Suchergebnisse

Objective: The present study was designed to evaluate the team workload questionnaire (TWLQ) in a task that was distinct from the task used to create it. Background: The TWLQ was created from workload ratings generated by members of athletic sports teams. Given that such teams represent only a portion of the diversity of operational teams, we aimed to assess the generalizability of the TWLQ. Method: The present study applied the TWLQ in a collaborative choice task (hiring decision) to determine whether the factor structure reported in the initial publication of the scale would generalize from the execution tasks it was developed from to a disparate team task focused on consensus building. Results: Confirmatory factor analysis indicated that the present data ( N = 144) were a poor fit for the three-factor structure of the TWLQ. Subsequent exploratory factor analysis revealed a much more interrelated model of team workload with no clear division between the three conceptual factors described in the original validation of the TWLQ. Conclusion: The factor structure of the TWLQ did not generalize to the present team-choice task. Application: Given that the duties of operational teams vary, it is critical that future research examine how the conceptual structure of team workload may be altered by task type.

Objective: In the present study, we explored the state versus trait aspects of measures of task and team workload in a disaster simulation. Background: There is often a need to assess workload in both individual and collaborative settings. Researchers in this field often use the NASA Task Load Index (NASA-TLX) as a global measure of workload by aggregating the NASA-TLX's component items. Using this practice, one may overlook the distinction between traits and states. Method: Fifteen dyadic teams (11 inexperienced, 4 experienced) completed five sessions of a tsunami disaster simulator. After every session, individuals completed a modified version of the NASA-TLX that included team workload measures. We then examined the workload items by using a between-subjects and within-subjects perspective. Results: Between-subjects and within-subjects correlations among the items indicated the workload items are more independent within subjects (as states) than between subjects (as traits). Correlations between the workload items and simulation performance were also different at the trait and state levels. Conclusion: Workload may behave differently at trait (between-subjects) and state (within-subjects) levels. Application: Researchers interested in workload measurement as a state should take a within-subjects perspective in their analyses.

Numerous contemporary work teams encompass both virtuality, marked by geographically dispersed members relying on technology for communication, and fluidity, involving the rapid assembly of members with limited prior experience for immediate, time-sensitive tasks. Instances include global virtual teams, military command and control teams, and similar contexts in which rapidly assembled distributed teams are prevalent. However, research on fluid virtual teams remains scarce. In this article, we expound upon the concept of team fluidity, explain how fluid virtual contexts influence team dynamics, and explore the implications for effectively supporting fluid virtual teams.

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.

Objective: The purpose of this article is to present and expand on current theories and measurement techniques for assessing team workload. Background: To date, little research has been conducted on the workload experienced by teams. A validated theory describing team workload, which includes an account of its relation to individual workload, has not been articulated. Method: The authors review several theoretical approaches to team workload. Within the team research literature, attempts to evaluate team workload have typically relied on measures of individual workload. This assumes that such measures retain their validity at the team level of measurement, but empirical research suggests that this method may lack sensitivity to the drivers of team workload. Results: On the basis of these reviews, the authors advance suggestions concerning a comprehensive theory of team workload and methods for assessing it in team settings. The approaches reviewed include subjective, performance, physiological, and strategy shift measures. Theoretical and statistical difficulties associated with aggregating individual-level workload responses to a team-level measure are discussed. Conclusion: Conception and measurement of team workload have not significantly matured alongside developments in individual workload. Application: Team workload remains a complex research area without simple measurement solutions, but as a research domain it remains open for contributions from interested and enterprising researchers.

Objective: The aim of this study was to examine the effects of uncertainty about where in the field of view critical signals for detection appear during a vigilance task (spatial uncertainty) on cerebral blood flow velocity (CBFV) and oculomotor fatigue. Background: Neuroergonomics is a dimension of human factors founded by Raja Parasuraman that studies brain functions underlying performance at work. Neuroergonomic studies have shown that observers in vigilance tasks lose information-processing resources over time and experience oculomotor fatigue as indexed by a temporal decline in CBFV and elevation in eye closure as reflected in the PERCLOS metric. Because spatial uncertainty increases an observer's need for visual scanning relative to a spatial certainty condition, it was anticipated that spatial uncertainty would result in a greater temporal decline in CBFV and increased eye closure in a vigilance session. Method: Observers performed a simulated unmanned aerial vehicle (UAV) control task wherein collision flight paths were the events to be detected. UAV images could appear at random in any one of five locations on the controller's display (spatial uncertainty) or only in a fixed location (spatial certainty). Results: Signal detection was poorer in the spatial-uncertain relative to the certain condition, and predictions regarding CBFV and eye closure were confirmed. Conclusion: Vigilance tasks involving spatial uncertainty are more neurophysiologically taxing than those in which spatial uncertainty is not a factor. Application: The neuroergonomic approach helps in understanding the effects of psychophysical factors in vigilance and to signify when performance aiding is needed.

Despite the importance that human error in the cyber domain has had in recent reports, cyber warfare research to date has largely focused on the effects of cyber attacks on the target computer system. In contrast, there is little empirical work on the role of human operators during cyber breaches. More specifically, there is a need to understand the human-level factors at play when attacks occur. This paper views cyber attacks through the lens of suspicion, a construct that has been used in other contexts, but inadequately defined, in prior research. After defining the construct of suspicion, the authors demonstrate the role that suspicion plays as the conduit between computer operators' normal working behaviors and their ability to alter that behavior to detect and react to cyber attacks. With a focus on the user, rather than the target computer, the authors empirically develop a latent structure for a variety of types of cyber attacks, link that structure to levels of operator suspicion, link suspicion to users' cognitive and emotional states, and develop initial implications for cyber training.

Objective: This simulation study investigated factors influencing sustained performance and fatigue during operation of multiple Unmanned Aerial Systems (UAS). The study tested effects of time-on-task and automation reliability on accuracy in surveillance tasks and dependence on automation. It also investigated the role of trait and state individual difference factors. Background: Warm's resource model of vigilance has been highly influential in human factors, but further tests of its applicability to complex, real-world tasks requiring sustained attention are necessary. Multi-UAS operation differs from standard vigilance paradigms in that the operator must switch attention between multiple subtasks, with support from automation. Method: 131 participants performed surveillance tasks requiring signal discrimination and symbol counting with a multi-UAS simulation configured to impose low cognitive demands, for 2 hr. Automation reliability was manipulated between-groups. Five Factor Model personality traits were measured prior to performance. Subjective states were assessed with the Dundee Stress State Questionnaire. Results: Performance accuracy on the more demanding surveillance task showed a vigilance decrement, especially when automation reliability was low. Dependence on automation on this task declined over time. State but not trait factors predicted performance. High distress was associated with poorer performance in more demanding task conditions. Conclusions: Vigilance decrement may be an operational issue for multi-UAS surveillance missions. Warm's resource theory may require modification to incorporate changes in information processing and task strategy associated with multitasking in low-workload, fatiguing environments. Application: Interface design and operator evaluation for multi-UAS operations should address issues including motivation, stress, and sustaining attention to automation.

Objective In this study, we evaluated the validity of the Sustained Attention to Response Task (SART) as a means for promoting mindlessness in vigilance performance. Background Vigilance tasks typically require observers to respond to critical signals and to withhold responding to neutral events. The SART features the opposite response requirements, which supposedly leads it to promote a mindless, nonthoughtful approach to the vigilance task. To test that notion, we compared the SART to the traditional vigilance format (TVF) in terms of diagnostic accuracy assessed through decision theory measures of positive and negative predictive power (PPP and NPP), perceived mental workload indexed by the Multiple Resource Questionnaire, and oculomotor activity reflected in the Nearest Neighbor Index and fixation dwell times. Method Observers in TVF and SART conditions monitored a video display for collision flight paths in a simulated air traffic control task. Results Diagnostic accuracy in terms of NPP was high in both format conditions. While PPP was poorer in the SART than in the TVF, that result could be accounted for by a loss of motor control rather than a lack of mindfulness. Identical high levels of workload were generated by the TVF and SART tasks, and observers in both conditions showed similar dynamic scanning of the visual scene. Conclusion The data indicate that the SART is not an engine of mindlessness. Application The results challenge the widespread use of the SART to support a model in which mindlessness is considered to be the principal root of detection failures in vigilance.

Objective: We tested the possibility that monitoring a display wherein critical signals for detection were defined by a stereoscopic three-dimensional (3-D) image might be more resistant to the vigilance decrement, and to temporal declines in cerebral blood flow velocity (CBFV), than monitoring a display featuring a customary two-dimensional (2-D) image. Background: Hancock has asserted that vigilance studies typically employ stimuli for detection that do not exemplify those that occur in the natural world. As a result, human performance is suboptimal. From this perspective, tasks that better approximate perception in natural environments should enhance performance efficiency. To test that possibility, we made use of stereopsis, an important means by which observers interact with their everyday surroundings. Method: Observers monitored a circular display in which a vertical line was embedded. Critical signals for detection in a 2-D condition were instances in which the line was rotated clockwise from vertical. In a 3-D condition, critical signals were cases in which the line appeared to move outward toward the observer. Results: The overall level of signal detection and the stability of detection over time were greater when observers monitored for 3-D changes in target depth compared to 2-D changes in target orientation. However, the 3-D display did not retard the temporal decline in CBFV. Conclusion: These results provide the initial demonstration that 3-D displays can enhance performance in vigilance tasks. Application: The use of 3-D displays may be productive in augmenting system reliability when operator vigilance is vital.

Objective We investigated performance, workload, and stress in groups of paired observers who performed a vigilance task in a coactive (independent) manner. Background Previous studies have demonstrated that groups of coactive observers detect more signals in a vigilance task than observers working alone. Therefore, the use of such groups might be effective in enhancing signal detection in operational situations. However, concern over appearing less competent than one's cohort might induce elevated levels of workload and stress in coactive group members and thereby undermine group performance benefits. Accordingly, we performed the initial experiment comparing workload and stress in observers who performed a vigilance task coactively with those of observers who performed the vigilance task alone. Method Observers monitored a video display for collision flight paths in a simulated unmanned aerial vehicle control task. Self-reports of workload and stress were secured via the NASA-Task Load Index and the Dundee Stress State Questionnaire, respectively. Results Groups of coactive observers detected significantly more signals than did single observers. Coacting observers did not differ significantly from those operating by themselves in terms of workload but did in regard to stress; posttask distress was significantly lower for coacting than for single observers. Conclusion Performing a visual vigilance task in a coactive manner with another observer does not elevate workload above that of observers working alone and serves to attenuate the stress associated with vigilance task performance. Application The use of coacting observers could be an effective vehicle for enhancing performance efficiency in operational vigilance.

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.