Visual Vigilance Task Research Articles

Effects of Aircraft Noise on Vigilance Performance and Perceived Workload

This study examined the effects of exposure to intermittent jet aircraft noise played through stereophonic speakers (70dBA or 95dBA maximum intensity) on performance efficiency and perceived workload in a 40-min visual vigilance task. The noise featured a Doppler-like quality in which planes seemed to approach from the monitor's left and recede to the right. Performance in noise, measured in terms of perceptual sensitivity (d***'), was significantly poorer than in a quiet condition. Moreover, in comparison to subjects performing in quiet, those who operated in noise were less able to profit from knowledge of results (KR) regarding performance efficiency. In addition to its negative effects upon signal detectability, noise significantly elevated perceived workload, as indexed by the NASA-TLX. This effect was robust; it was not mitigated by KR, even though KR served generally to reduce the overall level of perceived workload in the study. The consistency of the effects of noise in regard to both performance efficiency and perceived workload challenges a recent conclusion offered by Koelega and Brinkman (1986) that lawful relations are not observable in studies of the effects of noise on vigilant behavior.

The effect of D-amphetamine on visual vigilance performance in the squirrel monkey

Three male squirrel monkeys were tested for their ability to make detections on a visual vigilance task, using a within-subjects repeated measures design. Each animal was tested with four doses of D-amphetamine; 0.0, 0.1, 0.2, and 0.4 mg/kg, under both noise and quiet conditions, damphetamine decreased the frequency of detections as dose was increased. This effect occurred in the quiet but not the noise condition. Detection rate was lower and less consistent in the noise condition than in the quiet condition. The results are considered in terms of (1) a depressing effect of amphetamine on central nervous system arousal, and (2) the disrupting effect of white noise on a visual vigilance task.

Dynamic vs Static Stimuli in Their Effect on Visual Vigilance Performance

This report describes a test of the prediction, made by Teichner in 1974, that on visual vigilance tasks dynamic stimuli result in greater performance decrements than do static stimuli. For correct detections and sensitivity there was only a nonsignificant trend in the predicted direction, but for response latency (RT) the prediction was supported. Positional uncertainty within displays did not affect vigilance performance. Teichner's assumption that ocular demand is responsible for the impairing effect of dynamic stimuli is questioned. Depletion of central capacity rather than an ocular effect may explain deteriorating performance. Just as in studies of visual fatigue, the contributions of central and modality-specific impairing effects are difficult to separate.

Greater left cerebral hemispheric metabolism in bulimia assessed by positron emission tomography

Eight women with bulimia and eight age- and sex-matched normal control subjects were studied with positron emission tomography using [18F]-fluorodeoxyglucose (FDG) as a tracer of brain metabolic rate. Subjects performed a visual vigilance task during FDG uptake. In control subjects, the metabolic rate was higher in the right hemisphere than in the left, but patients with bulimia did not have this normal asymmetry. Lower metabolic rates in the basal ganglia, found in studies of depressed subjects, and higher rates in the basal ganglia, reported in a study of anorexia nervosa, were not found. This is consistent with the suggestion that bulimia is a diagnostic grouping distinct from these disorders.

Steady-State Visually Evoked Potential topography associated with a visual vigilance task

This paper describes data which demonstrate a correlation between the magnitude of the Steady-State Visually Evoked Potential (SSVEP) and visual vigilance. The SSVEP was recorded from 64 scalp sites and elicited by a 13Hz uniform visual flicker presented continuously while subjects undertook a visual vigilance task. Fifteen right-handed males were required to view three times a series of 180 geometrical shapes comprising a sequence of 60 squares, 60 circles and a further 60 squares. Each viewing of the 180 shapes constituted a trial. Trials 1 and 2 were identical while trial 3 differed from the first two in that one of the circles was modified. Subjects were ignorant as to the location of the modified circle and prior to the third trial, were challenged to identify the modified circle. A comparison of trials 2 and 3 indicated that the appearance of the modified circle was associated with an attenuation of the SSVEP in the occipito/parietal region. The same comparison indicated a pronounced SSVEP attenuation in the centro/parietal region during the interval that subjects were anticipating the appearance of the modified circle. These results suggest a distinction between the cortical activation patterns occurring during different phases of a visual vigilance task.

DYNAMIC VS STATIC STIMULI IN THEIR EFFECT ON VISUAL VIGILANCE PERFORMANCE

This report describes a test of the prediction, made by Teichner in 1974, that on visual vigilance tasks dynamic stimuli result in greater performance decrements than do static stimuli. For correct detections and sensitivity there was only a nonsignificant trend in the predicted direction, but for response latency (RT) the prediction was supported. Positional uncertainty within displays did not affect vigilance performance. Teichner's assumption that ocular demand is responsible for the impairing effect of dynamic stimuli is questioned. Depletion of central capacity rather than an ocular effect may explain deteriorating performance. Just as in studies of visual fatigue, the contributions of central and modality-specific impairing effects are difficult to separate.

Effect of attention on frontal distribution of delta activity and cerebral metabolic rate in schizophrenia

15 patients with schizophrenia and nine normal volunteers had 32 channel topographic EEG recorded for spectral analysis during the uptake of 18-F-deoxyglucose (FDG) for position emission tomography (PET). Both patients and controls performed the Continuous Performance Test, a visual vigilance task, during FDG uptake. EEG was also obtained during an initial pre-FDG resting period. Each EEG epoch was individually inspected for eye movement artifacts. Analysis confirmed increased delta activity in the frontal region of patients with schizophrenia in comparison to normal controls, and a significant correlation between increased frontal delta and relative reduction in frontal lobe metabolism among patients with schizophrenia. This finding of increased delta is consistent with PET, blood flow and topographic EEG studies of schizophrenia, suggesting reduced frontal activity.

Maternal smoking during pregnancy affects children's vigilance performance

Aspects of attentional behaviour in 4–7-year-olds, as assessed by auditory and visual vigilance tasks, were related to prenatal exposure to cigarettes. Data on 76–79 children born to healthy, white, predominantly middle-class women were analyzed using multiple regression techniques controlling for potentially confounding variables including postnatal second hand smoke exposure. Cigarette smoking during pregnancy was related to an increased activity level of the children during the tasks and increased errors of comission in the auditory task and, to a lesser degree, in the visual task. After controlling for confounding factors, the relationship between prenatal smoking and errors of omission did not retain significance. The combination of results suggest that the deficits in attention may reflect impulsive responding and increased overall activity.

Cortical glucose metabolic rate correlates of abstract reasoning and attention studied with positron emission tomography

Three groups of young, healthy males underwent positron emission tomography of the head, using 18fluoro-2-deoxyglucose as the uptake tracer. During the uptake, one group ( n = 8) did an abstract reasoning test (Raven's Advanced Progressive Matrices [RAPM]); another ( n = 13) performed a visual vigilance task (Continuous Performance Test [CPT] task); and the other ( n = 9) simply watched flashing visual stimuli (CPT no task). ANOVA revealed that both the RAPM and the CPT groups activated the right hemisphere. A priori and exploratory t-tests indicated some left-hemisphere areas of activation for the RAPM, especially posterior cortex. Performance on the RAPM showed significant negative correlations with cortical metabolic rates. CPT performace showed few significant correlations with cortical metabolic rate. Although this study does not strongly implicate any one brain region in performance of the RAPM or CPT task, the inverse glucose/RAPM performance correlations suggest that some individual differences in cognitive ability may be related to efficiency or density of neutral circuits.

The effect of intermittent noise on vigilance performance.

An experiment was conducted to determine the effect of the level of predictability of intermittent noise on performance on a visual vigilance task. Under a quiet condition and three intermittent noise conditions, subjects (Ss) carried out a 55-min task where they were required to detect a change in the brightness of one element of a visual display. The results indicated that Ss were less sensitive, less accurate, and more prone to response failures during intermittent noise, although responses were faster under noise conditions. Measures of response bias and response certainty were not significantly affected by the presentation of noise. Variation in the level of predictability of the noise affected only the accuracy of response measure during the final quarter of the vigilance task, with the group receiving the least predictable noise performing significantly worse than the other three groups. The results are discussed in relation to theories of noise and performance.

Geophysical variables and behavior: XXXVIII. Effects of ionized air on the performance of a vigilance task.

The effects of positively or negatively ionized air on the performance of a visual vigilance task were investigated. The ion level was 100,000 ions/cm3, +/- 10,000. Also investigated were the effects of task-induced stress and nonstress. 40 male college students were required to press a hand-held switch as soon as they detected a signal on a simulated cathode-ray display. Each subject monitored the display continuously for 3 hr. in a room specially equipped for ion exposure and for control of light and noise. All subjects received continuous identical false feedback about their performance. Half of the subjects (the stress group) were told that they would receive an electric shock when their performance fell below an acceptable level. The false feedback was programmed so subjects in this group believed that they were in danger of receiving a shock, but none were actually administered. Analysis indicated that the percentage of signals detected was higher in the presence of negatively ionized air than in the presence of positively ionized air. Also performance-contingent stress resulted in better performance than nonstress.

Effects of smoking and nicotine on EEG lateralization as a function of personality

The effects of nicotine/smoking on lateralization of the EEG were evaluated in 40 smokers while they responded to a low-stress, visual vigilance task. Smoking a high-nicotine cigarette was associated with a relatively larger increase in right hemisphere EEG arousal in extraverts and Type-A individuals, but with a relatively larger increase in left hemisphere EEG arousal in introverts and Type Bs. These findings suggest that nicotine/smoking may differentially influence the left and right hemispheres and that this interaction may be a function of personality.

Effects of noise on sensitivity of introverts and extraverts to signals in a vigilance task

Forty Ss, previously classified as introverts or extraverts on the basis of scores on the Eysenck Personality Inventory, performed a visual vigilance task while being stimulated with noise at an intensity level of either 65 or 85 dB. Introverts given noise of 65 dB intensity showed an improvement in detection rate across trials, whereas introverts given noise of 85 dB intensity showed a decline in detection rate. Extraverts responded to noise of 65 dB intensity with a slight decrease in detection rate, but showed an improvement in detection over trials when noise of 85 dB intensity was given. When noise of the lower intensity was given, introverts showed greater sensitivity to signals than extraverts. When noise of the higher intensity was given, introverts and extraverts were equal in sensitivity. The results are discussed in terms of a hypothesized relationship between stimulation and arousal, with E-I as a moderator variable.

Effects of noise on signal detection.

Twelve subjects were tested twice in visual vigilance tasks which lasted 40 min. Employing a two-category confidence rating scale they detected increments in light level from displays of five lights. The display was flashed on simultaneously for 0·5 s every 3·5 s. The subjects performed the task on different days under two conditions of continuous white noise: ‘quiet’ (70 dB) and ‘noise’ (l00 dB). Half of the subjects had the noise treatment in the order of quiet-noise and half in the reverse order. No effects of noise either upon the overall performance or upon the vigilance decrement were observed. For the risky criterion results showed mainly that during a run under the two conditions the percentage of correct and false responses decreased, d' remained unchanged and β partly increased as a function of time. For the cautious criterion only β increased during a run under the two conditions. The results were interpreted in terms of arousal theory

Monitoring for one kind of signal in the presence of another: the effects of signal mix on detectability.

Subjects in a 1-h visual vigilance task looked for the occasional presence of a signal inserted into a sequence of single items which consisted of either (a) homogeneous nonsignals or (b) a mixture of nonsignals and signals of another kind. The experiment also manipulated the nature (and discriminability) of the signal to be detected (two types) and its probability of Occurrence (0.05 or 0.15). Results indicate that signal detectability is impaired by the presence of another kind of signal, the impairment tending to be greater the lower the detectability of the signal considered on its own. But, due to a concomitant increase in response bias, the impairment is not reflected in correct detection. The presence of the second signal did not influence the extent of the within-session decline in detection, and the effect of signal probability on detection levels failed to emerge. The practical implications of the findings are discussed.

Sustained visual attention and carbon monoxide: elimination of adaptation effects.

Eighteen subjects performed a 1-h visual vigilance task, once during a control condition (filtered air) and once during an experimental condition (CO). The COHb level was elevated to 5% utilizing a bolus maintenance technique which raised the COHb level rapidly so that there would be no possibility of an adaptation occurring prior to vigilance testing. Physiological measurements included heart rate, blood pressure, and ventilation. Neither vigilance performance nor the physiological variables was statistically affected by the 5% COHb level. Subjects identified a significantly (p> 0.05) higher percentage of signals with the high frequency of signal presentation as compared to the low frequency under both filtered air and the 5% COHb level. Signal detection improved in 12 subjects during minutes 0-15, while 10 subjects showed improvement during minutes 31-45 with an elevated COHb level. The subjective questionnaire indicated that CO significantly (p < 0.01) decreased the subjects' confidence concerning their performance on the vigilance task, as well as causing significant (p < 0.05) irritation of the eyes and throat.

Effect of Prior Knowledge of Signal Probabilities on Vigilance Performance at a Two-Signal Task

Forty-eight subjects each performed for 1 hr on a visual vigilance task with two kinds of signal which differed in conspicuity and also in probability of occurrence. Prior to testing, 24 subjects were explicitly informed of the signal probabilities (0.05 and 0.15); the remaining 24 were not. Results indicate that the prior knowledge tends to eliminate or reduce the extent of the within-session criterion shift and, hence, to stabilize performance over the session. Even with this multiple-signal task, the findings offer support for the hypothesis that, in vigilance, the familiar within-session decline is primarily dependent on an initial disparity between the rate at which signals are presented and the rate with which affirmative responses are made and that subjects adapt their rate of affirmative responding to reduce this disparity. As predicted, the initial disparity tended to be greater for the lower signal probability and to be reduced by the prior information. By the end of the session, the aggregate affirmative response rate closely matched the aggregate signal rate of 0.20 (0.05 + 0.15), but there was some indication that subjects were unable to maintain the objective separation between the two signal rates, so that the differential response rates were more similar than the matching hypothesis predicts.

Vigilance for Two Kinds of Signal with Unequal Probabilities of Occurrence

Seventy-two subjects each performed for one hour on a visual vigilance task incorporating two kinds of signal, A and B, of which A was the easier to recognize. For 36 subjects, signal A occurred with a probability of 0.05, signal B with 0.15; for the remaining subjects these probabilities were reversed. Subjects were instructed either to look for one signal only (A or B), or to look for both. Results indicate that, whereas the additional requirement of looking for a second signal had a differential effect, reducing the discriminability of signal A, but depressing the differential response bias towards signal B, signal probability predictably influenced only the response bias towards signals A and B.

Autonomic differences between extraverts and introverts during vigilance.

ABSTRACTHeart rate and skin resistance indices were obtained from 30 introverts and 30 extraverts as they performed on one of three levels of a visual vigilance task. Introverts detected more signals than did extraverts during the vigilance task. This superiority by introverts was associated with a pattern of heart rate and electrodermal activity which supported H. J. Eysenck's (1967) theoretical formulation.

The Effects of Extraneous Speech on Visual Vigilance Performance of Children

First-grade males performed a 30-min visual vigilance task under 5 conditions of auditory background stimulation. The 5 conditions consisted of (1) continuous conversation, in which subjects listened to a tape of conversation spliced so that there were no intervals of silence lasting longer than 3 sec; (2) continuous reverse, in which subjects heard the continuous conversation tape played in reverse; (3) intermittent conversation, in which subjects heard alternating segments of conversation and silence; (4) intermittent reverse, in which subjects heard alternating segments of reverse conversation and silence; and (5) silence control. Compared with silence or continuous stimulation, intermittent stimulation produced better detection regardless of whether or not it was meaningful. High achievers made more correct detections than low achievers, but only in the second and third time periods. Few subjects made errors of commission.