bluuebunny/crossref_metadata_2025 huggingface dataset:
Contributions of Proprioception to Navigation in Virtual Environments
Authors: Grant Stuart C. , Magee Lochlan E.
Published: January 2007

Users immersed in virtual environments (VEs) are prone to disorientation and have difficulty transferring spatial knowledge to the real world. A single experiment investigated the contribution of inadequate proprioception to this problem by providing participants with interfaces to a virtual environment that either did (a walking interface) or did not (a joystick) afford proprioceptive feedback similar to that obtained during real walking. The 2 groups explored a large, complex building using a low-resolution head-mounted display. Later, their navigational abilities within the actual building were compared with those of control groups who either studied a map of the building, walked through the real building, or received no prior training. The walking interface conveyed no benefit on an orientation task performed during training in the VE, but it did benefit participants when they tried to find objects in the real world. Actual or potential applications include simulations of environments that are normally explored on foot but cannot be readily visited, such as infantry battlefields and facilities contaminated with chemical, biological, or radiological materials.
Effects of Localized Auditory Information on Visual Target Detection Performance Using a Helmet-Mounted Display
Authors: Nelson W. Todd , Hettinger Lawrence J. , Cunningham James A. , Brickman Bart J. , Haas Michael W. , McKinley Richard L.
Published: January 2007

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.
Measuring Skill Acquisition and Retention with an ATM Simulator: The Need for Age-Specific Training
Authors: Mead Sherry , Fisk Arthur D.
Published: January 2007

The present study focused on the type of information presented during training and its effects on initial and retention performance of older and younger adults interacting with computerized, new technology. The effects of emphasizing concepts versus actions during training on performance immediately after training and after a 1-month retention interval were examined. Younger and older adults completed either action or concept training for operating a virtual automatic teller machine (ATM). Overall, action training was associated with faster and more accurate performance immediately after training and better retention performance for older adults. For older adults, value of type of training interacted with type of task component. These findings are applicable to the development of age-specific training materials for computerized tasks.
Manipulation Performance in Interactive Virtual Environments
Authors: Werkhoven Peter J. , Groen Joris
Published: January 2007

We studied manipulation performance in virtual environments using two types of controllers: virtual hand control and three-dimensional (3D) mouse/cursor control. These manipulation methods were tested under monoscopic and stereoscopic viewing conditions. Participants were asked to discriminate, grasp, pitch, roll, and position virtual objects. Speed and accuracy of manipulation tasks were measured. Virtual hand control proved to be significantly faster and more accurate than 3D mouse cursor control. Participants made more head movements in the virtual hand condition than in the mouse-cursor condition. Further, it was shown that the speed and accuracy of manipulations are much improved under stereoscopic viewing conditions. Actual or potential applications of this research include virtual training environments (assembly, maintenance, etc.) virtual prototyping, teleoperations, and so forth.
Aurally and Visually Guided Visual Search in a Virtual Environment
Authors: Flanagan Patrick , McAnally Ken I. , Martin Russell L. , Meehan James W. , Oldfield Simon R.
Published: January 2007

We investigated the time participants took to perform a visual search task for targets outside the visual field of view using a helmet-mounted display. We also measured the effectiveness of visual and auditory cues to target location. The auditory stimuli used to cue location were noise bursts previously recorded from the ear canals of the participants and were either presented briefly at the beginning of a trial or continually updated to compensate for head movements. The visual cue was a dynamic arrow that indicated the direction and angular distance from the instantaneous head position to the target. Both visual and auditory spatial cues reduced search time dramatically, compared with unaided search. The updating audio cue was more effective than the transient audio cue and was as effective as the visual cue in reducing search time. These data show that both spatial auditory and visual cues can markedly improve visual search performance. Potential applications for this research include highly visual environments, such as aviation, where there is risk of overloading the visual modality with information.
Nonvisually Guided Locomotion to a Previously Viewed Target in Real and Virtual Environments
Authors: Witmer Bob G. , Sadowski Wallace J.
Published: January 2007

Comparing human performance in a virtual environment (VE) with performance in the real world can provide clues about which aspects of VE technology require improvement. Using a technique previously shown to measure real-world distance judgments accurately, we compared performance in a real-world environment with performance in a virtual model of that environment. The technique required participants to walk without vision to a target after viewing it for 10 s. VE distance judgments averaged 85% of the target distance, whereas real-world judgments averaged 92%. The magnitude of the relative errors in the VE was twice that in the real world, indicating that the VE degraded distance judgments. Our analysis suggests that VE performance deficits result either from poor binocular disparity cues or from distortion of pictorial depth cues. Actual or potential applications of this research include the development of virtual environments for training and the design of visual displays for virtual simulations.
Ocular Vergence Measurement in Projected and Collimated Simulator Displays
Authors: Morahan Paul , Meehan James W. , Patterson John , Hughes Philip K.
Published: January 2007

The purpose of this study was to investigate electrooculography (EOG) as a measurement of ocular vergence in both collimated and projected simulator environments. The task required participants to shift their gaze between a central fixation point and a target appearing at one of three eccentricities. EOG was effective in recording ocular vergence. The EOG results were similar between collimated and projected displays, except for differences in vergence changes during lateral movement of the eyes, and ocular excursions downward elicited a greater EOG response than the reverse upward movement. The computer-based technique of recording vergence was found to produce measurable traces from a majority of participants. The technique has potential for further development as a tool for measuring ocular vergence in virtual environments where methods that require the wearing of headmounted apparatus to track ocular structures (e.g., the pupil), which cannot be worn at the same time as a flight or flight-simulator helmet, are unsuitable.
The Influence of Body Movement on Subjective Presence in Virtual Environments
Authors: Slater Mel , Steed Anthony , McCarthy John , Maringelli Francesco
Published: January 2007

We describe an experiment to assess the influence of body movements on presence in a virtual environment. In the experiment 20 participants were to walk through a virtual field of trees and count the trees with diseased leaves. A 2 × 2 between-subjects design was used to assess the influence of two factors on presence: tree height variation and task complexity. The field with greater variation in tree height required participants to bend down and look up more than in the lower variation tree height field. In the higher complexity task participants were told to remember the distribution of diseased trees in the field as well as to count them. The results showed a significant positive association between reported presence and the amount of body movement - in particular, head yaw - and the extent to which participants bent down and stood up. There was also a strong interaction effect between task complexity and gender: Women in the morecomplex task reported a much lower sense of presence than in the simpler task. For applications in which presence is an important requirement, the research in this paper suggests that presence will be increased when interaction techniques are employed that permit the user to engage in whole-body movement.
The Relationship between Low Back Discomfort Ratings and the NIOSH Lifting Index
Authors: Wang Mao-Jiun J. , Garg Arun , Chang Yu-Cheng , Shih Yuh-Chuan , Yeh Wen-Yu , Lee Cheng-Lung
Published: January 2007

An epidemiological study was performed to evaluate the relation between lowback discomfort ratings and use of the revised NIOSH lifting guide to assess the risk of manual material handling (MMH) tasks. We surveyed 97 MMH workers on site in 15 factories and designed a questionnaire to systematically collect jobrelated information. Approximately 90% of the workers had suffered various degrees of lower back discomfort, and 80% had sought medical treatment. The survey showed that 42 of the 97 jobs analyzed had a recommended weight limit of 0, which was attributed to either a horizontal distance or a lifting frequency that exceeded the bounds of the NIOSH lifting index. Apparently, the limits for horizontal distance and maximum allowable frequency are too stringent to accommodate many existing MMH jobs. For the remaining 55 jobs, the significant positive correlation obtained between the lifting index and the severity of low-back discomfort suggests that the lifting index is reliable in assessing the potential risk of low-back injury in MMH. These findings provide useful information on the application of the NIOSH lifting guide to the assessment of lowback pain.
Telepresence
Authors: Draper John V. , Kaber David B. , Usher John M.
Published: January 2007

Telepresence, the perception of presence within a physically remote or simulated site, has been identified as a design ideal for synthetic environments. However, confusion exists within the literature about the precise definition of telepresence. Furthermore, there is a need for a plausible and parsimonious model of telepresence. This paper identifies three types of telepresence extant in the literature: simple telepresence, cybernetic telepresence, and experiential telepresence. The third definition is the most interesting. This paper reviews the origins of experiential telepresence and the theoretical approaches commonly used to explain it. One can term these technological approaches, which emphasize the role of control/display technology, and psychological approaches, which identify experiential telepresence with known psychological phenomena. Finally, the paper presents and discusses an integrative approach to telepresence featuring a structured attentional resource model. Actual or potential applications of this research include the design of future human-machine interfaces for teleoperated robots and virtual reality systems.
Empirical Models Based on Free-Modulus Magnitude Estimation of Perceived Presence in Virtual Environments
Authors: Snow Michael P. , Williges Robert C.
Published: January 2007

A series of 3 studies was conducted to test free-modulus magnitude estimation as a measure of perceived presence in virtual environments (VEs) and to model the first-and second-order effects of 11 VE system parameters on perceived presence across 5 subtasks. Sequential experimentation techniques were used to build 4 empirical models using polynomial regression. An integrated empirical model of data combined across 2 experiments demonstrated that all significant factors had a positive effect on perceived presence. Three of these parameters - field of view, sound, and head tracking - had almost 3 times as much influence on presence than the other 4 significant parameters, which were visual display resolution, texture mapping, stereopsis, and scene update rate. Sequential experimentation was an efficient tool for building empirical models of perceived presence, but the subjective nature of this phenomenon and individual differences made data bridging across sequential studies problematic. It was concluded that magnitude estimation is a useful measure of perceived presence, and the resulting polynomial regression models can be used to facilitate VE system design decisions. This research has broad application in the selection and design of VE system components and overall design of VE systems.
Frame of Reference Effects on Scientific Visualization Subtasks
Authors: McCormick Edward P. , Wickens Christopher D. , Banks Rachel , Yeh Michelle
Published: January 2007

Performance measures for 3 frames of reference (full exocentric, full egocentric, and tethered) were contrasted across 4 different scientific visualization subtasks: search, travel, local judgment support, and global judgment support. Participants were instructed to locate and follow a designated path through 15 simple virtual environments and to answer simple questions about that environment. Each participant completed 5 trials in every frame of reference condition (exocentric, egocentric, and tethered). The results revealed that frames of reference that utilize egocentric or tethered viewpoints support better travel performance, especially when nearing the target. However, the exocentric frame of reference supported better performance in the search subtasks and in the local and global judgment subtasks. Actual or potential applications of this research include proper uses of virtual reality to support certain scientific visualization subtasks.
Evidence from a Partial Report Task for Forgetting in Dynamic Spatial Memory
Authors: Gugerty Leo
Published: January 2007

G. Sperling (1960) and others have investigated memory for briefly presented stimuli by using a partial versus whole report technique in which participants sometimes reported part of a stimulus array and sometimes reported all of it. For simple, static stimulus displays, the partial report technique showed that participants could recall most of the information in the stimulus array but that this information faded quickly when participants engaged in whole report recall. An experiment was conducted that applied the partial report method to a task involving complex displays of moving objects. In the experiment, 26 participants viewed cars in a low-fidelity driving simulator and then reported the locations of some or all of the cars in each scene. A statistically significant advantage was found for the partial report trials. This finding suggests that detailed spatial location information was forgotten from dynamic spatial memory over the 14 s that it took participants to recall whole report trials. The experiment results suggest better ways of measuring situation awareness. Partial report recall techniques may give a more accurate measure of people's momentary situation awareness than whole report techniques. Potential applications of this research include simulator-based measures of situation awareness ability that can be part of inexpensive test batteries to select people for real-time tasks (e.g., in a driver licensing battery) and to identify people who need additional training.
Does CRM Training Improve Teamwork Skills in the Cockpit?: Two Evaluation Studies
Authors: Salas Eduardo , Fowlkes Jennifer E. , Stout Renée J. , Milanovich Dana M. , Prince Carolyn
Published: January 2007

Crew resource management (CRM) has been the most widely used instructional strategy to enhance teamwork skills within aviation. However, few studies have provided empirical evidence that this strategy results in increased use of teamwork behaviors. The current paper describes 2 evaluation studies of CRM training that were conducted with 96 naval aviators and followed a multiple assessment approach. Results indicated that highly experienced aviators benefited from the training, which focused on increasing the use of several critical teamwork skills. These rare evaluation data suggest that CRM training is a viable strategy for improving teamwork in the cockpit. Implications for team training are discussed.
The Effects of Complex Wrist and Forearm Posture on Wrist Range of Motion
Authors: Marshall Matthew M. , Mozrall Jacqueline R. , Shealy Jasper E.
Published: January 2007

Previous research on wrist functionality has focused almost entirely on range of motion (ROM) in 2 or 3 isolated planes (flexion/extension, radial/ulnar deviation, and forearm pronation/supination), without investigating the potential effects of complex wrist/forearm posture on ROM. A quantitative analysis of these effects on wrist ROM was performed. ROM was measured in one plane using both a manual method and an electrogoniometer while the participant maintained a fixed, secondary wrist and forearm posture. The study revealed that combinations of wrist/forearm postures have significant effects on wrist ROM; the largest effects are those of wrist flexion/extension on radial deviation ROM. The study also found that, consistent with previous research, wrist deviation measurements obtained with an electrogoniometer were significantly different from those obtained manually. Biomechanical theories for the results obtained are discussed. This research could be used to enhance ergonomic evaluation techniques by providing a more accurate risk assessment of certain complex wrist postures, particularly those in which wrist flexion/extension is combined with radial deviation.
The Utility of Display Space in Keeping Track of Rapidly Changing Information
Authors: Hess Stephen M. , Detweiler Mark C. , Ellis R. Darin
Published: January 2007

The results of 4 experiments suggest that the information available in graphic displays can have considerable performance consequences and that the kind of display invariants provided can interact with variables such as task difficulty, working-memory load, and the organization of information that is to be remembered. In Experiment 1, participants benefited from the presence of invariant spatial correlates of values to be remembered and showed superior performance (fewer errors and faster responses) relative to participants using a spatially impoverished display, regardless of information organization. Experiment 2 showed that the presence of unique verbal labels for items to be remembered aids keeping track performance. Experiments 3 and 4 provided further evidence that participants kept track of changing information best in conditions with spatial display invariants. These data are relevant to practitioners faced with designing soft monitoring displays - that is, displays involving multiple attributes of a single object in some cases (e.g., the temperature and pressure in a boiler) and one attribute of many objects in others (e.g., the current flow through several valves feeding the same system). Actual or potential applications of this research include improving computer displays designed to support complex, memoryintensive monitoring performance
Adaptive Team Coordination
Authors: Entin Elliot E. , Serfaty Daniel
Published: January 2007

It is hypothesized that highly effective teams adapt to stressful situations by using effective coordination strategies. Such teams draw on shared mental models of the situation and the task environment as well as mutual mental models of interacting team members' tasks and abilities to shift to modes of implicit coordination, and thereby reduce coordination overhead. To test this hypothesis, we developed and implemented a team-training procedure designed to train teams to adapt by shifting from explicit to implicit modes of coordination and choosing strategies that are appropriate during periods of high stress and workload conditions. Results showed that the adaptation training significantly improved performance from pre- to posttraining and when compared with a control group. Results also showed that several underlying team process measures exhibited patterns indicating that adaptive training improved various team processes, including efficient use of mental models, which in turn improved performance. The implication of these findings for team adaptive training is discussed. This research spawned the adaptive architectures for a command and control project investigating adaptive models that focus on changes in the structural and process architecture of large organizations. The research also produced a cadre of integrated performance assessment tools that have been used in training and diagnostic settings, and new components for a team training package focused on effective coordination in high-performance teams.
Age, Luminance, and Print Legibility in Homes, Offices, and Public Places
Authors: Charness Neil , Dijkstra Katinka
Published: January 2007

Field studies were conducted in homes, offices, and public places with younger and older adults to determine how legibility performance (in a proofreading and phone book search) changes with age and luminance. Homes and public places generally exhibited much lower than recommended luminance values for reading. Older adults had higher light levels in their homes than did younger adults at reading locations. Older adults performed less quickly than did younger adults on most legibility tasks. Adding light helped younger and older adults equally for most legibility tasks (in homes and public places), though increased luminance differentially improved the performance of older office workers. In response to feedback about low light levels, nearly 60% of building managers in public places indicated in a 6-month follow-up that they had improved lighting or were planning to do so. Actual or potential applications of this work include setting luminance guidelines for adults and identifying barriers to lighting changes.
Effects of Earplugs and Protective Headgear on Auditory Localization Ability in the Horizontal Plane
Authors: Vause Nancy L. , Grantham D. Wesley
Published: January 2007

The purpose of this study was to determine how well humans localize sound sources in the horizontal plane while wearing protective headgear with and without hearing protection. In a source identification task, a stimulus was presented from 1 of 20 loudspeakers arrayed in a semicircular arc, and participants stated which loudspeaker emitted the sound. Each participant was tested in 8 conditions involving various combinations of wearing a Kevlar® army helmet and two types of earplugs. Testing was conducted at each of 2 orientations (frontal and lateral). In the frontal orientation, overall error was slightly greater in all protected conditions than in the bare-head control condition. In the lateral orientation, overall error score in the protected conditions was substantially and significantly greater than in the bare-head control conditions. Most errors in the lateral orientation were accounted for by front-back confusions, indicating that the protective devices disrupted high-frequency spectral cues that are the basis for discriminating front from back sound sources. The results have practical implications for the use of protective headgear and earplugs in industrial or military environments where localization of critical sounds is important
An On-the-Road Comparison of In-Vehicle Navigation Assistance Systems
Authors: Eby David W. , Kostyniuk Lidia P.
Published: January 2007

We compared system performance and driver opinion of 3 in-vehicle navigation aids - two advanced traveler information systems (ATISs; Ali-Scout and TetraStar) and written instructions - when used on the road concurrently under identical conditions. Few drivers in the study had difficulty finding initial routes or became lost. Users of Ali-Scout, an ATIS that utilizes traffic information in routing, drove longer-distance routes, got lost more frequently, and gave their system less positive ratings than did TetraStar users. Users of the 2 ATISs traversed routes that were significantly shorter in duration than those driven by users of written instructions. The time savings benefit of the advanced technology systems over written instructions was greatest during peak traffic conditions. Drivers who were familiar with the road network, overall, had less difficulty finding destinations and drove shorter-duration routes than drivers who were unfamiliar with the road network. Actual or potential applications of this research include improving the design of technologies that provide navigation assistance to travelers.
Footwear Cushioning: Relating Objective and Subjective Measurements
Authors: Goonetilleke Ravindra S.
Published: January 2007

Footwear cushioning was evaluated objectively using an impact tester and related to perceived levels of cushioning (PLC). To evaluate the perceived levels of cushioning during standing, walking, and running, 3 experiments were conducted with 20 participants in each experiment. A 7-point subjective rating scale was used to rate the perceived levels of cushioning. At the end of the experiment, the subjective perceptions of cushioning were also recorded. During standing and running, the perceived level of cushioning can be predicted from the time to peak deceleration and/or stiffness (or compression). During walking, however, the magnitude of the peak deceleration on the impact tester appears to be a good predictor of PLC. Impact characterizations can reveal important differences between materials and how they are perceived during activity. In addition, the results seem to explain and link the differences that exist in the ergonomics and biomechanics literature on cushioning. Applications of this research include the design and selection of materials for footwear, floor mats, and other supporting surfaces.
Effects of Pacing When Using Material Handling Manipulators
Authors: Nussbaum Maury A. , Chaffin Don B.
Published: January 2007

Common manipulator-assisted materials handling tasks were performed in a laboratory simulation at self-selected and faster (paced) speeds. The effects of pacing on peak hand forces, torso kinematics, spine moments and forces, and muscle antagonism were determined, along with any influences of several task variables on these effects. The faster trials were performed 20% more rapidly than the self-paced trials. It was found that (a) achieving this level of performance required 10% higher hand forces and 5%-10% higher torso moments, (b) consistent torso postures and motions were used for both speed conditions, and (c) the faster trials resulted in 10% higher spine forces and 15% higher levels of lumbar muscle antagonism. On whole, these results suggest a higher risk of musculoskeletal injury associated with performance of object transfers at faster than self-selected speeds with and without a manipulator. Further analysis provided evidence that the use of manipulators involves higher levels of motor coordination than do manual tasks. Several implications regarding the use of material handling manipulators in paced operations are discussed. Results from this investigation can be used in the design, evaluation, and selection of material handling manipulators.
The Hysteresis Effect
Authors: Farrell Philip S. E.
Published: January 2007

The term hysteresis effect refers to the shape of a performance curve when plotted against increasing and then decreasing demand. Performance during increasing demand reaches a maximum point and begins to deteriorate at high demand levels, whereas performance during decreasing demand is significantly degraded. The Short-Term Memory, expectancy, and other hypotheses have attempted to explain the hysteresis effect. In this paper it is argued that the hysteresis effect could be described by three phases of cognitive processing: an ideal transmission phase, a varying reaction time phase, and a sampling strategy phase. A mathematical model of human information processing was developed to explore the hypothesis. The model was simulated using the Model Human Processor parameters (S. K. Card, T. P. Moran, & A. Newell, 1983). Experimental results demonstrated each processing phase in reproducing the hysteresis effect. Implications for human-machine systems are discussed. Actual or potential applications of this research include air traffic control, flight deck procedures, and interface design
Repetition Improves Older and Younger Adult Memory for Automated Appointment Messages
Authors: Morrow Daniel , Leirer Von O. , Carver Lisa M. , Tanke Elizabeth Decker , McNally Alison D.
Published: January 2007

Automated telephone messaging systems have dramatically expanded communication about health service appointments, but few studies have directly investigated these messages. The present study investigated whether message repetition (1, 2, or 3 presentations) and listener age (mean age = 71 or 19 years) improved memory for automated appointment messages. Repetition improved older and younger adult memory for appointment information. Moreover, 2 presentations reduced age differences in accuracy of answering questions about the messages. This was not the case for free recall, suggesting that older adults differentially benefited from repetition only when provided with additional retrieval support. These findings show that older as well as younger adults benefit from at least 1 repetition of appointment messages. Actual or potential applications of this research include the use of repetition to improve comprehension of automated telephone messages.
Effects of Head-Slaved and Peripheral Displays on Lane-Keeping Performance and Spatial Orientation
Authors: Kappé Bart , van Erp Jan , Korteling J. E. (Hans)
Published: January 2007

To improve the efficiency of images presented in low-cost vehicle simulators, the virtual viewing direction (i.e., the direction in which the image is rendered) can be head-slaved, the display can be surrounded with a less detailed peripheral image, or both. Three simulator experiments were used to evaluate the effect of these techniques on lane-keeping performance and spatial orientation. In Experiment 1, vehicle references or a head-slaved display (HSD) provided feedback on the virtual viewing direction. Vehicle references improved lane-keeping performance somewhat with a standard 50° h x 50° v display. An HSD (50° h x 50° v) allowed better steering performance, but not to the levels obtained with a wide display (150° h x 50° v). Experiments 2a and 2b evaluated the effects of surrounding the HSD with a less detailed peripheral image and of moving the HSD discretely or continuously. With the peripheral image, lane-keeping performance (Experiment 2a) and spatial orientation (Experiment 2b) were similar to those with a wide display. In both experiments, performance with the discretely moving HSD was superior to that with the continuously moving HSD. The results show that low-cost driving simulators can be equipped with more efficient displays that are as effective as wide displays for lane-keeping and spatial orientation.
Effectiveness of an Intervention to Increase Construction Workers' Use of Hearing Protection
Authors: Lusk Sally L. , Hong Oi Saeng , Ronis David L. , Eakin Brenda L. , Kerr Madeleine J. , Early Margaret R.
Published: January 2007

In this project we tested the effectiveness of a theory-based intervention (video, pamphlets, and guided practice session) to increase the use of hearing protection devices (HPDs) among Midwestern construction workers and a national group of plumber/pipefitter trainers. Posttest measures were collected 10--12 months following this intervention. Pender's Health Promotion Model (1987) provided the conceptual basis for development of the training program. A total of 837 highnoise- exposed workers were included in the analysis: 652 regional Midwestern construction workers and 185 national plumber/pipefitter trainers. Effectiveness of the intervention was determined through the sequence of analyses recommended by Braver and Braver (1988) for the Solomon Four-Group Design. Analysis of variance and covariance of postintervention use and intention to use HPDs and a meta-analytic test were done. These analyses indicated that the intervention significantly increased use of HPDs but had no effect on intention to use HPDs in the future. Pretesting had no effect on use. Actual or potential applications of this research include guidance in the development of successful theorybased interventions to increase use of HPDs.
Wrist and Forearm Postures of Users of Conventional Computer Keyboards
Authors: Simoneau Guy G. , Marklin Richard W. , Monroe John F.
Published: January 2007

The aim of this study was to perform a comprehensive investigation to document wrist and forearm postures of users of conventional computer keyboards. We instrumented 90 healthy, experienced clerical workers with electromechanical goniometers to measure wrist and forearm position and range of motion for both upper extremities while typing. For an alphabetic typing task, the left wrist showed significantly greater (p < .01) mean ulnar deviation (15.0° ± 7.7°) and extension (21.2° ± 8.8°) than the right wrist (10.1° ± 7.2° and 17.0° ± 7.4° for ulnar deviation and extension, respectively). Conversely, the right forearm had greater mean pronation (65.6° ± 8.3°) than the left forearm (62.2° ± 10.6°). We noted minimal functional differences in the postures of the wrists and forearms between alphabetic and alphanumeric typing tasks. Ergonomists should consider the statistically significant and probable practical difference in wrist and forearm posture between the left and right hand in ergonomic interventions in the office and in the design of computer keyboards. Actual or potential applications of this research include guiding the design of new computer keyboards.
Effects of Cueing and Knowledge of Results on Workload and Boredom in Sustained Attention
Authors: Hitchcock Edward M. , Dember William N. , Warm Joel S. , Moroney Brian W. , See Judi E.
Published: January 2007

Two models of recently reported high workload associated with vigilance tasks are the direct-cost and indirect-cost views. The former attributes high workload to the need for continuous observation in discriminating signals from neutral events; the latter attributes it to efforts to combat the boredom associated with monotonous vigilance tasks. These opposing views were tested by providing observers with reliable cueing, which rendered observation necessary only when low-probability critical signals were imminent, or with knowledge of results (KR) regarding performance efficiency. On the basis of cue and KR differences in elicited observation activity and motivational value, the direct-cost model led to the anticipation that cueing would result in a high-boredom, low-workload profile and a greater reduction in workload than KR. The indirect-cost model led to the prediction that cueing would result in a high-boredom, high-workload profile and a lesser reduction in workload than KR. The results clearly supported the direct-cost view that the workload of vigilance is task-induced. Consequently, efforts to combat high workload in complex automated systems requiring substantial monitoring by operators should focus specifically upon task-related determinants.
Modeling Computer Interest in Older Adults: The Role of Age, Education, Computer Knowledge, and Computer Anxiety
Authors: Ellis R. Darin , Allaire Jason C.
Published: January 2007

We proposed a mediation model to examine the effects of age, education, computer knowledge, and computer anxiety on computer interest in older adults. We hypothesized that computer knowledge and computer anxiety would fully mediate the effects of age and education on computer interest. A sample of 330 older adults from local senior-citizen apartment buildings completed a survey that included an assessment of the constructs included in the model. Using structural equation modeling, we found that the results supported the hypothesized mediation model. In particular, the effect of computer knowledge operated on computer interest through computer anxiety. The effect of age was not fully mitigated by the other model variables, indicating the need for future research that identifies and models other correlates of age and computer interest. The most immediate application of this research is the finding that a simple 3-item instrument can be used to assess computer interest in older populations. This will help professionals plan and implement computer services in public-access settings for older adults. An additional application of this research is the information it provides for training program designers.
Critique of "Distance Estimation with Night Vision Goggles: A Little Feedback Goes a Long Way"
Authors: DeLucia Patricia R.
Published: January 2007

The Editor invited me to critique the previous article in a "critique-rebuttal" format. Consistent with an approach adopted earlier (Maddox, 1996), I aim to foster a positive and informative scholarly exchange.

The article has several strengths. First, it addresses a topic that has practical importance. For example, night vision goggles (NVGs) have played an important role in military operations; it is critical that pilots make accurate judgments about depth and collision (e.g., DeLucia & Task, 1995). Furthermore, it is difficult to conduct research on NVGs; they are relatively costly and manipulations are constrained by available technology. Thus, studies on NVGs are important. Second, the authors' results regarding performance with NVGs extend those obtained without NVGs: (1) Reports of absolute distance can improve with training (e.g., Ferris, 1972; Gibson & Bergman, 1954); (2) Judgments of distance can vary with the orientation of the distance with respect to the viewer (Wagner, 1985). My comments focus on several aspects of the methods, and interpretations of the results.
Distance Estimation with Night Vision Goggles: A Little Feedback Goes a Long Way
Authors: Niall Keith K. , Reising Jack D. , Martin Elizabeth L.
Published: January 2007

Immediate feedback was given to correct observers' estimates of distance in an experiment in which those estimates were made outdoors at night while observers wore night vision goggles (NVGs). Initially observers made unguided estimates of distances between marked positions in an open field. Those distances ranged from 7.6 m (25 ft) to 64 m (210 ft). Later the same observers made more estimates. After each of these they were told the measured distance between the positions. During this training, the observers' height from the ground plane was either at a standing position or at an elevated position raised 2.3 m (7 ft 7 in) from standing position. After the training -- either immediately after, a week later, or at both times -- observers made unguided estimates of distance for a second time. These latter estimates of ground distance made with the NVGs were improved. Average improvement of the observers' estimates persisted for at least one week after training. This training can be applied to improve clearance estimates and estimates of hover height for pilots of rotarywing aircraft.
Visual Search of Food Nutrition Labels
Authors: Goldberg Joseph H. , Probart Claudia K. , Zak Robert E.
Published: January 2007

Using an eye-tracking methodology, we evaluated food nutrition labels' ability to support rapid and accurate visual search for nutrition information. Participants (5 practiced label readers and 5 nonreaders) viewed 180 trials of nutrition labels on a computer, finding answers to questions (e.g., serving size). Label manipulations included several alternative line arrangements, location of the question target item, and label size. Dependent measures included search time and number of fixations prior to visually capturing the target, as well as the accuracy and duration of the capturing fixation. Practiced label readers acquired the target more quickly and accurately than did less-practiced readers. Targets near the denser center of the label required 33% more time and were harder to find than targets at the top or bottom of the label. Thinner alignment lines were more influential than thicker anchoring lines on visual search time. Overall, the current nutrition label supported accurate and rapid search for desired information. Potential applications of the present methodology include the evaluation of warning labels and other static visual displays.
Perceptual Ability with Real-World Nighttime Scenes: Image-Intensified, Infrared, and Fused-Color Imagery
Authors: Essock Edward A. , Sinai Michael J. , McCarley Jason S. , Krebs William K. , DeFord J. Kevin
Published: January 2007

We investigated human perceptual performance allowed by relatively impoverished information conveyed in nighttime natural scenes. We used images of nighttime outdoor scenes rendered in image-intensified low-light visible (i2) sensors, thermal infrared (ir) sensors, and an i2/ir fusion technique with information added. We found that nighttime imagery provides adequate low-level image information for effective perceptual organization on a classification task, but that performance for exemplars within a given object category is dependent on the image type. Overall performance was best with the false-color fused images. This is consistent with the suggestion in the literature that color plays a predominate role in perceptual grouping and segmenting of objects in a scene and supports the suggestion that the addition of color in complex achromatic scenes aids the perceptual organization required for visual search. In the present study, we address the issue of assessment of perceptual performance with alternative night-vision sensors and fusion methods and begin to characterize perceptual organization abilities permitted by the information in relatively impoverished images of complex scenes. Applications of this research include improving night vision, medical, and other devices that use alternative sensors or degraded imagery.
Older Observers' Tolerance of Optical Blur: Age Differences in the Identification of Defocused Text Signs
Authors: Kline Donald W. , Buck Kimberly , Sell Yvonne , Bolan Thomas L. , Dewar Robert E.
Published: January 2007

To determine if visual aging affects the ability to identify blurred text signs in daytime or nighttime viewing conditions, the photopic and mesopic legibility thresholds of young and old adult observers were compared at three levels of optically induced acuity (Experiment 1). For both age groups, legibility was reduced by nighttime luminance and degraded acuity. Surprisingly, older observers were better than younger ones in identifying defocused (optically blurred) text in both daytime and nighttime conditions. In Experiment 2, older observers were also superior to younger ones in identifying defocused standard and spatially matched novel text signs. These findings indicate that older observers' tolerance of optical blur is a generic ability, rather than one explained by familiarity with the low-pass optical profile of specific signs. Consistent with the notion that factors beyond acuity contribute more importantly to text legibility for older than for younger observers, acuity was a stronger predictor of legibility thresholds in the younger group. Actual or potential applications of this research include the need to consider functional acuity in visual screening protocols and the design of text displays, as well as the utilization of compensatory letter-recognition training for older observers or others with diminished acuity.
Three Studies Testing the Effects of Role Models on Product Users' Safety Behavior
Authors: deTurck Mark A. , Chih I-Hua , Hsu Ya-Ping
Published: January 2007

Three studies were conducted to determine the effect of a role model's safety behavior on observers' safety behavior. In Studies 1 and 2, role models (confederates) used a cleaning product requiring them to wear safety gloves. Study 1 examined observers' safety behavior after they witnessed a friendly (unfriendly) role model's safety behavior in one of four conditions: 1) wearing rubber gloves, 2) not wearing rubber gloves and experiencing no chemical burn, 3) not wearing rubber gloves and experiencing a mild chemical burn, and 4) not wearing rubber gloves and experiencing a severe chemical burn. In Study 2, participants tested a cleaning product with a warning message (low hazard vs. high hazard) after observing a role model first test the cleaning product in one of the four conditions specified above. As predicted, in Studies 1 and 2, observers were influenced by the role model's safety behavior. However, the friendliness of the role model (Study 1) and level of hazard (Study 2) communicated in the warning message did not influence participants' safety behavior. Using an over-thecounter pain reliever, Study 3 tested the joint effects of: 1) the level of hazard communicated in the warning, 2) observers' outcome-relevant involvement, and 3) role model's compliance. Although the level of hazard communicated in the warning exerted no impact on observers' safety compliance, the role model's safety behavior and level of involvement jointly influenced observers' safety behavior. The implications of the findings and future research directions are discussed. Actual or potential applications of the research include, but are not limited to, using role models in warning messages and safety training programs to demonstrate the proper use of safety gear so as to enhance product users' compliance with safety recommendations.
Target-Directed Head Movements in a Head-Coupled Virtual Environment: Predicting the Effects of Lags Using Fitts' Law
Authors: So Richard H.Y. , Chung Germen K.M. , Goonetilleke Ravindra S.
Published: January 2007

Two experiments have investigated the effects of lag on discrete target-directed head movements in a virtual environment. Both the target and a head-slaved pointer (subjected to lag) were presented on a head-mounted display. Targetdirected head movements in the presence of a constant time lag were shown to obey Fitts' law (R2 < .93). A previously reported interaction between the effects of lag and the effects of index-of-difficulty on hand movement time could not be found in head movement time when the target width was kept constant. Further experiments suggested that there is a significant interaction between the effects of target width and lag but not between target distance and lag. A model predicting head movement strategy in the presence of lag is proposed to explain the experimental findings. This model predicts, and experiments verified, that for a target width from 1° to 8° and a target distance range of 2.5° to 30° , the effect of lag (up to 267 ms) on target-directed head movement is independent of target distance but dependent on target width. Actual or potential applications of this research include the design of virtual control panel and its layout in a Virtual Reality simulator.