Effects of acute simulated microgravity on nocturnal sleep, daytime vigilance, and psychomotor performance: comparison of horizontal and 6 degrees head-down bed rest

This study examined the effect of acute simulated microgravity on nocturnal sleep, daytime vigilance, and psychomotor performance. Each of 7 volunteers were maintained for 3 days of head-down and horizontal bed rest in a counter-balanced design. Assessment measures were polysomnographic recordings on the first night and performance on psychophysiological tasks on the second day involving subjective and objective vigilance, P300, simple reaction time tasks, and dual performance tasks. No clear difference in sleep structure was observed between the head-down and horizontal conditions, except for a slight decrease in Stage 4 for head-down. Both subjective and objective daytime vigilance, P300, and the simple RT task showed no statistical difference, although tracking performance on the dual task showed deterioration at 10:00 for the head-down condition. These results suggest that nocturnal sleep, daytime vigilance, and psychophysiological functions were not disturbed in head-down sleep conditions, although there was a mild deterioration of higher attentional function in the morning.     

One night of sleep deprivation affects reaction time, but not interference or facilitation in a Stroop task

The Stroop color-naming task is one of the most widely studied tasks involving the inhibition of a prepotent response, regarded as an executive function. Several studies have examined performance on versions of the Stroop task under conditions of acute sleep deprivation. Though these studies revealed effects on Stroop performance, the results often do not differentiate between general effects of sleep deprivation on performance and effects specifically on interference in the Stroop task. To examine the effect of prolonged wakefulness on performance on the Stroop task, we studied participants in a 40-h "constant routine" protocol during which they remained awake in constant conditions and performed a Stroop color-naming task every two hours. We found that reaction time was slowest when the color and word did not match (incongruent), fastest when the color and word did match (congruent), and intermediate when participants named the color of the non-word stimulus (neutral). Performance on all three trial types degraded significantly as a function of time awake. Extended wakefulness did not significantly change the additional time needed to respond when the color and word did not match (Stroop interference), nor did it change the amount of facilitation when color and word matched. These results indicate that one night of sleep deprivation influences performance on the Stroop task by an overall increase in response time, but does not appear to impact the underlying processes of interference or facilitation. The results suggest that the degree to which an "executive function" is affected by sleep deprivation may depend on the particular executive function studied and the degree to which it is subserved by the prefrontal cortex.     

Effects of sleep deprivation on Color-Word, Emotional, and Specific Stroop interference and on self-reported anxiety

The aim of this study was principally to assess the impact of sleep deprivation on interference performance in short Stroop tasks (Color-Word, Emotional, and Specific) and on subjective anxiety. Subjective sleepiness and performance on a psychomotor sustained attention task were also investigated to validate our protocol of sleep deprivation. Twelve healthy young subjects were tested at four-hourly intervals through a 36-h period of wakefulness under a constant routine protocol. Analyses of variance for repeated measurements revealed that self-assessment of sleepiness on a visual analogue scale as well as mean reaction time performance on the sustained attention task, both for the first minute and for 10 min of testing, were worsened by sleep deprivation. Analyses revealed an increase in self-reported anxiety scores on the STAI questionnaire but did not reveal any significant effect after sleep deprivation either on indexes of interference or on accuracy in Stroop tasks. However, analyses showed sensitivity to circadian effect on verbal reaction times in the threat-related (Emotional) and sleep-related (Specific) Stroop tasks. We concluded that 36 h of prolonged wakefulness affect self-reported anxiety and Emotional Stroop task resulting in a cognitive slowing. Moreover, total sleep deprivation does not affect interference control in any of the three short Stroop tasks.     

Test anxiety and visual vigilance

Twenty male and 20 female subjects, previously classified as high or low in test anxiety, participated in an experiment on visual vigilance under conditions designed either to enhance or minimize feelings of being tested. Detection rate declined across the 36 min of the task among subjects high in test anxiety who believed that they were being tested and in subjects low in test anxiety who did not. False detection rates revealed no significant differences among conditions. Analysis of sensitivity to signals according to statistical decision theory revealed low sensitivity in both the high-anxiety test and low-anxiety/no-test conditions than in the other two. Analysis of decisional criteria showed that subjects in the high-anxiety test condition were more conservative in setting a criterion than subjects in the other three conditions. No sex differences were found. The results are discussed in terms of an elaboration of Sarason's (1978) model of test anxiety.     

Mental Simulations, Affect, and Subjective Confidence: Timing Is Everything

Three studies demonstrated that mental simulations and affect are related to temporal changes in subjective confidence. In Study 1, students' confidence in their midterm exam performance lessened from the first day of class (3.5 weeks before the exam) to exam day, and confidence correlated negatively with upward simulations (i.e., simulations that are better than reality) and negative affect. In Study 2, manipulated upward simulations produced low confidence and negative mood even when the exam was viewed from a distance; students who were forced to think about upward simulations 1 month prior to the exam felt no more confident than did students on exam day. In Study 3, manipulated negative moods produced low confidence and more upward simulations when students anticipated laboratory tasks, and again distal and proximal confidence did not differ. Discussion centers around reciprocal relations between mental simulations and affect, and a possibly integrative account of previous explanations.     

Cognitive performance during successive sustained physical work episodes

The effects of physical work (30% of \(\dot VO_2 \) max), sleep loss (3-h nap during a 48-h operation), continuous work (CW), and time of day on cognitive performance were assessed (by ANOVA) in this repeated-measures study comparing two groups (exercise/nonexercise) of healthy young men (N=22). Treadmill walking did not accentuate or attenuate sleep loss effects on performance; however, sleep loss alone did degrade visual vigilance and memory for words. Time-of-day fluctuations were found in choice reaction time, logical reasoning, and word memory. Visual vigilance for nonexercising subjects degraded sooner on the 2nd CW day than it did for exercising subjects. A 3-h nap at 0400 h after 1 17-h CW day was not immediately recuperative. These findings indicate that exercise at 30% of \(\dot VO_2 \) max does not compound sleep-loss effects in cognitive performance. Indeed, physical activity during video terminal monitoring may delay any sleep-loss decrement. Variability of many cognitive abilities throughout the day appeared to show a greater effect than the sleep-loss and exercise effects over 2 days.     

The multiple vigilance test

The multiple vigilance test is a 30-min signal detection task designed to assess performance. Sixty target and 180 nontarget stimuli are presented with random interstimulus intervals ranging from 4 to 11 sec. Subjects respond by pressing the spacebar (or microswitch in an alternate version of the program) when they see the masking pattern transformed into the target. This vigilance test is used in conjunction with measures of physiological sleepiness (Multiple Sleep Latency Test) and subjective sleepiness (Stanford Sleepiness Scale). This behavioral information concerning manifest sleepiness provides a more complete picture of a subject’s state of alertness. The assessment of vigilance during long, monotonous, nonstimulating tasks is clinically important in patients with disorders of sleep and arousal.     

The effects of chronic sleep reduction on the performance of cognitive tasks sensitive to sleep deprivation

In four sleep loss experiments we aimed, first, to compare performance during long-term sleep reduction with performance during short-term total sleep deprivation, and second, to measure the effects of both methods of sleep loss on ability to ignore distracting irrelevant stimuli, using a finding embedded figures test (FEFT). Logical reasoning, auditory vigilance and finding embedded figures tasks were shown to be significantly sensitive to one night's sleep deprivation. However, in one sleep reduction study subjects reduced to a mean of 5.2 hours sleep per night for 4 weeks showed no performance deficits on logical reasoning. In a second sleep reduction study subjects reduced to a mean of 4.3 hours sleep per night for 4 nights, and subjects reduced to a mean of 5.3 hours sleep per night for 18 nights, showed no performance deficits on logical reasoning or auditory vigilance, despite their reports of severe increases in subjective sleepiness and reduced concentration. Both these sleep reduction groups, though, did show decrements on the FEFT, which we interpret in terms of dearousal increasing distractibility, which the sleep-reduced subjects could not overcome with effort, as they did with the other tests.     

General knowledge monitoring as a predictor of in‐class exam performance

Background. Current theories of self‐regulated learning predict a positive link between student monitoring accuracy and performance: students who more accurately monitor their knowledge of a particular set of materials are expected to more effectively regulate their subsequent study of those materials, which in turn should lead to higher test performance. Aims. The present study further explored the link between monitoring accuracy and performance by investigating whether monitoring of one set of materials would predict performance on a different set of materials. Sample. The participants were college students (N= 379) enrolled in an educational psychology course. Method. Students’ monitoring accuracy was measured at the start of the semester; the monitoring task involved materials that were not related to class content (i.e., general knowledge vocabulary) and that were related to class content (i.e., terms from educational psychology). Target performance was students’ scores on the final exam. Results. Monitoring accuracy significantly predicted student performance on the final exam, even when the monitoring task and final test were based on materials from different content domains. Also, the class‐related (vs. unrelated) materials in the monitoring task did not improve the predictive validity of monitoring accuracy, suggesting a limited role for domain specificity in the relationship between monitoring skill and performance. Conclusions. This study establishes a critical link between general monitoring accuracy and exam performance within a classroom setting.     

Test anxiety,self-evaluative worry,and sleep disturbance in college students

Abstract

The present research examined the extent to which sleep disturbance is involved in the experience of test anxiety. In Study 1, a sample of 80 subjects completed a trait measure of test anxiety and completed a sleep inventory with reference to the past 30 days. In Study 2, a sample of 188 subjects provided measures of trait and state test anxiety and completed a sleep inventory for the night preceding an actual test. The results of Study 1 and Study 2 confirmed that test anxiety is associated with self-reported sleep disturbance. In addition, the results of Study 2 showed that sleep disturbance is also associated with increased state test anxiety. Finally, it was found in Study 2 that sleep disturbance was not related to actual test performance. However, poorer test performance was associated with increased state and trait test anxiety. It is concluded that certain characteristics associated with test anxiety are stable and may be detected in evaluative and non-evaluative situations. The results are discussed with particular reference to their implications for the test anxiety construct itself as well as treatment strategies for the test-anxious student.     

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.     

Lack of degradation in visuospatial perception of line orientation after one night of sleep loss

Sleep deprivation impairs a variety of cognitive abilities including vigilance, attention, and executive function. Although sleep loss has been shown to impair tasks requiring visual attention and spatial perception, it is not clear whether these deficits are exclusively a function of reduced attention and vigilance or if there are also alterations in visuospatial perception. Visuospatial perception and sustained vigilance performance were therefore examined in 54 healthy volunteers at rested baseline and again after one night of sleep deprivation using the Judgment of Line Orientation Test and a computerized test of psychomotor vigilance. Whereas psychomotor vigilance declined significantly from baseline to sleep-deprived testing, scores on the Judgment of Line Orientation did not change significantly. Results suggest that documented performance deficits associated with sleep loss are unlikely to be the result of dysfunction within systems of the brain responsible for simple visuospatial perception and processing of line angles.     

Functional Equivalence of Sleep Loss and Time on Task Effects in Sustained Attention

Research on sleep loss and vigilance both focus on declines in cognitive performance, but theoretical accounts have developed largely in parallel in these two areas. In addition, computational instantiations of theoretical accounts are rare. The current work uses computational modeling to explore whether the same mechanisms can account for the effects of both sleep loss and time on task on performance. A classic task used in the sleep deprivation literature, the Psychomotor Vigilance Test (PVT), was extended from the typical 10‐min duration to 35 min, to make the task similar in duration to traditional vigilance tasks. A computational cognitive model demonstrated that the effects of time on task in the PVT were equivalent to those observed with sleep loss. Subsequently, the same mechanisms were applied to a more traditional vigilance task—the Mackworth Clock Task—providing a good fit to existing data. This supports the hypothesis that these different types of fatigue may produce functionally equivalent declines in performance.     

The effects of immediate forewarning of test difficulty on test performance

Whereas prior research has demonstrated that warning students of an exam's difficulty well in advance of the exam enhances performance, the current research demonstrated the effect of such forewarning immediately before examination administration. Moments before taking an examination in a laboratory environment, participants were either (a) informed that the examination would be difficult, (b) informed that the examination would be easy, or (c) not given any information about the exam's ostensible difficulty. Participants of low trait anxiety performed better when told the exam would be difficult than when told that the exam would be easy. Conversely, participants of high trait anxiety performed worse when told the exam would be difficult than they did when told the exam would be easy or when provided with no such information. Implications and directions for future research are discussed.     

STRESS AND PERFORMANCE: EFFECTS OF SUBJECTIVE WORK LOAD AND TIME URGENCY1

Subjective work load, time urgency, and other stress/motivation variables were measured for management personnel taking a demanding problem-solving exam at the end of a two-week training course. Comparing measures of precourse ability and final exam performance, the primary findings were that the corrected performance scores had strong negative linear (not inverted-U) relations with both subjective work load and time urgency. General state anxiety and task involvement did not substantially relate to performance. The results are discussed in terms of the nature of this particular task and the predictions of various stress/performance theories. In problem solving or other tasks requiring novel responses, these data suggest that increases in psychological stresses like subjectively high work load and time urgency uniformly impair performance across the whole range of these variables.     

Anxiety sensitivity, body vigilance and fear of pain

The aim of the present study was to investigate the role of anxiety sensitivity (AS) as a factor relevant to pain and pain persistence. Two studies were conducted to examine the relationship between AS, body vigilance and the experience of pain in non-clinical samples. Study 1 investigated the relationship between AS and body vigilance that was operationalized by the detection latency for innocuous electrical stimuli; trait anxiety and neuroticism were also included as covariates. Results indicated that the high AS group (N=69) presented shorter detection latency than the low AS group (N=70); neuroticism and trait anxiety did not have significant effects on detection latency. Using another sample, Study 2 investigated the relationship between AS, body vigilance, pain tolerance, catastrophizing, and self-reported distress and pain during a cold pressor task. Neuroticism, trait anxiety and fear of pain were included as covariates. Results showed significant differences between high- (N=66) and low- (N=69) AS groups in body vigilance, catastrophizing and tolerance. The covariates neuroticism, trait anxiety and fear of pain did not have any significant effects. No significant differences were found in pain and distress ratings. Results from both studies support the importance of AS in body vigilance and the experience of pain. The theoretical, preventive and clinical implications of these findings are discussed.     

Vigilance, personality and strength of the nervous system

Numerous attempts have been made to explain the overall level of performance and the change in performance over time in vigilance tasks in terms of the proposed inverted U relationship between performance and ‘arousal’. The present experiment investigated the effects on vigilance performance of the following variables: introversion, neuroticism, time of day, accessory sensory stimulation, ‘signal frequency’ and time on task. Some measures of subjective state and body temperature were also included. The behavioural measures of overall performance revealed interactions involving neuroticism and time of day, and between neuroticism and frequency. This may reflect the operation of response bias factors, though these may be influenced by ‘arousal’. There were also main effects for several of the factors which may have practical significance. There was a significant effect of time on task on all the behavioural measures but no clearcut effects of personality on the vigilance ‘decrement’. It is argued that the latter may not provide the most satisfactory test of the inverted U model and its relationship to personality. However, interactions between noise and time on task for some of the measures may have practical importance. Measures of subjective state showed a fall in the reported level of ‘arousal’ accompanied by a rise in reported ‘stress’ and ‘anxiety’ with time on task. Body temperature was higher after the task than before.     

Performance on a simple reaction time task while sleep deprived

Divergent results have been reported on the effect of a night's sleep loss on performance of a single monotonous task. The present experiment examined the effect that partial sleep deprivation had on 10 participants' performance on a simple reaction time task requiring low responding for 120 min. compared to performance on the same task when well rested. Participants missed significantly more signals and had slower reaction times when sleep deprived. Reaction times increased with time when participants were both sleep deprived and rested, but the number of misses did not significantly change over time. Reaction time was significantly correlated with subjective ratings of sleepiness and heart rate in both conditions. EEG and heart-rate variability measures did not correlate significantly with reaction time. Misses correlated significantly with subjective ratings and heart rate but only in the rested condition.     

Workload and stress in vigilance: the impact of display format and task type

Signal salience was manipulated using configural and object displays to examine their effects on the performance, workload, and stress of vigilance. Improving performance and reducing the workload and stress of vigilance are crucial concerns. Signal salience improves performance and reduces stress, but to date there have been no salience manipulations using configural displays in a vigilance task. Two task types (individual variable monitoring and midpoint identification) and 3 display formats (bar graph-different baselines, bar graph-common baseline, and a polygon graph display) were examined. Configural displays improved performance in the midpoint identification task but not in the individual variable monitoring task. Workload depended on the form of display features (bar graph vs. polygon). Stress increased across all conditions, but task and display format did not affect stress. The midpoint identification task was associated with more emotion-focused and avoidant coping. Increasing signal salience in a vigilance task using configural displays with emergent features or physical contours can improve performance and reduce the decrement. These displays may not reduce the stress of vigilance or encourage task-focused coping. Therefore, there may be hidden costs to vigilance performance even when highly salient configural displays are used.     

The effects of changing the phase and duration of sleep.

The relative effects of extended sleep, reduced sleep, and shifts of habitual sleep time on subsequent performance and mood were studied. Ten healthy male university students who regularly sleep 9.5-10.5 hr were the subjects. Measurements were obtained from a 45-min auditory vigilance task, a 5-min experimenter-paced addition task and a mood adjective check list 30 min after awakening, at midday, and in the evening following five electroencephalographically recorded nights of sleep. The experimental treatments compromised at 9.5-10.5 hr habitual sleep condition and four conditions in which the regular sleep period was lengthened, reduced, delayed, and advanced by 3hr. Following each 3-hr altered condition of sleep there was an equivalent decline in vigilance performance and in subjective arousal as measured by the mood scales. Together with other recent evidence, the present results support the hypothesis that acute disruption of the 24-hr sleep-wakefulness cycle produces degradations in human performance largely independent of total sleep time.