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

Determining the efficacy of visual inspections at detecting non-biosecurity-compliant goods

Examination of imported commodities by trained inspectors searching for pest organisms is a common practice that phytosanitary regulatory agencies use to mitigate biosecurity risks along trade pathways. To investigate the effects of target size and color on the efficacy of these visual assessments, we affixed square decals to polystyrene models of mandarins. Sample units of 100 model fruit containing up to 10 marked models were examined by inspectors. Six sizes in six shades of brown were tested across two prevalence levels. The experiment consisted of five inspection rounds where 11 inspectors examined 77 sample units within an allocated time. The probability that decals were detected increased with mark size and color contrast. Smaller, low-contrast marks were mainly missed. The prevalence rate did not affect the detectability. Through the experiment, the false-positive rate dropped from 6% to 3%, whereas false-negative rates were constant throughout. Large, dark targets were readily found with a mean recall of >90%, whereas small, pale marks had a mean recall of 9%. Increased experience made inspectors more competent at recognizing decals, reducing the false positive rate. However, constant false-negative rates indicate that experience did not prevent inspectors from overlooking targets they could not perceive.

HD-tDCS mitigates the executive vigilance decrement only under high cognitive demands

Maintaining vigilance is essential for many everyday tasks, but over time, our ability to sustain it inevitably decreases, potentially entailing severe consequences. High-definition transcranial direct current stimulation (HD-tDCS) has proven to be useful for studying and improving vigilance. This study explores if/how cognitive load affects the mitigatory effects of HD-tDCS on the vigilance decrement. Participants (N = 120) completed a modified ANTI-Vea task (single or dual load) while receiving either sham or anodal HD-tDCS over the right posterior parietal cortex (rPPC). This data was compared with data from prior studies (N = 120), where participants completed the standard ANTI-Vea task (triple load task), combined with the same HD-tDCS protocol. Against our hypotheses, both the single and dual load conditions showed a significant executive vigilance (EV) decrement, which was not affected by the application of rPPC HD-tDCS. On the contrary, the most cognitively demanding task (triple task) showed the greatest EV decrement; importantly, it was also with the triple task that a significant mitigatory effect of the HD-tDCS intervention was observed. The present study contributes to a more nuanced understanding of the specific effects of HD-tDCS on the vigilance decrement considering cognitive demands. This can ultimately contribute to reconciling heterogeneous effects observed in past research and fine-tuning its future clinical application.

Performance, Hemodynamics, and Stress in a Two-Day Vigilance Task: Practical and Theoretical Implications

OBJECTIVE

To explore vigilance task performance, cerebral blood flow velocity (CBFV), workload, and stress in a within-subjects, two-session experiment.

BACKGROUND

Vigilance, or sustained attention, tasks are often characterized by a decline in operator performance and CBFV with time on task, and high workload and stress. Though performance is known to improve with practice, past research has not included measures of CBFV, stress, and workload in a within-subjects multi-session design, which may also provide insight into ongoing theoretical debate.

METHOD

Participants performed a vigilance task on two separate occasions. Performance, CBFV, workload, and self-reported stress were measured.

RESULTS

Within each session, results were consistent with the vigilance profile found in prior research. Across sessions, performance improved but the time on task decrement remained. Mean CBFV and workload ratings did not differ between sessions, but participants reported significantly less distress, worry, and engagement after session two compared to one.

CONCLUSION

Though practice may not disrupt the standard vigilance profile, it may serve to improve overall performance and reduce stress. However, repeated exposure may have negative implications for engagement and mind-wandering.

APPLICATION

It is important to better understand the relationship between experience, performance, physiological response, and self-reported stress and workload in vigilance because real-world environments often require operators to do the same task over many occasions. While performance improvement and reduced distress is an encouraging result, the decline in engagement requires further research. Results across sessions fail to provide support to the mind-wandering theory of vigilance.

Effects of task demands on tactile vigilance

A performance decline during sustained monitoring of unpredictable and occasional signals, the vigilance decrement, has been studied mostly in the visual and auditory modalities, but a tactile vigilance decrement also has been observed and has been associated with high perceived workload, declines in sensitivity and task engagement, and increases in distress. The primary aim of the current study was to determine whether task demands affect the vigilance decrement in the tactile modality and whether the effects are similar to those observed in the auditory and visual modalities. Participants completed a 40-min vigil in which they monitored vibrotactile stimuli generated by a tactor and had to discriminate between durations of bursts of vibrations. Task demand was varied by including low and high event rates. Although correct detections decreased over time (vigilance decrement) and sensitivity was greater for the slower event rate, there was not an interaction between period of watch and event rate. There also were no differences in workload and stress between event rates. Results indicate that mean performance in tactile vigilance tasks is negatively impacted by increases in event rate, indicating that a typical source of task demand known to affect visual and auditory vigilance also affects tactile vigilance. Results could be explained by either an underload or overload theory of the vigilance decrement.

Tactile Vigilance Is Stressful and Demanding

OBJECTIVE

The primary aims of the study were to replicate the vigilance decrement in the tactile modality, examine whether a decrease in sensitivity is associated with the decrement, and determine whether tactile vigilance is stressful and demanding.

BACKGROUND

When people monitor occasional and unpredictable signals for sustained durations, they experience a decline in performance known as the vigilance decrement, which has important practical consequences. Prior studies of the vigilance decrement focused primarily on visual vigilance and, to a lesser degree, on auditory vigilance. There are relatively few studies of tactile vigilance.

METHOD

Participants monitored vibrotactile stimuli that were created from a tactor, for 40 min.

RESULTS

Sensitivity declined, self-report ratings of distress increased, and ratings of task engagement decreased, during the vigil, and perceived workload was moderately high.

CONCLUSION

Monitoring tactile signals is demanding and stressful and results in a decrement in signal detection.

APPLICATION

Monitoring tactile signals may result in a decrement in tasks requiring discrimination, such as monitoring lane position with the use of rumble strips; these require discrimination between current road vibration and increased vibration when the car drifts out of its lane and crosses over the strip.

Cognitive load mitigates the executive but not the arousal vigilance decrement

Previous research has shown opposite effects of dual tasking on the vigilance decrement phenomenon. We examined the executive (i.e., detecting infrequent critical signals) and arousal (i.e., sustaining a fast reaction to stimuli without much control on responses) vigilance decrements as a function of task load. Ninety-six participants performed either a single signal-detection (i.e., executive vigilance) task, a single reaction time (i.e., arousal vigilance) task, or a dual vigilance task with the same stimuli and procedure. All participants self-reported their fatigue' state along the session. Exploratory analyses included data from a previous study with a triple task condition. Task load significantly modulated the executive but not the arousal vigilance decrement. Interestingly, the largest increase in mental fatigue was observed in the single executive vigilance task condition. We discuss limitations of classic vigilance theories to account for the vigilance decrement and changes in mental fatigue as a function of task load.

Profiling a Spectrum of Mental Job Demands and their Linkages to Employee Outcomes

Working life is becoming more mentally demanding and intense due to technological acceleration. The present study explored employees' experiences of different mental job demands (MJDs) and their outcomes (job burnout, job performance, and meaning of work). We focused on intra- and inter-individual variations and possible harmful combinations of MJDs, which we explored via latent profile analysis (LPA). To identify harmful combinations of MJDs, we also investigated how the profiles of MJDs related to the outcomes of interest. The study was based on a diverse sample of Finnish employees (n = 4,583). LPA showed that both intra-individual and inter-individual variation characterized MJDs as we identified five latent profiles of MJDs. The most harmful profile, which predicted the most negative outcomes (particularly job burnout), was characterized by employees' scoring high on all MJDs. A profile characterized by low learning demands and moderate level of other MJDs was also a harmful combination in terms of outcomes. In contrast, a profile characterized by moderate level of learning demands and low level of other MJDs did not relate to negative outcomes. Altogether, the findings suggest that different MJDs may co-occur implying risks to employee well-being and performance. However, MJDs simultaneously form a complex spectrum that may differ within and between individuals.

Autopilots in the Operating Room

Automated medical technology is becoming an integral part of routine anesthetic practice. Automated technologies can improve patient safety, but may create new workflows with potentially surprising adverse consequences and cognitive errors that must be addressed before these technologies are adopted into clinical practice. Industries such as aviation and nuclear power have developed techniques to mitigate the unintended consequences of automation, including automation bias, skill loss, and system failures. In order to maximize the benefits of automated technology, clinicians should receive training in human–system interaction including topics such as vigilance, management of system failures, and maintaining manual skills. Medical device manufacturers now evaluate usability of equipment using the principles of human performance and should be encouraged to develop comprehensive training materials that describe possible system failures. Additional research in human–system interaction can improve the ways in which automated medical devices communicate with clinicians. These steps will ensure that medical practitioners can effectively use these new devices while being ready to assume manual control when necessary and prepare us for a future that includes automated health care.