Employee acceptance of wearable technology in the workplace

Wearable technology has many industrial applications. Optimal use adherence and outcomes largely depend on employee acceptance of the technology. This study determined factors that predict employee acceptance of wearables. An online survey of 1273 employed adults asked about demographics, job and organizational characteristics, experience with and beliefs about wearables, and willingness to use wearables. Use cases focused on workplace safety elicited the highest acceptance. An employee's performance expectancy and their organizational safety climate were common predictors of acceptance across use cases. Positive past experiences coincided with involving employees in choosing the device and adequately informing them about data use. Organizations intending to implement wearable technology should (a) focus its use on improving workplace safety, (b) advance a positive safety climate, (c) ensure sufficient evidence to support employees' beliefs that the wearable will meet its objective, and (d) involve and inform employees in the process of selecting and implementing wearable technology.

Passive restraint reduces visually induced motion sickness in older adults

Virtual environments such as those used in video games and driving/flight simulators are used for entertainment and training, but are often associated with visually induced motion sickness (VIMS). In this study, we asked whether passive restraint of the head and torso could reduce VIMS in younger and older adults. Twenty-one younger (18-35 years) and 16 older (65 + years) healthy adults engaged in a simulated driving task using a console video game while seated. On different days, participants completed 2 conditions: (a) in the unrestrained condition, participants were seated in a chair without a backrest and were free to move and (b) in the restrained condition, participants' head and torso were passively restrained to the backrest and headrest of the seat using tense elastic strips. Before and after exposure to the driving game, we measured standing postural sway with eyes closed. VIMS severity was quantified using the Fast Motion Sickness Scale and the Simulator Sickness Questionnaire. Results showed that older (but not younger) participants who became sick in the unrestrained condition reported significantly less VIMS when they were passively restrained. The present findings suggest that passive restraint may be useful to reduce, but not fully prevent, VIMS, particularly in older adults. (PsycINFO Database Record

Human Performance Assessment of a Prototype Multimodal Naval Command Center

A user-centered design philosophy attaches primary importance to human-machine system performance as the key criterion in assessing the operational utility of complex systems. When the system under consideration is uniquely novel and emphasizes the use of relatively immature technologies, system validation must occur at a number of points in the design process. Particularly in these situations, human-system performance testing must inform engineering development throughout the entire design cycle, and not just at its conclusion. In this paper we describe an empirical effort designed to validate novel technical approaches to the design of a naval command center intended to support high levels of tactical performance in a severely reduced personnel environment. Using a human-in-the-loop simulation, we assessed the initial validity of our design concepts by measuring individual and team performance in realistic simulated tasks. By analyzing metrics associated with operational system performance, operator workload and situation awareness, we were able to identify functional aspects of the design, as well as those that needed further user-centered development

Adaptive Integration of Head-Coupled Multi-Sensory Displays for Target Localization

The purpose of this study was to determine the efficacy of providing target location information via head-coupled visual and spatial audio displays presented in adaptive and non-adaptive configurations. Twelve USAF pilots performed a simulated flight task in which they were instructed to maintain flight parameters while searching for ground and air targets. The integration of visual displays with spatial audio cueing enhanced performance efficiency, especially when targets were most difficult to detect. Several of the interface conditions were also associated with lower ratings of perceived mental workload. The benefits associated with multi-sensory cueing were equivalent in both adaptive and non-adaptive configurations.

Developing Automated Methods to Quantify the Visual Stimulus for Cybersickness

Simulator sickness is a significant human factors issue in simulator and virtual environment systems. The extent to which users are adversely affected by sickness-inducing stimuli in virtual environments may hinder the behavioral goals sought (training, systems evaluation, etc.). To alleviate the problem, it is first necessary to accurately and reliably quantify the amount and type of visual motion stimulation that leads to motion sickness-like discomfort. This paper describes a human performance-based approach to the development of a system capable of measuring the visual stimulus for motion sickness. Military flight simulator trainees reported severity levels of sickness. A video camera was used to capture a significant portion of the simulated out-the-window visual stimuli to which they were exposed and a PC-mounted, frame-grabber algorithm was used to score the kinematic characteristics of that stimulation. Results show a significant positive correlation between roll motion and overall sickness. Development of these and other methods to quantify the visual stimulus for cybersickness are discussed.

Effects of Virtually-Augmented Fighter Cockpit Displays on Pilot Performance, Workload, and Situation Awareness

Virtually-augmented display concepts are being developed at the US Air Force Armstrong Laboratory's Synthesized Immersion Research Environment (SIRE) Facility at Wright-Patterson Air Force Base, Ohio, for use in future USAF crew stations. These displays incorporate aspects of virtual environment technology to provide users with intuitive, multisensory representations of operationally relevant information. This paper describes an evaluation that was recently conducted to contrast the effects of conventional, F-15 types of cockpit displays and virtually-augmented, multisensory cockpit displays on pilot-aircraft system performance, workload, and situation awareness in a simulated air combat task. Eighteen military pilots from the United States, France, and Great Britain served as test pilots. The results indicate a statistically significant advantage for the virtually-augmented cockpit configuration across all three classes of measures investigated. The results are discussed in terms of their relevance for the continuing evolution of advanced crew station design.

An Evaluation of Unisensory and Multisensory Adaptive Flight Path Navigation Displays: An Initial Investigation

Unisensory and multisensory adaptive interfaces for precision aircraft navigation were tested under varying concurrent task demands. Participants - 12 USAF pilots - were required to perform a simulated terrain-following, terrain-avoidance navigation task, including evasive maneuvers, while also performing: (1) no additional task; (2) a visual search task; or (3) an auditory monitoring task. Real-time performance efficiency, as measured by lateral deviation from the flight course, was used to activate the adaptive navigation displays consisting of a visual azimuth steering line on the head-up display, a spatial auditory beacon, or a combination of the two displays. A completely factorial, within-subjects design was used to assess the effects of secondary task load and adaptive interface configurations on flight performance. The results indicated that the efficacy of multisensory, adaptive navigation displays is mediated not only upon the supplementary task confronting the pilots, but also upon the type of flight task performed and the strategies they adopted to acquire and use the information offered. Implications for the use of adaptive multisensory displays in tactical aircraft displays will be discussed.

Return-to-Work Within a Complex and Dynamic Organizational Work Disability System

Background Return-to-work (RTW) within a complex organizational system can be associated with suboptimal outcomes. Purpose To apply a sociotechnical systems perspective to investigate complexity in RTW; to utilize system dynamics modeling (SDM) to examine how feedback relationships between individual, psychosocial, and organizational factors make up the work disability system and influence RTW. Methods SDMs were developed within two companies. Thirty stakeholders including senior managers, and frontline supervisors and workers participated in model building sessions. Participants were asked questions that elicited information about the structure of the work disability system and were translated into feedback loops. To parameterize the model, participants were asked to estimate the shape and magnitude of the relationship between key model components. Data from published literature were also accessed to supplement participant estimates. Data were entered into a model created in the software program Vensim. Simulations were conducted to examine how financial incentives and light duty work disability-related policies, utilized by the participating companies, influenced RTW likelihood and preparedness. Results The SDMs were multidimensional, including individual attitudinal characteristics, health factors, and organizational components. Among the causal pathways uncovered, psychosocial components including workplace social support, supervisor and co-worker pressure, and supervisor-frontline worker communication impacted RTW likelihood and preparedness. Interestingly, SDM simulations showed that work disability-related policies in both companies resulted in a diminishing or opposing impact on RTW preparedness and likelihood. Conclusion SDM provides a novel systems view of RTW. Policy and psychosocial component relationships within the system have important implications for RTW, and may contribute to unanticipated outcomes.

Visual Display Factors Contributing to Simulator Sickness

The history of research on visually-induced illusory self motion, or vection, has demonstrated that in many instances observers have experienced disturbances similar to those of motion sickness. Visual displays in flight simulators may also produce the experience of vection, and illusions of self motion are likely to become more common with the increased use of wide field-of-view presentations of realistic imagery. Many of the disturbances observed in laboratory studies of vection have also been found in simulators, and are likely to become more common. This paper presents a background to the study of visual-vestibular disturbances associated with illusory self motion in flight simulators, and an overview of current experimental efforts aimed at identifying the causal factors.

Individual Differences in Flight Simulation Performance Experiments

In a review of flight simulation performance experiments conducted at the U.S. Navy's Visual Technology Research simulator (VTRS), it was observed that individual difference variables accounted for a major portion of the total explained variance, in many cases more than the simulator equipment variables that were deliberately manipulated. This finding underscores the importance of individual differences in performance and training research in support of man-machine systems development and implementation. The identification of the substrates underlying individual differences will impact on equipment design considerations and training program requirements for military and industrial systems.

A Stakeholder-Based System Dynamics Model of Return-to-Work: A Research Protocol

Background

Returning to work following a job-related injury or illness can be a complex process, influenced by a range of interrelated personal, psychosocial, and organizational components. System dynamics modelling (SDM) takes a sociotechnical systems perspective to view return-to-work (RTW) as a system made up of multiple feedback relationships between influential components.

Design and Methods

To build the RTW SDM, a mixed-method approach will be used. The first stage, that has already been completed, involved creating a baseline model using key informant interviews. Second, in two manufacturing companies, stakeholder-based models will be developed through interviews and focus groups with senior management, frontline workers, and frontline supervisors. Participants will be asked about the RTW process in general and more targeted questions regarding influential components. Participants will also be led through a reference mode exercise where they will be asked to estimate the direction, shape and magnitude of relationships between influential components. Data will be entered into the software program Vensim that provides a platform for visualizing system-structure and simulating the effects of adapting components. Finally, preliminary model validity testing will be conducted to provide insights on model generalizability and sensitivity.

Expected Impact of the study for Public Health

The proposed methodology will create a SDM of the RTW process using feedback relationships of influential components. It will also provide an important simulation tool to understand system behaviour that underlies complex RTW cases, and examine anticipated and unanticipated consequences of disability management policies.

Vection and visually induced motion sickness: how are they related?

The occurrence of visually induced motion sickness has been frequently linked to the sensation of illusory self-motion (vection), however, the precise nature of this relationship is still not fully understood. To date, it is still a matter of debate as to whether vection is a necessary prerequisite for visually induced motion sickness (VIMS). That is, can there be VIMS without any sensation of self-motion? In this paper, we will describe the possible nature of this relationship, review the literature that addresses this relationship (including theoretical accounts of vection and VIMS), and offer suggestions with respect to operationally defining and reporting these phenomena in future.

Capturing complexity in work disability research: application of system dynamics modeling methodology

BACKGROUND

Work disability (WD) is characterized by variable and occasionally undesirable outcomes. The underlying determinants of WD outcomes include patterns of dynamic relationships among health, personal, organizational and regulatory factors that have been challenging to characterize, and inadequately represented by contemporary WD models.

METHOD

System dynamics modeling (SDM) methodology applies a sociotechnical systems thinking lens to view WD systems as comprising a range of influential factors linked by feedback relationships. SDM can potentially overcome limitations in contemporary WD models by uncovering causal feedback relationships, and conceptualizing dynamic system behaviors. It employs a collaborative and stakeholder-based model building methodology to create a visual depiction of the system as a whole. SDM can also enable researchers to run dynamic simulations to provide evidence of anticipated or unanticipated outcomes that could result from policy and programmatic intervention.

DISCUSSION

SDM may advance rehabilitation research by providing greater insights into the structure and dynamics of WD systems while helping to understand inherent complexity. Challenges related to data availability, determining validity, and the extensive time and technical skill requirements for model building may limit SDM's use in the field and should be considered.

IMPLICATIONS FOR REHABILITATION

Contemporary work disability (WD) models provide limited insight into complexity associated with WD processes. System dynamics modeling (SDM) has the potential to capture complexity through a stakeholder-based approach that generates a simulation model consisting of multiple feedback loops. SDM may enable WD researchers and practitioners to understand the structure and behavior of the WD system as a whole, and inform development of improved strategies to manage straightforward and complex WD cases.

Modelling and simulation of complex sociotechnical systems: envisioning and analysing work environments

Accurate comprehension and analysis of complex sociotechnical systems is a daunting task. Empirically examining, or simply envisioning the structure and behaviour of such systems challenges traditional analytic and experimental approaches as well as our everyday cognitive capabilities. Computer-based models and simulations afford potentially useful means of accomplishing sociotechnical system design and analysis objectives. From a design perspective, they can provide a basis for a common mental model among stakeholders, thereby facilitating accurate comprehension of factors impacting system performance and potential effects of system modifications. From a research perspective, models and simulations afford the means to study aspects of sociotechnical system design and operation, including the potential impact of modifications to structural and dynamic system properties, in ways not feasible with traditional experimental approaches. This paper describes issues involved in the design and use of such models and simulations and describes a proposed path forward to their development and implementation.

PRACTITIONER SUMMARY

The size and complexity of real-world sociotechnical systems can present significant barriers to their design, comprehension and empirical analysis. This article describes the potential advantages of computer-based models and simulations for understanding factors that impact sociotechnical system design and operation, particularly with respect to process and occupational safety.

Sociotechnical attributes of safe and unsafe work systems

Theoretical and practical approaches to safety based on sociotechnical systems principles place heavy emphasis on the intersections between social-organisational and technical-work process factors. Within this perspective, work system design emphasises factors such as the joint optimisation of social and technical processes, a focus on reliable human-system performance and safety metrics as design and analysis criteria, the maintenance of a realistic and consistent set of safety objectives and policies, and regular access to the expertise and input of workers. We discuss three current approaches to the analysis and design of complex sociotechnical systems: human-systems integration, macroergonomics and safety climate. Each approach emphasises key sociotechnical systems themes, and each prescribes a more holistic perspective on work systems than do traditional theories and methods. We contrast these perspectives with historical precedents such as system safety and traditional human factors and ergonomics, and describe potential future directions for their application in research and practice.

PRACTITIONER SUMMARY

The identification of factors that can reliably distinguish between safe and unsafe work systems is an important concern for ergonomists and other safety professionals. This paper presents a variety of sociotechnical systems perspectives on intersections between social--organisational and technology--work process factors as they impact work system analysis, design and operation.

Sociotechnical approaches to workplace safety: Research needs and opportunities

The sociotechnical systems perspective offers intriguing and potentially valuable insights into problems associated with workplace safety. While formal sociotechnical systems thinking originated in the 1950s, its application to the analysis and design of sustainable, safe working environments has not been fully developed. To that end, a Hopkinton Conference was organised to review and summarise the state of knowledge in the area and to identify research priorities. A group of 26 international experts produced collaborative articles for this special issue of Ergonomics, and each focused on examining a key conceptual, methodological and/or theoretical issue associated with sociotechnical systems and safety. In this concluding paper, we describe the major conference themes and recommendations. These are organised into six topic areas: (1) Concepts, definitions and frameworks, (2) defining research methodologies, (3) modelling and simulation, (4) communications and decision-making, (5) sociotechnical attributes of safe and unsafe systems and (6) potential future research directions for sociotechnical systems research.

PRACTITIONER SUMMARY

Sociotechnical complexity, a characteristic of many contemporary work environments, presents potential safety risks that traditional approaches to workplace safety may not adequately address. In this paper, we summarise the investigations of a group of international researchers into questions associated with the application of sociotechnical systems thinking to improve worker safety.

Editorial: emerging issues in sociotechnical systems thinking and workplace safety

The burden of on-the-job accidents and fatalities and the harm of associated human suffering continue to present an important challenge for safety researchers and practitioners. While significant improvements have been achieved in recent decades, the workplace accident rate remains unacceptably high. This has spurred interest in the development of novel research approaches, with particular interest in the systemic influences of social/organisational and technological factors. In response, the Hopkinton Conference on Sociotechnical Systems and Safety was organised to assess the current state of knowledge in the area and to identify research priorities. Over the course of several months prior to the conference, leading international experts drafted collaborative, state-of-the-art reviews covering various aspects of sociotechnical systems and safety. These papers, presented in this special issue, cover topics ranging from the identification of key concepts and definitions to sociotechnical characteristics of safe and unsafe organisations. This paper provides an overview of the conference and introduces key themes and topics.

PRACTITIONER SUMMARY

Sociotechnical approaches to workplace safety are intended to draw practitioners' attention to the critical influence that systemic social/organisational and technological factors exert on safety-relevant outcomes. This paper introduces major themes addressed in the Hopkinton Conference within the context of current workplace safety research and practice challenges.

Demonstrating the potential for dynamic auditory stimulation to contribute to motion sickness

Auditory cues can create the illusion of self-motion (vection) in the absence of visual or physical stimulation. The present study aimed to determine whether auditory cues alone can also elicit motion sickness and how auditory cues contribute to motion sickness when added to visual motion stimuli. Twenty participants were seated in front of a curved projection display and were exposed to a virtual scene that constantly rotated around the participant's vertical axis. The virtual scene contained either visual-only, auditory-only, or a combination of corresponding visual and auditory cues. All participants performed all three conditions in a counterbalanced order. Participants tilted their heads alternately towards the right or left shoulder in all conditions during stimulus exposure in order to create pseudo-Coriolis effects and to maximize the likelihood for motion sickness. Measurements of motion sickness (onset, severity), vection (latency, strength, duration), and postural steadiness (center of pressure) were recorded. Results showed that adding auditory cues to the visual stimuli did not, on average, affect motion sickness and postural steadiness, but it did reduce vection onset times and increased vection strength compared to pure visual or pure auditory stimulation. Eighteen of the 20 participants reported at least slight motion sickness in the two conditions including visual stimuli. More interestingly, six participants also reported slight motion sickness during pure auditory stimulation and two of the six participants stopped the pure auditory test session due to motion sickness. The present study is the first to demonstrate that motion sickness may be caused by pure auditory stimulation, which we refer to as “auditorily induced motion sickness”.

Vection and simulator sickness

Simulator sickness has been identified as a form of motion sickness in which users of simulators exhibit symptoms characteristic of true motion sickness. In a fixed-base simulator, visual and vestibular sources of information specifying dynamic orientation are in conflict to the extent that the optical flow pattern viewed by the pilot creates a compelling illusion of self-motion, which is not corroborated by the inertial forces transmitted through the vestibular sense organs. Visually induced illusory self-motion is known as vection, and a strict interpretation of sensory conflict theory of motion sickness suggests that vection in a fixed-base simulator would be a necessary precondition for simulator sickness. Direct confirmation of this relation is reported in this article.

Target detection performance in helmet-mounted and conventional dome displays

An experiment was conducted to assess visual target detection performance using a helmet-mounted display (HMD) and a conventional flight simulation dome display. Measures of workload and mood were also obtained. Participants in both viewing conditions scanned an area 120 degrees vertical by 240 degrees horizontal while attempting to locate targets that appeared to be approaching them from one of a possible 18 locations. Results indicated significantly superior performance in the conventional dome display. Workload and mood measures also showed a significant advantage for the dome display. Results are discussed in terms of their implications for the design and use of HMD systems as components of airborne virtual environment interfaces.

Postural instability and motion sickness in a fixed-based flight simulator

We evaluated the prediction that postural instability would precede the subjective symptoms of motion sickness in a fixed-base flight simulator. Participants sat in a cockpit in a video projection dome and were exposed to optical flow that oscillated in the roll axis with exposure durations typical of flight simulation. The frequencies of oscillation were those that characterize spontaneous postural sway during stance. Head motion was measured prior to and during exposure to imposed optical flow. Of 14 participants, 6 were classified as motion sick, either during or after exposure to the optical oscillation. Prior to the onset of subjective symptoms, head motion among participants who later became sick was significantly greater than among participants who did not become motion sick. We argue that the results support the postural instability theory of motion sickness. Actual or potential applications include the prevention or mitigation of motion sickness in virtual environments.

Effects of localized auditory information on visual target detection performance using a helmet-mounted display

An experiment was conducted to evaluate the effects of localized auditory information on visual target detection performance. Visual targets were presented on either a wide field-of-view dome display or a helmet-mounted display and were accompanied by either localized, nonlocalized, or no auditory information. The addition of localized auditory information resulted in significant increases in target detection performance and significant reductions in workload ratings as compared with conditions in which auditory information was either nonlocalized or absent. Qualitative and quantitative analyses of participants' head motions revealed that the addition of localized auditory information resulted in extremely efficient and consistent search strategies. Implications for the development and design of multisensory virtual environments are discussed. Actual or potential applications of this research include the use of spatial auditory displays to augment visual information presented in helmet-mounted displays, thereby leading to increases in performance efficiency, reductions in physical and mental workload, and enhanced spatial awareness of objects in the environment.

Design of a haptic stick interface as a pilot's assistant in a high turbulence task environment

A study involving 8 Air Force pilots was conducted to examine the efficacy of a force-reflecting joystick to improve performance during a simulated landing task in wind turbulence. By adding certain force characteristics to a joystick, it was of interest to see if performance may change, different control effort may be utilized, and workload measures may be altered based on the joystick utilized. The main results show that certain performance measures significantly improved by having the force reflection condition on. The implications of this study are that in certain types of precision tracking tasks, subjected to external disturbances, the addition of the force characteristics to the joystick can significantly improve performance, result in less effort for control, and lower subjective workload.

Psychophysical Scaling of Circular Vection (CV) Produced by Optokinetic (OKN) Motion: Individual Differences and Effects of Practice

Vection (V) refers to the compelling visual illusion of self-motion experienced by stationary individuals when viewing moving visual surrounds. The phenomenon is of theoretical interest because of its relevance for understanding the neural basis of ordinary self-motion perception, and of practical importance because it is the experience that makes simulation, virtual reality displays, and entertainment devices more vicarious. This experiment was performed to address whether an optokinetically induced vection illusion exhibits monotonic and stable psychometric properties and whether individuals differ reliably in these (V) perceptions. Subjects were exposed to varying velocities of the circular vection (CV) display in an optokinetic (OKN) drum 2 meters in diameter in 5 one-hour daily sessions extending over a 1 week period. For grouped data, psychophysical scalings of velocity estimates showed that exponents in a Stevens' type power function were essentially linear (slope =0.95) and largely stable over sessions. Latencies were slightly longer for the slowest and fastest induction stimuli, and the trend over sessions for average latency was longer as a function of practice implying time course adaptation effects. Test-retest reliabilities for individual slope and intercept measures were moderately strong (r=0.45) and showed no evidence of superdiagonal form. This implies stability of the individual circularvection (CV) sensitivities. Because the individual CV scores were stable, reliabilities were improved by averaging 4 sessions in order to provide a stronger retest reliability (r=0.80). Individual latency responses were highly reliable (r=0.80). Mean CV latency and motion sickness symptoms were greater in males than in females. These individual differences in CV could be predictive of other outcomes, such as susceptibility to disorientation or motion sickness, and for CNS localization of visual-vestibular interactions in the experience of self-motion.

Psychophysical scaling of circular vection (CV) produced by optokinetic (OKN) motion: individual differences and effects of practice

Vection (V) refers to the compelling visual illusion of self-motion experienced by stationary individuals when viewing moving visual surrounds. The phenomenon is of theoretical interest because of its relevance for understanding the neural basis of ordinary self-motion perception, and of practical importance because it is the experience that makes simulation, virtual reality displays, and entertainment devices more vicarious. This experiment was performed to address whether an optokinetically induced vection illusion exhibits monotonic and stable psychometric properties and whether individuals differ reliably in these (V) perceptions. Subjects were exposed to varying velocities of the circular vection (CV) display in an optokinetic (OKN) drum 2 meters in diameter in 5 one-hour daily sessions extending over a 1 week period. For grouped data, psychophysical scalings of velocity estimates showed that exponents in a Stevens' type power function were essentially linear (slope = 0.95) and largely stable over sessions. Latencies were slightly longer for the slowest and fastest induction stimuli, and the trend over sessions for average latency was longer as a function of practice implying time course adaptation effects. Test-retest reliabilities for individual slope and intercept measures were moderately strong (r = 0.45) and showed no evidence of superdiagonal form. This implies stability of the individual circularvection (CV) sensitivities. Because the individual CV scores were stable, reliabilities were improved by averaging 4 sessions in order to provide a stronger retest reliability (r = 0.80). Individual latency responses were highly reliable (r = 0.80). Mean CV latency and motion sickness symptoms were greater in males than in females. These individual differences in CV could be predictive of other outcomes, such as susceptibility to disorientation or motion sickness, and for CNS localization of visual-vestibular interactions in the experience of self-motion.

Changes in the dark focus of accommodation associated with simulator sickness

The relationship between the dark focus of accommodation and simulator sickness, a form of motion sickness, was examined in three experiments. In Experiment 1, dark focus was measured in 18 college students in a laboratory setting before and after they viewed a projected motion scene depicting low altitude helicopter flight. In Experiments 2 and 3, dark focus was measured in pilots (N = 16 and 23, respectively) before and after they "flew" in moving-base helicopter flight simulators with optical infinity CRT visual systems. The results showed that individuals who experienced simulator sickness had either an inward (myopic) change in dark focus (Experiments 1 and 3) or attenuated outward shifts in dark focus (Experiment 2) relative to participants who did not get sick. These results are consonant with the hypothesis that parasympathetic activity, which may be associated with simulator sickness, should result in changes in dark focus that are in a myopic direction. Night vision goggles, virtual environments, extended periods in microgravity, and heads-up displays all produce related visual symptomatology. Changes in dark focus may occur in these conditions, as well, and should be measured.

Visual tasks in helicopter shipboard landing

The purpose of this research was to identify visual scene content important in helicopter shipboard landings, particularly in the hover phase, for further study in a research simulator. A second purpose was to illustrate the use of a methodology (Protocol Analysis) which may hold promise for many areas of human factors research. Discussions with pilots, reviews of relevant Naval Aviation Training and Operational Procedures (NATOPS) manuals and observation of simulated helicopter shipboard landings suggested that the visual elements required in helicopter shipboard landings may depend upon whether experienced or inexperienced pilots are flying, a simulator or an aircraft is flown, the environment is day or night, or the pilot seeks to acquire or maintain a skill level. A scenario involving an experienced pilot flying dusk/night approaches in a simulator was intensively studied. As he flew each approach, the pilot dictated real-time verbal protocols of his visual and control activities. These protocols were subsequently partitioned by the authors into nine phases defined in terms of range or altitude from the ship, and the visual tasks required in each segment were described. An outcome of this analysis was a list of visual cue augmentations that may be useful for providing augmented feedback in training.

Optical information for detecting loss in one's own forward speed

An experiment was conducted to determine whether accuracy and efficiency of detecting loss in one's own forward speed are constant when optical information is invariant over a wide range of environmental variables. Deceleration rate, initial forward velocity, and altitude were varied so as to isolate initial optical flow rate, optical flow deceleration, and optical flow damping invariants specified in observer-relevant metrics. The candidate resulting in the most consistent effect on performance was global damping, which specifies a contrast of flow deceleration with initial flow rate. The finding is a first step toward validating a procedure for identifying functional invariants by assessing the usefulness of mathematically specified optical information for the perception of egomotion. The research represents both a methodological development and empirical support for the broader program of ecological functionalism.