Stress reduces attention to irrelevant information: Evidence from the Stroop task

Stroop interference can be reduced by stress, and this has been taken as evidence that stress decreases the attention paid to irrelevant information, a theory known as ‘Easterbrook’s hypothesis’. This contradicts more recent theories, which state that attentional control deteriorates in stress. Fifty-five participants undertook a Stroop task under high stress (loud white noise) and low stress conditions. Attention to the irrelevant word information was assessed by manipulating the proportion of congruent trials (e.g. the word RED in the colour red); it is known that Stroop interference increases when many such trials are presented. This effect was reduced when participants were stressed, which is evidence that stress does indeed reduce attention to irrelevant information. This pattern of results was not present in participants with low working memory spans, presumably because these participants had less attentional control. These findings highlight an important weakness in contemporary theories of cognition in stress.     

Individual differences in event-based prospective memory: Evidence for multiple processes supporting cue detection

The multiprocess view proposes that different processes can be used to detect event-based prospective memory cues, depending in part on the specificity of the cue. According to this theory, attentional processes are not necessary to detect focal cues, whereas detection of nonfocal cues requires some form of controlled attention. This notion was tested using a design in which we compared performance on a focal and on a nonfocal prospective memory task by participants with high or low working memory capacity. An interaction was found, such that participants with high and low working memory performed equally well on the focal task, whereas the participants with high working memory performed significantly better on the nonfocal task than did their counterparts with low working memory. Thus, controlled attention was only necessary for detecting event-based prospective memory cues in the nonfocal task. These results have implications for theories of prospective memory, the processes necessary for cue detection, and the successful fulfillment of intentions.     

The role of working memory in syntactic ambiguity resolution: a psychometric approach

In 2 studies, the authors used a combination of psychometric and experimental techniques to investigate the effects of domain-general and domain-specific working memory factors on offline decisions concerning attachment of an ambiguous relative clause. Both studies used English and Dutch stimuli presented to English- and Dutch-speaking participants, respectively. In Study 1, readers with low working memory spans were less likely to use recency strategies for disambiguation than were readers with high spans. This finding is inconsistent with predictions of locality- and resource-based accounts of attachment. Psychometric analyses showed that both domain-specific (verbal) and domain-general working memory accounted for the effect. Study 2 found support for the hypothesis that segmentation strategies imposed during silent reading can account for the counterintuitive relationship. Results suggest that readers with low spans have a greater tendency to break up large segments of text because of their limited working memory, leading to high attachment of the ambiguous relative clause.     

Working-memory capacity, proactive interference, and divided attention: limits on long-term memory retrieval

Two experiments examined how individual differences in working-memory capacity (WM) relate to proactive interference (PI) susceptibility. We tested high and low WM-span participants in a PI-buildup task under single-task or dual-task ("load") conditions. In Experiment 1, a finger-tapping task was imposed during encoding and retrieval of each list; in Experiment 2, tapping was required during encoding or retrieval. In both experiments, low spans showed greater PI than did high spans under no load, but groups showed equivalent PI under divided attention. Load increased PI only for high spans, suggesting they use attention at encoding and retrieval to combat PI. In Experiment 2, only low spans showed a dual-task cost on List 1 memory, before PI built up. Results indicate a role for attentional processing, perhaps inhibitory in nature, at encoding and retrieval, and are discussed with respect to theories of WM and prefrontal cortex function.     

Individual differences in visuospatial working memory: benefits from environmental support for rehearsal

ABSTRACT

Previous research has suggested that participants with low working memory spans are less likely than those with high spans to engage in rehearsal and other effective strategies during memory tasks. However, most of this research has been conducted in the verbal domain, and less is known about strategy differences in visuospatial working memory. Therefore, the present experiments investigated potential individual differences in the benefit participants receive from environmental support for visuospatial rehearsal. In Experiment 1, memory spans were significantly larger when support was present (i.e. when the array of possible locations remained on the screen) during long inter-item intervals, but importantly, the observed benefit was larger for high-span participants than low-span participants, suggesting that high spans were more likely to use support to facilitate their rehearsal. Other research has suggested that low spans may benefit more than high spans from rehearsal instructions, and so in Experiment 2, participants also were provided with such instructions. However, the rehearsal instructions did not improve memory spans significantly in either group, suggesting that low spans are not only naturally less strategic than high spans, but they may be less capable of taking advantage of effective rehearsal strategies, even when environmental support is present.     

Attentional interference in judgments of musical timbre: individual differences in working memory

Researchers have shown that working memory is related to a variety of high-level cognitive processes. However, the results of recent research have suggested that may be because of its role in attentional control. In the present experiment, the authors investigated that hypothesis by using an attentional interference task with musical stimuli. Listeners were asked to monitor one ear for either a clarinet or violin tone and to ignore any information in the other ear. On some of the trials, they heard only one tone and on other trials, either the same instrument in both ears or different instruments. Individual differences were measured in working memory and musical experience. The results showed more attentional interference in the different-instrument condition for participants with lower working memory scores, which suggested that working memory involves the ability to control attention to inhibit irrelevant information.     

Changes in Skin Potentials During the Psychogalvanic Reflex

Researchers have shown that working memory is related to a variety of high-level cognitive processes. However, the results of recent research have suggested that may be because of its role in attentional control. In the present experiment, the authors investigated that hypothesis by using an attentional interference task with musical stimuli. Listeners were asked to monitor one ear for either a clarinet or violin tone and to ignore any information in the other ear. On some of the trials, they heard only one tone and on other trials, either the same instrument in both ears or different instruments. Individual differences were measured in working memory and musical experience. The results showed more attentional interference in the different-instrument condition for participants with lower working memory scores, which suggested that working memory involves the ability to control attention to inhibit irrelevant information.     

Individual differences in working memory capacity predict action monitoring and the error-related negativity

Neuroscience suggests that the anterior cingulate cortex (ACC) is responsible for conflict monitoring and the detection of errors in cognitive tasks, thereby contributing to the implementation of attentional control. Though individual differences in frontally mediated goal maintenance have clearly been shown to influence outward behavior in interference-rich contexts, it is unclear whether corresponding differences exist in neural responses that arise out of the ACC. To investigate this possibility, we conducted an electrophysiological study using a variant of the Simon Task, recording event-related potentials (ERPs) in healthy normal individuals with varying working memory capacity (high vs. low spans; a behavioral proxy for variability in goal maintenance). Primary analyses focused on the magnitude of the error-related negativity (ERN), a response-locked ERP component associated with the commission of errors thought to arise because of action monitoring in the ACC. Our results revealed that frontally mediated working memory capacity may alter error monitoring by the ACC, with high spans showing a greater ERN than low spans. These individual differences were also observed in the posterror positivity, a response-locked ERP component associated with updating cognitive strategies, suggesting greater awareness of errors with increased working memory capacity. These results are interpreted within 2-process models of attentional control, suggesting individuals with greater working memory capacity may better maintain task goals by more strongly biasing neural activity in frontal-executive networks.     

工作记忆表征的激活与抑制状态对注意引导效应的影响

本研究采用双任务范式, 通过定向遗忘任务操纵工作记忆表征状态, 分别在目标无关和目标相关条件下考察工作记忆激活与抑制状态对视觉搜索早期注意引导效应的影响。实验1与实验2发现当工作记忆表征只可能与视觉搜索分心物匹配时(目标无关条件), 处于激活状态的工作记忆表征会引导视觉注意偏向到与之匹配的分心物, 表现出注意引导效应, 而处于抑制状态的工作记忆表征则没有观察到注意引导效应。实验3与实验4发现, 当工作记忆表征有可能与视觉搜索目标匹配时(目标相关条件), 处于激活状态的工作记忆表征能捕获注意, 而处于抑制状态的工作记忆表征只有与视觉搜索目标匹配时, 才表现出对该搜索目标反应的延迟。这些研究的结果表明(1)处于激活状态的工作记忆表征能有效地引导注意偏向到与之匹配的搜索目标或分心物, 并且这种注意引导效应并未受到抑制动机的影响而被消除或反转; (2)处于抑制状态的工作记忆表征能将抑制状态传递到视觉搜索阶段, 并延迟对与之匹配的搜索目标的反应。     

Electrophysiological evidence for greater attention to threat when cognitive control resources are depleted

In this study, we investigated the time course of attentional bias for threat-related (angry) facial expressions under conditions of high versus low cognitive (working memory) load. Event-related potential (ERP) and reaction time (RT) data were recorded while participants viewed pairs of faces (angry paired with neutral face) displayed for 500 ms and followed by a probe. Participants were required to respond to the probe while performing a concurrent task of holding in working memory a sequence of digits that were either in the same order (low memory load) or in a random mixed order (high memory load). The ERP results revealed that higher working memory load resulted in enhanced lateralized neural responses to threatening relative to neutral faces, consistent with greater initial orienting of attention to threatening faces (early N2pc: 180–252 ms) and enhanced maintenance of processing representations of threat (late N2pc, 252–320 ms; SPCN, 320–500 ms). The ERP indices showed significant positive relationships with each other, and also with the behavioral index of attentional bias to threat (reflected by faster RTs to probes replacing angry than neutral faces at 500 ms), although the latter index was not significantly influenced by memory load. Overall, the findings indicate that depletion of cognitive control resources, using a working memory manipulation, increases the capacity of task-irrelevant threat cues to capture and hold attention.     

Evaluation of the attentional capacities and working memory of early and late blind persons

Although attentional processes and working memory seem to be significantly involved in the daily activities (particularly during navigating) of persons who are blind and who use these abilities to compensate for their lack of vision, few studies have investigated these mechanisms in this population. The aim of this study is to evaluate the selective, sustained and divided attention, attentional inhibition and switching and working memory of blind persons. Early blind, late blind and sighted participants completed neuropsychological tests that were designed or adapted to be achievable in the absence of vision. The results revealed that the early blind participants outperformed the sighted ones in selective, sustained and divided attention and working memory tests, and the late blind participants outperformed the sighted participants in selective, sustained and divided attention. However, no differences were found between the blind groups and the sighted group in the attentional inhibition and switching tests. Furthermore, no differences were found between the early and late blind participants in this set of tests. These results suggest that early and late blind persons can compensate for the lack of vision by an enhancement of the attentional and working memory capacities.     

Remembered duration: working memory and the reproduction of intervals

On the basis of attention allocation models of time estimation, the role of working memory in prospective duration reproduction is explored. In four experiments, adult participants performed a counting task (duration, 400 sec) that allowed coordinative and sequential demands on working memory to be varied. After completing the counting task, the participants reproduced the time that they had worked on this task It emerged that (1) increased coordinative demands on working memory (but not increased sequential demands) reduced the accuracy of prospective duration reproduction (Experiments 1 and 2), (2) presenting context information during the reproduction phase enhanced the accuracy of the reproduced duration (Experiment 3), and (3) individual differences in coordinative working memory capacity affected duration reproduction in the same direction as the experimental manipulation of coordinative task demands (Experiment 4). The results suggest that attention allocation models of time estimation may benefit from taking a more differentiated view of the types of attentional demands that affect temporal cognition.     

Processing resource capacity and the comprehension of garden path sentences

Three experiments explored the relationship between verbal working memory capacity and the comprehension of garden path sentences. In Experiment 1, subjects with high, medium, and low working memory spans made acceptability judgments about garden path and control sentences under whole sentence and rapid serial visual presentation (RSVP) conditions. There were no significant differences between subjects with different working memory spans in the comprehension of garden path sentences in either condition. In Experiments 2A and 2B, subjects with high and low working memory spans were tested on the same materials at three RSVP rates. There were no significant differences between subjects with different working memory spans in the magnitude of the effect of garden path sentences at any presentation rate. The results suggest that working memory capacity, as measured by the Daneman and Carpenter (1980) reading span task, is not a major determinant of individual differences in the processing of garden path sentences.     

Examining cognitive performance: Do perfectionism and rumination matter?

Research has looked to possible personality constructs that can affect cognitive performance. Studies have demonstrated that working memory and attentional effectiveness can be directly related to the cognitive resources upon which one is readily able to call. Whereas limited research has examined the role of perfectionism in relation to problem solving abilities, to date, no studies have specifically examined how it may affect working memory or attention. The study’s purpose was to assess the impact of task difficulty (high, medium, or low) and personality constructs on working memory and attention. Following completion of the personality measures, participants completed the d2 test of attention and an N-back task. Results indicated that perfectionism and rumination significantly affected accuracy but not reaction time on the N-back task and that rumination significantly affected the total number of items processed on the d2 test of attention. Given the lack of elevated scores on the personality indicators within this sample, future research might examine this process in those more strongly endorsing these traits, allowing us to better ascertain the degree to which cognitive deficits may be evident.     

Do the contents of visual working memory automatically influence attentional selection during visual search?

In many theories of cognition, researchers propose that working memory and perception operate interactively. For example, in previous studies researchers have suggested that sensory inputs matching the contents of working memory will have an automatic advantage in the competition for processing resources. The authors tested this hypothesis by requiring observers to perform a visual search task while concurrently maintaining object representations in visual working memory. The hypothesis that working memory activation produces a simple but uncontrollable bias signal leads to the prediction that items matching the contents of working memory will automatically capture attention. However, no evidence for automatic attentional capture was obtained; instead, the participants avoided attending to these items. Thus, the contents of working memory can be used in a flexible manner for facilitation or inhibition of processing.     

工作记忆广度：资源限制、记忆消退还是转换机制？

为了检验工作记忆广度有限性的3种假说,即资源限制假说、记忆消退假说和转换机制假说,实验要求被试首先完成一项转换效率任务,然后完成工作记忆广度任务。结果发现,加工负荷对工作记忆广度具有重要影响,保持时间不影响工作记忆广度,转换效率与工作记忆广度也没有显著相关。实验结果支持工作记忆广度受认知资源限制的观点     

Spatial working memory load impairs signal enhancement, but not attentional orienting

The present study examined the effect of spatial working memory load on the attentional cuing effect. It is well-known that spatial working memory and spatial attention functionally overlap or share a common resource. Given this functional overlapping, it is possible that spatial working memory would also interact with the attentional cuing effect. Considering the distinction between channel selection and channel enhancement by attention (Prinzmetal, McCool, & Park, 2005), we expected that the interaction between spatial working memory and the cuing effect would differ with attentional processing type. Two experiments conducted with the spatial cuing paradigm showed that the magnitude of the cuing effect as measured by reaction time, reflecting channel selection, was uninfluenced by spatial working memory load. In contrast, spatial working memory load reduced the cuing effect as measured by accuracy, reflecting channel enhancement. These results suggest that spatial working memory load impairs signal enhancement by attention and does not influence attentional orienting per se. The interaction between spatial working memory and visual perception is also discussed.     

Role of frontal cortex in attentional capture by singleton distractors

The role of frontal cortex in selective attention to visual distractors was examined in an attentional capture task in which participants searched for a unique shape in the presence or absence of an additional colour singleton distractor. The presence of the additional singleton was associated with slower behavioural responses to the shape target, and a greater neural signal in inferior frontal gyrus. To investigate the involvement of cognitive control functions of the frontal lobes in the capture of attention by the additional singletons, we measured the effect of the additional singleton in a context of either low or high working memory load. Whereas behavioural capture was unaffected by the level of load on working memory, greater activity associated with the presence of the additional singleton was observed in inferior frontal gyrus, but only under high load. This effect was greater in participants who experienced greater capture. We argue that the role of inferior frontal gyrus in selective attention is to detect potential sources of distraction.     

Time constraints and resource sharing in adults' working memory spans

This article presents a new model that accounts for working memory spans in adults, the time-based resource-sharing model. The model assumes that both components (i.e., processing and maintenance) of the main working memory tasks require attention and that memory traces decay as soon as attention is switched away. Because memory retrievals are constrained by a central bottleneck and thus totally capture attention, it was predicted that the maintenance of the items to be recalled depends on both the number of memory retrievals required by the intervening treatment and the time allowed to perform them. This number of retrievals:time ratio determines the cognitive load of the processing component. The authors show in 7 experiments that working memory spans vary as a function of this cognitive load.     

Working memory load moderates late attentional bias in social anxiety

The vigilance–avoidance hypothesis suggests that socially anxious individuals attempt to detect signs that they are being evaluated (vigilance) and subsequently direct attention away from such stimuli (avoidance). Although extensive evidence supports vigilance, data concerning subsequent avoidance is equivocal. Drawing from models of attention, the current study hypothesised that working memory load moderates late attentional bias in social anxiety such that avoidance occurs if working memory load is low, and difficulty disengaging attention occurs if working memory load is high. Forty-one undergraduates (19 socially anxious; 22 non-anxious controls) completed a dot-probe task with emotional (happy and disgust) and neutral facial expressions and a concurrent n-back task. Results supported the hypothesis such that socially anxious subjects demonstrated avoidance of disgust faces when working memory load was absent, but had difficulty disengaging attention during high working memory load. Theoretical implications and directions for future research are discussed.