Physical load affects duration judgments: A meta-analytic review

This article reports a meta-analytic review of seven extant experiments, with 235 participants, concerning effects of physical workload on duration judgments. It also provides a qualitative assessment of related studies that, for specific reasons, were not includable in the quantitative meta-analysis. All analyzed experiments used the prospective duration-judgment paradigm and the production method, in which participants knew in advance that duration estimation was required. A large overall effect size reveals that increasing physical workload results in longer prospective duration productions. Physical workload effects are comparable to those of cognitive load. Implications for applied research, theory, and applications are discussed.

On the paradoxical decrease of self-reported cognitive failures with age

The science of Human Factors and Ergonomics (HF/E) often relies on self-report. This is a cause for concern because subjective methods are inherently susceptible to bias. Here, we present, examine and discuss a puzzling association between age and self-reported cognitive failures as assessed with Broadbent's Cognitive Failures Questionnaire (CFQ). Despite many well-established age-associated forms of cognitive decline, older persons actually report almost equivalent, or even less, cognitive failures on the CFQ than younger persons. Our present analysis indicates that this paradox may be resolved through the fact that people show age-related learning/adaptation/compensation and by the observation that the CFQ measures peoples' beliefs with respect to an individually idiosyncratic reference. Yet, at the heart of the paradox may be the idea that people cannot remember their own cognitive failures, pointing to even greater concerns with all forms of subjective self-report and its use in HF/E. Practitioner Summary: Scientists and practitioners often try to understand and improve human performance with the help of self-report questionnaires. Our paper discusses the validity of self-reported errors measured with the Cognitive Failures Questionnaire (CFQ). We look to resolve the curious paradox that older persons tend to report fewer failures than younger persons do.

The effects of display size on performance

We examined the systematic effects of display size on task performance as derived from a standard perceptual and cognitive test battery. Specifically, three experiments examined the influence of varying viewing conditions on response speed, response accuracy and subjective workload at four differing screen sizes under three different levels of time pressure. Results indicated a ubiquitous effect for time pressure on all facets of response while display size effects were contingent upon the nature of the viewing condition. Thus, performance decrement and workload elevation were evident only with the smallest display size under the two most restrictive levels of time pressure. This outcome generates a lower boundary threshold for display screen size for this order of task demand. Extrapolations to the design and implementation of all display sizes and forms of cognitive and psychomotor demand are considered.

The impact of emotions and predominant emotion regulation technique on driving performance

Emotion-provoking stimuli abound on modern roadways. Driving measures, of both longitudinal and lateral control of the vehicle, have been shown to vary based on affective influences. Research, however, has yet to address how drivers' individual techniques to mitigate emotional reactions influence driving performance. To address this issue, the present study featured a dual-task protocol involving simulated driving together with processing of emotionally-valenced images with a focus on different Predominant Emotion Regulation Techniques (PERT): one adaptive strategy (task-focused coping) and one maladaptive style (emotion-focused coping). Dependent measures included mean driving speed and number of lane excursions. Results indicated that pleasant images degraded longitudinal control to the greatest extent, while unpleasant images produced the greatest detriment in lateral control. Additionally, individuals' PERT played a major interactive role in drivers' longitudinal control leading task-focused females and emotion-focused males to adhere more closely to the speed limit; yet, it did not affect their lateral control. Results hold important potential implications for the amount or variety of training necessary for driver licensure to promote and sustain safe vehicle control.

Google Glass

Objective:

We assess the driving distraction potential of texting with Google Glass (Glass), a mobile wearable platform capable of receiving and sending short-message-service and other messaging formats.

Background:

A known roadway danger, texting while driving has been targeted by legislation and widely banned. Supporters of Glass claim the head-mounted wearable computer is designed to deliver information without concurrent distraction. Existing literature supports the supposition that design decisions incorporated in Glass might facilitate messaging for drivers.

Method:

We asked drivers in a simulator to drive and use either Glass or a smartphone-based messaging interface, then interrupted them with an emergency brake event. Both the response event and subsequent recovery were analyzed.

Results:

Glass-delivered messages served to moderate but did not eliminate distracting cognitive demands. A potential passive cost to drivers merely wearing Glass was also observed. Messaging using either device impaired driving as compared to driving without multitasking.

Conclusion:

Glass in not a panacea as some supporters claim, but it does point the way to design interventions that effect reduced load in multitasking.

Application:

Discussions of these identified benefits are framed within the potential of new in-vehicle systems that bring both novel forms of distraction and tools for mitigation into the driver’s seat.

Coding warnings without interfering with dismounted soldiers' missions

OBJECTIVES

Warnings are an effective way to communicate hazard, yet they can also increase task demand when presented to operators involved in real-world tasks. Furthermore, in military-related tasks warnings are often given in codes to avoid counter-intelligence, which may foster additional working memory load.

BACKGROUND

Adherence to warnings in the military domain is crucial to promote safety and reduce accidents and injuries. The empirical question arises as to how aspects of coding the warning may interfere with the primary task the individual is currently performing and vice versa.

METHOD

Six experimental conditions were designed to assess how warning-code storage format, response format, and increasing working memory demand (retention) affected both performance on the primary task and the rate of compliance to warnings, considered here as the secondary task.

RESULTS

Results revealed that the combination of warning-code storage and response format affected compliance rate and the highest compliance occurred when warnings were presented as pictorials and responses were coded verbally. Contrary to the proposed hypotheses, warning storage format did not affect performance on the primary task, which was only affected by the level of working memory demand. Thus, the intra-modal warning storages did not interfere with the visual/spatial nature of the primary operational task. However, increase in working memory demand, by increasing the number of memorized warning codes, had an effect on both compliance rate and primary task performance.

CONCLUSIONS

Rather than warning code storage alone, it is the coupling of warning storage and response format that has the most significant effect on compliance.

Vigilance on the move: video game-based measurement of sustained attention

Vigilance represents the capacity to sustain attention to any environmental source of information over prolonged periods on watch. Most stimuli used in vigilance research over the previous six decades have been relatively simple and often purport to represent important aspects of detection and discrimination tasks in real-world settings. Such displays are most frequently composed of single stimulus presentations in discrete trials against a uniform, often uncluttered background. The present experiment establishes a dynamic, first-person perspective vigilance task in motion using a video-game environment. 'Vigilance on the move' is thus a new paradigm for the study of sustained attention. We conclude that the stress of vigilance extends to the new paradigm, but whether the performance decrement emerges depends upon specific task parameters. The development of the task, the issues to be resolved and the pattern of performance, perceived workload and stress associated with performing such dynamic vigilance are reported.

PRACTITIONER SUMMARY

The present experiment establishes a dynamic, first-person perspective movement-based vigilance task using a video-game environment. 'Vigilance on the move' is thus a new paradigm for the evaluation of sustained attention in operational environments in which individuals move as they monitor their environment. Issues addressed in task development are described.

The impact of emotions and predominant emotion regulation technique on driving performance

Emotion-provoking stimuli abound on modern roadways. Driving measures, of both longitudinal and lateral control of the vehicle, have been shown to vary based on affective influences. Research, however, has yet to address how drivers' individual techniques to mitigate emotional reactions influence driving performance. To address this issue, the present study featured a dual-task protocol involving simulated driving together with processing of emotionally-valenced images with a focus on different Predominant Emotion Regulation Techniques (PERT): one adaptive strategy (task-focused coping) and one maladaptive style (emotion-focused coping). Dependent measures included mean driving speed and number of lane excursions. Results indicated that pleasant images degraded longitudinal control to the greatest extent, while unpleasant images produced the greatest detriment in lateral control. Additionally, individuals' PERT played a major interactive role in drivers' longitudinal control leading task-focused females and emotion-focused males to adhere more closely to the speed limit; yet, it did not affect their lateral control. Results hold important potential implications for the amount or variety of training necessary for driver licensure to promote and sustain safe vehicle control.

Putting mind and body back together: a human-systems approach to the integration of the physical and cognitive dimensions of task design and operations

As human factors and ergonomics professionals we should be considering the total context within which the person must operate when performing a task, providing a service, or using a product. We have traditionally thought of the person as having a cognitive system and a physical system and much of our scientific literature has been myopically focused on one or the other of these systems while, in general, totally ignoring the other. However, contemporary efforts have begun to recognize the rich interactions occurring between these systems that can have a profound influence on performance and dictate overall system output. In addition, modern efforts are beginning to appreciate the many interactions between the various elements of the environment that can influence the components of the human systems. The next level of sophistication in the practice of human factors and ergonomics must begin to consider the totality of the human-system behavior and performance and must consider systems design interactions which result from these collective effects. Only then will we be able to truly optimize systems for human use.

Automation: how much is too much?

The headlong rush to automate continues apace. The dominant question still remains whether we can automate, not whether we should automate. However, it is this latter question that is featured and considered explicitly here. The suggestion offered is that unlimited automation of all technical functions will eventually prove anathema to the fundamental quality of human life. Examples of tasks, pursuits and past-times that should potentially be excused from the automation imperative are discussed. This deliberation leads us back to the question of balance in the cooperation, coordination and potential conflict between humans and the machines they create.

Task partitioning effects in semi-automated human-machine system performance

Twelve professional pilots performed a flight simulation consisting of three component sub-tasks: (i) tracking, (ii) monitoring and (iii) targeting, respectively. The targeting sub-task required (i) target identification, (ii) weapon selection and then (iii) weapon release. Pilots performed in a fully manual condition, a partial automation condition or a fully automated condition. Automated assistance was provided for the targeting sub-task only, while tracking and monitoring sub-tasks were always performed manually. During full automation, the computer located the target, identified it and released the appropriate weapon without any pilot input. During partial automation, the computer located and identified the target while the pilot retained final control over weapon release. Significantly higher levels of tracking error distinguished manual from both automated conditions and also between the two levels of automation. Monitoring response times were also sensitive to the degree of automation engaged, with the partial-automation condition exhibiting faster responses than full automation. Findings support a design principle in which pilots retain control over final weapons release directly on the basis of objective performance outcome. These collective results support the contention that effective and principled task-partitioning should represent a central strategy for the evolution of complex human-machine systems.

PRACTITIONER SUMMARY

Advantages of partitioning tasks between human and automated control are contingent upon the overall context of performance and the actual way the partitioning is accomplished. Simple algorithms, for example, automate on every feasible occasion, are poor design heuristics and may even prove actively harmful to overall response capacity. Transitioning humans from active controllers to passive monitors can be a problematic design choice, especially when that individual is socially deemed to retain overall responsibility for ultimate system effects in the real world.

In search of vigilance: the problem of iatrogenically created psychological phenomena

To what extent are identified psychological processes created in laboratories? The present work addresses this issue with reference to one particular realm of behavior: vigilance. Specifically, I argue that the classic vigilance decrement function can be viewed more realistically and advantageously as an "invigilant" increment function. Rather than characterizing the transient decrease in detection capability that is evident on exposure to enforced monitoring as a diminishment in capacity, it may be more usefully seen as an appropriate scaling by the designated observer to adapt to the nonoptimal circumstances that he or she is forced to endure. This proposition emphasizes the dynamic response characteristics of the observer and locates the origin of the phenomenon and the onus for practical improvements in the design of operational displays with designers rather than apportioning blame for performance decrements to the operator. This perspective reinforces the recognition of a crucial presence of the necessary but often unrecognized external arbiter in the vigilance paradigm and the extrinsically imposed imperative to sustain attention. Explicit recognition of this fact also helps explain the stress involved with extended vigils. In identifying the traditional vigilance decrement as a form of iatrogenic disease, I argue that modern design of work systems should alleviate the need for either the acute or the chronic expressions of such enforced human monitoring activity. It is possible that the case of vigilance is itself representative of a modern propensity to create new psychological phenomena in the face of human exposure to modern, evolving technical environments.

The psychology of time: a view backward and forward

We selectively review the progress of research on the psychology of time during the past 125 years, starting with the publication of the first English-language psychological journal, The American Journal of Psychology. A number of important articles on the psychology of time appeared in this journal, including the widely cited early article by Nichols (1891). The psychology of time is a seminal topic of psychological science, and although it entered a phase of decline and even moribund neglect, the past several decades have seen a prominent renaissance of interest. This renewed vigor represents the rebirth of the recognition of the centrality of the psychology of time in human cognition and behavior. Our selective overview highlights a number of strands of progress and how they have helped lead to the present, in which the cognitive neuroscience of time and timing in the brain is one of the most fervent and fertile modern areas of brain research. We also discuss some remaining challenges and potential lines of progress.

Finding the team for Mars: a psychological and human factors analysis of a Mars Desert Research Station crew

A two-week mission in March and April of 2011 sent six team members to the Mars Desert Research Station (MDRS). MDRS, a research facility in the high Utah desert, provides an analogue for the harsh and unusual working conditions that will be faced by men and women who one day explore Mars. During the mission a selection of quantitative and qualitative psychological tests were administered to the international, multidisciplinary team. A selection of the results are presented along with discussion.

Can You Trust Your Robot?

It is proposed that trust is a critical element in the interactive relations between humans and the automated and robotic technology they create. This article presents (a) why trust is an important issue for this type of interaction, (b) a brief history of the development of human-robot trust issues, and (c) guidelines for input by human factors/ergonomics professionals to the design of human-robot systems with emphasis on trust issues. Our work considers trust an ongoing and dynamic dimension as robots evolve from simple tools to active, sentient teammates.

On the left hand of time

The present experiment examined the effects of sex and handedness on the perception of brief intervals up to 20 s in duration. In order to obtain participants with sufficiently high scores on a scale of handedness, we screened 1,276 people; the process yielded 16 men and 16 women eligible for testing. In an empty production procedure, each person estimated 4 intervals of 1, 3, 7, and 20 s, respectively, using both their preferred and nonpreferred hands to provide recorded responses. The order of presentation was randomized across participants but yoked across the sexes in each of the respective handedness subgroups. Results indicated significant effects for handedness in conjunction with the hand used to make the respective response. The pattern of these interactive effects differed between male and female participants, however. These results are discussed in terms of a hemispheric account of interval timing control and potential sex difference in hemispheric specialization.

Driver responses to differing urban work zone configurations

This study reports the results of a simulator-based assessment of driver response to two different urban highway work zone configurations. One configuration represented an existing design which was contrasted with a second configuration that presented a reduced taper length prototype work zone design. Twenty-one drivers navigated the two different work zones in two different conditions, one with and one without a lead vehicle; in this case a bus. Measures of driver speed, braking, travel path, and collision frequency were recorded. Drivers navigated significantly closer to the boundary of the work area in the reduced taper length design. This proximity effect was moderated by the significant interaction between lead vehicle and taper length and such interactive effects were also observed for driver speed at the end of the work zone and the number of collisions observed within the work zone itself. These results suggest that reduced taper length poses an increase in risk to both drivers and work zone personnel, primarily when driver anticipation is reduced by foreshortened viewing distances. Increase in such risk is to a degree offset by the reduction of overall exposure to the work zone that a foreshortened taper creates. The benefits and limitations to a simulation-based approach to the assessment and prediction of driver behavior in different work zone configurations are also discussed.

An age-structured model to evaluate the potential of novel malaria-control interventions: a case study of fungal biopesticide sprays

It has recently been proposed that mosquito vectors of human diseases, particularly malaria, may be controlled by spraying with fungal biopesticides that increase the rate of adult mortality. Though fungal pathogens do not cause instantaneous mortality, they can kill mosquitoes before they are old enough to transmit disease. A model is developed (i) to explore the potential for fungal entomopathogens to reduce significantly infectious mosquito populations, (ii) to assess the relative value of the many different fungal strains that might be used, and (iii) to help guide the tactical design of vector-control programmes. The model follows the dynamics of different classes of adult mosquitoes with the risk of mortality due to the fungus being assumed to be a function of time since infection (modelled using the Weibull distribution). It is shown that substantial reductions in mosquito numbers are feasible for realistic assumptions about mosquito, fungus and malaria biology and moderate to low daily fungal infection probability. The choice of optimal fungal strain and spraying regime is shown to depend on local mosquito and malaria biology. Fungal pathogens may also influence the ability of mosquitoes to transmit malaria and such effects are shown to further reduce vectorial capacity.