegant explanation of variance in WMC is that the efficiency of filtering irrelevant information is the crucial determining factor, rather than differences in capacity per se. We examined this hypothesis by relating WMC (as measured by complex span tasks) to accuracy and eye movements during visual change detection tasks with different degrees of attentional filtering and allocation requirements. Our results did not indicate strong filtering differences between high- and low-WMC groups, and where differences were observed, they were counter to those predicted by the strongest attentional filtering hypothesis. Bayes factors indicated evidence favoring positive or null relationships between WMC and correct responses to unemphasized information, as well as between WMC and the time spent looking at unemphasized information. These findings are consistent with the hypothesis that individual differences in storage capacity, not only filtering efficiency, underlie individual differences in working memory.     

Investigating the role of attentional resources in the irrelevant speech effect

Irrelevant words can be disruptive to performance, and the frequency of usage of the irrelevant words has affected the magnitude of such disruption (Buchner &; Erdfelder, 2005). The finding of word frequency differences in the magnitude of the irrelevant speech effect (ISE) implicated a role for attentional processes. Using a different conceptualization of attention, researchers have found that individual differences in working memory capacity did not predict the magnitude of the ISE, which questioned the role of attentional control (Beaman, 2004; Sörqvist, 2010). The current study investigated aspects of the construct of attention and the ISE, using both individual and developmental difference approaches. Results showed no significant difference between serial recall performances in the presence of high or low word frequency distractors. Furthermore, effects of working memory capacity differences were not found, but children displayed a larger ISE than college students. The weight of the evidence appears against an attentional resource view of the ISE.     

视觉工作记忆的过滤效能

过滤效能反映了视觉工作记忆的干扰抑制功能, 研究者可基于储存容量或表征精度对其进行测量, 其神经加工过程主要分为觉察分心项目、过滤启动、实现过滤或储存, 涉及前额叶皮层和基底核、后顶叶皮层的协同作用。过滤效能的变化方向受到年龄、特殊障碍、情绪、认知特点等因素的影响。未来研究仍需解决的问题包括厘清过滤效能与工作记忆容量的关系, 辨明过滤效能的心理实现过程, 探索不同年龄、特殊障碍和职业等群体过滤效能的脑机制以及提升基础研究范式的生态学效度。     

Switching between filter settings reduces the efficient utilization of visual working memory

The capacity limitation of working memory requires that only relevant information gains access to the workspace, while irrelevant information is kept out. Thus, the ability to use attention to filter out irrelevant information is an important factor in how efficiently the limited storage space is used. Here, we examined to what degree the requirement to flexibly change filter settings affects filtering efficiency. Participants were presented with visual objects in different colors, and a cue presented in advance indicated which objects had to be stored. The contralateral delay activity, an event-related brain potential that reflects working-memory load was used to assess filtering efficiency during the retention interval. The data of two experiments showed that when filter settings had to be adjusted on a trial-by-trial basis, more irrelevant information passed the gate to working memory. Moreover, this switching-induced filtering deficit was restricted to those items that matched the previous, but currently irrelevant, filter settings. Thus, lingering effects of the selection history seem to counteract goal-directed encoding, and thus constitute an important attentional limitation for the efficient utilization of our limited workspace.     

The role of working memory capacity in multiple-cue probability learning

Multiple-cue probability learning (MCPL) involves learning to predict a criterion when outcome feedback is provided for multiple cues. A great deal of research suggests that working memory capacity (WMC) is involved in a wide range of tasks that draw on higher level cognitive processes. In three experiments, we examined the role of WMC in MCPL by introducing measures of working memory capacity, as well as other task manipulations. While individual differences in WMC positively predicted performance in some kinds of multiple-cue tasks, performance on other tasks was entirely unrelated to these differences. Performance on tasks that contained negative cues was correlated with working memory capacity, as well as measures of explicit knowledge obtained in the learning process. When the relevant cues predicted positively, however, WMC became irrelevant. The results are discussed in terms of controlled and automatic processes in learning and judgement.     

The role of working memory capacity in multiple-cue probability learning

Multiple-cue probability learning (MCPL) involves learning to predict a criterion when outcome feedback is provided for multiple cues. A great deal of research suggests that working memory capacity (WMC) is involved in a wide range of tasks that draw on higher level cognitive processes. In three experiments, we examined the role of WMC in MCPL by introducing measures of working memory capacity, as well as other task manipulations. While individual differences in WMC positively predicted performance in some kinds of multiple-cue tasks, performance on other tasks was entirely unrelated to these differences. Performance on tasks that contained negative cues was correlated with working memory capacity, as well as measures of explicit knowledge obtained in the learning process. When the relevant cues predicted positively, however, WMC became irrelevant. The results are discussed in terms of controlled and automatic processes in learning and judgement.     

Individual differences in dispositional focus of attention predict attentional blink magnitude

When identifying two targets presented in a rapid serial visual presentation stream, one’s accuracy on the second target is reduced if it is presented shortly (within 500 msec) after the first target—an attentional blink (AB). Individuals differ greatly in the size of their AB. One way to learn about the AB is to understand what underlies these individual differences. Recent studies have suggested that when a broadened or diffused attentional state is induced, the AB deficit can be attenuated. The present study examined whether natural (dispositional) individual differences in focus and diffusion of attention as assessed by the global/local task could predict performance on the AB task. Performance that was consistent with diffusion correlated negatively with AB size, and performance that was consistent with focusing correlated positively with AB size, showing that dispositional focus and diffusion of attention can predict individual differences in the AB. These findings are consistent with the Olivers and Nieuwenhuis (2006) overinvestment hypothesis.     

Picture span test: Measuring visual working memory capacity involved in remembering and comprehension

The working memory system is assumed to operate with domain-specific (verbal and visuospatial) resources that support cognitive activities. However, in research on visuospatial working memory, an appropriate visual working memory task has not been established. For the present study, a novel task was developed: the picture span test (PST). This test requires memorizing parts of scene images while comprehending various scene situations simultaneously. Results of correlation analyses and a factor analysis among college students (n=52) validated that PST can predict visuospatial cognitive skills whereas a simple visual storage task and a verbal working memory task cannot. Furthermore, an error analysis indicated that inhibition is important for visuospatial working memory. Additionally, PST is considered to reflect individual differences in the visual working memory capacity. These findings suggest that the PST is appropriate for measuring visual working memory capacity and can elucidate its relationship to higher cognition.     

Relationships between attentional blink magnitude, RSVP target accuracy, and performance on other cognitive tasks

When two masked, to-be-attended targets are presented within approximately half a second of each other, performance on the second target (T2) suffers, relative to when the targets are presented further apart in time or when the first target (T1) can be ignored. This pattern of results is known as the attentional blink (AB). Typically, participants differ with respect to the magnitude of their AB and their overall target accuracy. Despite investigations as to what participant characteristics may influence AB performance (e.g., age, brain damage, or mood state), there has been no focused examination of whether individual differences in cognitive performance measures predict the magnitude of the AB or overall rapid serial visual presentation(RSVP) target accuracy. Our university studentparticipants performed single-target and dual-target RSVP tasks, as well as a selection of cognitive tasks that did not use RSVP presentations, with color, letter, digit, and object stimuli. Overall performance on each of the RSVP targets (T1, T2, and single target) was predicted by speeded manual and vocal identification times to isolated stimuli and by performance with other RSVP targets. However, the magnitude of the AB was predicted only by T1 accuracy, not by any other performance measures. The results suggest that individual differences in AB magnitude do not result from differences in effective RSVP target encoding and are not well explained by varied information-processing abilities.     

Working memory capacity predicts search accuracy for novel as well as repeated targets

Visual search behaviour is guided by mental representations of targets that direct attention toward relevant features in the environment. Electrophysiological data suggests these target templates are maintained by visual working memory during search for novel targets and rapidly transfer to long term memory with target repetition. If this account is correct, an individual’s working memory capacity should be more predictive of search performance for novel targets than repeated targets. Across six experiments, we tested this hypothesis using both single (Experiments 5 and 6) and multiple (Experiments 1–4) target search tasks with three different types of stimuli (real world objects, letters, and triple conjunction shapes). Each target set was repeated for six consecutive trials. In addition, we estimated visual working memory capacity using a change detection working memory task. Overall, working memory capacity did not predict response time or efficiency in the visual search task. However, working memory capacity was equally predictive of search accuracy for both novel and repeated targets. These results suggest that working memory requirements do not substantially differ between novel and repeated target search, and working memory capacity may continue to play an important role in the encoding or maintenance of target representations after they are presumed to be in long term memory.     

Generalization on the Basis of Prior Experience Is Predicted by Individual Differences in Working Memory

Generalization on the basis of prior experience is a central feature of human and nonhuman behavior, and anomalies in generalization can give rise to a wide array of problems. For instance, elevated levels of generalization have been shown in individuals suffering from an anxiety disorder. Identifying the individual difference variables that influence the extent to which behavior generalizes to novel stimuli may help our understanding of generalization and its potential maladaptive consequences. In this study, we first present an index of generalization that captures individual differences in generalization in a single continuous measure, thereby surpassing problems associated with traditional analyzing techniques. Further, we investigate whether generalization is predicted by working memory capacity. More precisely, it is hypothesized that generalization is a function of individual differences in the capacity to compare the current situation with previous learning experiences in working memory, and to adjust subsequent behavior accordingly. In a community sample, we found higher levels of generalization in individuals who were less efficient at filtering out irrelevant information from access to working memory. These results suggest that working memory impairments may contribute to elevated and potentially maladaptive levels of generalization.     

Seven-year-olds allocate attention like adults unless working memory is overloaded

Previous studies have indicated that visual working memory performance increases with age in childhood, but it is not clear why. One main hypothesis has been that younger children are less efficient in their attention; specifically, they are less able to exclude irrelevant items from working memory to make room for relevant items. We examined this hypothesis by measuring visual working memory capacity under a continuum of five attention conditions. A recognition advantage was found for items to be attended as opposed to ignored. The size of this attention-related effect was adult-like in young children with small arrays, suggesting that their attention processes are efficient even though their working memory capacity is smaller than that of older children and adults. With a larger working memory load, this efficiency in young children was compromised. The efficiency of attention cannot be the sole explanation for the capacity difference.     

Selective attention,filtering, and the development of working memory

Selective attention is fundamental for learning across many situations, yet it exhibits protracted development, with young children often failing to filter out distractors. In this research, we examine links between selective attention and working memory (WM) capacity across development. One possibility is that WM is resource‐limited, with development resulting in an increase in the amount of resources available for processing information. However, it is also possible that development results in greater efficiency of using available resources. In the current research, we explore the latter possibility by examining the developmental trajectory of selectivity and filtering in relation to WM capacity. We report that filtering efficiency of adults (N = 30), 7‐year‐olds (N = 29), and 4‐year‐olds (N = 28) was uniquely predictive of WM capacity. We also report that filtering efficiency continues to develop after 7 years of age, whereas WM capacity may reach an asymptote around 7 years of age. The latter finding suggests that selective attention plays a critical role in developmental and individual differences in visual working memory capacity.     

Working memory and the attentional blink: Blink size is predicted by individual differences in operation span

The attentional blink (AB) is often attributed to resource limitations, but the nature of these resources is commonly underspecified. Recent observations rule out access to short-term memory or storage capacity as limiting factors, but operation bottlenecks are still an option. We considered the operation span of working memory (WM) as a possible factor and investigated the relationship between individual WM operation span (as measured by OSPAN), fluid intelligence (as measures by Raven’s SPM), and the size of the AB. WM operation span was negatively correlated with the AB, whereas fluid intelligence was associated with higher overall accuracy but not with AB magnitude. These results support the idea that individual processing limitations (with regard to either attentional allocation policies or the speed of global cortical integration processes) play a key role in the AB.     

Working memory and inattentional blindness

Individual differences in working memory predict many aspects of cognitive performance, especially for tasks that demand focused attention. One negative consequence of focused attention is inattentional blindness, the failure to notice unexpected objects when attention is engaged elsewhere. Yet, the relationship between individual differences in working memory and inattentional blindness is unclear; some studies have found that higher working memory capacity is associated with greater noticing, but others have found no direct association. Given the theoretical and practical significance of such individual differences, more definitive tests are needed. In two studies with large samples, we tested the relationship between multiple working memory measures and inattentional blindness. Individual differences in working memory predicted the ability to perform an attention-demanding tracking task, but did not predict the likelihood of noticing an unexpected object present during the task. We discuss the reasons why we might not expect such individual differences in noticing and why other studies may have found them.     

Effects of phonological length on the attentional blink for words

The authors tested whether the attentional blink (AB), a deficit in the ability to report a second target appearing within half a second of a first target, may reflect limitations for consolidating visual stimuli into working memory and awareness. Previous research has shown that people are severely limited in the rate that they can identify and report visual events presented in rapid succession. Word length was examined, a variable known to affect verbal working memory. Experiment 1 showed that the AB was modulated by the phonological length of the first target. Phonologically longer pseudowords triggered larger blink deficits. Experiment 2 also demonstrated the word-length effect on the AB using real-world stimuli, anagrams, that controlled for low-level visual differences between conditions. These data support proposals that the AB reflects a difficulty in consolidating information into working memory.     

Individual differences in electrophysiological responses to performance feedback predict AB magnitude

The attentional blink (AB) is observed when report accuracy for a second target (T2) is reduced if T2 is presented within approximately 500 ms of a first target (T1), but accuracy is relatively unimpaired at longer T1–T2 separations. The AB is thought to represent a transient cost of attending to a target, and reliable individual differences have been observed in its magnitude. Some models of the AB have suggested that cognitive control contributes to production of the AB, such that greater cognitive control is associated with larger AB magnitudes. Performance-monitoring functions are thought to modulate the strength of cognitive control, and those functions are indexed by event-related potentials in response to both endogenous and exogenous performance evaluation. Here we examined whether individual differences in the amplitudes to internal and external response feedback predict individual AB magnitudes. We found that electrophysiological responses to externally provided performance feedback, measured in two different tasks, did predict individual differences in AB magnitude, such that greater feedback-related N2 amplitudes were associated with larger AB magnitudes, regardless of the valence of the feedback.     

What causes auditory distraction?

The role of separating task-relevant from task-irrelevant aspects of the environment is typically assigned to the executive functioning of working memory. However, pervasive aspects of auditory distraction have been shown to be unrelated to working memory capacity in a range of studies of individual differences. We measured individual differences in global pattern matching and deliberate recoding of auditory sequences, and showed that, although deliberate processing was related to short-term memory performance, it did not predict the extent to which that performance was disrupted by task-irrelevant sound. Individual differences in global sequence processing were, however, positively related to the degree to which auditory distraction occurred. We argue that much auditory distraction, rather than being a negative function of working memory capacity, is in fact a positive function of the acuity of obligatory auditory processing.     

Memory search for the first target modulates the magnitude of the attentional blink

The resolution of temporal attention is limited in a manner that makes it difficult to identify two targets in short succession. This limitation produces the phenomenon known as the attentional blink (AB), in which processing of a first target (T1) impairs identification of a second target (T2). In the AB literature, there is broad agreement that increasing the time it takes to process T1 leads to a larger AB. One might, therefore, predict that increasing the number of possible T1 identities, or target set, from 1 to 16 would lead to a larger AB. We were surprised to find that this manipulation of T1 difficulty had no influence on AB magnitude. In subsequent experiments, we found that AB magnitude interacts with T1 processing time only under certain circumstances. Specifically, when the T1 task was either well masked or had to be completed online, we found a reliable interaction between AB magnitude and the target set size. When neither of these conditions was fulfilled, there was no interaction between target set size and the AB. Previous research found that when the target set changes from trial to trial, trials with more possible targets elicited a larger AB. In the present study, the target set is held constant, reducing the demands on working memory. Nevertheless, AB magnitude still interacts with target set size, as long as the T1 task cannot be processed offline. Thus, the act of searching memory delays subsequent processing, even when the role of working memory has been minimized.