Swimming with a head-mounted display: dual-task costs.

Head-up displays (HUDs) have the potential to change work in operation environments by providing hands-free information to wearers. However, these benefits may be accompanied by trade-offs, primarily by increasing cognitive load due to dividing attention. Previous studies have attempted to understand the trade-offs of HUD usage; however, all of which were focused on land-based tasks. A gap in understanding exists when examining HUD use in aquatic environments as immersion introduces unique environmental and physiological factors that could affect multitasking. In this study, we investigated multitasking performance associated with swimming with a HUD. Eighteen participants completed three tasks: swimming only, a HUD-administered word recall task, and a dual-task combining both tasks. Results revealed significant dual-task interference in both tasks, though possibly less pronounced than in land-based tasks. These findings enhance not only help characterise dual-task performance, but also offer valuable insights for HUD design for aquatic settings.

HUDs have become an increasingly popular tool to present information to users in complex working environments. However, past research examining HUD task performance has been restricted to land-based contexts. The current study examines HUD use while swimming and provides characterisation of multitasking performance within aquatic environments.

The Role of State and Trait Self-Control on the Sustained Attention to Response Task.

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.

The frequency of positive and negative interactions influences relationship equity and trust in automation.

The purpose of this study was to 1) examine whether frequency of positive and negative interactions (manipulated via reliability) with a computer agent had an impact on an individual's trust resilience after a major error occurs and 2) empirically test the notion of relationship equity, which encompasses the total accumulation of positive and negative interactions and experiences between two actors, on user trust on a separate transfer task. Participants were randomized into one of four groups, differing in agent positivity and frequency of interaction, and completed both a pattern recognition task and transfer task with the aid of the same computer agent. Subjective trust ratings, performance data, compliance, and agreement were collected and analyzed. Results demonstrated that frequency of positive and negative interactions did have an impact on user trust and trust resilience after a major error. Additionally, it was shown that relationship equity has an impact on user trust and trust resilience. This is the first empirical demonstration of relationship equity's impact on user trust in an automated teammate.

A Closer Look at Warning Cues on the Sustained Attention to Response Task Performance.

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.

The effects of dual-task interference on visual search and verbal memory.

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.

Evaluating the dual-task decrement within a simulated environment: Word recall and visual search.

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.

Prolonging the Response Movement Reduces Commission Errors in a High-Go, Low-No-Go Target Detection Task and Composite Metrics of Performance Miss This Effect.

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.

Measurement of Trust in Automation: A Narrative Review and Reference Guide.

With the rise of automated and autonomous agents, research examining Trust in Automation (TiA) has attracted considerable attention over the last few decades. Trust is a rich and complex construct which has sparked a multitude of measures and approaches to study and understand it. This comprehensive narrative review addresses known methods that have been used to capture TiA. We examined measurements deployed in existing empirical works, categorized those measures into self-report, behavioral, and physiological indices, and examined them within the context of an existing model of trust. The resulting work provides a reference guide for researchers, providing a list of available TiA measurement methods along with the model-derived constructs that they capture including judgments of trustworthiness, trust attitudes, and trusting behaviors. The article concludes with recommendations on how to improve the current state of TiA measurement.

Transcranial Doppler sonography reveals sustained attention deficits in young adults diagnosed with ADHD.

The National Institute of Mental Health has recently launched the Research Domain Criteria framework that seeks to inform clinical classification schemes by elevating the status of neuroscience research in the diagnosis of mental disorders. The current research seeks to contribute to that initiative by using a neurophysiological measure, transcranial Doppler sonography that has been shown to be sensitive to decrements in sustained attention and may provide an additional biomarker of executive dysfunction in ADHD. Twenty-seven participants performed a 12-min vigilance task while cerebral blood flow velocity (CBFV) was recorded. Thirteen participants were included in an ADHD condition if they had been formally diagnosed with ADHD. The remaining 14 participants who had never been formally diagnosed with ADHD were included in the control condition. Participants that had been diagnosed with ADHD demonstrated a steeper decrement in performance accuracy, a steeper decrement in perceptual sensitivity, and employed a more liberal response bias over time as compared to the control participants. Critically, the decrement in CBFV was steeper for participants previously diagnosed with ADHD than those who were not. Moreover, CBFV was found to better predict decreases in sensitivity and hit rate, as well as increases in liberal responding above and beyond self-reported ADHD symptoms. Results suggest that CBFV can be used to index failures of executive control in ADHD and can predict response strategy, and that the measure may provide an additional index of the sustained attention deficits associated with ADHD compared to traditional diagnostic methods.

Does Depleting Self-Control Result in Poorer Vigilance Performance?

OBJECTIVE: To investigate whether depleting self-control prior to vigilance results in a steeper vigilance decrement. BACKGROUND: The resource-control theory of vigilance asserts that an inherent bias toward self-generated mind-wandering draws attentional resources away from the primary task. This study seeks to test whether depleting self-control, the potential mechanism of self-generated mind-wandering, results in poorer vigilance performance. METHOD: This study featured a between-subjects design where participants either completed a typing task that depleted self-control resources or a standard typing task that did not require self-control before performing a vigilance task. In the self-control depletion condition, participants typed a passage while omitting any "e" and "space" keys. In the standard typing task, participants typed the same passage without skipping any keys. Following both typing tasks, participants in both conditions completed an identical 12-min vigilance task. RESULTS: Results demonstrated decreased accuracy and increased reaction times over time for both groups. Depleting self-control did not result in significant differences in accuracy, reaction time, nor a steeper vigilance decrement. CONCLUSION: These results provide evidence against resource-control theory and self-control as an explanation for vigilance, and provide further support for cognitive resource theory as the predominant explanation for vigilance impairments. APPLICATION: It is still unclear exactly what constitutes a "resource." A better understanding of the nature of these resources can help researchers and practitioners identify how they can be replenished, which could enhance human performance in situations requiring vigilance such as baggage screening.

From 'automation' to 'autonomy': the importance of trust repair in human-machine interaction.

Modern interactions with technology are increasingly moving away from simple human use of computers as tools to the establishment of human relationships with autonomous entities that carry out actions on our behalf. In a recent commentary, Peter Hancock issued a stark warning to the field of human factors that attention must be focused on the appropriate design of a new class of technology: highly autonomous systems. In this article, we heed the warning and propose a human-centred approach directly aimed at ensuring that future human-autonomy interactions remain focused on the user's needs and preferences. By adapting literature from industrial psychology, we propose a framework to infuse a unique human-like ability, building and actively repairing trust, into autonomous systems. We conclude by proposing a model to guide the design of future autonomy and a research agenda to explore current challenges in repairing trust between humans and autonomous systems. Practitioner Summary: This paper is a call to practitioners to re-cast our connection to technology as akin to a relationship between two humans rather than between a human and their tools. To that end, designing autonomy with trust repair abilities will ensure future technology maintains and repairs relationships with their human partners.

Transcranial Doppler Sonography Reveals Reductions in Hemispheric Asymmetry in Healthy Older Adults during Vigilance.

Given that older adults are remaining longer in the workforce, their ability to perform demanding cognitive tasks such as vigilance assignments needs to be thoroughly examined, especially since many vigilance assignments affect public safety (e.g., aviation, medicine and long distance driving). Previous research exploring the relation between aging and vigilance is conflicted, with some studies finding decreased vigilance performance in older adults but others finding no effect of age. We sought a better understanding of effects of age on vigilance by assessing neurophysiological change over the course of a vigil in young (aged 18-24) and healthy older (aged 66-77) adults. To measure temporal changes in cerebral blood flow, participants underwent functional transcranial doppler (fTCD) recording during a 1 h vigilance task. Based on research showing a compensatory effect of increased left hemisphere activation during vigilance in young adults and the "hemispheric asymmetry reduction in older adults" (HAROLD) model, we predicted that during vigilance our older adults would show greater left hemisphere activation but perform at a similar level compared to young adults. While cerebral blood flow velocity (CBFV) declined over time in both groups, only young adults showed the typical right-lateralized CBFV pattern. Older adults showed greater left hemisphere activation consistent with the HAROLD model. However, the increased left hemisphere activation did not appear to be compensatory as the older adults performed at a significantly lower level compared to young adults over the vigil. Findings are discussed in terms of the HAROLD model of healthy aging and the resource theory of vigilance.

The Neuroergonomics of Vigilance.

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

Cerebral hemovelocity reveals differential resource allocation strategies for extraverts and introverts during vigilance.

Extraversion--one of the Big 5 personality factors--correlates negatively with vigilance, but most studies focus on performance outcomes and not the performance process. Previous research has shown that transcranial Doppler sonography (TCD), which measures cerebral blood flow velocity (CBFV), can be used to examine resource allocation strategies during vigilance performance. Hence, this study was designed to assess the attentional resource allocation strategies of introverts and extraverts using the CBFV measure. Twelve extroverts and 13 introverts monitored a 60-min vigilance task for a critical signal--the absence of a line on a five-circle array. The results revealed an overall performance decrement that was not modulated by extraversion. We observed an interaction between extraversion and time; CBFV declined in the introversion group, but not in the extraversion group. Additionally, an interaction between cerebral hemisphere and personality revealed that extraverts were recruiting resources from both the left and right cerebral hemispheres, while introverts only recruited resources from the right hemisphere. The results suggest that extraverts can allocate compensatory effort to mask performance differences. We discuss the theoretical and practical implications of these findings and offer future research directions that may help us understand these effects.

Neuroticism and vigilance revisited: A transcranial doppler investigation.

Selecting for vigilance assignments remains an important factor in human performance research. The current study revisits the potential relationship between vigilance performance and trait neuroticism, in light of two possible theories. The first theory suggests that neuroticism impairs vigilance performance by competing for available resources. The second theory, attentional control theory, posits that high neuroticism can result in similar or superior performance levels due to the allocation of compensatory effort. In the present study, Transcranial Doppler Sonography was used to investigate the neurophysiological underpinnings of neuroticism during a 12-min abbreviated vigilance task. Performance results were not modified by level of neuroticism, but high neuroticism was associated with higher initial CBFV levels and a greater CBFV decrement over time. These findings indicate that participants higher in neuroticism recruited additional cognitive resources in order to achieve similar performance, suggesting that there is more of an effect on processing efficiency than effectiveness.

The effects of self-control on cognitive resource allocation during sustained attention: a transcranial Doppler investigation.

Vigilance, or sustained attention, is a required ability in many operational professions. While past research has consistently indicated that vigilance performance declines over time, referred to as the vigilance decrement, the theoretical mechanisms underlying the decrement continue to be explored. In the current study, trait self-control was examined to determine how this individual differences measure may contribute to the theoretical explanation of vigilance decrement. Transcranial Doppler sonography (TCD) was used as a measure of cerebral blood flow velocity (CBFV), as previous research has indicated that CBFV may index attentional resource allocation during vigilance (e.g., Shaw et al. in Hum Factors Ergon Soc 50:1619-1623, 2009). Participants performed a demanding 12-min computer-based vigilance task. Prior to the task, a validated self-report measure was used to determine trait-level self-control, and subjective workload was measured after the task was completed. Participants were divided, based upon survey responses, as either low- or high-trait self-control. Performance results showed a significant decrement across participants, but no significant main effect or interaction relating to the self-control measure was observed. Results relating to the TCD measure showed a significant decline in CBFV in the low self-control group, but no CBFV decrement was observed in the high self-control group. The subjective workload results revealed a nonsignificant trend of the low self-control group becoming more frustrated after the task. These results suggest that there are differences in the resource allocation strategies between low and high self-control participants. How trait self-control can add to an understanding of the theoretical underpinnings of sustained attention performance is discussed.

The sustained attention to response task (SART) does not promote mindlessness during vigilance performance.

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

Predicting battlefield vigilance: a multivariate approach to assessment of attentional resources.

Technological innovation increasingly requires operators in various applied settings to maintain vigilance for extended periods. However, standard psychometric tests typically predict less than 10% of performance variance. The present study (N = 462) aimed to apply the resource theory of sustained attention to construct a multivariate test battery for predicting battlefield vigilance. The battery included cognitive ability tests, a high-workload short vigilance task and subjective measures of stress response. Four versions of a 60- min simulated military battlefield monitoring task were constructed to represent different operational requirements. The test battery predicted 24-44% of criterion variance, depending on task version, suggesting that it may identify vigilant operators in military and other applied contexts. A multiple-groups path analysis showed that relationships between ability and vigilance were moderated by working memory demands. Findings are consistent with a diffuse theoretical concept of 'resources' in which performance energisation depends on multiple, loosely coupled processes.

Event-related cerebral hemodynamics reveal target-specific resource allocation for both "go" and "no-go" response-based vigilance tasks.

Transcranial Doppler sonography was used to measure cerebral blood flow velocity (CBFV) in the right and left cerebral hemispheres during the performance of a 50-min visual vigilance session. Observers monitored a simulated flight of unmanned aerial vehicles for cases in which one of the vehicles was flying in an inappropriate direction relative to its cohorts. Two types of vigilance tasks were employed: a traditional task in which observers made button press ("go") responses to critical signals, and a modification of the traditional task called the Sustained Attention to Response Task (SART) in which "go" responses acknowledged nonsignal events and response withholding ("no-go") signified signal detection. Signal detections and global CBFV scores declined over time. In addition, fine-grained event-related analyses revealed that the detection of signals was accompanied by an elevation of CBFV that was not present with missed signals. As was the case with the global scores, the magnitude of the transient CBFV increments associated with signal detection also declined over time, and these findings were independent of task type. The results support the view of CBFV as an index of the cognitive evaluation of stimulus significance, and a resource model of vigilance in which the need for continuous attention produces a depletion of information-processing assets that are not replenished as the task progresses. Further, temporal declines in the magnitude of event-related CBFV in response to critical signals only is evidence that the decrement function in vigilance is due to attentional processing and not specific task elements such as the required response format.

Using cerebral hemovelocity to measure workload during a spatialised auditory vigilance task in novice and experienced observers.

This experiment was designed to assess cognitive load using transcranial Doppler sonography during the performance of a 40-min communication vigilance task in which messages were presented in different spatial locations or across a single monaural radio channel. In addition, some observers received 14 hours of practice to determine whether the neurophysiological measure was sensitive to a potential attenuation of workload. Critical messages were detected more frequently in the spatialised audio presentation mode condition, but there were no performance differences between experienced and novice observers. Neurophysiological data show that activation was greater in the novice condition than in the experienced condition, suggesting that novice observers expended greater effort. Furthermore, the neurophysiological measure showed more activation in the monaural radio condition than in the spatialised audio condition. The results support a resource account of vigilance and suggest that cerebral blood flow velocity can be used to diagnose the degree of attentional resource utilisation during vigilance tasks. PRACTITIONER SUMMARY: Due to high workload experienced during vigilance tasks, displays and methods are sought which enhance performance. This study shows that spatialising auditory communications in a monitoring task enhances performance and attenuates mental workload. Also, experience mitigates excessive workload, and cerebral hemovelocity can be used to diagnose attentional resource utilisation.