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Objective: This study aimed to assess the plausibility of self-control depletion, or ego-depletion, as the underlying cognitive resource responsible for performance decrements on the sustained attention to response task., Background: Researchers suggested that self-control is a limited cognitive resource used to complete a myriad of processes, including sustained attention. Past research showed that trait self-control affects some sustained attention tasks. However, little research has investigated the effect of self-control as a limited cognitive resource that varies over time (i.e., as a state-dependent variable)., Methods: This experiment investigated the effect of self-control (trait and state) on a sustained motor-inhibition task (e.g., sustained attention to response task; SART). State self-control was manipulated using a between-subjects design-participants in the experimental condition completed a task designed to deplete state self-control prior to performing the SART while the control condition completed a modified version that did not deplete self-control., Results: Trait self-control predicted performance on the SART, but the depletion task (state self-control) had no detectable effect., Conclusion: Given the evidence, it is unlikely that state self-control plays a causal role in performance decrements in the SART, but there appears to be some association between performance on the SART and trait self-control., Application: Trait self-control ought to be considered in future work for personnel selection in real-world tasks that the SART models such as long-distance driving, air traffic control, and TSA operations.

Background: Dismounted military operations require soldiers to complete cognitive tasks whilst undertaking demanding and repeated physical taskings., Objective: To assess the effects of repeated fast load carriage bouts on cognitive performance, perceptual responses, and psychophysiological markers., Methods: Twelve civilian males (age, 28 ± 8 y; stature, 186 ± 6 cm; body mass 84.3 ± 11.1 kg; V̇O 2max , 51.5 ± 6.4 mL·kg -1 ·min -1 ) completed three ∼65-min bouts of a Fast Load Carriage Protocol (FLCP), each interspersed with a 65-min recovery period, carrying a representative combat load of 25 kg. During each FLCP, cognitive function was assessed using a Shoot/Don't-Shoot Task (SDST) and a Military-Specific Auditory N-Back Task (MSANT), along with subjective ratings. Additional psychophysiological markers (heart rate variability, salivary cortisol, and dehydroepiandrosterone-sulfate concentrations) were also measured., Results: A main effect of bout on MSANT combined score metric ( p < .001, Kendall's W = 69.084) and for time on the accuracy-speed trade-off parameter of the SDST ( p = .025, Ѡ 2 = .024) was evident. These likely changes in cognitive performance were coupled with subjective data indicating that participants perceived that they increased their mental effort to maintain cognitive performance (bout: p < .001, Ѡ 2 = .045; time: p < .001, Ѡ 2 = .232). Changes in HRV and salivary markers were also evident, likely tracking increased stress., Conclusion: Despite the increase in physiological and psychological stress, cognitive performance was largely maintained; purportedly a result of increased mental effort., Application: Given the likely increase in dual-task interference in the field environment compared with the laboratory, military commanders should seek approaches to manage cognitive load where possible, to maintain soldier performance.

Objective: This study aimed to explore the relationship between system interface elements' design features and interaction performance in simulated vehicle vibration environments., Background: Touch screens have been widely used in vehicle information systems, but few studies have focused on the decline of touchscreen interaction performance and task load increase when driving on unpaved roads., Method: The interaction performance (reaction time and task accuracy rate) with vibration frequencies below 3 Hz (1.5, 2.0, and 2.5 Hz) and different interface design elements was investigated employing a touch screen computer and E-prime software., Results: The results indicate that vehicle vibration (below 3 Hz) can significantly reduce interaction performance with a vehicle information system interface., Conclusion: An appropriate increase in the physical size of the interface design features (visual stimulus materials and touch buttons) can help to mitigate this negative effect of vibration., Application: The results and findings of this study can be utilized for the design of information system interfaces as it relates to the vibration scenario of unpaved roads.

Objective: This study uses a detection task to measure changes in driver vigilance when operating four different partially automated systems., Background: Research show temporal declines in detection task performance during manual and fully automated driving, but the accuracy of using this approach for measuring changes in driver vigilance during on-road partially automated driving is yet unproven., Method: Participants drove four different vehicles (Tesla Model 3, Cadillac CT6, Volvo XC90, and Nissan Rogue) equipped with level-2 systems in manual and partially automated modes. Response times to a detection task were recorded over eight consecutive time periods., Results: Bayesian analysis revealed a main effect of time period and an interaction between mode and time period. A main effect of vehicle and a time period x vehicle interaction were also found., Conclusion: Results indicated that the reduction in detection task performance over time was worse during partially automated driving. Vehicle-specific analysis also revealed that detection task performance changed across vehicles, with slowest response time found for the Volvo., Application: The greater decline in detection performance found in automated mode suggests that operating level-2 systems incurred in a greater vigilance decrement, a phenomenon that is of interest for Human Factors practitioners and regulators. We also argue that the observed vehicle-related differences are attributable to the unique design of their in-vehicle interfaces.

Background: In Physical Human-Robot Interaction (pHRI), the need to learn the robot's motor-control dynamics is associated with increased cognitive load. Eye-tracking metrics can help understand the dynamics of fluctuating mental workload over the course of learning., Objective: The aim of this study was to test eye-tracking measures' sensitivity and reliability to variations in task difficulty, as well as their performance-prediction capability, in physical human-robot collaboration tasks involving an industrial robot for object comanipulation., Methods: Participants (9M, 9F) learned to coperform a virtual pick-and-place task with a bimanual robot over multiple trials. Joint stiffness of the robot was manipulated to increase motor-coordination demands. The psychometric properties of eye-tracking measures and their ability to predict performance was investigated., Results: Stationary Gaze Entropy and pupil diameter were the most reliable and sensitive measures of workload associated with changes in task difficulty and learning. Increased task difficulty was more likely to result in a robot-monitoring strategy. Eye-tracking measures were able to predict the occurrence of success or failure in each trial with 70% sensitivity and 71% accuracy., Conclusion: The sensitivity and reliability of eye-tracking measures was acceptable, although values were lower than those observed in cognitive domains. Measures of gaze behaviors indicative of visual monitoring strategies were most sensitive to task difficulty manipulations, and should be explored further for the pHRI domain where motor-control and internal-model formation will likely be strong contributors to workload., Application: Future collaborative robots can adapt to human cognitive state and skill-level measured using eye-tracking measures of workload and visual attention.

Objective: To evaluate neck muscle coactivation across different levels of mental workload during simulated flight tasks., Background: Neck pain (NP) is highly prevalent among military aviators. Given the complex nature within the flight environment, mental workload may be a risk factor for NP. This may induce higher levels of neck muscle coactivity, which over time may accelerate fatigue, increase neck discomfort, and affect flight task performance., Method: Three counterbalanced mental workload conditions represented by simulated flight tasks modulated by interstimulus frequency and complexity were investigated using the Modifiable Multitasking Environment (ModME). The primary measure was a neck coactivation index to describe the neuromuscular effort of the neck muscles as a system. Additional measures included perceived workload (NASA TLX), subjective discomfort, and task performance. Participants ( n = 60; 30M, 30F) performed three test conditions over 1 hr each while seated in a simulated seating environment., Results: Neck coactivation indices (CoA) and subjective neck discomfort corresponded with increasing level of mental workload. Average CoAs for low, medium, and high workloads were: .0278(SD = .0232), .0286(SD = .0231), and .0295(SD = .0228), respectively. NASA TLX mental, temporal, effort, and overall scores also increased with the level of mental workload assigned. For ModME task performance, the overall performance score, monitoring accuracy, and resource management accuracy decreased while reaction times increased with the increasing level of mental workload. Communication accuracy was lowest with the low mental workload but had higher reaction times relative to increasing workload., Conclusion: Mental workload affects neck muscle coactivation during combinations of simulated flight tasks within a simulated helicopter seating environment., Application: The results of this study provide insights into the physical response to mental workload. With increasing multisensory modalities within the work environment, these insights may assist the consideration of physical effects from cognitive factors.

Objective: This study developed a fixation-related electroencephalography band power (FRBP) approach for situation awareness (SA) assessment in automated driving., Background: Maintaining good SA in Level 3 automated vehicles is crucial to drivers' takeover performance when the automated system fails. A multimodal fusion approach that enables the analysis of the visual behavioral and cognitive processes of SA can facilitate real-time assessment of SA in future driver state monitoring systems., Method: Thirty participants performed three simulated automated driving tasks. After each task, the Situation Awareness Global Assessment Technique (SAGAT) was deployed to capture their SA about key elements that could affect their takeover task performance. Participants eye movements and brain activities were recorded. Data on their brain activity after each eye fixation on the key elements were extracted and labeled according to the correctness of the SAGAT. Mixed-effects models were used to identify brain regions that were indicative of SA, and machine learning models for SA assessment were developed based on the identified brain regions., Results: Participants' alpha and theta oscillation at frontal and temporal areas are indicative of SA. In addition, the FRBP technique can be used to predict drivers' SA with an accuracy of 88% using a neural network model., Conclusion: The FRBP technique, which incorporates eye movements and brain activities, can provide more comprehensive evaluation of SA. Findings highlight the potential of utilizing FRBP to monitor drivers' SA in real-time., Application: The proposed framework can be expanded and applied to driver state monitoring systems to measure human SA in real-world driving.

Objective: This on-road study employed behavioral and neurophysiological measurement techniques to assess the influence of six weeks of practice driving a Level 2 partially automated vehicle on driver workload and engagement., Background: Level 2 partial automation requires a driver to maintain supervisory control of the vehicle to detect "edge cases" that the automation is not equipped to handle. There is mixed evidence regarding whether drivers can do so effectively. There is also an open question regarding how practice and familiarity with automation influence driver cognitive states over time., Method: Behavioral and neurophysiological measures of driver workload and visual engagement were recorded from 30 participants at two testing sessions-with a six-week familiarization period in-between. At both testing sessions, participants drove a vehicle with partial automation engaged (Level 2) and not engaged (Level 0) on two interstate highways while reaction times to the detection response task (DRT) and neurophysiological (EEG) metrics of frontal theta and parietal alpha were recorded., Results: DRT results demonstrated that partially automated driving placed more cognitive load on drivers than manual driving and six weeks of practice decreased driver workload-though only when the driving environment was relatively simple. EEG metrics of frontal theta and parietal alpha showed null effects of partial automation., Conclusion: Driver workload was influenced by level of automation, specific highway characteristics, and by practice over time, but only on a behavioral level and not on a neural level., Application: These findings expand our understanding of the influence of practice on driver cognitive states under Level 2 partial automation.

Objective: Using eye tracking technology, this study sought to determine if differences in hazard statement (HS) compliance based on design elements are attributable to attention maintenance (AM)., Background: Recent empirical work has demonstrated counter-intuitive findings for HS designs embedded in procedures. Specifically, prevalent HS designs in procedures were associated with lower compliance., Method: The current study utilized eye tracking technology to determine whether participants are attending to HSs differently based on the inclusion or absence of visually distinct HS design elements typically used for consumer products. We used two different designs that previously yielded the largest gap in HS compliance. In a fully-crossed design, 33 participants completed four rounds of tasks using four procedures with embedded HSs. To assess AM, eye tracking was used to measure gaze and fixation duration., Results: The results indicated there are differences in AM between the two designs. The HSs that included elements traditionally considered effective in the consumer products literature elicited lower fixation duration times, and were associated with lower compliance. However, AM did not mediate the design effect on compliance., Conclusions: The study results suggest the design of HSs are impacting individuals as early as the AM stage of the C-HIP model. The absence of HS design-AM-compliance mediation suggests other C-HIP elements more directly explain the HS design-compliance effects., Application: These results provide more evidence that the communication of Health, Environment, and Safety information in procedures may need to be different from those on consumer products, suggesting design efficacy may be task dependent.

Objectives: This study aimed to investigate drivers' disengagement from nondriving related tasks (NDRT) during scheduled takeovers and to evaluate its impact on takeover performance., Background: During scheduled takeovers, drivers typically have sufficient time to prepare. However, inadequate disengagement from NDRTs can introduce safety risks., Method: Participants experienced scheduled takeovers using a driving simulator, undergoing two conditions, with and without an NDRT. We assessed their takeover performance and monitored their NDRT disengagement from visual, cognitive, and physical perspectives., Results: The study examined three NDRT disengagement timings (DTs): DT1 (disengaged before the takeover request), DT2 (disengaged after the request but before taking over), and DT3 (not disengaged). The impact of NDRT on takeover performance varied depending on DTs. Specifically, DT1 demonstrated no adverse effects; DT2 impaired takeover time, while DT3 impaired both takeover time and quality. Additionally, participants who displayed DT1 exhibited longer eye-off-NDRT duration and a higher eye-off-NDRT count during the prewarning stage compared to those with DT2 and DT3., Conclusion: Drivers can benefit from earlier disengagement from NDRTs, demonstrating resilience to the adverse effects of NDRTs on takeover performance. The disengagement of cognition is often delayed compared to that of eyes and hands, potentially leading to DT3. Moreover, visual disengagement from NDRTs during the prewarning stage could distinguish DT1 from the other two., Application: Our study emphasizes considering NDRT disengagement in designing systems for scheduled takeovers. Measures should be taken to promote early disengagement, facilitate cognitive disengagement, and employ visual disengagement during the prewarning period as predictive indicators of DTs.

Objective: The study aimed to enhance transparency in autonomous systems by automatically generating and visualizing confidence and explanations and assessing their impacts on performance, trust, preference, and eye-tracking behaviors in human-automation interaction., Background: System transparency is vital to maintaining appropriate levels of trust and mission success. Previous studies presented mixed results regarding the impact of displaying likelihood information and explanations, and often relied on hand-created information, limiting scalability and failing to address real-world dynamics., Method: We conducted a dual-task experiment involving 42 university students who operated a simulated surveillance testbed with assistance from intelligent detectors. The study used a 2 (confidence visualization: yes vs. no) × 3 (visual explanations: none, bounding boxes, bounding boxes and keypoints) mixed design. Task performance, human trust, preference for intelligent detectors, and eye-tracking behaviors were evaluated., Results: Visual explanations using bounding boxes and keypoints improved detection task performance when confidence was not displayed. Meanwhile, visual explanations enhanced trust and preference for the intelligent detector, regardless of the explanation type. Confidence visualization did not influence human trust in and preference for the intelligent detector. Moreover, both visual information slowed saccade velocities., Conclusion: The study demonstrated that visual explanations could improve performance, trust, and preference in human-automation interaction without confidence visualization partially by changing the search strategies. However, excessive information might cause adverse effects., Application: These findings provide guidance for the design of transparent automation, emphasizing the importance of context-appropriate and user-centered explanations to foster effective human-machine collaboration., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: To determine whether (i) low back loads and/or (ii) kinematic coordination patterns differed across theoretical expert, contextual expert and novice groups when completing both generic and occupation-specific lifts., Background: Experience has been proposed as a factor that could reduce biomechanical exposures in lifting, but the literature reports mixed effects. The inconsistent relationship between experience and exposures may be partially attributable to the broad classification of experience and experimental lifting protocols not replicating the environment where experience was gained., Methods: Purposive sampling was used to recruit 72 participants including theoretical experts (formal training on lifting mechanics), contextual experts (paramedics), and novices. Participants performed 10 barbell and crate (generic) lifts, as well as backboard and stretcher (occupation-specific) lifts while whole-body kinematics and ground reaction forces were collected. Peak low back compression and anteroposterior shear loads normalized to body mass, as well as kinematic coordination patterns, were calculated as dependent variables., Results: No significant differences in low back loads were observed across expertise groups. However, significant differences were seen in kinematic coordination patterns across expertise groups in occupation-specific lifts, but not in generic lifts., Conclusion: Increasing expertise is unlikely to minimize low back loads in lifting. However, contextual expertise did influence lifting kinematics, but only when performing occupationally specific lifts., Application: Contextual expertise may help lifters adopt lifting kinematics that enhance the tolerance of their musculoskeletal system to withstand applied loads, but does not seem to reduce the applied low back loads relative to noncontextual expert groups.

Objective: The primary purpose was to determine how trust changes over time when automation reliability increases or decreases. A secondary purpose was to determine how task-specific self-confidence is associated with trust and reliability level., Background: Both overtrust and undertrust can be detrimental to system performance; therefore, the temporal dynamics of trust with changing reliability level need to be explored., Method: Two experiments used a dominant-color identification task, where automation provided a recommendation to users, with the reliability of the recommendation changing over 300 trials. In Experiment 1, two groups of participants interacted with the system: one group started with a 50% reliable system which increased to 100%, while the other used a system that decreased from 100% to 50%. Experiment 2 included a group where automation reliability increased from 70% to 100%., Results: Trust was initially high in the decreasing group and then declined as reliability level decreased; however, trust also declined in the 50% increasing reliability group. Furthermore, when user self-confidence increased, automation reliability had a greater influence on trust. In Experiment 2, the 70% increasing reliability group showed increased trust in the system., Conclusion: Trust does not always track the reliability of automated systems; in particular, it is difficult for trust to recover once the user has interacted with a low reliability system., Applications: This study provides initial evidence into the dynamics of trust for automation that gets better over time suggesting that users should only start interacting with automation when it is sufficiently reliable., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: This article tackles the issue of correct data interpretation when using stimulus detection tasks for determining the operator's workload., Background: Stimulus detection tasks are a relative simple and inexpensive means of measuring the operator's state. While stimulus detection tasks may be better geared to measure conditions of high workload, adopting this approach for the assessment of low workload may be more problematic., Method: This mini-review details the use of common stimulus detection tasks and their contributions to the Human Factors practice. It also borrows from the conceptual framework of the inverted-U shape model to discuss the issue of data interpretation., Results: The evidence being discussed here highlights a clear limitation of stimulus detection task paradigms., Conclusion: There is an inherent risk in using a unidimensional tool like stimulus detection tasks as the primary source of information for determining the operator's psychophysiological state., Application: Two recommendations are put forward to Human Factors researchers and practitioners dealing with the interpretation conundrum of dealing with stimulus detection tasks., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: This study investigated the effects of different approach directions, movement speeds, and trajectories of a co-robot's end-effector on workers' mental stress during handover tasks., Background: Human-robot collaboration (HRC) is gaining attention in industry and academia. Understanding robot-related factors causing mental stress is crucial for designing collaborative tasks that minimize workers' stress., Methods: Mental stress in HRC tasks was measured subjectively through self-reports and objectively through galvanic skin response (GSR) and electromyography (EMG). Robot-related factors including approach direction, movement speed, and trajectory were analyzed., Results: Movement speed and approach direction had significant effects on subjective ratings, EMG, and GSR. High-speed and approaching from one side consistently resulted in higher fear, lower comfort, and predictability, as well as increased EMG and GSR signals, indicating higher mental stress. Movement trajectory affected GSR, with the sudden stop condition eliciting a stronger response compared to the constrained trajectory. Interaction effects between speed and approach direction were observed for "surprise" and "predictability" subjective ratings. At high speed, approach direction did not significantly differ, but at low speeds, approaching from the side was found to be more surprising and unpredictable compared to approaching from the front., Conclusion: The mental stress of workers during HRC is lower when the robot's end effector (1) approaches a worker within the worker's field of view, (2) approaches at a lower speed, or (3) follows a constrained trajectory., Application: The outcome of this study can serve as a guide to design HRC tasks with a low level of workers' mental stress., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Nicole Lindenblatt acts as a consultant and scientific advisor for Medical Microinstruments.

Objective: This study investigated the effects of nondriving-related task (NDRT) touchscreen location and NDRT difficulty level on the driver task performance, eye gaze behavior, and workload during SAE Level 3 conditionally automated driving. Two driver tasks were considered: a visuomanual NDRT and a take-over task., Background: Touchscreens are expected to play important roles inside automated vehicles. However, few studies have investigated the driver-touchscreen interaction during automated driving., Method: A driving simulator experiment was conducted. The experimental task consisted of two successive subtasks: an NDRT followed by a take-over task. NDRT touchscreen location (Upper Left, Upper Right, and Lower Right) and NDRT difficulty level (Easy and Hard) were the independent variables. A set of driver task performance, eye gaze behavior, and perceived workload measures were employed for each subtask as the dependent variables., Results: NDRT touchscreen location significantly affected both the NDRT and the take-over task performance. Lower Right was superior to Upper Right in the NDRT performance but was inferior in the take-over task performance. NDRT touchscreen location affected the perceived physical workload of the NDRT. NDRT difficulty level affected the perceived workload of the take-over task., Conclusion: The research findings enhance our understanding of how NDRT touchscreen location and NDRT difficulty level impact the driver task performance during conditionally automated driving, and, further provide useful design implications and knowledge., Application: The study results would inform the NDRT touchscreen interface design and the NDRT design for conditionally automated vehicles., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: To evaluate the effectiveness of passive back-support exosuit on postural control and cognitive performance during a fatigue-inducing posture maintenance task., Background: Wearable support systems (exoskeletons/exosuits) reduce physical demands but may also influence postural control and cognitive performance by reducing muscular fatigue., Method: Eighteen participants visited on two different days to test an exosuit system and performed dual-task cognitive assessments based on human information processing (information acquisition, information integration, and action implementation) while maintaining a 35° trunk flexion posture for 16 minutes. Center-of-pressure (CoP), cognitive performance, and perceived workload were recorded, while erector spinae muscle activity was captured to quantify muscle fatigue., Results: The exosuit was effective in reducing erector spinae muscle fatigue during the static posture maintenance task (61% less in Δmedian frequency: -9.5 Hz (EXO-Off) versus -3.7 Hz (EXO-On)). The fatigue-inducing task increased CoP velocity as a function of time (29% greater: 9.3 mm/sec (pre) versus 12.0 mm/sec (post)), and exosuit use decreased CoP velocity (23% less: 12.1 mm/sec (EXO-Off) versus 9.4 mm/sec (EXO-On)). The exosuit was also effective at mitigating cognitive degradation, as evidenced by a higher hit-to-signal ratio (8% greater: 81.3 (EXO-Off) versus 87.9 (EXO-On)) in the information integration task and reducing perceived workload in all stages of human information processing., Conclusion: Exosuit provided benefits of postural control and information integration processing during a 16-min static posture maintenance task., Application: Torso exoskeletons/suits can have positive implications for occupations with concurrent physical and cognitive demands.

Objective: To examine the effect of concurrent physical and cognitive demands as well as age on indicators of muscle fatigue at the wrist., Background: There are few studies examining risk indicators for musculoskeletal disorders associated with work-related physical and cognitive demands that often occur simultaneously in the workplace., Methods: Twenty-four gender-balanced older and 24 gender-balanced younger (mean age 60 and 23 years) participants performed four 30 min dual tasks. Tasks differed by the muscular load level during force tracking: 5% and 10% of maximum voluntary contraction force (MVC) and concurrent cognitive demands on the working memory: easy and difficult. Muscle fatigue was assessed by MVC decline and changes in surface electromyography (increased root mean square: RMS, decreased median frequency: MF) at the extensor digitorum (ED) and extensor carpi ulnaris (EU)., Results: A decline in MVC was found in all participants when tracking was performed at 10% MVC (mean ± SD: 137.9 ± 49.2 - 123.0 ± 45.3 N). Irrespective of age, muscular, or cognitive load, RMS increased (ED 12.3 ± 6.5 - 14.1 ± 7.0% MVE, EU 15.4 ± 7.6 - 16.9 ± 8.6% MVE) and MF decreased (ED 85.4 ± 13.6 - 83.2 ± 12.8 Hz, EU 107.2 ± 17.1 - 104.3 ± 16.7 Hz) in both muscles. However, changes in MF of EU tended to be more pronounced in the older group at higher cognitive and lower muscular load, without reaching statistical significance., Conclusion: Maximum voluntary contraction indicated no interaction between muscle fatigue, cognitive load, or age. However, the tendencies toward altered muscle activity due to an increase in cognitive load and older age suggest muscular adaptations while maintaining tracking performance during the onset of fatigue signs in the sEMG signal., Application: If the tendencies in muscle activity are confirmed by further studies, ergonomic assessments in industrial workplaces should consider cognitive load and age when describing the risk of musculoskeletal disorders.

Objective: This study examines low-, medium-, and high-performing Human-Autonomy Teams' (HATs') communication strategies during various technological failures that impact routine communication strategies to adapt to the task environment., Background: Teams must adapt their communication strategies during dynamic tasks, where more successful teams make more substantial adaptations. Adaptations in communication strategies may explain how successful HATs overcome technological failures. Further, technological failures of variable severity may alter communication strategies of HATs at different performance levels in their attempts to overcome each failure., Method: HATs in a Remotely Piloted Aircraft System-Synthetic Task Environment (RPAS-STE), involving three team members, were tasked with photographing targets. Each triad had two randomly assigned participants in navigator and photographer roles, teaming with an experimenter who simulated an AI pilot in a Wizard of Oz paradigm. Teams encountered two different technological failures, automation and autonomy, where autonomy failures were more challenging to overcome., Results: High-performing HATs calibrated their communication strategy to the complexity of the different failures better than medium- and low-performing teams. Further, HATs adjusted their communication strategies over time. Finally, only the most severe failures required teams to increase the efficiency of their communication., Conclusion: HAT effectiveness under degraded conditions depends on the type of communication strategies enacted by the team. Previous findings from studies of all-human teams apply here; however, novel results suggest information requests are particularly important to HAT success during failures., Application: Understanding the communication strategies of HATs under degraded conditions can inform training protocols to help HATs overcome failures.

Objective: This study examined the impact of monitoring instructions when using an automated driving system (ADS) and road obstructions on post take-over performance in near-miss scenarios., Background: Past research indicates partial ADS reduces the driver's situation awareness and degrades post take-over performance. Connected vehicle technology may alert drivers to impending hazards in time to safely avoid near-miss events., Method: Forty-eight licensed drivers using ADS were randomly assigned to either the active driving or passive driving condition. Participants navigated eight scenarios with or without a visual obstruction in a distributed driving simulator. The experimenter drove the other simulated vehicle to manually cause near-miss events. Participants' mean longitudinal velocity, standard deviation of longitudinal velocity, and mean longitudinal acceleration were measured., Results: Participants in passive ADS group showed greater, and more variable, deceleration rates than those in the active ADS group. Despite a reliable audiovisual warning, participants failed to slow down in the red-light running scenario when the conflict vehicle was occluded. Participant's trust in the automated driving system did not vary between the beginning and end of the experiment., Conclusion: Drivers interacting with ADS in a passive manner may continue to show increased and more variable deceleration rates in near-miss scenarios even with reliable connected vehicle technology. Future research may focus on interactive effects of automated and connected driving technologies on drivers' ability to anticipate and safely navigate near-miss scenarios., Application: Designers of automated and connected vehicle technologies may consider different timing and types of cues to inform the drivers of imminent hazard in high-risk scenarios for near-miss events.

Background: Human performers often recruit environment-based assistance to acquire or process information, such as relying on a smartphone app, a search engine, or a conversational agent. To make informed choices between several of such extended cognitive strategies, performers need to monitor the performance of these options., Objective: In the present study, we investigated whether participants monitor an extended cognitive strategy's performance-here, speed-more closely during initial as compared to later encounters., Methods: In three experiments, 737 participants were asked to first observe speed differences between two competing cognitive strategies-here, two competing algorithms that can obtain answers to trivia questions-and eventually choose between both strategies based on the observations., Results: Participants were sensitive to subtle speed differences and selected strategies accordingly. Most remarkably, even when participants performed identically with both strategies across all encounters, the strategy with superior speed in the initial encounters was preferred. Worded differently, participants exhibited a technology-use primacy effect. Contrarily, evidence for a recency effect was weak at best., Conclusion: These results suggest that great care is required when performers are first acquainted with novel ways to acquire or process information. Superior initial performance has the potential to desensitize the performer for inferior later performance and thus prohibit optimal choice., Application: Awareness of primacy enables users and designers of extended cognitive strategies to actively remediate suboptimal behavior originating in early monitoring episodes.

Objective: We investigated the extent to which a voluntary-use range and bearing line (RBL) tool improves return-to-manual performance when supervising high-degree conflict detection automation in simulated air traffic control., Background: High-degree automation typically benefits routine performance and reduces workload, but can degrade return-to-manual performance if automation fails. We reasoned that providing a voluntary checking tool (RBL) would support automation failure detection, but also that automation induced complacency could extend to nonoptimal use of such tools., Method: Participants were assigned to one of three conditions, where conflict detection was either performed: manually, with RBLs available to use (Manual + RBL), automatically with RBLs (Auto + RBL), or automatically without RBLs (Auto). Voluntary-use RBLs allowed participants to reliably check aircraft conflict status. Automation failed once., Results: RBLs improved automation failure detection - with participants intervening faster and making fewer false alarms when provided RBLs compared to not (Auto + RBL vs Auto). However, a cost of high-degree automation remained, with participants slower to intervene to the automation failure than to an identical manual conflict event (Auto + RBL vs Manual + RBL). There was no difference in RBL engagement time between Auto + RBL and Manual + RBL conditions, suggesting participants noticed the conflict event at the same time., Conclusions: The cost of automation may have arisen from participants' reconciling which information to trust: the automation (which indicated no conflict and had been perfectly reliable prior to failing) or the RBL (which indicated a conflict)., Applications: Providing a mechanism for checking the validity of high-degree automation may facilitate human supervision of automation.

Objective: This study investigated the effect of auditory working memory task on situation awareness (SA) and eye-movement patterns in complex dynamic environments., Background: Many human errors in aviation are caused by a lack of SA, and distraction from auditory secondary tasks is a serious threat to SA. However, it remains unclear how auditory working memory tasks affect SA and eye-movement patterns., Method: Participants (n = 28) were randomly allocated to two groups and received different periods of visual search training (short versus long). They subsequently completed a situation awareness measurement task in three auditory secondary task conditions (without secondary task, auditory calculation task, and auditory 2-back task). Eye-movement data were collected during the situation awareness measurement task., Results: The auditory 2-back task significantly reduced overall SA, Level 1 SA, dwell times, and total percentage of fixation time on task-related areas of interests in the SA measurement task. Overall SA and Level 3 SA were not reduced by the auditory 2-back task in individuals in the longer visual search training time condition., Conclusion: Auditory working memory load impairs SA in the perception and projection stage; however, greater experience can overcome impairment of SA in the projection stage., Application: This study provided possible approaches to preventing loss of SA: (1) improving crew members' communication skills to ensure the accurate and clear transmission of information, reducing the difficulty of processing information, and (2) providing targeted cognitive training tailored to each pilot's level of experience.

Objective: We investigated secondary-task-based countermeasures to the vigilance decrement during a simulated partially automated driving (PAD) task, with the goal of understanding the underlying mechanism of the vigilance decrement and maintaining driver vigilance in PAD., Background: Partial driving automation requires a human driver to monitor the roadway, but humans are notoriously bad at monitoring tasks over long periods of time, demonstrating the vigilance decrement in such tasks. The overload explanations of the vigilance decrement predict the decrement to be worse with added secondary tasks due to increased task demands and depleted attentional resources, whereas the underload explanations predict the vigilance decrement to be alleviated with secondary tasks due to increased task engagement., Method: Participants watched a driving video simulating PAD and were required to identify hazardous vehicles throughout the 45-min drive. A total of 117 participants were assigned to three different vigilance-intervention conditions including a driving-related secondary task (DR) condition, a non-driving-related secondary task (NDR) condition, and a control condition with no secondary tasks., Results: Overall, the vigilance decrement was shown over time, reflected in increased response times, reduced hazard detection rates, reduced response sensitivity, shifted response criterion, and subjective reports on task-induced stress. Compared to the DR and the control conditions, the NDR displayed a mitigated vigilance decrement., Conclusion: This study provided convergent evidence for both resource depletion and disengagement as sources of the vigilance decrement., Application: The practical implication is that infrequent and intermittent breaks using a non-driving related task may help alleviate the vigilance decrement in PAD systems., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: This study explored the impact of in-vehicle messages relative to roadside messages to alert drivers to events within a simulated work zone, in order to determine if these messages can improve driving performance within the work zone., Background: Safety risks in work zones are usually mitigated by design standards and clear signage to communicate work zone information to drivers. Due to distraction and other driving task demands, these signs are not always noticed by motorists, nor are they always followed when they are noticed., Method: The driving simulation tested drivers in two different types of work zones, shoulder work, and lane closure. Participants drove through these work zones three times, each with different messaging interfaces to communicate hazardous events to the driver. The interfaces included a roadside, portable changeable message sign, a smartphone presenting only auditory messages, and a smartphone presenting audio-visual messages., Results: There was significantly better driving performance on key metrics including lane deviation for the in-vehicle message conditions relative to the roadside signs. Furthermore, drivers directed visual attention toward the roadway for the in-vehicle message conditions relative to the roadside sign condition., Conclusion: The results indicate that in-vehicle messaging could provide benefits to primary task performance in driving if the message content is appropriately designed., Application: The findings provide support for a design framework to support in-vehicle communication to drivers approaching work zones and other environments to safely alert them to hazards.

Objective: This study aimed to examine operator state variables (workload, fatigue, and trust in automation) that may predict return-to-manual (RTM) performance when automation fails in simulated air traffic control., Background: Prior research has largely focused on triggering adaptive automation based on reactive indicators of performance degradation or operator strain. A more direct and effective approach may be to proactively engage/disengage automation based on predicted operator RTM performance (conflict detection accuracy and response time), which requires analyses of within-person effects., Method: Participants accepted and handed-off aircraft from their sector and were assisted by imperfect conflict detection/resolution automation. To avoid aircraft conflicts, participants were required to intervene when automation failed to detect a conflict. Participants periodically rated their workload, fatigue and trust in automation., Results: For participants with the same or higher average trust than the sample average, an increase in their trust (relative to their own average) slowed their subsequent RTM response time. For participants with lower average fatigue than the sample average, an increase in their fatigue (relative to own average) improved their subsequent RTM response time. There was no effect of workload on RTM performance., Conclusions: RTM performance degraded as trust in automation increased relative to participants' own average, but only for individuals with average or high levels of trust., Applications: Study outcomes indicate a potential for future adaptive automation systems to detect vulnerable operator states in order to predict subsequent RTM performance decrements.

Objective: Discuss the human factors relevance of attention control (AC), a domain-general ability to regulate information processing functions in the service of goal-directed behavior., Background: Working memory (WM) measures appear as predictors in various applied psychology studies. However, measures of WM reflect a mixture of memory storage and controlled attention making it difficult to interpret the meaning of significant WM-task relations for human factors. In light of new research, complex task performance may be better predicted or explained with new measures of attention control rather than WM., Method: We briefly review the topic of individual differences in abilities in Human Factors. Next, we focus on WM, how it is measured, and what can be inferred from significant WM-task relations., Results: The theoretical underpinnings of attention control as a high-level factor that affects complex thought and behavior make it useful in human factors, which often study performance in complex and dynamic task environments. To facilitate research on attention control in applied settings, we discuss a validated measure of attention control that predicts more variance in complex task performance than WM. In contrast to existing measures of WM or AC, our measures of attention control only require 3 minutes each (10 minutes total) and may be less culture-bound making them suitable for use in applied settings., Conclusion: Explaining or predicting task performance relations with attention control rather than WM may have dramatically different implications for designing more specific, equitable task interfaces, or training., Application: A highly efficient ability predictor can help researchers and practitioners better understand task requirements for human factors interventions or performance prediction.

Objective: To examine the effect of interruption value type (utilitarian, hedonic) and source (external, internal) in different phases of an interruption process., Background: Prior studies on interruption mostly focused on the cognitive outcomes of utilitarian interruptions. Hedonic interruptions are common in life; however, they are not sufficiently explored through research. Hedonic value is closely associated with emotional experiences, and, in turn, influences behaviors. Moreover, the way the effect of values is moderated by interruptions initiated by intrinsic motives is worth exploring., Method: A 2 × 2 mixed design experiment was conducted with 48 participants who were asked to respond to instant messages during the writing task. The interruption value was induced by work or non-work tasks. The interruption source was manipulated by providing an alert. Functional near-infrared spectroscopy, behavioral data, and subjective measurements were collected and analyzed., Results: Hedonic interruptions increased emotional valence, while utilitarian interruptions decreased it. These effects were strengthened by internal interruptions. The effect of interruption value type on work exhaustion was also moderated by the source. Interruption value type and source influenced the attention allocation before an interruption occurred. Hedonic interruptions led to longer resumption lags, whereas utilitarian interruptions required longer interruption durations. Internal interruptions led to improved performance in the resumed task., Conclusion: Interruption source modulate the effect of interruption value type, especially on emotional experience and attention allocation before an interruption occurs., Application: Self-initiated hedonic interruptions have emotional benefits, while alerts for utilitarian interruptions will improve attention on the main task before interruptions.

Objective: This study developed and evaluated a mental workload-based adaptive automation (MWL-AA) that monitors surgeon cognitive load and assist during cognitively demanding tasks and assists surgeons in robotic-assisted surgery (RAS)., Background: The introduction of RAS makes operators overwhelmed. The need for precise, continuous assessment of human mental workload (MWL) states is important to identify when the interventions should be delivered to moderate operators' MWL., Method: The MWL-AA presented in this study was a semi-autonomous suction tool. The first experiment recruited ten participants to perform surgical tasks under different MWL levels. The physiological responses were captured and used to develop a real-time multi-sensing model for MWL detection. The second experiment evaluated the effectiveness of the MWL-AA, where nine brand-new surgical trainees performed the surgical task with and without the MWL-AA. Mixed effect models were used to compare task performance, objective- and subjective-measured MWL., Results: The proposed system predicted high MWL hemorrhage conditions with an accuracy of 77.9%. For the MWL-AA evaluation, the surgeons' gaze behaviors and brain activities suggested lower perceived MWL with MWL-AA than without. This was further supported by lower self-reported MWL and better task performance in the task condition with MWL-AA., Conclusion: A MWL-AA systems can reduce surgeons' workload and improve performance in a high-stress hemorrhaging scenario. Findings highlight the potential of utilizing MWL-AA to enhance the collaboration between the autonomous system and surgeons. Developing a robust and personalized MWL-AA is the first step that can be used do develop additional use cases in future studies., Application: The proposed framework can be expanded and applied to more complex environments to improve human-robot collaboration.

Objective: Two studies serve as a manipulation check of a new experimental multi-task paradigm that can be applied to human-automation research (Virtual Reality Testbed for Risk and Automation Studies; ViRTRAS), in which a subjectively experienceable risk can be manipulated as part of a virtual reality environment., Background: Risk has been postulated as an important contextual factor affecting human-automation interaction. However, experimental evidence is scarce due to the difficulty operationalizing risk in an ethical way. In the new paradigm, risk is varied by the altitude at which participants carry out the task, including the possibility of virtually falling in case of a mistake., Method: Key components of the paradigm were used to investigate participants' risk perception in a low (0.5 m) and high altitude (70 m) using subjective self-reports and objective behavioral measures., Results: In the high-altitude condition risk perception was significantly higher with medium to large effect sizes. In addition, results of the behavioral measures reveal that participants habituated with length of exposure. However, this habituation seems to occur similarly in both altitude conditions., Conclusion: The manipulation checks were successful. The new paradigm is a promising tool for automation research. It incorporates the contextual factor of risk and creates a situation which is more comparable to what real-life operators experience. Additionally, it meets the same requirements of other multi-task environments in human-automation research., Application: The new paradigm provides the basis to vary the contextual factor of risk in human-automation research, which has previously been either neglected or operationalized in an arguably inferior way.

Objective: The present study was designed to evaluate human performance and workload associated with an auditory vigilance task that required spatial discrimination of auditory stimuli., Background: Spatial auditory displays have been increasingly developed and implemented into settings that require vigilance toward auditory spatial discrimination and localization (e.g., collision avoidance warnings). Research has yet to determine whether a vigilance decrement could impede performance in such applications., Method: Participants completed a 40-minute auditory vigilance task in either a spatial discrimination condition or a temporal discrimination condition. In the spatial discrimination condition, participants differentiated sounds based on differences in spatial location. In the temporal discrimination condition, participants differentiated sounds based on differences in stimulus duration., Results: Correct detections and false alarms declined during the vigilance task, and each did so at a similar rate in both conditions. The overall level of correct detections did not differ significantly between conditions, but false alarms occurred more frequently within the spatial discrimination condition than in the temporal discrimination condition. NASA-TLX ratings and pupil diameter measurements indicated no differences in workload., Conclusion: Results indicated that tasks requiring auditory spatial discrimination can induce a vigilance decrement; and they may result in inferior vigilance performance, compared to tasks requiring discrimination of auditory duration., Application: Vigilance decrements may impede performance and safety in settings that depend on sustained attention to spatial auditory displays. Display designers should also be aware that auditory displays that require users to discriminate differences in spatial location may result in poorer discrimination performance than non-spatial displays.

Objective: This study used electroencephalography to explore the behavioral and electrophysiological effects of task interruption on performance., Background: Task interruption is known to harm work performance, especially on working memory-related tasks. However, most studies pay little attention to cognitive processes by exploring brain activity and ignore the cumulative effect of sequential interruptions., Method: Thirty-four healthy participants performed a spatial 2-back in three conditions: (1) interruptions with simple math questions, (2) suspensions with prolonged fixation cross, and (3) a pure 2-back. The measured outcomes comprise performance data, ERP amplitudes, EEG power, and subjective workload., Results: Work performance decreased in the resumption trials, and cumulative interruptions had a more destructive effect on performance. EEG results showed that the P2 and P3 amplitudes induced by the 2-back task significantly increased after interruptions; theta and alpha power increased after interruptions. The P3 amplitude and alpha power induced by interruptions were significantly higher than that induced by suspensions., Conclusion: Behavioral data revealed the disruptive effect of interruptions on postinterruption performance and the cumulative effect of interruptions on accuracy. Changes in ERP amplitudes and EEG power indicate the mechanisms of attention reallocation and working memory during interruptions. Larger P3 amplitudes and alpha power after interruptions than after suspensions suggested the inhibition of irrelevant information. These results may support the memory for goals model and improve the understanding of the effects of interruption on working memory., Application: Focusing upon the mechanisms at play during the interruption process can support interruption management to ensure work safety and efficiency.

Objective: To understand the impact of time pressure and automated decision support systems (DSS) in a simulated medical visual search task., Background: Time pressure usually impairs manual performance in visual search tasks, but DSS support might neutralize this negative effect. Moreover, understanding the impact of time pressure and DSS support seems relevant for many real-world applications of visual search., Method: We used a visual search paradigm where participants had to search for target letters in a simulated medical image. Participants performed the task either manually or with support of a highly reliable DSS. Time pressure was varied within-subjects by either a trialwise time-pressure manipulation (Experiment 1) or a blockwise manipulation (Experiment 2). Performance was assessed based on signal detection measures. To further analyze visual search behavior, a mouse-over approach was used., Results: In both experiments, results showed impaired sensitivity under high compared to low time pressure in the manual condition, but no negative effect of time pressure when working with a highly reliable DSS. Moreover, participants searched less under time pressure and when receiving DSS support, indicating participants followed the automation without thoroughly checking recommendations. However, the human-DSS team's sensitivity was always worse than that of the DSS alone, independent of the strength of time pressure., Conclusion: Negative effects of time pressure can be ameliorated when receiving support by a DSS, but joint overall performance remains below DSS-alone performance., Application: Highly reliable DSS seem capable of ameliorating the negative impact of time pressure in complex detection tasks.

Objective: This research aimed to investigate the relationship between gaze behaviour dynamics and operator performance., Background: Individuals differ in their approach when learning a new task often resulting in performance disparity. During training some individuals learn the structure and dynamics of the task and develop a systematic approach, whereas others may achieve the same result albeit with increased perceived workload, or indeed some may fail to achieve superior performance levels. Previous research has shown that comparing gaze of experts with novices can provide unique insights into cognitive functioning of superior performers., Methods: Twenty-five individuals participated in a computer-based simulation task. The concept of coefficient of variation (CoV) of task scores was used to compute the participants' consistency of performance. Based on CoV, the cohort was split into two performance categories. The temporal patterns in participants gaze data were transformed using autocorrelation, and recurrence quantification analysis (RQA) was employed to analyse and quantify the patterns., Results: A Mann-Whitney U analysis demonstrated significantly ( p < .01) higher determinism, entropy and laminarity in the superior group compared to the moderate group. Pearson's correlation revealed a significant ( p < .01) negative correlation between the consistency of task performance (CoV) and the RQA measures., Conclusion: The results demonstrated that eye gaze dynamics can be used as an objective measure of performance. Participants classified as superior performers consistently demonstrated a systematic gaze activity which were in line with the task structure., Application: The methods presented here are applicable to observe and evaluate operators' strategic distribution of gaze. Specifically, for tactical monitoring and decision making in task environments where spatial locations of elements-of-interest vary continuously.

Objective: This study investigated the effect of the spatial disorientation (SD) events on an attentive blank stare in the cockpit scene and demonstrated how much the flight task and visual delayed discrimination task were competing for the pilots' attention., Background: SD in flight is the leading cause of human error-related aircraft accidents in the military, general and commercial aviation, and has been an unsolved problem since the inception of flight. In-flight safety research, visually scanning cockpit instruments, and detecting changes are critical countermeasures against SD., Method: Thirty male military pilots were performing a dual task involving piloting a flight simulator and visual change detection, while eye movements were obtained using an eye tracker., Results: Pilots made more flight errors and spent less time gazing at the area of change in SD-conflict than in non-conflict flights. The vestibular origin SD-conflict led not only to deteriorated piloting and visual scanning but also to problems coordinating overt and covert attention, resulting in lower noticeability of visual changes despite gazing at them., Conclusion: Our study shows that looking at a given area in space is not a sufficient condition for effective covert attention allocation and the correct response to a visual stimulus. It seems to be important to make pilots aware of this during SD training., Application: To reduce change blindness, some strategies, such as reducing the number of secondary tasks is extremely valuable. Particular efforts should also be focused on improving the design of the aircraft cockpit by increasing the conspicuousness of critical information.

Objective: This study manipulates the presence and reliability of AI recommendations for risky decisions to measure the effect on task performance, behavioral consequences of trust, and deviation from a probability matching collaborative decision-making model., Background: Although AI decision support improves performance, people tend to underutilize AI recommendations, particularly when outcomes are uncertain. As AI reliability increases, task performance improves, largely due to higher rates of compliance (following action recommendations) and reliance (following no-action recommendations)., Methods: In a between-subject design, participants were assigned to a high reliability AI, low reliability AI, or a control condition. Participants decided whether to bet that their team would win in a series of basketball games tying compensation to performance. We evaluated task performance (in accuracy and signal detection terms) and the behavioral consequences of trust (via compliance and reliance)., Results: AI recommendations improved task performance, had limited impact on risk-taking behavior, and were under-valued by participants. Accuracy, sensitivity ( d' ), and reliance increased in the high reliability AI condition, but there was no effect on response bias ( c ) or compliance. Participant behavior was only consistent with a probability matching model for compliance in the low reliability condition., Conclusion: In a pay-off structure that incentivized risk-taking, the primary value of the AI recommendations was in determining when to perform no action (i.e., pass on bets)., Application: In risky contexts, designers need to consider whether action or no-action recommendations will be more influential to design appropriate interventions.

Objective: Trade-offs between productivity, physical workload (PWL), and mental workload (MWL) were studied when integrating collaborative robots (cobots) into existing manual work by optimizing the allocation of tasks., Background: As cobots become more widely introduced in the workplace and their capabilities greatly improved, there is a need to consider how they can best help their human partners., Methods: A theoretical data-driven analysis was conducted using the O*NET Content Model to evaluate 16 selected jobs for associated work context, skills, and constraints. Associated work activities were ranked by potential for substitution by a cobot. PWL and MWL were estimated using variables from the O*Net database that represent variables for the Strain Index and NASA-TLX. An algorithm was developed to optimize work activity assignment to cobots and human workers according to their most suited abilities., Results: Human workload for some jobs decreased while workload for some jobs increased after cobots were reassigned tasks, and residual human capacity was used to perform job activities designated the most important to increase productivity. The human workload for other jobs remained unchanged., Conclusions: The changes in human workload from the introduction of cobots may not always be beneficial for the human worker unless trade-offs are considered. Application : The framework of this study may be applied to existing jobs to identify the relationship between productivity and worker tolerances that integrate cobots into specific tasks.

Objective: The aim of this study was to establish the effects of simultaneous and asynchronous masking on the detection and identification of visual and auditory alarms in close temporal proximity., Background: In complex and highly coupled systems, malfunctions can trigger numerous alarms within a short period of time. During such alarm floods, operators may fail to detect and identify alarms due to asynchronous and simultaneous masking. To date, the effects of masking on detection and identification have been studied almost exclusively for two alarms during single-task performance. This research examines 1) how masking affects alarm detection and identification in multitask environments and 2) whether those effects increase as a function of the number of alarms., Method: Two experiments were conducted using a simulation of a drone-based package delivery service. Participants were required to ensure package delivery and respond to visual and auditory alarms associated with eight drones. The alarms were presented at various stimulus onset asynchronies (SOAs). The dependent measures included alarm detection rate, identification accuracy, and response time., Results: Masking was observed intramodally and cross-modally for visual and auditory alarms. The SOAs at which asynchronous masking occurred were longer than reported in basic research on masking. The effects of asynchronous and, even more so, simultaneous masking became stronger as the number of alarms increased., Conclusion: Masking can lead to breakdowns in the detection and identification of alarms in close temporal proximity in complex data-rich domains., Application: The findings from this research provide guidance for the design of alarm systems., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: Assess operator performance in a simulation of US Coast Guard small boat recovery to a larger vessel on a large scale, six degree-of-freedom, full motion simulator., Background: Studies of human performance in small boat recovery task have never been conducted on a high amplitude, low frequency simulator. Empirical evidence of small boat recovery task performance in challenging motion conditions is needed to inform future maritime systems designs., Method: Experienced active-duty boat crewmembers ( N = 13) conducted a small boat recovery task in three sea states on the Vertical Motion Simulator (VMS) at the NASA Ames Research Center. Task performance was assessed using a task equivalent for time to complete the task. Participant behaviors associated with increasing motion severity were observed., Results: Task performance declined as motion conditions became more severe. Participants were more likely to use at least one hand to maintain balance during motion conditions, becoming more frequent with increasing motion severity. Many participants used one hand to complete the task despite contrary instructions and previous experience., Conclusion: Two design recommendations were proposed to counter declining task performance in increasingly severe motion conditions. Handholds available to participants during the task, and task design supporting single handed completion were recommended for small boat recovery systems., Application: This research is directly applicable to gross motor tasks requiring simultaneous maintenance of balance in a maritime environment, and may be extended to other environments where humans experience complex motions while completing tasks.

Objective: In this review, we investigate the relationship between agent transparency, Situation Awareness, mental workload, and operator performance for safety critical domains., Background: The advancement of highly sophisticated automation across safety critical domains poses a challenge for effective human oversight. Automation transparency is a design principle that could support humans by making the automation's inner workings observable (i.e., "seeing-into"). However, experimental support for this has not been systematically documented to date., Method: Based on the PRISMA method, a broad and systematic search of the literature was performed focusing on identifying empirical research investigating the effect of transparency on central Human Factors variables., Results: Our final sample consisted of 17 experimental studies that investigated transparency in a controlled setting. The studies typically employed three human-automation interaction types: responding to agent-generated proposals, supervisory control of agents, and monitoring only. There is an overall trend in the data pointing towards a beneficial effect of transparency. However, the data reveals variations in Situation Awareness, mental workload, and operator performance for specific tasks, agent-types, and level of integration of transparency information in primary task displays., Conclusion: Our data suggests a promising effect of automation transparency on Situation Awareness and operator performance, without the cost of added mental workload, for instances where humans respond to agent-generated proposals and where humans have a supervisory role., Application: Strategies to improve human performance when interacting with intelligent agents should focus on allowing humans to see into its information processing stages, considering the integration of information in existing Human Machine Interface solutions.

Objectives: We investigated the effects of auditory cues of varying reliability levels on response inhibition performance using a target detection task to determine if external cues offer performance benefits. Further, we examined how the slope of the speed accuracy trade-off changes as a function of auditory cue reliability and used the trade-off to understand where any performance gains may be realized., Background: Researchers have proposed that the sustained attention to response task (SART) can be used to study the mechanisms causing failures of response inhibition. External cues may mitigate the results of motor inhibition failure. The extent to which external cues can effectively aid performance depends on the level of cue reliability., Method: Ninety-one participants performed three SARTs with auditory cue assistance at three different levels of reliability (i.e. 0%, 60% and 100% reliable at cueing imminent No-Go stimuli)., Results: We observed fewer errors of commission and faster reaction time in conditions with higher cue reliability. The slope of speed-accuracy trade-off relationship was impacted by cue reliability and was not a simple linear function., Conclusion: Reliable auditory cues aid performance by reducing reaction time and errors of commission. Auditory cues also impact the relationship between speed and accuracy trade-off., Application: Insights of cue effectiveness at different reliability levels help people make informed decisions in developing automation interfaces or sensors based on expected performance. Reliable cues mitigate the risk of impulsive errors; however, the reliability has to be high to have a noticeable impact on the speed-accuracy trade-off., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: We define and demonstrate the use of OPM-TA-a model-based task analysis (TA) framework that uses object-process methodology (OPM) ISO 19450 as a viable alternative to traditional TA techniques., Background: A variety of different TA methods exist in human factors engineering, and several of them are often applied successively for a broad task representation, making it difficult to follow., Method: Using OPM-TA, we modeled how an International Space Station (ISS) astronaut would support extravehicular activities using the existing robotic arm workstation with a new control panel and an electronic procedure system. The modeling employed traditional TA methods and the new OPM-TA approach, enabling a comparison between them., Results: While the initial stages of modeling with OPM-TA follow those of traditional TA, OPM-TA modeling yields an executable and logically verifiable model of the entire human-robot system. Both OPM's hierarchical set of diagrams and the equivalent, automatically generated statements in a subset of natural language text specify how objects and processes relate to each other at increasingly detailed levels. The graphic and textual OPM modalities specify the system's architecture, which enables its function and benefits its users. To verify the model logical correctness model, we executed it using OPM's simulation capability., Conclusion: OPM-TA was able to unify traditional TA methods and expand their capabilities. The formal yet intuitive OPM-TA approach fuses and extends traditional TA methods, which are not amenable to simulation. It therefore can potentially become a widely used means for TA and human-machine procedure development and testing.

Objective: This work examines two human-autonomy team (HAT) training approaches that target communication and trust calibration to improve team effectiveness under degraded conditions., Background: Human-autonomy teaming presents challenges to teamwork, some of which may be addressed through training. Factors vital to HAT performance include communication and calibrated trust., Method: Thirty teams of three, including one confederate acting as an autonomous agent, received either entrainment-based coordination training, trust calibration training, or control training before executing a series of missions operating a simulated remotely piloted aircraft. Automation and autonomy failures simulating degraded conditions were injected during missions, and measures of team communication, trust, and task efficiency were collected., Results: Teams receiving coordination training had higher communication anticipation ratios, took photos of targets faster, and overcame more autonomy failures. Although autonomy failures were introduced in all conditions, teams receiving the calibration training reported that their overall trust in the agent was more robust over time. However, they did not perform better than the control condition., Conclusions: Training based on entrainment of communications, wherein introduction of timely information exchange through one team member has lasting effects throughout the team, was positively associated with improvements in HAT communications and performance under degraded conditions. Training that emphasized the shortcomings of the autonomous agent appeared to calibrate expectations and maintain trust., Applications: Team training that includes an autonomous agent that models effective information exchange may positively impact team communication and coordination. Training that emphasizes the limitations of an autonomous agent may help calibrate trust.

Objective: Examine the extent to which increasing information integration across displays in a simulated submarine command and control room can reduce operator workload, improve operator situation awareness, and improve team performance., Background: In control rooms, the volume and number of sources of information are increasing, with the potential to overwhelm operator cognitive capacity. It is proposed that by distributing information to maximize relevance to each operator role (increasing information integration), it is possible to not only reduce operator workload but also improve situation awareness and team performance., Method: Sixteen teams of six novice participants were trained to work together to combine data from multiple sensor displays to build a tactical picture of surrounding contacts at sea. The extent that data from one display were available to operators at other displays was manipulated (information integration) between teams. Team performance was assessed as the accuracy of the generated tactical picture., Results: Teams built a more accurate tactical picture, and individual team members had better situation awareness and lower workload, when provided with high compared with low information integration., Conclusion: A human-centered design approach to integrating information in command and control settings can result in lower workload, and enhanced situation awareness and team performance., Application: The design of modern command and control rooms, in which operators must fuse increasing volumes of complex data from displays, may benefit from higher information integration based on a human-centered design philosophy, and a fundamental understanding of the cognitive work that is carried out by operators.

Objective: Investigating dual-task (DT) performance during simulated weightlessness by water submersion, using a manual tracking and a choice reaction task. In contrast to previous work, we focus on performance changes over time., Background: Previous research showed motor tracking and choice reaction impairments under DT and single-task (ST) conditions in shallow water submersion. Recent research analyzed performance as average across task time, neglecting potential time-related changes or fluctuations of task-performance., Method: An unstable tracking and a choice reaction task was performed for one minute under ST and DT conditions in 5 m water submersion and on dry land in 43 participants. Tracking and choice reaction time performance for both tasks were analyzed in blocks of 10 seconds., Results: Tracking performance deteriorated underwater compared to dry land conditions during the second half while performing one minute in DT conditions. Choice reaction time increased underwater as well, but independent of task time and type., Conclusion: Tracking error increased over time when performing unstable tracking and choice reaction together. Potentially, physiological and psychological alterations under shallow submersion further strain the human system during DT operations, exceeding available recourse capacities such that DT performance deteriorated over time., Application: Humans operating in simulated weightlessness underwater should be aware of substantial performance declines that can occur within a short amount of time during DT situations that include continuous tracking.

Objective: This project quantifies operationally relevant measures of flight performance and workload in a high-fidelity long-duration spaceflight analog, longitudinally across mission duration, using a portable simulation platform., Background: Real-time performance measures allow for the objective assessment of task performance and the timely identification of performance degradations., Methods: Measures of flight performance on a piloted lunar lander task were collected on 32 total crewmembers across 8 simulated space missions of 45 days each (623 total sessions)., Results: Mission duration demonstrated a significant effect on measures of flight performance across all campaigns. Flight measures showed a general pattern of peaking in accuracy during the middle-late quartiles of overall mission time, then degrading again towards baseline. On the workload measure, however, a general linear decrease in workload consistent with progressive task learning was observed in both campaigns., Conclusion: This investigation demonstrated the disruptive effect of time in mission on some, but not all, aspects of task performance. While mission interval differentially impacted measures of flight accuracy, workload, by contrast, seemed to steadily decrease with in-mission time., Application: While more work is needed, the observed discrepancy between progression of flight performance and workload assessment highlights the importance of sensitive and specific measurement tools for the tracking of distinct performance metrics.

Objective: Investigate the effects of scheduling task complexity on human performance for novice schedulers creating spaceflight timelines., Background: Future astronauts will be expected to self-schedule, yet will not be experts in creating timelines that meet the complex constraints inherent to spaceflight operations., Method: Conducted a within-subjects experiment to evaluate scheduling task performance in terms of scheduling efficiency, effectiveness, workload, and situation awareness while manipulating scheduling task complexity according to the number of constraints and type of constraints., Results: Each participant ( n = 15) completed a set of scheduling problems. Results showed main effects of the number of constraints and type of constraint on efficiency, effectiveness, and workload. Significant interactions were observed in situation awareness and workload for certain types of constraints. Results also suggest that a lower number of constraints may be manageable by novice schedulers when compared to scheduling activities without constraints., Conclusion: Results suggest that novice schedulers' performance decreases with a high number of constraints, and future scheduling aids may need to target a specific type of constraint., Application: Knowledge on the effect of scheduling task complexity will help design scheduling systems that will enable self-scheduling for future astronauts. It will also inform other domains that conduct complex scheduling, such as nursing and manufacturing.

Objective: Several studies were conducted to assess media-specific communication protocols as a countermeasure to challenges of asynchronous space-ground communication., Background: Previous research demonstrated that transmission delay can negatively impact space-ground communication, collaboration, and task performance. We created media-specific protocols designed to mitigate identified problems associated with asynchronous communication and examined their effects on team communication and task performance., Methods: The lab study included 24 teams of three who collaborated remotely via voice or text on computer-based tasks simulating failures in a spacecraft's life support system. Training and availability of communication protocols was the between-groups variable. Perceived usability, criticality, and effectiveness of the communication protocols were also assessed in space-analog simulations., Results: Lab study data revealed that communication protocols facilitated some aspects of team communication; specifically, they reduced threats to common ground and information splitting but not instances of miscommunication. Analog data indicated that protocol compliance was high, participants evaluated most elements as highly important, and protocols maintained perceived communication effectiveness between space crews and mission control during time delay comparably to no-time-delay conditions., Conclusion: Converging data attest to the feasibility, usability, and effectiveness of empirically derived communication protocols as a countermeasure to the negative impacts of transmission delay and also point to technological solutions., Application: The communication protocols have been adopted for training in NASA analog simulations involving time-delayed communication. They could also support communication among remote team members in medical operations, command-and-control teams, or disaster response under asynchronous conditions or when time is limited and precise communication is critical.

Objective: We use a set of unobtrusive measures to estimate subjectively reported trust, mental workload, and situation awareness (henceforth "TWSA")., Background: Subjective questionnaires are commonly used to assess human cognitive states. However, they are obtrusive and usually impractical to administer during operations. Measures derived from actions operators take while working (which we call "embedded measures") have been proposed as an unobtrusive way to obtain TWSA estimates. Embedded measures have not been systematically investigated for each of TWSA, which prevents their operational utility., Methods: Fifteen participants completed twelve trials of spaceflight-relevant tasks while using a simulated autonomous system. Embedded measures of TWSA were obtained during each trial and participants completed TWSA questionnaires after each trial. Statistical models incorporating our embedded measures were fit with various formulations, interaction effects, and levels of personalization to understand their benefits and improve model accuracy., Results: The stepwise algorithm for building statistical models usually included embedded measures, which frequently corresponded to an intuitive increase or decrease in reported TWSA. Embedded measures alone could not accurately capture an operator's cognitive state, but combining the measures with readily observable task information or information about participants' backgrounds enabled the models to achieve good descriptive fit and accurate prediction of TWSA., Conclusion: Statistical models leveraging embedded measures of TWSA can be used to accurately estimate responses on subjective questionnaires that measure TWSA., Application: Our systematic approach to investigating embedded measures and fitting models allows for cognitive state estimation without disrupting tasks when administering questionnaires would be impractical.

Objective: In future deep space exploration missions, crew will have to work more autonomously from Earth. Greater crew autonomy will increase dependence on automated systems. This study investigates the performance effects of different strategies to automate procedural work for space exploration operations., Background: The following strategies are investigated for performing procedural work:•  Manual Work uses no procedure automation and crew performs all actions.•  Shared Work uses procedure automation to perform some actions within a procedure while crew performs other actions.•  Supervised Work uses procedure automation to perform procedure actions while crew supervises the automation., Method: Twenty-seven participants participated in a planetary habitat scenario-based simulation using electronic procedures with automatable actions to investigate the effect of these strategies on situation awareness (SA) and workload. This study used a modification of the Situation Presence Assessment Method to measure SA and the Bedford Workload Scale to measure subjective workload., Results: Mean response times and accuracy for SA queries show no significant difference among the three strategies. Bedford Workload ratings compared across the three strategies indicate that participants rated their workload as highest in the Manual Work condition, followed by the Shared Work condition, and lowest in the Supervised Work condition., Conclusion: The study hypothesized that increased levels of automation would lead to lower subjective workload and decreased SA. Although no significant difference in SA was observed, subjective workload was lower in automation strategies. Based on subjective ratings, 93% of participants preferred some form of automation, with 56% preferring the Shared Work automation condition.