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Objective The purpose was to explore how event segmentation theory (EST) can be used to determine optimal moments for an interruption relying on hierarchical task analysis (HTA) to identify coarse and fine event boundaries. Background Research on the effects of interruptions shows that they can be either disruptive or beneficial, depending on which aspects of an interruption are manipulated. Two important aspects that contribute to these conflicting results concern when and how often interruptions occur. Method Undergraduates completed a trip planning task divided into three subtasks. The within-subjects factor was interruption timing with three levels: none, coarse breakpoints, and fine breakpoints. The between-subjects factor was interruption frequency with two levels: one and three. The dependent measures included resumption lag, number of errors, mental workload, and frustration. Results Participants took longer to resume the primary task and reported higher mental workload when interruptions occurred at fine breakpoints. The effect of interruptions at coarse breakpoints was similar to completing the task without interruption. Interruption frequency had no effect on performance; however, participants spent significantly longer attending to interruptions in the initial task, and within a task, the first and second interruptions were attended to significantly longer than the third interruption. Conclusion The disruptiveness of an interruption is tied to the point within the task hierarchy where it occurs. Application The performance cost associated with interruptions must be considered within the task structure. Interruptions occurring at coarse breakpoints may not be disruptive or have a negative effect on mental workload.

The present study examined the effects of instruction type and boredom proneness (BP) on vigilance performance, workload, and boredom. Subjects completed the Boredom Proneness Scale and were assigned to high and low groups based on their scores. They then monitored a VDT for critical signals. Half the subjects were instructed to detect "critical" flickers (detection emphasis), and the remaining subjects were instructed to relax but to respond to any flickers observed (relaxation emphasis). Subjects also provided pre- and postvigil ratings of workload, stress, and boredom. A performance decrement was observed for all conditions. Low-BP subjects outperformed high-BP subjects and reported less boredom. Thus the results from the present study provide evidence for the long-sought, elusive link between trait boredom and performance in vigilance. In addition, subjects who received relaxation-emphasis instructions reported lower workload, frustration, and stress for the vigil than did those receiving detection-emphasis instructions. These results are discussed in terms of a recent dynamic model of stress as it relates to sustained attention.

The present paper discusses vigilance phenomena in terms of the automatic/control processing theory (Schneider and Shiffrin, 1977) of attention and human information processing. Fisk and Schneider (1981) interpreted vigilance decrements within the automatic/control process framework and discussed system design implications as well as training methods for vigilance environments. Recent results concerning the effects of various stressors on automatic and control processes are presented. Taken as a whole, these results from vigilance, alcohol intoxication, heat stress, and mental workload experiments highlight why, when addressing sustained attention issues, it is critical to understand the mode of information processing (i.e., automatic/control) available to perform the task.

The present study was designed to determine whether a biocybernetic, adaptive system could enhance vigilance performance. Participants were asked to monitor the repetitive presentation of white bars on a computer screen for occasional increases in length. An index of task engagement was derived from participants' electroencephalographic (EEG) activity and was used to change the presentation rate of events among 3 values (6, 20, and 60 events/min). Under a negative feedback contingency, event rates increased if the engagement index decreased and, conversely, decreased if the index increased. Under positive feedback, the opposite contingency existed. Each experimental participant had a yoked control partner who received the same pattern of changes in event rates irrespective of his or her EEG activity. The results showed that better vigilance performance was obtained under negative feedback and that the performance of the yoked participants was similar to that of their experimental partners. These findings suggest that it may be possible to improve monitoring performance on critical activities such as air traffic control and radar and sonar operation through a pattern of event rate changes that do not rely on an operator's overt behavior.

Objective: The present study compared the effectiveness of a virtual reality (VR) simulator for training phlebotomy with that of a more traditional approach using simulated limbs. Background: Phlebotomy, or drawing blood, is one of the most common medical procedures; yet, there are no universal standards for training and assessing performance. The absence of any standards can lead to injuries and inaccurate test results if the procedure is improperly performed. Method: Twenty 3rd-year medical students were trained under one of the two methods and had their performance assessed with a 28-item checklist. Results: The results showed that performance improvements were limited to those who trained with the simulated limbs, and a detailed comparison of the two systems revealed several functional and physical differences that may explain these findings. Conclusion: Participants trained with simulated limbs performed better than those trained with a VR simulator; however, the metrics recorded by the VR system may address some aspects of performance that could eventually prove beneficial. Application: The present study highlights the potential for medical simulators to improve patient safety by enabling trainees to practice procedures on devices instead of patients. Applications of this research include training, performance assessment, and design of simulator systems.

Objective: The goal of the present study was to examine the effects of domain-relevant expertise on running memory and the ability to process handoffs of information. In addition, the role of active or passive processing was examined. Background: Currently, there is little research that addresses how individuals with different levels of expertise process information in running memory when the information is needed to perform a real-world task. Method: Three groups of participants differing in their level of clinical expertise (novice, intermediate, and expert) performed an abstract running memory span task and two tasks resembling real-world activities, a clinical handoff task and an air traffic control (ATC) handoff task. For all tasks, list length and the amount of information to be recalled were manipulated. Results: Regarding processing strategy, all participants used passive processing for the running memory span and ATC tasks. The novices also used passive processing for the clinical task. The experts, however, appeared to use more active processing, and the intermediates fell in between. Conclusion: Overall, the results indicated that individuals with clinical expertise and a developed mental model rely more on active processing of incoming information for the clinical task while individuals with little or no knowledge rely on passive processing. Application: The results have implications about how training should be developed to aid less experienced personnel identify what information should be included in a handoff and what should not.

Objective: Two experiments are presented examining adaptive and adaptable methods for invoking automation. Background: Empirical investigations of adaptive automation have focused on methods used to invoke automation or on automation-related performance implications. However, no research has addressed whether performance benefits associated with brain-based systems exceed those in which users have control over task allocations. Method: Participants performed monitoring and resource management tasks as well as a tracking task that shifted between automatic and manual modes. In the first experiment, participants worked with an adaptive system that used their electroencephalographic signals to switch the tracking task between automatic and manual modes. Participants were also divided between high-and low-reliability conditions for the system-monitoring task as well as high- and low-complacency potential. For the second experiment, participants operated an adaptable system that gave them manual control over task allocations. Results: Results indicated increased situation awareness (SA) of gauge instrument settings for individuals high in complacency potential using the adaptive system. In addition, participants who had control over automation performed more poorly on the resource management task and reported higher levels of workload. A comparison between systems also revealed enhanced SA of gauge instrument settings and decreased workload in the adaptive condition. Conclusion: The present results suggest that brain-based adaptive automation systems may enhance perceptual level SA while reducing mental workload relative to systems requiring user-initiated control. Application: Potential applications include automated systems for which operator monitoring performance and high-workload conditions are of concern.

Posner's theory of pathway inhibition leads to the expectation that stimulus heterogeneity should attenuate the event rate effect and the decrement function in sustained attention. These predictions were tested through a sensory alternation procedure in which stimulation was shuttled between the auditory and visual modalities. Subjects detected slight reductions in the duration of recurrent flashes of light or bursts of white noise at two event rates (5 and 40 events/min) during a 50-min vigil. Consistent with the model, sensory alternation eliminated the event rate effect. It did not, however, moderate the decrement function. Although pathway inhibition can account for the effects of event rate, other factors are probably responsible for the vigilance decrement.

The present study examined the effects of an electroencephalographic- (EEG-) based system for adaptive automation on tracking performance and workload. In addition, event-related potentials (ERPs) to a secondary task were derived to determine whether they would provide an additional degree of workload specificity. Participants were run in an adaptive automation condition, in which the system switched between manual and automatic task modes based on the value of each individual's own EEG engagement index; a yoked control condition; or another control group, in which task mode switches followed a random pattern. Adaptive automation improved performance and resulted in lower levels of workload. Further, the P300 component of the ERP paralleled the sensitivity to task demands of the performance and subjective measures across conditions. These results indicate that it is possible to improve performance with a psychophysiological adaptive automation system and that ERPs may provide an alternative means for distinguishing among levels of cognitive task demand in such systems. Actual or potential applications of this research include improved methods for assessing operator workload and performance.