Sleepy and grumpy go hand in hand for US Navy Sailors

Study Objectives

The study explores how sleep, sleep-related practices, and behaviors, in addition to various demographic and occupational characteristics, are related to overall mood of US Navy sailors when they are underway.

Methods

Longitudinal assessment of US Navy sailors performing their underway duties (N = 873, 79.2% males, median age 25 years). Participants completed standardized questionnaires, wore wrist-worn actigraphs, and completed daily activity logs.

Results

Sailors who reported worse profile of mood states (POMS) total mood disturbance scores had shorter sleep duration, worse sleep quality, and more episodes of split sleep. The group with worse mood also reported more symptoms of excessive daytime sleepiness as well as more symptoms of insomnia. In addition to sleep results, sailors with worse mood also tended to be younger, more likely to use nicotine and tobacco products, and less likely to have an exercise routine when compared to sailors with better POMS scores. Finally, the group with worse POMS scores included more enlisted personnel, tended to work more hours per day, and were more likely to stand watch-especially on rotating watch schedules.

Conclusions

The results found significant associations between the sleep practices and mood of sailors aboard US Navy ships. Numerous other demographic and occupational factors were also strongly associated with mood. This paper is part of the Sleep and Circadian Rhythms: Management of Fatigue in Occupational Settings Collection.

Vigilance Tasks: Unpleasant, Mentally Demanding, and Stressful Even When Time Flies

OBJECTIVE

To determine whether perceived time progression (PTP) moderates participants' negative reactions to vigilance tasks.

BACKGROUND

Vigilance tasks are rated by participants to be unenjoyable and as having high levels of workload and stress. Based on the adage, "You are having fun when time flies," we tested the possibility that accelerating PTP might reduce these negative experiences.

METHOD

Two studies were performed, involving a long 30-min and a short 12-min vigil. We manipulated participants' PTP by creating a mismatch between their expectations about how long they would perform the task and the actual time that they were engaged.

RESULTS

PTP was significantly faster for participants who were led to expect that the vigilance task would last longer than it did relative to those led to expect that task duration would be shorter than it actually was and for controls for whom task duration was equal to the expected duration. However, accelerating PTP had no effect in either experiment on undesirable reactions to the vigilance tasks. Participants uniformly rated both tasks as unenjoyable, as having a high level of workload, and as stressful. Apparently, vigilance isn't fun even when time flies.

CONCLUSION

Our findings greatly underscore the depth to which negative subjective reactions are embedded in the nature of vigilance tasks and therefore that these tasks can have potentially serious costs to participants in terms of health, safety, and productivity.

APPLICATION

These costs must be considered at the operational level.

Short Vigilance Tasks are Hard Work Even If Time Flies

Vigilance research has found that observers find the task to be unpleasant and mentally demanding (Warm, Finomore, Vidulich, & Funke, 2015). However sustained attention plays a critical role in numerous operational settings where human operators must monitor automated human-machine systems in the event of potential problems. The current study extended the work from Dillard and his colleagues (Dillard, Warm, Funke, Vidulich, Nelson, Eggemeier, et al., 2013) who explored if there are other dimensions that might affect the workload associated with performing a vigilance task. The area that they explored was the temporal context of the vigilance task on its effects on task performance and perceived mental workload. Borrowing from a temporal manipulation procedure developed by Sackett and colleagues (Sackett, Meyvis, Nelson, Converse & Sackett, 2010) in which they manipulated perceived time progression (PTP) of the participant while they performed a cognitive task. Sackett et al., (2010) manipulated the PTP by developing their studies to deceive the participant into thinking the task they were performing was longer or shorter than the actual time. Upon completion of the task, participants filled out questionnaires related to the hedonic and temporal evaluation of the task. Participants that were told the task was longer than they actually participated for (time flies conditions) rated times as flying and the task more as more enjoyable.

Helmet Mounted Display Layouts

Head mounted displays (HMDs) are being explored as an alternative means of displaying relevant information to dismounted operators. The goal of this project was to examine different visual display concepts and evaluate participant’s attention allocation to information presented on their HMD. Additionally, their ability to detect potential threats in the environment was also evaluated. This information will help revamp the design of information displays for HMDs. The task in this study required participants to monitor their HMD for critical alerts and respond accordingly while also making shoot/no shoot decisions to threats in their environment. We hypothesized that as information is presented in different layouts on the HMD, it will reduce the participants’ ability to detect real world events. Accuracy of the shoot/no shoot decisions was collected along with accuracy of detection of information on the HMD. We found that shooting performance was not affected between the three HMD layouts however information detected on the HMD was worst when all information was in the center of the HMD. The data from this study will be used to help develop intelligent visual displays used by Battlefield Airmen to accomplish their mission.

Stress training improves performance during a stressful flight

OBJECTIVE

This study investigated whether stress training introduced during the acquisition of simulator-based flight skills enhances pilot performance during subsequent stressful flight operations in an actual aircraft.

BACKGROUND

Despite knowledge that preconditions to aircraft accidents can be strongly influenced by pilot stress, little is known about the effectiveness of stress training and how it transfers to operational flight settings.

METHOD

For this study, 30 participants with no flying experience were assigned at random to a stress-trained treatment group or a control group. Stress training consisted of systematic pairing of skill acquisition in a flight simulator with stress coping mechanisms in the presence of a cold pressor. Control participants received identical flight skill acquisition training but without stress training. Participants then performed a stressful flying task in a Piper Archer aircraft.

RESULTS

Stress-trained research participants flew the aircraft more smoothly, as recorded by aircraft telemetry data, and generally better, as recorded by flight instructor evaluations, than did control participants.

CONCLUSIONS

Introducing stress coping mechanisms during flight training improved performance in a stressful flying task.

APPLICATION

The results of this study indicate that stress training during the acquisition of flight skills may serve to enhance pilot performance in stressful operational flight and, therefore, might mitigate the contribution of pilot stress to aircraft mishaps.