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The NASA-TLX is arguably the most widely used self-report measure of workload in the field of Human Factors and Ergonomics. Previous research utilizing factor analysis has indicated it may not actually be a good unitary measure of workload. In the present study, we have modified two of the original six items, Frustration and Performance, to better reflect workload by replacing them with Emotional Demand and Performance Monitoring Demand items. Confirmatory factor analyses indicate the new scale is an improvement but Physical Demand should also be considered for removal; this results in a five-item measure of mental workload, not overall task workload, as physical demands may not be meaningfully combinable with cognitive demands.

Viewing people and other animals elicits social and emotional processes. Similarly, robots are sometimes seen as social agents, but limited emotion-priming research for robots exists. Fifty-nine participants completed three sessions of an emotion recognition task, primed with a dog, robot or random motion (control) video. There was no significant effect from exposure to dog videos (or control) on emotional recognition; however, participants performed significantly worse following robot exposure. A follow-up study of 184 participants) included new videos of all stimuli. Similarly, no significant effects occurred after dog exposure, but robot priming decreased performance. Robot priming appears to worsen emotion recognition, which is interesting. This may be due to motor resonance priming - mimicking observed behavior and actions - or due to pre-existing stereotypes of robots and perceived experimental demands. Further studies should include controlled variations of all videos and live interactions to compare priming effects on emotion recognition.

Visual searches are done frequently and commonly while doing other tasks. Previous research has shown that multitasking inhibits performance of tasks done together, however little has examined visual search and word recall performed together, especially when there are an undisclosed number of targets to be found. The purpose of this study is to examine how multitasking affects visual search and word recall. Participants recalled words shown on a heads-up display while simultaneously searching realistic landscape images for target distortions. The participants also completed these tasks individually. It was found that during multitasking, participants found significantly less targets and remembered significantly less words than when doing those tasks individually. It was also shown that prioritizing tasks led to small improvements in performance for that task. The results of this study could be used to influence design of technology made for individuals searching environments who also need to communicate information.

The sustained attention to response task (SART) has been used for over 20 years to assess participants’ response times and inability to withhold to No-Go stimuli (commission errors). While there is debate in the literature regarding what causes commissions errors in the SART, there is agreement the SART is subject to a speed-accuracy trade-off (SATO). Researchers have demonstrated that performance on the SART can be influenced by directive instructions to participants to prioritize either speed or accuracy during the task. In the present study, we investigated whether real-time performance feedback and whether feedback emphasis (emphasizing speed or accuracy) affected participants’ response times and accuracy. We found performance feedback per se had no impact on performance, but performance emphasis did affect performance, apparently shifting the SATO. This finding provides further evidence that the commission errors in the SART are not indicative of sustained attention or vigilance as those terms are commonly used in the literature, but more likely assess response strategy and motor control (or lack of motor control). These findings have implications for the psychological assessment literature, as well as applied areas where SART findings have been utilized such as shoot/no-shoot decision making.

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.

Minimally invasive approach represents the gold standard for the resection of the left lateral section of the liver. Recently, the American Minimally Invasive Liver Resection (AMILES) registry has become available to track outcomes of laparoscopic and robotic liver resection in the Americas. The aim of the present study is to determine the benchmark performance of MILLS throughout the AMILES database.The AMILES registry was interrogated for cases of minimally invasive left lateral sectionectomies (MILLS). Centers with best practices according to the achievement of textbook outcomes (TOs) were identified and were used to define benchmark performances.Seven institutions from US and Canada entered 1665 minimally invasive liver resections, encompassing 203 MILLS. Overall, 49% of cases of MILLS satisfied contemporarily all textbook outcomes. While all centers obtained TOs with different rates of success, the outcomes of the top-ranking centers were used for benchmarking. Benchmark performance metrics of MILLS across North America are: conversion rate ≤ 3.7%, blood loss ≤ 200 ml, OR time ≤ 199 min, transfusion rate ≤ 4.5%, complication rate ≤ 7.9%, LOS ≤ 4 days.Benchmark performances of MILLS have been defined on a large multi-institutional database in North America. As more institutions join the collaboration and more prospective cases accrue, benchmark for additional procedures and approaches will be defined.

The operational costs of multitasking are more pressing given the increase in wearable technologies (head-up displays; HUDs) that facilitate multitasking. Often multitasking comes with performance costs, where the addition of more tasks impairs the performance of the tasks. The current study explored the extent to which multitasking interference can be characterised in simulated environments, as opposed to risky and harsh environments in real operational contexts. Forty-eight participants completed several trials where they performed a visual search task while navigating a simulated environment. There were three conditions: a standalone memory task, a standalone search task, and both tasks simultaneously. Results revealed significant dual-task interference when comparing the dual-task to each of the single-tasks. Results were corroborated by subjective workload and stress metrics. The results could prove useful for designing systems for individuals who routinely multitask in operational environments. Specifically, by furthering the understanding of their performance capabilities and trade-offs due to multitasking. Practitioner summary: Due to the demands of multitasking in operational environments, quantifying the degree of information lost on each task individually will aid in the understanding of the deficits of multitasking performance. This study shows that deficits in multi-tasking (via a HUD) can be understood in simulated environments to a similar degree as real-world tasks.

Simulated environments have become better able to replicate the real world and can be used for a variety of purposes, such as testing new technology without any of the costs or risks associated with working in the real world. Because of this, it is now possible to gain a better understanding of cognitive demands when working in operational environments, where individuals are often required to multitask. Multitasking often results in performance decrements, where adding more tasks can cause a decrease in performance in each of the individual tasks. However, little research investigated multitasking performance in simulated environments. In the current study we examined how multitasking affects performance in simulated environments. Forty-eight participants performed a dual visual search and word memory task where participants were navigated through a simulated environment while being presented with words. Performance was then compared to single-task performance (visual search and word memory alone). Results showed that participants experienced significant dual-task interference when comparing the dual-tasks to the single-tasks and subjective measures confirmed these findings. These results could provide useful insight for the design of technology in operational environments, but also serve as an evaluation of MRT in simulated environments.

Vigilance, or the ability to sustain attention for extended periods of time, has been of interest to the human factors and ergonomics community for 70 years. During this time, several theories have...

The sustained attention to response task (SART) is a popular measure in the psychology and neuroscience of attention. The underlying psychological cause for errors, in particular errors of commission, in the SART is actively disputed. Some researchers have suggested task-disengagement due to mind-wandering or mindlessness, and others have proposed strategic choices. In this study we explored an alternative perspective based on Signal Detection Theory, in which the high rate of commission errors in the SART reflects simply a shift in response bias (criterion) due to the high prevalence of Go-stimuli. We randomly assigned 406 participants to one of ten Go-stimuli prevalence rates (50%, 64%, 74%, 78%, 82%, 86%, 90%, 94%, 98% and 100%). As Go-stimuli prevalence increased reaction times to both Go and No-Go stimuli decreased, omission errors decreased and commission errors increased. These all were predicted from a hypothesized bias shift, but the findings were not compatible with some alternative theories of SART performance. These findings may have implications for similar tasks.

Research documents that forecasts about the emotional consequences of decisions are prone to error. However, there is relatively little known about affective forecasts regarding engaging in activities (versus about the consequences of decisions or outcomes). Here, we examined affective forecasting in the context of a trail race, hypothesizing that forecasts about engaging in an activity (i.e., running the race) were more accurate than forecasts about completing it (i.e., finishing the race). We also investigated whether forecasting accuracy differed for the valence and arousal dimensions of affect and among different discrete emotions. Results of the within-person study showed that affective forecasts largely were inaccurate in reference to engaging in the activity and completing it. Accuracy varied between valence and arousal as well as among emotions of a given valence.

Objective Expand research on the Sustained Attention to Response Task (SART) to a more applied agricultural target detection/selection task and examine the utility of various performance metrics, including composite measures of speed and accuracy, in a High-Go/Low-No-Go stimuli task. Background Modified SARTs have been utilized to investigate mechanisms, such as failures of response inhibition, occurring in friendly fire and collateral damage incidents. Researchers have demonstrated that composite measures of speed and accuracy are useful for Low Go/High No-Go stimuli tasks, but this has not been demonstrated for High-Go/Low-No-Go tasks, such as the SART. Method Participants performed a modified SART, where they selected (“sprayed”) images of weeds (Go stimuli) that appeared on a computer screen, while withholding to rarer soybean plant images (No-Go stimuli). Results Response time was a function of distance from a central starting point. Participants committed commission errors (sprayed the soybeans) at a significantly higher rate when the stimuli appeared under the cursor centered on the screen for each trial. Participant’s omission errors (failure to spray a weed) increased significantly as a function of distance. The composite measures examined were primarily influenced by response time and omission errors limiting their utility when commission errors are of particular interest. Conclusion Participants are far more accurate in their decision making when required to execute a longer duration motor task in High-Go/Low-No-Go experiments. Application Demonstrates a serious human factors liability of target detection and snap-to-target systems.

Objective A dual-task study was performed to explore the performance effects for swimming, word recall, and the combination of the two tasks performed simultaneously. Background Dual-task interference studies have been performed for a variety of tasks; however, there has not been much dual-task interference research where one of the tasks is a naturalistic physically strenuous task. Swimming is a unique physical task that requires spatial orientation on three dimensional axes, similar to that of flying, but has no risk of falling. Previous studies have been conducted in other activity combinations with word-free recall, such as running and climbing, but swimming has yet to be explored. Method A verbal memory recall task and swimming task were performed in isolated (single-task) and simultaneous conditions. A comparison of effects across these different activities was also explored. Results Swimming and the word-recall task resulted in significant dual-task interference: almost as much as when word recall was paired with another verbal task, but more than running and less than climbing. Conclusion Consistent with other dual-task studies, this study observed dual-task interference between the physical swimming task and the cognitive verbal memory task. Application Future technologies and training for personnel who engage in water rescue or commercial diving, such as underwater welding and fiber optic cable, may be improved by these findings.

Objective The purpose of this investigation was to elucidate the role of button-response complexity to targets in a response inhibition task. Background Response inhibition is the ability to correctly inhibit an overt response to a target. The U.S. military is actively pursuing development of armed, combat robots as a force multiplier, which may present challenges to operators of combat robots in the form of response inhibition errors. Method A total of 15 participants completed two 51-min versions of a modified sustained attention to response task (SART). Participants were outfitted with an electrocardiogram to index heart-rate variability and completed the NASA–Task Load Index (NASA-TLX) to index workload. Results The results demonstrated that the complex SART reduced errors of commission (4%) and slowed response times (874 ms) to correct Go targets relative to the simple SART (14%, 739 ms). The NASA-TLX did not show differences between the modified SARTs; however, heart-rate variability did demonstrate that Soldiers had an increased autonomic stress response to the complex SART. Conclusion Increasing the behavioral response requirement during a response inhibition task can decrease errors of commission; however, it comes at the cost of slower response times to target stimuli. Heart-rate variability may provide better insight into objective workload relative to subjective measures. Application The use of complex behavioral responses may provide a viable option to reduce potential “friendly fire” or collateral damage by Soldiers remotely engaging a target-rich environment.

Consensus guidelines recommend patients with symptomatic cholelithiasis and suspected choledocholithiasis have common bile duct exploration (CBDE) at the time of cholecystectomy to prevent downstream problems. Despite superiority of single-stage cholecystectomy with CBDE, 2-stage precholecystectomy/postcholecystectomy with endoscopic clearance of the duct is commonly practiced. This is related to inadequate training in minimally invasive techniques, lack of technical support for efficient and safe CBDE, and surgeons' inexperience with complex biliary pathologic condition. This article provides a framework for evaluating and treating patients with CBD pathologic condition with an emphasis on technical aspects of CBDE and preoperative planning and preparation.