Cognitive Vigilance Task Research Articles

Wearable EEG-Based Brain-Computer Interface for Stress Monitoring.

Detecting stress is important for improving human health and potential, because moderate levels of stress may motivate people towards better performance at cognitive tasks, while chronic stress exposure causes impaired performance and health risks. We propose a Brain-Computer Interface (BCI) system to detect stress in the context of high-pressure work environments. The BCI system includes an electroencephalogram (EEG) headband with dry electrodes and an electrocardiogram (ECG) chest belt. We collected EEG and ECG data from 40 participants during two stressful cognitive tasks: the Cognitive Vigilance Task (CVT), and the Multi-Modal Integration Task (MMIT) we designed. We also recorded self-reported stress levels using the Dundee Stress State Questionnaire (DSSQ). The DSSQ results indicated that performing the MMIT led to significant increases in stress, while performing the CVT did not. Subsequently, we trained two different models to classify stress from non-stress states, one using EEG features, and the other using heart rate variability (HRV) features extracted from the ECG. Our EEG-based model achieved an overall accuracy of 81.0% for MMIT and 77.2% for CVT. However, our HRV-based model only achieved 62.1% accuracy for CVT and 56.0% for MMIT. We conclude that EEG is an effective predictor of stress in the context of stressful cognitive tasks. Our proposed BCI system shows promise in evaluating mental stress in high-pressure work environments, particularly when utilizing an EEG-based BCI.

Evaluative social presence can improve vigilance performance, but vigilance is still hard work and is stressful.

Vigilance is the ability to sustain attention over a period of time. Previous research has indicated that vigilance tasks are hard work and are stressful for human operators. Performance tends to decline with time on task, and workload and stress typically increase during the course of the vigil. Methods that could be used to overcome the adverse effects of vigilance (i.e., stress, workload, poor performance) includes social facilitation factors, such as performing the task while under observation. Thus, the present experiments examined the effects of multiple forms of social facilitation on vigilance, as well as the stress and workload associated with performing the task. Over 2 experiments, 284 participants completed a 24-min cognitive vigilance task. The results indicated that evaluative-based forms of social presence (i.e., direct monitoring, electronic performance monitoring) were associated with improved detection performance. The mere social presence of a monitor did not significantly influence vigilance performance. The results also demonstrated that social facilitation (in any form) did not impose additional stress or workload on the observers. These novel results have both important practical and theoretical implications for both vigilance performance and social facilitation. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The Effects of Event Rate on a Cognitive Vigilance Task.

The present experiment sought to examine the effects of event rate on a cognitive vigilance task. Vigilance, or the ability to sustain attention, is an integral component of human factors research. Vigilance task difficulty has previously been manipulated through increasing event rate. However, most research in this paradigm has utilized a sensory-based task, whereas little work has focused on these effects in relation to a cognitive-based task. In sum, 84 participants completed a cognitive vigilance task that contained either 24 events per minute (low event rate condition) or 40 events per minute (high event rate condition). Performance was measured through the proportion of hits, false alarms, mean response time, and signal detection analyses (i.e., sensitivity and response bias). Additionally, measures of perceived workload and stress were collected. The results indicated that event rate significantly affected performance, such that participants who completed the low event rate task achieved significantly better performance in terms of correction detections and false alarms. Furthermore, the cognitive vigil utilized in the present study produced performance decrements comparable to traditional sensory vigilance tasks. Event rate affects cognitive vigilance tasks in a similar manner as traditional sensory vigilance tasks, such that a direct relation between performance and level of event rate was established. Cognitive researchers wishing to manipulate task difficulty in their experiments may use event rate presentation as one avenue to achieve this result.

Individual Differences in Achievement Motivation are related to Vigilance Performance

Vigilance, or sustained attention, tasks require observers to attend to information over a prolonged period of time. One individual difference that may be associated with sustained attention performance is achievement motivation, given recent findings in the literature that indicate a relationship between human motivation and attention. Fifty-nine participants were randomly assigned to either a cognitive or sensory vigilance task. The present study indicated that individuals high in achievement motivation detected more critical signals and made fewer false alarms in the cognitive vigilance task. Participants high in achievement motivation in the cognitive condition also demonstrated some of the highest distress and worry scores post-task. Implications for sustained attention tasks are discussed.

Acute effects of caffeine on attention: a comparison of non-consumers and withdrawn consumers

Despite the large number of studies on caffeine and attention, interpretation is often difficult because of methodological weaknesses. In the present study, use of a small battery of tests with four key outcome measures, combined with an appropriate sample size, addresses many of these problems. This methodology was used to examine whether effects of caffeine (a dose of 2 mg/kg) could be explained in terms of reversal of the effects of caffeine withdrawal. This was achieved by examining effects in non-consumers (N = 35), who could not be withdrawn, and also in a group of consumers (N = 35) who had undergone withdrawal for a week and no longer reported symptoms of withdrawal. The results showed no effect of short-term withdrawal on the performance measures, even though subjective reports showed an increase in symptoms after withdrawal. In contrast, the caffeine challenge carried out on Day 8 showed that ingestion of caffeine was associated with faster simple reaction time, fewer long responses, greater detection of targets in the cognitive vigilance task, and faster encoding of new information. These results suggest that it is important to continue to investigate mechanisms underlying these effects of caffeine and to further evaluate the practical implications of such effects.

The Joint Effect of Task Characteristics and Extraversion on The Performance, Workload, and Stress of Signal Detection

The present study tests an extension of the Dynamic Adaptability Theory of Stress (Hancock & Warm, 1989) that incorporated individual differences into the model (Szalma, 2008). The purpose was to investigate how the task characteristics of information rate (event rate) and information structure (number of displays to be monitored) interact with participant personality (extraversion) to affect the performance, workload, and stress associated with a cognitive vigilance task. As expected, extraversion moderated the relationship of task characteristics to performance, global workload, distress, and task engagement, although the relationship of extraversion to the worry dimensions of stress was not significant.

The Joint Effect of Task Characteristics and Neuroticism on the Performance, Workload, and Stress of Signal Detection

The present study tests an extension of the Maximal Adaptability Model of Stress (Hancock & Warm, 1989) that incorporated individual differences into the model (Szalma, 2008). The purpose was to investigate how the task characteristics of information rate (event rate) and information uncertainty (number of displays to be monitored) interact with participant personality (Neuroticism) to affect the performance, workload, and stress associated with a cognitive vigilance task. Results supported claim by Szalma (2008) that the maximal adaptability model should be modified to include person characteristics.

Selection for vigilance assignments: a review and proposed new direction

Vigilance or sustained attention is a critical aspect of operational tasks including air-traffic control, airport security, industrial quality control and inspection, and medical screening and monitoring. Consequently, the selection of personnel for assignments involving vigilance is a key ergonomic concern. As reviewed herein, traditional approaches to personnel selection for tasks requiring vigilance have concentrated on unidimensional measures involving sensory acuity, aptitude, sex, age and personality factors. These approaches have been ineffective. In this article, we suggest an alternative approach in which the selection issue is considered in terms of a theory-driven analysis of different types of vigilance tasks and multidimensional predictors. As an example of that approach, we made use of a resource model of vigilance and measures of cerebral blood flow velocity and subjective state obtained from a short battery of high-workload tasks to successfully predict individual performance on subsequent high-workload sensory and cognitive vigilance tasks.

Task engagement, cerebral blood flow velocity, and diagnostic monitoring for sustained attention.

Loss of vigilance may lead to impaired performance in various applied settings including military operations, transportation, and industrial inspection. Individuals differ considerably in sustained attention, but individual differences in vigilance have proven to be hard to predict. The dependence of vigilance on workload factors is consistent with a resource model of sustained attention. Thus, measures of attentional resource availability may predict the operator's subsequent vigilance performance. In this study, we investigated whether a diagnostic battery of measures of response to a cognitive challenge would predict subsequent sustained attention. Measures that may relate to the mobilization of resources in response to task demands include subjective task engagement and coping, and a novel psychophysiological index, cerebral bloodflow velocity (CBFV). A two-phase design was used. First, participants were exposed to a challenging battery of short tasks that elevated CBFV. Second, participants performed a 36-min vigilance task. Two subgroups of participants performed either a sensory vigilance (N = 187) or a cognitive vigilance (N = 107) task. Measures of task engagement, coping, and CBFV response to the short task battery were compared as predictors of subsequent vigilance. Both subjective and CBFV indices of energization predicted sensory and cognitive vigilance, consistent with resource theory. Structural equation modeling was used to develop a latent factor model of influences on sustained attention. It is concluded that measures of resources, conceptualized as multiple energization processes, are potentially useful for diagnostic monitoring in applied settings. Use of a diagnostic task battery in military and transportation settings is discussed, along with some potential limitations on validity of the diagnostic test.

Abstract at the Least (Reviews of Data-Based Studies of a Whimsical Nature)

Performance technologists consider motivational, environmental, and knowledge deficiencies as they diagnose causes of performance problems. Environmental factors are assumed to include equipment, space, and ergonomic considerations to name a few. Andrew Smith and Miles extend our understanding of the effects on performance of an often overlooked environmental factor - lunch, in their study: “The Effects of Lunch on Cognitive Vigilance Tasks.”

Predicting Cognitive Vigilance Performance from Cerebral Blood Flow Velocity and Task Engagement

Responses to a brief six-min screening battery involving high-workload tracking, verbal working memory, and line discrimination tasks were used to predict subsequent performance on a 36-min cognitive vigilance task. Two predictors of interest were subjective state, as indexed by the Dundee Stress State Questionnaire (DSSQ), and cerebral blood flow velocity (CBFV), measured via transcranial Doppler ultrasonography. The results testify to the importance of assessing task-induced responses for predicting cognitive vigilance performance. They also indicate that forecasting vigilance performance is a complex endeavor requiring a set of multidimensional predictors. Specifically, higher post-battery task engagement scores on the DSSQ in this study and higher levels of CBFV during performance of the screening battery predicted more correct detections on the subsequent vigilance task. These findings are interpreted in the light of the resource-workload model of vigilance, and their practical significance is discussed.

Increased Capacity and Density of Choline Transporters Situated in Synaptic Membranes of the Right Medial Prefrontal Cortex of Attentional Task-Performing Rats

Cholinergic neurons innervating the cortex have been conceptualized as a major component of the attention system of the brain. Because of recent evidence indicating plastic mechanisms regulating choline transporter (CHT)-mediated high-affinity choline uptake, which is the rate-limiting step of acetylcholine synthesis, the present experiment determined the capacity of cholinergic terminals to transport choline, and the proportion of choline transporters localized in the membrane of synaptic terminals, in several brain regions of rats performing a cognitive vigilance task (CVT) and a simple reaction time task (SRTT) and nonperforming (NP) rats. Compared with evidence from NP rats, increased choline transporter capacity [as indicated by maximum transporter velocity (Vmax)] and an increased density of CHTs situated in synaptic plasma membrane, relative to intracellular locations, were observed in the medial prefrontal cortex of the right but not left hemisphere of CVT-performing animals. Furthermore, right medial prefrontal Vmax values of CVT-performing rats correlated positively and left medial Vmax values correlated negatively with the animals' performance in signal trials. Measures of CHT function in the brains of SRTT-performing animals did not differ significantly from those in NP rats. The present data support the hypothesis that an increased capacity of choline transporters in the right medial prefrontal cortex, primarily attributable to increased trafficking of transporters from intracellular compartments to the terminal membrane, represents a cellular mechanism contributing to the mediation of attentional performance.

Evaluating the Utility of a Multi-Layer Visual Display for Air Battle Managers

Air Battle Managers in the United States Air Force must continually monitor a situation display (SD) in addition to performing a number of secondary tasks, which typically occlude part or all of the SD. The purpose of the present investigation was to determine whether the use of a multi-layer display, on which visual information is presented at two different depths, with varying degrees of transparency, would reduce the performance decrement associated with concurrent task performance by eliminating the effects of occlusion. A multi-element tracking task was employed as an analogy to the SD, while a cognitive vigilance task was used to represent the additional visual task. Analyses suggest that transparency effects may play a role in reducing the deficits introduced by occlusion, and may also reduce perceived mental workload. However, despite the findings of previous research, there was no significant effect of depth.

An evaluation of an adaptive automation system using a cognitive vigilance task

The performance of an adaptive automation system was evaluated using a cognitive vigilance task. Participants responded to the presence of a green “K” in an array of two, five, or nine distractor stimuli during a 40-min vigil. The array with the target stimulus was presented once each minute. Participants EEG was recorded and an engagement index (EI=20×beta/(alpha+theta)) was derived. In the negative feedback condition, increases in the EI caused the number of stimuli in the array to decrease while decreases in the EI caused the number of stimuli to increase. For the positive feedback condition, increases in the index caused an increase in the array size (AS) while decreases caused a decrease in the array size. Each experimental participant had a yoked control partner who received the same pattern of changes in array irrespective of their engagement index. A vigilance decrement was seen only for the positive feedback, experimental group.

The Effects of Event Rate and Array Size on a Cognitive Vigilance Task with Associated EEG Rhythms and a Derived Engagement Index

This study investigated the effects of event rate and stimulus array size during a vigilance task on performance and relative EEG power bandwidths (alpha, beta, theta) and a derived EEG engagement index, EI = (beta/(alpha+ theta)). Forty participants, ages 18 to 40, engaged in a visual search task. Participants were required to distinguish a green “K” from an array of stimuli (yellow-green, green, and blue-green factorially combined with K, X, N, R). Each participant searched for the signal in arrays of 2 or 5 stimuli presented at either 12 or 24 events per minute over forty minutes. The design was a 2×2 factorial with four groups. The results indicated poorer performance, higher false alarm rates in the first 10-minute period, and longer response times associated with the larger array size. There were no performance effects for event rate. The EI decreased over periods. Relative alpha and beta power in the midline sites (PZ, CZ, and FZ) were greater for the higher event rate, but were unrelated to array size. These EEG findings are discussed in the context of earlier vigilance studies using EEG measures.

Attention deficits in stroke patients with aphasia

Attentional capacity and sustained attention were investigated in 21 aphasic stroke patients and 21 non-brain-damaged patients. Attentional capacity was assessed using a series of reaction time (RT) tasks. The aphasic patients demonstrated impaired attentional capacity as shown by slower processing speed than the non-brain-damaged group (p < .01) and greater increases in RT with increased processing load (p < .05). Similar patterns were found for both verbal and spatial material. There was no significant relationship between severity of auditory comprehension deficits and attentional capacity. Sustained attention was assessed using a cognitive vigilance task requiring identification of a target letter presented infrequently over 32 minutes. Both the aphasic and the non-brain-damaged group demonstrated a decline in performance with time on task as shown by a steady increase in RTs (p < .0001), but the decline was equivalent across the groups. Thus, the aphasic group did not show a specific deficit in the ability to sustain attention.

Effects of Caffeine and Noise on Mood, Performance and Cardiovascular Functioning

An experiment was conducted to examine the effects of caffeine and noise on mood, mental performance and cardiovascular function. One hundred and six young adults (mean age 21·2 years) took part in the study. Subjects were assigned to one of six groups formed by combining noise/quiet and drink (caffeinated coffee, decaffeinated coffee and fruit juice) conditions. Subjects were familiarized with the tasks and then completed a pre-drink baseline session (conducted in the quiet). Subjects were then given either caffeinated coffee (1·5 mg/kg caffeine), decaffeinated coffee or fruit juice. Following consumption of the drink subjects were re-tested 1 h later, either in noise (75 dBA conglomerate noise, consisting of speech, music and machinery noise) or in quiet. The subjects exposed to noise felt more anxious and showed an increase in blood pressure. Their performance of a cognitive vigilance task also declined over time. There were no significant main effects of caffeine, although simple reaction time was quickest in the caffeinated coffee group. Caffeine did not modify the effects of noise on mood, cardiovascular functioning or sustained attention. Indeed, the only interaction between drinks and noise was found in recall and recognition memory tasks, with the caffeine/noise group having better memory performance than the decaffeinated/noise subjects. Overall, the results show that low levels of caffeine do not increase the behavioural and physiological changes observed in a stressful situation.

Effects of Caffeine and Noise on Mood, Performance and Cardiovascular Functioning

An experiment was conducted to examine the effects of caffeine and noise on mood, mental performance and cardiovascular function. One hundred and six young adults (mean age 21·2 years) took part in the study. Subjects were assigned to one of six groups formed by combining noise/quiet and drink (caffeinated coffee, decaffeinated coffee and fruit juice) conditions. Subjects were familiarized with the tasks and then completed a pre-drink baseline session (conducted in the quiet). Subjects were then given either caffeinated coffee (1·5 mg/kg caffeine), decaffeinated coffee or fruit juice. Following consumption of the drink subjects were re-tested 1 h later, either in noise (75 dBA conglomerate noise, consisting of speech, music and machinery noise) or in quiet. The subjects exposed to noise felt more anxious and showed an increase in blood pressure. Their performance of a cognitive vigilance task also declined over time. There were no significant main effects of caffeine, although simple reaction time was quickest in the caffeinated coffee group. Caffeine did not modify the effects of noise on mood, cardiovascular functioning or sustained attention. Indeed, the only interaction between drinks and noise was found in recall and recognition memory tasks, with the caffeine/noise group having better memory performance than the decaffeinated/noise subjects. Overall, the results show that low levels of caffeine do not increase the behavioural and physiological changes observed in a stressful situation. © 1997 John Wiley & Sons, Ltd.

Effects of fat content, weight, and acceptability of the meal on postlunch changes in mood, performance, and cardiovascular function

This study examined the effects of fat content and meal size on postlunch changes in mood, performance, and cardiovascular function. Forty-six subjects (20 males, 26 females) were tested before and after lunch. Subjects were assigned to one of the following lunch condition: a) low fat (23 g), large meal (860 g); b) low fat (18 g), small meal (600 g); c) high fat (84 g), large meal (840 g); d) high fat (79 g), small meal (530 g). The results showed only small effects of fat composition and meal size, with no cardiovascular effects being observed and no evidence of fat content or the weight of the meal influencing performance of logical reasoning or cognitive vigilance tasks. A few effects of meal type were significant in the mood data, but given the large number of analyses conducted, these could represent chance effects. Results from two selective attention tasks showed that subjects given the high-fat meals responded more slowly but more accurately, which differs from the effects of carbohydrate, protein, and calorie content reported in earlier papers. Weight of the meal influenced the degree of distraction from near and far distractors and also the accuracy of responses to central and peripheral targets. However, both the effects of fat and meal size were modified by task parameters, and further research is required before firm conclusions can be drawn about the functional importance of the influences of nutrient content and meal size on performance. The high-fat and large meals were rated as more acceptable than the low-fat and small meals. These differences in acceptability could not, however, account for the changes in performance observed after consumption of the different meal types.

Effects of sleep deprivation, lunch, and personality on performance, mood, and cardiovascular function

The present study examined the effects of sleep deprivation on performance, mood, and cardiovascular functioning in the late morning and early afternoon. The results showed that the sleep-deprived subjects felt less alert and detected fewer targets in a cognitive vigilance task. Selective impairments due to sleep deprivation were also observed in a logical reasoning task. There was little evidence to suggest that consumption of lunch altered these effects of sleep deprivation. However, individual differences in the effects of sleep deprivation were apparent, with trait anxiety being related to the changes in subjective alertness produced by sleep deprivation, and sleep-deprived extraverts showing greater performance impairments than the sleep-deprived introverts.