bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimizing the Touch Tablet: The Effects of Control-Display Gain and Method of Cursor Control
Authors: Arnaut Lynn Y. , Greenstein Joel S.
Published: July 2017

The purpose of this research was to assess the effects of control-display gain, method of cursor control, and target size on target selection performance with a touch tablet. In addition, an attempt was made to determine a definition of control-display gain that would generalize across different control-display combinations. The results indicated that a relatively low gain (approximately 0.8 to 1.0) resulted in more efficient target selection performance than did higher or lower gains. An absolute mode of cursor control, in which the cursor appears on the display in a position corresponding to the location of the finger on the touch tablet, resulted in faster selection rates and fewer target entries prior to confirmation than did a relative mode of cursor control. Selection of large targets was faster and more accurate than selection of small targets. Alternative explanations for performance differences are discussed.
Trunk Force Development during Static and Dynamic Lifts
Authors: Marras William S. , Rangarajulu Sudhakar L. , Wongsam Patricia E.
Published: July 2017

Most lifting analyses have used static models to evaluate the loading of the trunk during the performance of work. Recent research has reported many differences in trunk muscle force capability when a wide range of trunk velocities are observed. This study focused upon these differences during slow trunk velocities, which would be expected during a lift. Forty-five subjects were tested for their ability to exert torque about their low back under static and dynamic sagittally symmetric lifting conditions. Trunk muscle electromyography was used as a measure of trunk loading. The results reveal that significantly greater loading occurs under slow dynamic conditions, as compared with static conditions. Hence, static models, which assume quasistatic motion, are not good indicators of dynamic trunk load. A regression model was developed that described trunk loading as a function of trunk angle and velocity. The correlation between torque and muscle electromyography in the erector spinae muscles was also found to increase significantly as trunk velocity increased. The implication of these findings upon lifting is discussed.
The Threshold for Hypoxia Effects on Perceptual- Motor Performance
Authors: Fowler Barry , Elcombe David D. , Kelso Barry , Porlier Gerald
Published: July 2017

The hypoxia threshold for a decrement in perceptual-motor performance was determined with six subjects using a serial choice response time task at two levels of stimulus brightness. Low-oxygen mixtures were used to reduce SaO2 (arterial oxyhemoglobin saturation) to hypoxic levels ranging from 86% to 76% in steps of 2%. These values correspond to altitudes ranging from 8900 ft to 11 400 feet. Response time was slowed in a dose-dependent manner with a significant effect becoming apparent at an SaO2 of 82% (10 000 feet). The slope of the dose-response function was steeper for the low than for the high brightness condition. These results provide a threshold estimate of 9750 feet for performance decrements due to hypoxia and point to the disruption of vision as a factor influencing this decrement.
Pressure of Menswear on the Neck in Relation to Visual Performance
Authors: Langan Leonora M. , Watkins Susan M.
Published: July 2017

This study examined the incidence of neckwear tightness among a group of 94 white-collar working men and the effect of a tight business-shirt collar and tie on the visual performance of 22 male subjects. Of the white-collar working men measured, 67% were found to be wearing neckwear that was tighter than their neck circumference. The visual discrimination of the 22 subjects was evaluated using a critical flicker frequency (CFF) test. Results of the CFF test indicated that tight neckwear significantly decreased the visual performance of the subjects and that visual performance did not improve immediately when tight neckwear was removed.
Shift Sequences, Duration of Rest Periods, and Accident Risk of Bus Drivers
Authors: Pokorny M. L. I. , Blom D. H. J. , van Leeuwen P. , van Nooten W. N.
Published: July 2017

This paper presents a portion of the results of a comprehensive analysis of the etiology of bus driver accidents. This portion of the analysis concentrates on two questions. First, does the sequence of various shifts influence accident risk on a given day? Various analyses led us to conclude that there was no interaction between the type of shift (either stand-by shift or day off) on preceding days, the actual shift, and the bus drivers' accident risk. This leads to the supposition that the actual situation on the working day is an important factor in determining accident risk. Second, is there any interaction between accident risk and the duration of total (added) rest periods during the shift up to the moment of the accident? No such association could be detected. Our analysis and conclusions are restricted to possible effects of total resting time and cannot be extended to possible effects on accident risk of particular rest periods of different duration and at a different stage within a shift.
The Case Against Coplanar Pedals in Automobiles
Authors: Casey Steven M. , Rogers Steven P.
Published: July 2017

Speed of movement is only one of several critical variables in the design of foot controls, and it should not be used in isolation to dictate automobile design recommendations. Although studies have shown that movement times between the accelerator pedal and the brake pedal are somewhat faster when both pedals are in the same plane, more inclusive human factors analyses reveal that there are several important reasons to locate the brake pedal above the accelerator pedal.
Training Consistent Task Components: Application of Automatic and Controlled Processing Theory to Industrial Task Training
Authors: Myers Greta L. , Fisk Arthur D.
Published: July 2017

Two experiments were conducted to examine the generality of automatic/controlled processing training principles to rich, complex tasks. In both experiments, subjects' tasks were modeled after a job function performed in the telecommunications industry. These tasks required subjects to process conjunctions of information. Large quantitative and qualitative differences were found between the consistently and variably mapped training conditions. The need for determining trainable consistent components of complex tasks is discussed. The present experiments indicate that theories of automatic and controlled processing can be expanded to include many domains of rich, complex industrial tasks.
Internal Models, Tracking Strategies, and Dual-Task Performance
Authors: Eberts Ray E.
Published: July 2017

The effects of internal models and tracking strategies on workload were investigated in a dual-task, second-order tracking and auditory detection experiment. Internal models and tracking strategies were manipulated by providing subjects with augmenting cues. A control group was compared with two groups provided with different kinds of display augmentation, parabola or point cues, during single-task tracking training. The display augmentation had the effect of changing tracking strategy as subjects practiced on cued and noncued trials, and it had an effect on the internal models developed. Both point and parabola augmentation reduced workload when displayed on the cued trials. On the noncued trials, the parabola augmentation, training had the effect of reducing the workload, compared with the point augmentation, even if the parabola cues were not displayed. A control group that did not change strategy during training also had low workload requirements in the dual task. The results indicate that a consistent tracking strategy or the development of a visually based internal model is needed to lessen the workload.
Slot versus Insertion Magnetic Stripe Readers: User Performance and Preference
Authors: Lewis James R.
Published: July 2017

Four magnetic stripe readers were evaluated for percentage of good reads, throughput, and user preference using a simulated time-and-attendance task. Two were slot readers, one with a vertical slot and one with a horizontal slot. Two were insertion readers, one with the insertion parallel to the horizontal plane and one with the insertion 20 deg below the horizontal plane. Twelve participants were divided into four groups of three members each. Each group approached each reader from both directions. The percentage of good reads was high on all readers and was not significantly different. The differences in throughput and preference were significant and favored the slot readers. It did not seem to matter whether the slot was vertical or horizontal. The angle of entry for the insertion readers produced no significant differences.
Aircraft and Equipment Factors in the Occurrence of Suspension Line Twists with U.S. Army Parachutes
Authors: Burke William P.
Published: July 2017

Data were collected by self-report for the trainees of two classes of the Basic Airborne Course at Fort Benning, Georgia, who were asked if they had developed twists in their suspension line during each of the five jumps of the course. These data were then related to the conditions of deployment for each jump-type of parachute used, type of equipment carried, type of aircraft jumped from, and so forth. The proportion of jumpers with twists during a given jump with its associated conditions of deployment was compared by the chi-square test with the proportion of jumpers with twists from other jumps made under different conditions of deployment. No effect of type of parachute on the occurrence of twists was detected, but a strong and significant effect of combat equipment was associated with an increase in the proportion of twists. There was, in addition, a significant but slightly smaller effect attributable to the type of aircraft used for jumps, with more twists occurring during jumps from the C-141 than during jumps from the C-123.
Effects of Task Type and Stimulus Heterogeneity on the Event Rate Function in Sustained Attention
Authors: Lanzetta Thomas M. , Dember William N. , Warm Joel S. , Berch Daniel B.
Published: July 2017

The goals of the present experiment were (1) to determine the function relating rate of presentation of neutral background events to accuracy of signal detection in both a simultaneous (comparative judgment) and a successive (absolute judgment) vigilance task, and (2) to test differential predictions from Posner's pathway inhibition theory and Jerison's elicited observing-rate theory about the effects of heterogeneity in the shape of the neutral events. Data for simultaneous and successive tasks at four event rates (6, 12, 24, and 48 events/min) under both homogeneous and heterogeneous neutral-event conditions showed that the event-rate function (a decline in detections with increments in event rate) was steeper for the successive than for the simultaneous task. Consistent with Jerison's view but not with Posner's, stimulus heterogeneity did not moderate the effects of either time on watch or event rate.
Signal Detection Theory and Probability Matching Apply to Vigilance
Authors: Craig Angus
Published: July 2017

Many vigilance tasks require discrimination of infrequent signal events from frequent nonsignals. During performance on these tasks signal detections often decline. But this does not generally signify a loss of vigilance, if one can rely on signal detection analyses showing that signal discriminability remains constant during a vigil and hence that neither attention nor signal processing has waned. This paper confirms that signal detection theory does provide a good fit to vigilance data and that the analyses can therefore be relied on. The paper also shows that probability matching (of signal reports to signal occurrence) occurs. In the main it is the adjustment of report rate toward matching by an alert observer, in control of his or her performance, that produces the vigilance decrement in detections.
The Effects of Target Wavelength on Dynamic Visual Acuity under Photopic and Scotopic Viewing
Authors: Long Gerald M. , Garvey Philip M.
Published: July 2017

The effects of target wavelength on the resolution of moving targets were investigated over a range of target velocities under both photopic and scotopic viewing conditions. The wavelength of the photopically matched targets had no effect on dynamic acuity under the bright background condition. However, with low background luminance the wavelength of the targets had pronounced effects, with blue targets producing far superior resolution and red targets, the poorest resolution. These results were maintained over both 250- and 400-ms target durations and regardless of whether initial target position was foveal or peripheral. The likely contribution of the rod system to dynamic visual acuity under some conditions is proposed, and possible implications for applied settings are discussed.
The Role of Stimulus-to-Rule Consistency in Learning Rapid Application of Spatial Rules
Authors: Fisk Arthur D. , Lloyd Shirley J.
Published: July 2017

Five experiments addressed the effects of intercomponent consistency on skill acquisition in a class of cognitively demanding tasks requiring rapid integration of information and rapid application of rules. The role of consistency of external stimulus-to-rule linkage in facilitating learning and performing rule-based tasks was examined. After extensive consistent practice, subjects' performance was remarkably similar to performance observed in traditional perceptual learning tasks. This similarity suggests that mechanisms underlying perceptual learning (in visual search) and rule-based spatial learning are similar. Subjects who were trained such that consistent stimulus-to-rule association could be built up and strengthened with practice performed in a manner qualitatively and quantitatively different from subjects trained with inconsistent stimulus-to-rule relationships. This superiority of the consistent stimulus-to-rule-trained subjects over the inconsistent stimulus-to-rule subjects was even more exaggerated in dual-task situations. The data have implications for the understanding and training of skilled problem-solving tasks. When training affords development of subcomponent automatization of the problem-solving activity, the chance of memory overload is reduced. The results suggest one such trainable subcomponent-the perceptual/rule-based components.
The Occurrence of Accelerator and Brake Pedal Actuation Errors during Simulated Driving
Authors: Rogers Steven B. , Wierwille Walter W.
Published: July 2017

Observations were made of subjects' foot movements while they drove an automobile simulator modified to represent the pedal, floor, and seating geometries of four actual automobiles. The type and frequency of pedal actuation errors that occurred were documented and recorded. The results indicate that a wide variety of pedal errors occur and that their frequency of occurrence varies greatly according to the seriousness of the error. Configuration differences were found for the less serious categories of error but not for the serious category.
Dimensions of Operator Workload
Authors: Derrick William L.
Published: July 2017

Multiple measures of operator workload may dissociate, or fail to agree, for a given task. The goal of this study was to determine how workload as indexed by processing resource demand could explain the attendant variance in a second measure of workload—subjective ratings. A multiple structure model of processing resources (Wickens, 1984) guided construction of tasks that were both performed by subjects and rated on workload similarity. Multidimensional scaling analyses of the similarity ratings produced three dimensions of workload that were explained by parameters of the resource model. Performance data, effort ratings, and heart period variability scores used to support the scaling analyses revealed expected dissociations. These dissociations were examined within the structure of the resource model.
Dissociation of Performance and Subjective Measures of Workload
Authors: Yeh Yei-Yu , Wickens Christopher D.
Published: July 2017

A theory is presented to identify sources that produce dissociations between performance and subjective measures of workload. The theory states that performance is determined by (1) amount of resources invested, (2) resource efficiency, and (3) degree of competition for common resources in a multidimensional space described in the multiple-resources model. Subjective perception of workload, multidimensional in nature, increases with greater amounts of resource investment and with greater demands on working memory. Performance and subjective workload measures dissociate when greater resources are invested to improve performance of a resource-limited task; when demands on working memory are increased by time-sharing between concurrent tasks or between display elements; and when performance is sensitive to resource competition and subjective measures are more sensitive to total investment. These dissociation findings and their implications are discussed and directions for future research are suggested.
Using Color Dimensions to Display Data Dimensions
Authors: Ware Colin , Beatty John C.
Published: July 2017

One of the advantages of computer graphics is that it enables an unprecedented degree of control over color. Since color vision is three-dimensional, this provides three additional perceptual dimensions that may be used in addition to the two spatial dimensions available on a flat display to present multidimensional data. This research probes the usefulness of color in enabling human observers to perceive clusters of points in a multidimensional space. Comparing the resolution of clusters in color and in space shows that color is an effective extension of space for conveying information about data dimensions. However, the perceptual space defined by color and space is not homogeneous and resolution is poor in a few specific directions. For this reason, the use of multiple views is advocated whenever color is used as a tool in exploratory data analysis.
Operator Performance as a Function of Type of Display: Conventional versus Perspective
Authors: Bemis Suzanne V. , Leeds Jeffrey L. , Winer Ernst A.
Published: July 2017

The purpose of this experiment was to evaluate operator performance on a perspective tactical display. The distinguishing feature of the perspective display is its visual representation of vertical as well as horizontal craft information. In contrast, current tactical display systems provide only two-dimensional views requiring numerical representation for altitude information. Subjects were required to perform two tasks: detect threats and select the closest interceptor for each detected threat. Errors and response time were recorded for each subject by the computer in a completely within-subjects experimental design. The experiment revealed a significant reduction in errors of detection and interception with the use of a perspective display. Response time for selecting interceptors was greatly reduced. The discussion recommends relevant directions for future research.
Effects of Visual Display and Motion System Delays on Operator Performance and Uneasiness in a Driving Simulator
Authors: Frank Lawrence H. , Casali John G. , Wierwille Walter W.
Published: July 2017

The role of visual-motion coupling delays and cuing order on operator performance and uneasiness was assessed in a driving simulator by means of a response surface methodology central-composite design. The most salient finding of the study was that visual delay appears to be more disruptive to an individual's control performance and well-being than motion delay. Empirical mutliple regression models were derived to predict 10 reliable measures of simulator operator driving performance and comfort. Principal components analysis on these 10 models decomposed the dependent measures into two significant models, which were labeled vestibular disruption and degraded performance. Examination of the empirical models revealed that for asynchronous delay conditions, better performance and wellbeing were achieved when the visual system led the motion system. A secondary analysis of the role of subject gender and perceptual style on susceptibility to simulator sickness revealed that neither of these independent variables was a significant source of variance.
Effects of Vehicle Handling Characteristics on Driving Strategy
Authors: Godthelp Hans , Käuppler Wolf-Dieter
Published: July 2017

The time-to-line-crossing (TLC) concept has been used as a time-related measure to describe driving strategy. The purpose of this research is to analyze whether TLC might enlarge our understanding of the relation between vehicle handling characteristics and a driver's looking and lateral control strategy in a straight-lane-keeping task. Earlier results indicated that in the case of a normally understeering car, drivers accept occlusion periods that correlate highly with TLC. The present study shows that drivers are well able to maintain this strategy with a more heavily understeering vehicle. However, the adaptation to the characteristics of an oversteering vehicle is far less accurate. Although drivers devote considerable steering and looking effort to control such a vehicle, it appears that this compensation process is insufficient and results in very low TLC levels at high speeds.
Magnification Effects with Imaging Displays Depend on Scene Content and Viewing Condition
Authors: Meehan James W. , Triggs Thomasj
Published: July 2017

Previous research has shown that imaging displays require a degree of magnification to appear the same size as a natural view of the same scene. A single-lens reflex camera fitted with a zoom lens was used as an imaging device so that the magnification of four outdoor scenes could be varied. Subjects were required to adjust the focal length of the lens so that the perceived size of objects in the viewfinder matched that in normal direct viewing of the scene, either monocular or binocular. When viewed through the apparatus, scenes with more depth information produced smaller overestimates of judged size. When the normal direct view was monocular, smaller overestimates were produced than when the same scenes were viewed by normal direct binocular vision. The possible roles of scene content and oculomotor effects in judgments of size made with imaging displays are discussed.
The Effect of Adding Symbols to Written Warning Labels on User Behavior and Receall
Authors: Frienmann Keyla
Published: July 2017

The use of consumer products by 144 college students was studied to determine the effects that (a) adding symbols to written warnings, (b) subjects' familiarity with the product, and (c) type of hazard would have on their noticing, recalling, or complying with the warning. Subjective ratings of perceived confidence, hazardousness, likelihood of injury, and severity of injury were also collected. Across all behavioral measures there was a steady decline in the number of subjects who first noticed (88%), then read (46%), and finally followed the warning (27%). In some conditions, however, compliance levels were as high as 42%. Symbols added to written warning labels did not significantly increase levels of compliance. A significant positive relationship was found between the perceived hazardousness of the product and reading, following, and recalling the warning. Factors affecting the user's motivation to read and follow on-product warnings were also noted.
The Role of Practice in Dual-Task Performance: Toward Workload Modeling a Connectionist/Control Architecture
Authors: Schneider Walter , Detweiler Mark
Published: July 2017

The literature on practice effects and transfer from single- to dual-task performance is briefly reviewed. The review suggests that single-task training produces limited transfer to dual-task performance. Past theoretical frameworks to explain multitask performance are reviewed. A connectionist/control architecture for skill acquisition is presented. The architecture involves neural-like units at the micro level of processing, with information transmitted between modules at the macro level. Simulations within the architecture exhibit five phases of skill acquisition. Dual-task interference and performance are predicted as a function of the phase of practice a skill has reached. Seven compensatory activities occur in the architecture during dual-task training that do not appear in single-task training, including (1) shedding and delaying tasks and preloading buffers, (2) letting go of high-workload strategies, (3) utilizing noncompeting resources, (4) multiplexing over time, (5) shortening transmissions. (6) converting interference from concurrent transmissions, and (7) chunking of transmissions. Future research issues suggested by the architecture are discussed.
Codes and Modalities in Multiple Resources: A Success and a Qualification
Authors: Wickens Christopher D. , Liu Yili
Published: July 2017

This article includes two sections that address the relevance of codes (verbal-spatial) and modalities (auditory-visual) in the multiple-resource model to the prediction of task interference. The first section describes an experiment in which either verbal or spatial decision tasks, responded to with either voice or keypress, were time-shared with second-order tracking. Decision problem difficulty was manipulated, and subjective workload as well as performance measures were assessed. The results provided support for the importance of the dichotomy between verbal and spatial processing codes in accounting for task interference. Interference with tracking was consistently greater and difficulty/performance trade-offs were stronger when the spatial decision task was performed and the manual response was used.

The second section reviews literature on the interference between a continuous visual task and a discrete task whose modality is either auditory or visual. The review suggests that scanning produces a dominant cost to intramodal configurations when visual channels are separated in space; when visual separation is eliminated, however, the differences between cross-modal and intramodal performance may be best accounted for by a mechanism of preemption. Discrete auditory stimuli preempt the processing of a continuous visual task, facilitating their own processing at the expense of the continuous task. Such preemption does not occur when visual discrete and continuous tasks are time-shared.
Simultaneous Adaptation to Size, Distance, and Curvature Underwater
Authors: Vernoy Mark W.
Published: July 2017

Perceptual adaptation to underwater size, distance, and curvature distortion was measured for four different adaptation conditions. These conditions consisted of (a) playing Chinese checkers underwater, (b) swimming with eyes open underwater, (c) viewing a square underwater, and (d) an air control. Significant adaptation to underwater distortions was recorded in all except the air control condition. In the viewing square condition a positive correlation between size and distance adaptation was noted. It was suggested that adaptation to curvature may have mediated the positive correlation. Possible applications for the training of divers are discussed.
Simulator Design and Instructional Features for Air-to-Ground Attack: A Transfer Study
Authors: Lintern Gavan , Shepard Daniel J. , Parker Donna L. , Yates Karen E. , Nolan Margaret D.
Published: July 2017

A transfer experiment was conducted to define simulator design requirements and instructional procedures for an air-to-ground attack trainer. Two levels of scene detail, three levels of field of view, and three levels of simulator training trials were manipulated. Student naval aviators were pretrained in the Visual Technology Research Simulator (VTRS) on a 30-deg bombing maneuver before their performances were assessed in their standard weapon training course. Other students not pretrained in the VTRS were used for control comparisons. Prior experience in the VTRS helped student pilots use their weapon flight time more effectively. The most substantial transfer gains were produced by the first 24 simulation training trials; there was little additional benefit from further training. There was no evidence of differential transfer from the different simulator conditions. These trends indicate that physical fidelity is not a requirement for positive transfer and lend further support to the need for a concept such as psychological fidelity or functional equivalence.
Visual Performance and Subjective Discomfort in Prolonged Viewing of Chromatic Displays
Authors: Matthews Michael L. , Lovasik John V. , Mertins Karen
Published: July 2017

Visual search and decision-making performance together with subjective fatigue were investigated over a 4-hr time block as a function of display foreground and background chromaticity using colors matched for brightness. Although some small differences in performance related to chromaticity were observed, these were not exacerbated over time. On the basis of the performance data obtained and the subjective reports, there was no support for the general recommendation to avoid the use of red and blue stimuli, either alone or in combination, in CRT displays.
Transfer of Fault-Finding between Simulated Chemical Plants
Authors: Patrick John , Haines Bridget , Munley Gary , wallace Amanda
Published: July 2017

This study investigated the effect of training with either a qualitative model of plant functioning or a set of diagnostic heuristics on the transfer of fault-finding. Two simulated chemical plants were used. After training both conditions improve in accuracy of diagnosis of previously encountered faults, though the qualitative model condition is superior at transfer to novel faults. However, neither training condition exhibited positive transfer of training, in terms of accuracy, when tested on a second plant involving a recycle loop. Different reasons may explain this lack of transfer for each condition. Significantly, qualitative differences were found between the training conditions in the order in which plant variables were examined during fault-finding. These qualitative differences persisted in transfer to the second plant but only for faults whose symptoms were not affected by the recycle loop. Such qualitative measures offer a means of inferring the cognitive processes inculcated by different training programs.
Effect of Uncertainty and diagnosticity on Classification of Multidimensional Data with Integral and Separable Displays of System Status
Authors: Coury Bruce G. , Boulette Margery D. , Smith Robert A.
Published: July 2017

Integrative, objectlike displays have been advocated for presenting multidimensional system data. In this research two experiments assess the effect of uncertainty on the processing of integral and separable displays. In each experiment 30 subjects were trained to classify instances of system state into one of four state categories using a configural display, a bar graph display, or a digital display. In Experiment 1 the range of instances from the state categories was uniform; in Experiment 2 the distribution was biased toward those instances of highly uncertain state category membership. After training, subjects received extended practice classifying system data. In both experiments uncertainty was found to have the greatest effect on classification performance. In Experiment 1 the bar graph display was consistently superior; the configural display was superior to the digital display only under conditions of low uncertainty. In Experiment 2 the superiority of the bar graph display diminished, producing results equivalent to those of the digital display, with the configural display producing the worst performance. The effect of uncertainty on classification performance is discussed, with specific attention paid to the apparent configural and separable properties of the bar graph display.
Effects of Different Data Base Formats on Information Retrieval
Authors: Boehm-Davis Deborah A. , Holt Robert W. , Koll Matthew , Yastrop Gloria , Peters Robert
Published: July 2017

This research examined the effects of three different data base formats on the information retrieval performance of users. Spatial, tabular, and verbal forms of two data base domains (airline and thesaurus) were constructed, along with questions that required users to search through the data base to determine the correct response. Three types of questions, compatible with the forms of the data bases, were designed-spatial, tabular, and verbal. The data indicate that users' responses to the questions are faster and more accurate when the format of the information in the data base matches the type of information needed to answer the question. Although the importance of matching data base format to query type may seem obvious, it would appear that the designers of most current data base systems have not taken this into account.
Mental Models: Theory and Application in Human Factors
Authors: Wilson John R. , Rutherford Andrew
Published: July 2017

This review points out confusion surrounding the concept and use of mental models from the viewpoints of both human factors and psychology. Noted are the ways in which the notion is conceived according to the needs and approaches of different specialties, and the relationships of mental models to other forms of knowledge representation are considered. The manner in which the human factors community has and should utilize the concept in applications across a number of fields is addressed and discussed in relation to the psychological perspective.
Trends in Finger Pinch Strength in Children, Adults, and the Elderly
Authors: Imrhan Sheik N.
Published: July 2017

This study explores empirical relationships among different types of pinches in three age groups. Peak maximum voluntary forces of several pinches-lateral, chuck, and pulp pinches with digits 2, 3, 4, and 5-were tested in 182 subjects comprising 62 children (5-12 years), 70 adults (18-40 years), and 50 elderly (60-89 years). Analysis of the forces indicated four groups of strength magnitude: (1) lateral and chuck, (2) pulp 2 and 3, (3) pulp 4, and (4) pulp 5, in that order; the strength of each type of pinch bears a definite quantitative relationship to every other type, regardless of age group or gender. The female-to-male strength ratio was greatest in children (89%) and least in adults (69%). Comparison with other pinch strength studies established that although force magnitudes may be strongly influenced by specific experimental conditions, empirical relationships among different pinch forces are fairly stable and predictable.
Static Anthropometry of Civilian Chinese in Taiwan Using Computer-Analyzed Photography
Authors: Li Chang-Chung , Hwang Sheue-Ling , Wang Min-Yang
Published: July 2017

The purpose of this study was to establish a static anthropometric data bank for Chinese civilians in Taiwan using a computer-analyzed photographic method. Stratified random sampling was applied to decide the sampling site; sample size was established by considering standard errors in a pilot study. Then a photographic method was employed in addition to direct measurement of selected body dimensions. In all, 933 subjects were measured. The data were entered via a digitizer into a microcomputer for processing. The resulting anthropometric data bank was organized by age, sex, and occupational groupings. Comparisons with data from previous studies were made, and recommendations for further research presented.
Data Bases of Accommodative Aids for Computer Users with Disabilities
Authors: Casalii Sherry Perdue , Williges Robert C.
Published: July 2017

Computers offer an almost limitless range of opportunities for persons with nearly any type and degree of disability. Standard computer configurations, however, can be difficult to access for users with disabilities. Six of the major data bases that describe adaptive computer hardware and software for users with disabilities are reviewed. The most appropriate data base to use depends not only on the type of aid desired but also on the means of access available to the individual, the frequency of use of the data base, and the price of the data base information. None of the data bases reviewed contains the detailed information needed when choosing devices compatible with the user's physical skills and task needs. Consequently, a less-than-systematic approach is currently taken when choosing accommodative aids. An integrated approach combining a capability assessment, a comprehensive needs analysis based on the tasks to be performed, a more detailed data base describing hardware and software, and usability testing is recommended for selecting the appropriate accommodative aid for computer users with disabilities.
A Method for Evaluating Head-Controlled Computer Input Devices Using Fitts' Law
Authors: Radwin Robert G. , Vanderheiden Gregg C. , Lin Mei-Li
Published: July 2017

The discrete movement task employed in this study consisted of moving a cursor from the center of a computer display screen to circular targets located 24.4 and 110.9 mm in eight radial directions. The target diameters were 2.7, 8.1, and 24.2 mm. Performance measures included movement time, cursor path distance, and root-mean-square cursor deviation. Ten subjects with no movement disabilities were studied using a conventional mouse and a lightweight ultrasonic headcontrolled computer input pointing device. Average movement time was 306 ms greater (63%) for the head-controlled pointer than for the mouse. The effect of direction on movement time for the mouse was relatively small compared with the head-controlled pointer, which was lowest at 90 and 270 deg, corresponding to head extension and head flexion, respectively. Average path distance and root mean square displacement was lowest at off-diagonal directions (0, 90, 180, and 270 deg). This methodology was also shown to be useful for evaluating performance using an alternative head-controlled input device for two subjects having cerebral palsy, and measured subtle performance improvements after providing a disabled subject with lateral torso support.
Psychometric Properties of Subjective Workload Measurement Techniques: Implications for Their Use in the Assessment of Perceived Mental Workload
Authors: Nygren Thomas E.
Published: July 2017

This paper examines fundamental measurement issues that have largely been ignored in scaling techniques for assessing perceived mental workload. It is argued that both theoretical and practical advances in workload assessment have been unnecessarily slowed by a lack of concern for measurement issues. Typical of this impedance are some recently reported “empirical results“ comparing various workload assessment techniques which actually follow directly from some misunderstood statistical properties of the scales. The commonly used subjective workload assessment procedures have distinct psychometric properties that make each procedure sensitive to different kinds of workload measurement. Examination of the properties for the National Aeronautics and Space Administration Task Load Index (NASA TLX) support its potential as a general prediction model for experienced workload and for the Subjective Workload Assessment Technique (SWAT) as a cognitive model sensitive to individual differences.
Effects of Skill Integration and Perceptual Competition on Age-Related Differences in Dual-Task Performance
Authors: Korteling J. E.
Published: July 2017

Age-related differences in dual-task performance may be affected by factors such as skill integration and perceptual competition. Therefore these factors were examined in a dual-task experiment with young and older adults involving two one-dimensional compensatory tracking tasks. Single-task difficulty was individually adjusted for each subject. It was found that differences in pure dual-task performance between young and older subjects increase when the subtasks are coherent such that skills can be integrated. In addition, the degree to which integration reduces the effects of visual competition was larger for the young than for the older subjects. It is concluded that in dual tasks with coherent subtasks, older adults may show an impaired ability to perform the sub tasks in an integrated manner.
Cognitive Factors And The Use Of Over-The-Counter Medication Organizers By Arthritis Patients
Authors: Park Denise C. , Morrell Roger W. , Frieske David , Blackburn A. Boyd , Birchmore Daniel
Published: July 2017

The present study investigated the ability of 45 arthritis patients, all using three or more prescription medications, to correctly load their medications into three types of over-the-counter medication organizers. The results indicated that use of a seven-day organizer with compartments for different times resulted in fewer errors than did an hour-by-hour wheel organizer or a seven-day organizer with only one compartment for each day. It was concluded that the seven-day organizer with compartments for different times appears to have the potential to improve compliance behaviors, but the usefulness of the other two organizers in promoting compliance is uncertain. Data analyses also indicated that age was not related to comprehension or loading accuracy of the organizers but that individuals using seven or more prescribed medications were particularly likely to make comprehension errors.
The Design of Electronic Map Displays
Authors: Aretz Anthony J.
Published: July 2017

This paper presents a cognitive analysis of a pilot's navigation task and describes an experiment comparing a new map display that employs the principle of visual momentum with the two traditional approaches, track-up and north-up. The data show that the advantage of a track-up alignment is its congruence with the egocentered forward view; however, the inconsistency of the rotating display hinders development of a cognitive map. The stability of a north-up alignment aids the acquisition of a cognitive map, but there is a cost associated with the mental rotation of the display to a track-up alignment for tasks involving the ego-centered forward view. The data also show that the visual momentum design captures the benefits and reduces the costs associated with the two traditional approaches.
Learning to Operate Complex Devices: Effects of Conceptual and Operational Similarity
Authors: Dixon Peter , Gabrys Gareth
Published: July 2017

In two experiments we investigated the effect of prior knowledge of a given device on learning to operate a similar device. Two kinds of similarity were investigated: conceptual similarity, in which the underlying concepts of how the devices worked were the same, and operational similarity, in which the organization and structure of the operating procedure were the same. Experiment 1 used devices that were always physically the same, regardless of how they were described and the procedure used to operate them. Experiment 2 used devices that were always physically different but required the same logical sequence of steps. In both experiments there were substantial effects of operational similarity but no reliable effect of conceptual similarity. It was concluded that prior experience with similar devices often helps because similar devices have similar operating procedures, not because similar devices work similarly.
A Three-Dimensional Motion Model of Loads on the Lumbar Spine: II. Model Validation
Authors: Marras William S. , Sommerich Carolyn M.
Published: July 2017

A three-dimensional motion model has been developed that estimates loads on the lumbar spine under laboratory conditions that simulate manual materials handling conditions. Eleven subjects experienced spinal loading during an experiment in which conditions of trunk velocity, trunk torque output, and trunk asymmetric posture were varied in a series of isokinetic velocity trunk extensions. The electromyographic activity of 10 trunk muscles, subject anthropometry, and trunk kinetics were used as input to a biomechanical simulation model described in Part I of this study. The model calculated estimates of compression, shear, and torsion loading in the lumbar spine, as well as the torque production of the trunk, continuously throughout the exertion. Trunk torque estimates derived from this model were compared with measured trunk torque. The effects of trunk motion, posture, and torque level on spine loading as estimated by the model are discussed. It was concluded that this approach provides a straightforward means of assessing loading of the spine attributable to laboratory simulations of workplace conditions.
Work Posture, Workstation Design, and Musculoskeletal Discomfort in a VDT Data Entry Task
Authors: Sauter Steven L. , Schleifer Lawrence M. , Knutson Sheri J.
Published: July 2017

Self-report data on musculoskeletal discomfort were collected from several hundred VDT users in two agencies of a state government. Aspects of worker posture and workstation design were objectively assessed for 40 of the VDT users. Multiple regression analyses were used to examine the relationship between these ergonomic variables and musculoskeletal discomfort. Effects of ergonomic factors on musculoskeletal discomfort were clearly evident in the analyses. Regression models explained up to 38% of the variance in discomfort at different body sites. Of special interest was that leg discomfort increased with low, soft seat pans, suggesting that postural constraint is more important than thigh compression as a risk factor for leg discomfort in VDT work. In addition, arm discomfort increased with increases in keyboard height above elbow level, supporting arguments for low placement of the keyboard. Finally, high levels of neck and shoulder girdle discomfort observed in the study population suggest the need for further attention to the control of cervicobrachial pain syndromes in VDT work.
Designing Help Using a GOMS Model: An Information Retrieval Evaluation
Authors: Elkerton Jay , Palmiter Susan L.
Published: July 2017

The GOMS model was used to develop the structure and content of a help system from the goals, operators, methods, and selection rules needed to perform HyperCard™ authoring tasks. The retrieval effectiveness of the GOMS help system was compared with an original help system developed by Apple® Computer. Two groups, each consisting of 14 novice HyperCard users, retrieved help for 56 authoring tasks separated into four blocks using either the GOMS or original help system. Users of GOMS help were significantly faster than were the original system users, with the largest difference occurring during the first block. Retrieval performance with GOMS help was stable, whereas original system users improved significantly over blocks. The explicit procedural structure of GOMS help seemed to ease retrieval, whereas original system users had to learn the location of specific information. This study suggests that a GOMS model can aid in the development of a procedural help system that is easy to learn and use for retrieving help information.