Event-related cerebral hemodynamics reveal target-specific resource allocation for both “go” and “no-go” response-based vigilance tasks

Transcranial Doppler sonography was used to measure cerebral blood flow velocity (CBFV) in the right and left cerebral hemispheres during the performance of a 50-min visual vigilance session. Observers monitored a simulated flight of unmanned aerial vehicles for cases in which one of the vehicles was flying in an inappropriate direction relative to its cohorts. Two types of vigilance tasks were employed: a traditional task in which observers made button press (“go”) responses to critical signals, and a modification of the traditional task called the Sustained Attention to Response Task (SART) in which “go” responses acknowledged nonsignal events and response withholding (“no-go”) signified signal detection. Signal detections and global CBFV scores declined over time. In addition, fine-grained event-related analyses revealed that the detection of signals was accompanied by an elevation of CBFV that was not present with missed signals. As was the case with the global scores, the magnitude of the transient CBFV increments associated with signal detection also declined over time, and these findings were independent of task type. The results support the view of CBFV as an index of the cognitive evaluation of stimulus significance, and a resource model of vigilance in which the need for continuous attention produces a depletion of information-processing assets that are not replenished as the task progresses. Further, temporal declines in the magnitude of event-related CBFV in response to critical signals only is evidence that the decrement function in vigilance is due to attentional processing and not specific task elements such as the required response format.     

Interactions between endogenous and exogenous attention during vigilance

The ability to remain vigilant over long periods of time is critical for many everyday tasks, but controlled studies of visual sustained attention show that performance declines over time when observers are required to respond to rare stimulus events (targets) occurring in a sequence of standard stimulus events (nontargets). When target discrimination is perceptually difficult, this vigilance decrement manifests as a decline in perceptual sensitivity. We examined whether sudden-onset stimuli could act as exogenous attentional cues to improve sensitivity during a traditional sustained attention task. Sudden-onset cues presented immediately before each stimulus attenuated the sensitivity decrement, but only when stimulus timing (the interstimulus interval [ISI]) was constant. When stimulus timing was variable, exogenous cues increased overall sensitivity but did not prevent performance decline. Finally, independent of the effects of sudden onsets, a constant ISI improved vigilance performance. Our results demonstrate that exogenous attention enhances perceptual sensitivity during vigilance performance, but that this effect is dependent on observers’ being able to predict the timing of stimulus events. Such a result indicates a strong interaction between endogenous and exogenous attention during vigilance. We relate our findings to a resource model of vigilance, as well as to theories of endogenous and exogenous attention over short time periods.     

Positive post‐disaster images: A daydream machine?

This study explores the impact of post‐earthquake images inserted in a vigilance task, in terms of performance, self‐reports of task‐focus, and cerebral activity using functional near‐infrared spectroscopy (fNIRS). Vigilance tasks present a sequence of stimuli in which only a few are pre‐designated critical or target stimuli requiring an overt response from the participant. Seventy‐one residents participated (51 women, 20 men) by taking part in a vigilance task with task‐irrelevant images inserted in the sequence. There were three conditions consisting positive (emotive inducing), negative (emotive inducing), and control (devoid of meaning) images embedded in the vigilance task to assess possible impacts on vigilance performance. The images were obtained through crowdsourcing and represented parts of the city 3–4 years post‐earthquake. Task performance was assessed with signal detection theory metrics of sensitivity A’ and bias β’’. This enables the separation of an individual's ability to accurately discriminate critical signals from non‐critical stimuli (sensitivity) and shifts in their willingness to respond to any stimuli whether critical or not (bias). Individuals viewing the positive images, relating to progress, rebuild, or aesthetic aspects within the city, had a more conservative response bias (they responded less to both rare critical and distractor stimuli) than those in the other conditions. These individuals also reported lower task‐focus, as would be expected. However, contrary to expectations, indicators of cerebral activity (fNIRS) did not differ significantly between the experimental groups. These results, when combined, suggest that mind wandering events may be being generated when exposed to positive post‐earthquake images.     

Brief and rare mental “breaks” keep you focused: Deactivation and reactivation of task goals preempt vigilance decrements

We newly propose that the vigilance decrement occurs because the cognitive control system fails to maintain active the goal of the vigilance task over prolonged periods of time (goal habituation). Further, we hypothesized that momentarily deactivating this goal (via a switch in tasks) would prevent the activation level of the vigilance goal from ever habituating. We asked observers to perform a visual vigilance task while maintaining digits in-memory. When observers retrieved the digits at the end of the vigilance task, their vigilance performance steeply declined over time. However, when observers were asked to sporadically recollect the digits during the vigilance task, the vigilance decrement was averted. Our results present a direct challenge to the pervasive view that vigilance decrements are due to a depletion of attentional resources and provide a tractable mechanism to prevent this insidious phenomenon in everyday life.     

Neuroticism and vigilance revisited: A transcranial doppler investigation

Selecting for vigilance assignments remains an important factor in human performance research. The current study revisits the potential relationship between vigilance performance and trait neuroticism, in light of two possible theories. The first theory suggests that neuroticism impairs vigilance performance by competing for available resources. The second theory, attentional control theory, posits that high neuroticism can result in similar or superior performance levels due to the allocation of compensatory effort. In the present study, Transcranial Doppler Sonography was used to investigate the neurophysiological underpinnings of neuroticism during a 12-min abbreviated vigilance task. Performance results were not modified by level of neuroticism, but high neuroticism was associated with higher initial CBFV levels and a greater CBFV decrement over time. These findings indicate that participants higher in neuroticism recruited additional cognitive resources in order to achieve similar performance, suggesting that there is more of an effect on processing efficiency than effectiveness.     

On the automatic nature of the task-appropriate processing effect in event-based prospective memory

This research tested competing predictions about the cognitive processes underlying the task-appropriate processing effect in prospective memory. Participants had to press a designated key whenever a word from the semantic category of animals or from the structural category of palindromes occurred in an ongoing lexical decision task. The availability of attentional resources was manipulated by varying the effort to the ongoing task in terms of speed or accuracy. In the task-appropriate semantic prospective memory task, performance was robust against the speed versus accuracy instructions. In the task-inappropriate structural prospective memory task, performance declined under speed instructions that detracted attentional resources. Accordingly, a facilitating effect of task-appropriate processing was observed under speed instructions but not accuracy instructions. The results support the notion that the task-appropriate processing effect is due to a larger contribution of automatic cue detection to prospective memory performance under task-appropriate than task-inappropriate conditions.     

Does Absence of Hearing Ability Enhance Visual Vigilance? It Depends on Task Complexity

Successful performance of a vigilance task in a particular modality can be affected by the allocation of attentional resources to other cognitive processes using same or different modalities. The present study investigated whether loss of hearing affects visual vigilance task performance and also if it’s a function of increased task complexity. A sample of 30 adolescents ( 15 with hearing loss and 15 with normal hearing) were selected by matching them in pairs according to their working memory functioning and other relevant organismic variables. A software program measured the performance on vigilance task with varying task complexity levels. Analysis of the obtained data indicates that the effect of hearing impairment on visual vigilance is moderated by task complexity and that is contingent to attentional resources. Here, deprivation in hearing ability negatively affects functioning of visual vigilance significantly only when the task complexity increases. But no significant differences are observed in hearing and hearing impaired adolescents when the task demanded less attentional resources.     

Signal probability effects on high-workload vigilance tasks

Signal probability is an important influence on vigilance. Typically, higher signal probability is associated with higher hit rate, lower response criterion, and lower response:signal ratio. However, signal probability effects on demanding, high-workload vigilance tasks have not been investigated. It is believed that attentional resources become depleted during performance of such tasks, leading to perceptual sensitivity decrements. Forty subjects performed high- (.35) and low- (.10) probability versions of a demanding vigilance task. Results differed in two important respects from those previously obtained with less demanding tasks. First, the decrement in perceptual sensitivity over time was greater for the high-probability task. Second, there were no effects of signal probability on response criterion. Subjective workload was higher for the high-probability task. Implications of the data for resource-depletion and expectancy theories of vigilance are discussed.     

Cutting stress off at the pass: reducing vigilance and responsiveness to social threat by manipulating attention

Personality processes relating to social perception have been shown to play a significant role in the experience of stress. In 5 studies, the authors demonstrate that early stage attentional processes influence the perception of social threat and modify the human stress response. The authors first show that cortisol release in response to a stressful situation correlates with selective attention toward social threat. Second, the authors show in 2 laboratory studies that this attentional pattern, most evident among individuals with low self-esteem, can be modified with a repetitive training task. Next, in a field study, students trained to modify their attentional pattern to reduce vigilance for social threat showed lower self-reported stress related to their final exam. In a final field study with telemarketers, the attentional training task led to increased self-esteem, decreased cortisol and perceived stress responses, higher confidence, and greater work performance. Taken together, these results demonstrate the impact of antecedent-focused strategies on the late-stage consequences of social stress.     

Effects of depression on expectancy in sustained attention

The effects of expectancies generated during a pretest on the subsequent vigilance performance of depressed and nondepressed observers were assessed. Among the nondepressed, those who were exposed to a high signal probability during the pretest detected more signals in the main watch than those exposed to a low pretest probability, regardless of the signal probability in the vigil itself (high or low). This expectancy effect was not evident among the depressed. The vigilance decrement in both subject categories was steeper under conditions of low as compared to high test probability. These results indicate that depressed monitors do not demonstrate a deficit in attentional capacity. It is suggested that the nonperseveration of pretest expectancies among the depressed may stem from a lack of motivation to effortfully process information in the same manner as nondepressed observers.The authors would like to thank Mark Scerbo and Tom Lanzetta for their technical assistance.     

CRT信号显示的刺激率和信号率对警觉作业的影响

本实验系统地考察了在不同刺激率、信号率条件下警觉水平的变化 ,并分析了以往警觉理论的适应条件。实验一采用 5次 /分、1 5次 /分和 30次 /分的刺激率条件 ,发现检测正确率在各条件下随时间的变化是由于 d′下降所致 ,而β值基本不变 ,可以认为警觉随时间下降是由于疲劳所致 ;中等刺激率条件下的 d′最高 ,低刺激率次之 ,高刺激率最差并且高刺激率导致被试唤醒水平降低。实验二在 30次 /分的高刺激率条件下变化信号率 (分别为 3次 /分、6次 /分和 1 2次 /分 ) ,发现信号率变化不会改变 d′,但导致β值的变化 ,可以认为高信噪比导致被试的唤醒水平升高     

The cognitive load of narrative lies

Lying is assumed to increase cognitive load, and it has been shown to slow response times to simple questions. We employed a dual‐task methodology, the detection response task (DRT), to assess cognitive load in telling narrative lies in a live, open‐question interview. The DRT requires participants to press a button in response to a tactile stimulus every 3–5 s while performing a primary task, in this case, recounting either truthful or deceitful narratives. We found weak support for slowing in the time to initiate a narrative response when lying. In contrast, we found strong support for an increase in cognitive load when producing a narrative lie, as measured by both slowed DRT responses and increased response omissions, although this effect decreased with time on task. We advocate dual‐task methodologies such as the DRT for increasing understanding of the assumptions made by theories of deception and for refining lie detection techniques.     

Some methodological issues in assessing attentional biases for threatening faces in anxiety: a replication study using a modified version of the probe detection task.

Various versions of the probe detection task have been developed to assess attentional biases in anxiety and there is debate about their relative merits in terms of reliability and sensitivity to such biases. The present study used a pictorial version of the probe detection task to examine attentional biases for emotional facial expressions. The main aims were (1) to see if our previous finding of greater vigilance for threatening faces in high than low trait anxiety could be replicated [Bradley, B. P., Mogg, K., Falla, S. J., & Hamilton, L. R. (1998). Attentional bias for threatening facial expressions in anxiety: manipulation of stimulus duration. Cognition and Emotion, in press] and (2) to examine whether the same pattern of results and a similar effect size, would be obtained using a 'probe position' task (i.e. where is the probe?), rather than the 'probe classification' task (i.e. what is the type of the probe?) used by Bradley et al. (1998). The probe position task produced similar results to those obtained from the probe classification task, so providing further evidence of an anxiety-related attentional bias for threatening faces. Results also indicated that, for non-clinical participants, the probe position task yielded faster overall RTs, fewer errors and a similar effect size, compared with the probe classification task. Implications for the assessment of attentional biases in non-clinical and clinical samples are discussed.     

Event asynchrony and signal regularity in sustained attention

Subjects monitored the repetitive presentation of a vertically oriented line of light (background events) for occasional increments in the height of the line (critical signals). Signals for detection occurred in either a temporally regular or an irregular manner and were blended within a background of temporally synchronous (regular) or asynchronous (irregular) background events. The vigilance decrement, as reflected by a decline in perceptual sensitivity (A‘), during the watch was eliminated when critical signals appeared regularly within a synchronous event context. By contrast, in the context of event asynchrony, regular signal appearances exacerbated the decrement. The results highlight the importance of event asynchrony as a factor in vigilance performance, and link vigilance to a growing list of psychological processes that are dependent upon contextual rhythmicity. This report was completed while Joel S. Warm was a National Science Foundation senior postdoctoral fellow at the National Institute of Occupational Safety and Health Taft Laboratory, Cincinnati, Ohio.     

Selective attention to threat in the dot probe paradigm: differentiating vigilance and difficulty to disengage

The dot probe task [J Abnorm Psychol 95 (1986) 15] is an often-used paradigm to investigate selective attention to threat. A facilitated response to probes that appear at the same location of threat information in comparison with responses to probes at the opposite location of threat information is interpreted as vigilance for threat. We argue that the findings in the dot probe paradigm are ambiguous evidence for the vigilance to threat hypothesis. Results can also be interpreted as a difficulty to disengage from threat. In this study, 44 undergraduates performed a pictorial version of the probe detection task. Taking into account the reaction times on neutral trials, we found no evidence for a facilitated detection of threatening information. It was found that the dot probe effects are at least partially due to disengagement effects. The implications of these results for the understanding of attentional bias in normal and anxious individuals are discussed.     

When causality shapes the experience of time: Evidence for temporal binding in young children

It is well established that the temporal proximity of two events is a fundamental cue to causality. Recent research with adults has shown that this relation is bidirectional: events that are believed to be causally related are perceived as occurring closer together in time—the so‐called temporal binding effect. Here, we examined the developmental origins of temporal binding. Participants predicted when an event that was either caused by a button press, or preceded by a non‐causal signal, would occur. We demonstrate for the first time that children as young as 4 years are susceptible to temporal binding. Binding occurred both when the button press was executed via intentional action, and when a machine caused it. These results suggest binding is a fundamental, early developing property of perception and grounded in causal knowledge. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=EQC_MqjxZQQ     

When you fail to see what you were told to look for: Inattentional blindness and task instructions

Inattentional blindness studies have shown that an unexpected object may go unnoticed if it does not share the property specified in the task instructions. Our aim was to demonstrate that observers develop an attentional set for a property not specified in the task instructions if it allows easier performance of the primary task. Three experiments were conducted using a dynamic selective-looking paradigm. Stimuli comprised four black squares and four white diamonds, so that shape and colour varied together. Task instructions specified shape but observers developed an attentional set for colour, because we made the black–white discrimination easier than the square–diamond discrimination. None of the observers instructed to count bounces by squares reported an unexpected white square, whereas two-thirds of observers instructed to count bounces by diamonds did report the white square. When attentional set departs from task instructions, you may fail to see what you were told to look for.     

Effects of anxiety on attentional allocation and task performance: An information processing analysis

An information processing signal detection methodology was employed to examine attentional allocation and its correlates in both normal comparison (NC) and generalized anxiety disorder (GAD) participants. In particular, the impact of neutral distractor and negative feedback cues on performance of an attention vigilance task was investigated. Individuals with GAD (N = 15) evidenced impaired performance on an attention vigilance task relative to NC participants (N = 15) when neutral distractor cues were presented. Contrary to prediction, no group differences in performance were detected under conditions in which participants were presented negative feedback cues they were told were relevant to their performance. Instead, GAD participants exhibited improvement during the experimental task such that their performance was equivalent to NC participants. Across trials, the clinically anxious group endorsed significantly higher levels of worry and negative affectivity; however, they failed to respond with concomitant physical arousal (e.g. increased muscle tension). These data are discussed within the context of Eysenck and Calvo's (1992, Cognition and Emotion, 6, 409–434) processing efficiency theory. Additionally, the results of this investigation provide support for Barlow's (1988, Anxiety and its disorders: The nature and treatment of anxiety and panic) conceptualization of anxiety as requiring the interaction of cognitive schema and physiological arousal.     

Task-induced fatigue states and simulated driving performance

States of fatigue are implicated in driver impairment and motor vehicle accidents. This article reports two studies investigating two possible mechanisms for performance impairment: (1) loss of attentional resources; and (2) active regulation of matching effort to task demands. The first hypothesis predicts that fatigue effects will be accentuated by high task demands, but the second hypothesis predicts that fatigue effects will be strongest in "underload" conditions. In two studies, drivers performed a stimulated driving task, in which task demands were manipulated by varying road curvature. In a "fatigue induction" condition, the early part of the drive was occupied by performance of a demanding secondary task concurrently with driving, after which the concurrent task ceased. Post-induction driving performance was compared with a control condition in which drivers were not exposed to the induction. In both studies, the fatigue induction elicited various subjective fatigue and stress symptoms, and also raised reported workload. Fatigue effects on vehicle control and signal detection were assessed during and after the fatigue induction. The fatigue induction increased heading error, reduced steering activity, and, in the second study, reduced perceptual sensitivity on a secondary detection task. These effects were confined to driving on straight rather than on curved road sections, consistent with the effort regulation hypothesis. The second study showed that fatigue effects were moderated by a motivational manipulation. Results are interpreted within a control model, such that task-induced fatigue may reduce awareness of performance impairment, rather than reluctance or inability to mobilize compensatory effort following detection of impairment.     

The role of metacognition in prospective memory: Anticipated task demands influence attention allocation strategies

The present study investigates how individuals distribute their attentional resources between a prospective memory task and an ongoing task. Therefore, metacognitive expectations about the attentional demands of the prospective-memory task were manipulated while the factual demands were held constant. In Experiments 1a and 1b, we found attentional costs from a prospective-memory task with low factual demands to be significantly reduced when information about the low to-be-expected demands were provided, while prospective-memory performance remained largely unaffected. In Experiment 2, attentional monitoring in a more demanding prospective-memory task also varied with information about the to-be-expected demands (high vs. low) and again there were no equivalent changes in prospective-memory performance. These findings suggest that attention–allocation strategies of prospective memory rely on metacognitive expectations about prospective-memory task demands. Furthermore, the results suggest that attentional monitoring is only functional for prospective memory to the extent to which anticipated task demands reflect objective task demands.