bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic Noise, An Informational Definition
Authors: Burrows Alan A.
Published: July 2017

Some theoretical considerations are made on the previous definitions of acoustic noise and the classification of its effects on organisms. A definition is proposed relating acoustic noise to its environmental source and the informational content of the specific task in which it occurs. An experimental study explores this proposal.
A Model for Visual Memory Tasks
Authors: Sperling George
Published: July 2017

A model for visual recall tasks was presented in terms of visual information storage (VIS), scanning, rehearsal, and auditory information storage (AIS). It was shown first that brief visual stimuli are stored in VIS in a form similar to the sensory input. These visual “images” contain considerably more information than is transmitted later. They can be sampled by scanning for items at high rates of about 10 msec per letter. Recall is based on a verbal receding of the stimulus (rehearsal), which is remembered in AIS. The items retained in AIS are usually rehearsed again to prevent them from decaying. The human limits in immediate-memory (reproduction) tasks are inherent in the AIS-Rehearsal loop. The main implication of the model for human factors is the importance of the auditory coding in visual tasks.
Analysis of Proximities as a Technique for the Study of Information Processing in Man
Authors: Shepard Roger N.
Published: July 2017

A recently developed method is described for the reductive analysis of confusion matrices by means of a high-speed digital computer. Illustrative applications of this method to several previously published matrices of the confusions between signals of the Morse code are presented for the first time. The results seem to provide useful information about how these dot-and-dash patterns are processed in man.
Group Decision Making under Conditions of Realistic Complexity
Authors: Shure Gerald H. , Rogers Miles S. , Meeker Robert J.
Published: July 2017

Is it possible, through laboratory control of a realistic and complex environment; that classes of decision situations can be objectively defined and designed, and can these situations evoke consistent and predictable patterns of search and decision resolution? This paper describes the experimental strategy undertaken to answer this question. The command staff in the SAGE Air Defense system was seelcted as a reference system for simulation. SAGE documents were flow-charted to identify rule-following situations and decision situations proper. Air defense decision situations were presented to subjects in the simulated environment. Four three-man teams, extensively pretrained, performed as battle staff. Transcriptions of verbalized responses—intracrew interactions and “thinking out loud”—constituted the basic data for analyzing resolution behavior. Preliminary results indicated that experimental control of a complex environment is a feasible means of creating objectively defined decision situations.
Factors Affecting Control Activation Time
Authors: Siegel Arthur I. , Schultz Douglas G. , Lanterman Richard S.
Published: July 2017

Control activation time as a junction of control number, control density, activation sequence, control complexity, and link multiplicity was investigated. Although activation time was found to be significantly related to each factor, the number, density, and link multiplicity factors were considered to exert the greatest operational significance.
Monte Carlo Model of Tracking Behavior
Authors: Adams Jack A. , Webber Carl E.
Published: July 2017

A Monte Carlo model was devised for simulation of human tracking behavior with a digital computer. The model had four basic equations and included provision for one- and two-dimensional tracking, repetitive and irregular input signals, and practice trials. Four groups of 12 human subjects each were given 40 practice trials on either one- or two-dimensional tracking, and either repetitive or irregular input signals. The model was then used to simulate corresponding data for four groups of 12 hypothetical subjects each, and comparisons of the real and hypothetical subject samples were made for various measures of proficiency. Overall, the adequacy of the simulation was judged as good. Research tactics are discussed for arriving at a generalized model of n-dimensional tracking behavior, and for elaborated models that will include procedural and decision acts to simulate more complex man-machine systems.
The Core System. A Proposal for a Man—Machine System Research Tool
Authors: Story Anne W.
Published: July 2017

The concept of a core system is developed and proposed as a tool for system research. The core system is defined and differentiated from subsystems and simulated systems. The relative advantages and disadvantages of all these approaches are discussed.
Use of Comic Effect for Control of Dysfunctional Human Behavior in Outer Space
Authors: Friedman Lee A.
Published: July 2017

The literature in the field of human factors suggests that there is a substantial need for developing certain controls over expected human reactions to the isolation and hostile environment in outer space. These studies cite numerous experimental and experiential situations in which human participants had manifested dysfunctional reactions to stress, unknown dangers and isolation. A hypothesis is put forth that the comic effect as a major part of structured leisure time activities can do much to prevent and/or ameliorate these human reactions so that astronauts can effectively accomplish system missions even under strain situations.
Analysis of a Complex Skill: Vehicle Driving
Authors: Herbert Marvin J.
Published: July 2017

A battery of twelve driving tests, a majority of which represented new designs, were constructed in the desert. 180 subjects were divided into five groups on the basis of the number of hours members of each group drove a truck on a fatigue course after an initial test and prior to a retest on the battery. The fatigue periods were of 0, 1,3, 7, or 9 hr duration.

Pre-and post-fatigue test results were correlated with hours of fatigue driving, where hours-of-driving served as the test criterion. Test-retest reliabilities ranged from 0.35 to 0.88. Validities reached a maximum of 0.38. A small-scale factor analysis was performed on a correlation matrix based upon a single measure from each of eight tests. Proprioception, reaction-time, spatial orientation, response orientation, and multilimb coordination were identified as basic skills in vehicle driving.
Monitoring of Complex Visual Display: V. Effects of Repeated Sessions and Heavy Visual Load on Human Vigilance
Authors: Adams Jack A. , Humes John M. , Sieveking Nicholas A.
Published: July 2017

An earlier experiment on repeated monitoring sessions used a complex visual display with a moderate load of six stimulus sources. Nine consecutive daily sessions, a seven-day rest, and a tenth session were administered. Each daily session was 3 hr. The present study used the same experimental design as the earlier study but extended it by using a heavy visual load of thirty-six stimulus sources that required extensive visual scanning. A single group of twelve subjects was used. Reliable vigilance decrement was found within sessions, but the overall trend with sessions was one of increasing performance level, suggesting learning. The small amount of decrement commonly found for complex monitoring tasks is discussed, and an optimistic note is sounded for man's tolerance of boredom.
Sensory Alternation and Performance in a Vigilance Task
Authors: Gruber Alin
Published: July 2017

The effects of four experimental conditions on performance in a vigilance task were studied using eight subjects in a repeated measurements design. The four conditions were: visual detection alone; auditory detection alone; combined (redundant) visual and auditory detection; and alternating, in 30-min periods, auditory and visual detection. Subjects were required to detect 0.1-sec aperiodic interruptions in either or both a visually displayed horizontal line or a 1000 c/s tone. The intensities of both signals were adjusted to near-threshold levels against constant noise backgrounds. Data were collected on the number of signals detected, the number of false responses, and response times during the 2-hr testing session. It was found that: (1) sensory alternation was an effective means of maintaining alertness; (2) redundant, dual sense monitoring resulted in significantly fewer false responses; (3) there were no differences between the four conditions with respect to median response times; and (4) response times did increase with the length of the watch over the four conditions.
Performance Decrement under Psychological Stress
Authors: Berkun Mitchell M.
Published: July 2017

Army trainees unaware that they were serving in an experiment were, under controlled conditions, led to believe that either (1) an aircraft in which they were passengers was about to make an emergency crash landing, (2) their outpost was now an artillery impact area, or (3) they had caused serious injury to a buddy by a mistake in wiring up explosive charges. They were required to demonstrate knowledge of crash-landing procedures or repair a malfunctioning telephone to summon aid. Average performance under threat was significantly poorer than performance of the same act by other Ss motivated without threat. Soldiers with more military experience than trainees react differently both to the threat condition (they do better) and to the comparable non-threat condition (poorer).
Objective Difficulty and Input History as Factors in Sequential Decision Making
Authors: Schrenk Lorenz P.
Published: July 2017

Amount of displayed input history and level of problem difficulty were varied in a four-alternative, sequential decision task. Problem difficulty, defined by the number of inputs necessary to achieve one standard deviation separation between input sequences with different growth rates, was varied by decreasing growth-rate differences and by increasing input variability. The results indicated that information taking decreases (without increasing wrong decisions) with increasing input history. It was found that the relative amount of information taken decreases and the number of wrong decisions increases with increasing problem difficulty. Further, information taking was found to increase more with decreasing input-sequence growth-rate differences than with increasing input variability to statistically equivalent levels. When scored in the same way as terminal decisions and as compared to them, riskless estimates showed poorer performance. Finally, the results indicated that information taking increases on trials following wrong decisions.
The Load-Endurance Relationship for a Static Manual Response
Authors: Caldwell Lee S.
Published: July 2017

Each of 64 male subjects was required to maintain certain proportions of his maximum response strength as long as possible. An essentially linear relationship was obtained between the relative load (the percentage-of-maximum strength) and the endurance of the manual response within the range of loads employed. As the load was increased from 50% to 80% of maximum strength, the mean endurance of manual pull decreased from 63.3 sec to 21.4 sec. A comparison of endurance scores for two arm positions yielding different response strengths revealed little difference in performance despite the fact that the mean force to be maintained was 41% greater at one arm position than at the other. Thus, relative loading tended to equalize endurance despite large differences in the actual force of the sustained response.
Effects of Practice on Dial Reading
Authors: Carveth John W. , Adams Jack A.
Published: July 2017

The effects of practice and exposure time were studied for circular and linear (vertically arrayed for this study) dials of the moving pointer type. Type of dial was a between-groups variable, with one group of 11 subjects having the vertical dial and another group of 11 subjects the circular dial. Practice for five daily sessions, and exposure times of 100 or 500 msec, were within-groups variables. The circular dial was superior to the vertical dial for both exposure times, whether per cent correct or amount of reading error was the measure. The practice variable had a minor effect and was statistically significant only for the circular dial at 100 msec. exposure time, and only for the per cent correct measure. Practice tended to alter the distribution of errors for the circular dial.
Command-and-Control and Management Decision Making
Authors: Rhine Ramon J.
Published: July 2017

Development of command-and-control systems in support of decision making and action taking has been accomplished by military organizations. Upon examination, the major concepts underlying these systems are management concepts. Experience in building command-and-control systems should be valuable in helping to sharpen management concepts and also in perfecting techniques of engineering, computer-programming, and operational methods and procedures applicable to automatic management systems. The command-and-control type system for top management decision making is a man-machine system having at its core an ongoing, dynamic operation. Current technology is adequate for the development by non-military organizations of the command-and-control type of system for management decision making.
Vigilance as a Function of Stimulus Variety and Response Complexity
Authors: Luce Terrence S.
Published: July 2017

A vigilance experiment was conducted in which subjects monitored a multistimulus source display for a 100-min period. The purpose of the experiment was to determine the effects on vigilance performance of random insertion of artificial signals and complexity of required response. Several measures of task performance were analyzed: average time to detect real signals; intrasubject variability in detection time; percentage of real signals detected; number of errors made under different conditions of response complexity; and occurrence of movements extraneous to task requirements. Results indicated that the introduction of artificial signals enhanced vigilance performance by reducing the variability in detection response times and by increasing percentage of signals detected. There was no significant decrement in response times over the task session. Introduction of a complex response requirement into the task did not result in improved vigilance performance, as predicted. Results are discussed in terms of a single “construct” of vigilance and in terms of implications for applied situations.
The Driver's Reference Point as a Function of Vehicle Type, Direction and Radius of Turn
Authors: Olson Paul L.
Published: July 2017

A study was conducted to determine the location of the point on the long axis of an automobile which intersects the center line of a prescribed path when driven under a variety of conditions. The variables investigated were: (1) Vehicle type; a large full-size car, a compact car and a bus-type vehicle were employed. (2) Radius of turn; 50 and 25 ft to the center of a circular lane. (3) Direction of turn; right and left turns. Twenty-four subjects participated in the study, each driving all cars under all conditions. Significant differences in the location of the mean points of intersection relative to the front bumper within and between cars were associated with the various conditions. Location of the driver eye points relative to the points of intersection differed little, especially in the 25-ft radius condition.
A New Method of Evaluating the Effects of Fatigue on Driver Performance
Authors: Platt Fletcher N.
Published: July 2017

A new research instrument has been developed over the last four years and is now available for studying driver performance objectively under actual driving conditions. This report describes a new method of evaluating the effects of fatigue on driving performance using this equipment. A mathematical rating system is developed based on the results of this preliminary experiment and pre-tests. Examples demonstrate how the equations are used for rating the degree of driver fatigue at several stages of the test run. The results of this test are now being used in planning a new experiment for studying driving fatigue on a small population of drivers. The same approach can also be applied to study the effects of drugs, alcohol, and physical deficiencies on driver performance.
The Effectiveness of Curved Surface Traffic Markers
Authors: Nelson Thomas M.
Published: July 2017

Commands issued by traffic markers are not meant to be acted upon by every driver. Drivers are intended to only obey -signs placed at right angles to the lane they are driving. Perception of orientation is therefore important in determining whether or not the command is to be obeyed. Experimentation shows that flat surface markers are grossly mislocated under many circumstances and are hence faulty devices for referring commands. Curved surface markers are more accurately located due to the fact that they change in proportion rapidly as they leave the frontal plane. Highway use of curved markers is suggested.
Predicting Attention-Gaining Characteristics of Highway Traffic Signs: Measurement Technique
Authors: Forbes Theodore W.
Published: July 2017

This report describes an experimental procedure being developed for measuring the probability that a highway traffic sign of given brightness, color, and contrast characteristics can be seen against various day and night background conditions. From the laboratory measurements with this technique, probabilities that a sign will be seen can be determined. Later, field checks with full-scale observations are made to validate the laboratory results.
A Development of a Conceptual Framework of the Driving Task
Authors: Algea Charles W.
Published: July 2017

A conceptual framework is developed based on observations of driving behavior under actual traffic conditions. After the framework has been established, the assumptions and implications are contrasted with those in the theories of traffic flow that relegate the driver's contribution to a minor role. It would appear that theorists are mainly concerned with traffic flow and safety while each driver is more concerned with independence and constancy of his vehicle's movement.
Quantification in Man–Machine Systems
Authors: Leuba Harald R.
Published: July 2017

Quantification is defined as the pairing of elements of two sets. This definition and the characteristics of the sets in question is expanded, and the varieties and methods for quantifying in man-machine systems are described. Special attention is given to a brief overview of psychophysics and to probability theory as they relate to the problems of quantification in this area. Finally, guidelines are presented to aid in the search for adequate quantification.
Computers: Applications to the Quantification of Human Behavior
Authors: Rath Gustave J. , Allman William P.
Published: July 2017

This paper discusses the use of computing machines in the biological and social sciences, namely the ultilization of computerized behavior analysis systems in the quantification of human behavior. Only systems of which living human organisms are a part are considered.

Some specific functional uses of computers for stimulus preparation and presentation, response collection, and apparatus scheduling and control are presented. All of these functions may be performed by automated systems characterized by the amount of experimental integration and control performed by the computer. Systems types include on-line open-loop, on-line closed loop single or multiple purpose, and off-line.

The multiple-man, multiple-purpose system which permits numerous automated investigations upon different source subjects to occur simultaneously is highlighted as the culmination of current automated behavioral analysis systems. But the possibility of behavioral scientists “tapping” into operating systems is presented as possibly having revolutionary consequences with respect to the data gathering of human behaviour.

Finally, a general automated behavioral analysis system schematic assists in discussing current advantages, potential advances, and impending limitations of contributions of computers to the quantification of human behavior.
Simulation, Models, and Games: Sources of Measurement
Authors: Obermayer Richard W.
Published: July 2017

Simulation, models and games are analogies. They resemble in some way something else about which information is desired. We may therefore measure on the analogy instead of the real world objects. Critical dimensions of analogies are the level of abstraction and the fidelity of simulation, however, if the objective is to measure the most critical aspect is the validity of measurement. Unfortunately, validity is not always a practical concept. Since the objective of measurement is to derive information, simulation studies are analyzed with respect to information objectives in the attempt to derive criteria for measure selection.
Quantification of Human Performance in Large, Complex Systems
Authors: Pickrel E. W. , McDonald T. A.
Published: July 2017

A method for the identification of human-induced equipment failures in complex systems is presented. This method requires a description of the tasks to be performed, the determination that the tasks can be performed in the time available and finally a specification of task criticality. The probability of error occurrence and estimation of the effect of potential errors are also major parts of the analysis. Efforts for failure reduction are concentrated on errors most likely to occur and to affect the system negatively.
Individual and Situational Variables Affecting Human Performance
Authors: Ware Claude T.
Published: July 2017

Present methods of measuring and predicting operator performance are criticized because of their failure to consider individual and situational variables which mediate that performance.
Are Ballistic Missile Test Programs Structured to Support Adequate Evaluation of Human Performance?
Authors: Borchers Kenneth H.
Published: July 2017

This paper explores the problem of the adequacy of personnel performance testing on a current Ballistic Missile Test Program. It advances the thesis that criteria for judgment of technical worth must consider program/system requirements and cost-effectiveness. Examples of three categories of human performance testing on the Minuteman Ballastic Missile Program are described.
Improvements Needed in a Central Store of Human Performance Data
Authors: Altman James W.
Published: July 2017

A central data store represents an attempt to make quantitative information about human performance conveniently available for system planning, functions allocation, equipment design, selection and training, and evaluation. Major areas for future improvement of data store technology include establishment of a central function to integrate human performance data, quantification of meaningful categories of psychological processes, development of an error taxonomy, improved scaling of laboratory to operational performance, inclusion of new types of behavior, relating of conditions under which performance is accomplished to performance levels, and development of a basis for forecasting behavioral loading from early system information.
Studies of Divers' Performance During the SEALAB II Project
Authors: Bowen Hugh M. , Andersen Birger , Promisel David
Published: July 2017

Field studies of the three 10 men teams of divers participating in the SEALAB II project were undertaken. During each team's 15 day submergence at 205 feet, psychomotor tests and a vision test were conducted in the water, and a mental arithmetic test in the habitat. Compared to base line performance (dry-land and shallow water conditions), performance on the mental arithmetic test showed no deterioration while performance on the psychomotor tests showed considerable deterioration. Many divers found that their in-water work activities proceeded slowly; among other causes of a more physical nature, concern for one's safety may detract from the amount of attention one gives to the task at hand. The most active divers in the SEALAB group were those who indicated that they were least fearful and least aroused by the conditions and who were helpful, gregarious, and made least telephone contact with the outside world.
The “Feel” of Rotary Controls: Friction and Inertia
Authors: Knowles William B. , Sheridan Thomas B.
Published: July 2017

The purpose of this study was to determine the influence of friction and inertia levels on the “feel” of rotary controls. Detection thresholds for changes in friction and inertia were determined and found to be about 10 to 20 per cent of the initial values. Preference ratings obtained for various combinations of friction and inertia increased as a function of inertia level and decreased as a function of friction level. Preferences for viscous friction were greater than for stick-slip friction. Psychophysical evaluations such as these are related to customer acceptance factors and provide a useful supplement to purely functional design criteria.
Horizontal versus Vertical Display of Numbers
Authors: Williams C. M.
Published: July 2017

A task was constructed to compare performance on a horizontal to that of a vertical array of 3-digit numbers. 16 Ss were required to scan arrays of pairs of numbers and mark the pairs that contained nonidentical members. The average time required to complete the vertical array was 73 sec and 44 sec. for the horizontal. The finding that an average of 66% more time was spent on the vertical than on the horizontal array is significant at the .005 level.
The Effect of Changes in some Vehicle Handling Variables on Driver Steering Performance
Authors: Hoffmann Errol R. , Joubert Peter N.
Published: July 2017

The literature on vehicle handling is summarized. Experiments were carried out to determine the effect of vehicle response time, steering gear ratio, and near- and far-sight distances on driver performance on a tracking task consisting of driving through a narrow winding course marked by traffic cones. The vehicle response time was found to affect greatly the number of cones touched by the vehicle during a set testing time. On the particular track used in these tests, the driver performed best when the vehicle response time was 0.20 seconds. The near and far distances over which the driver could see the test course were also found to be of importance. Increasing near-sight distance, with no limit on the far-sight distance produced poorer driver performance. This also occurred for the case of decreasing far-sight distance with fixed near-sight distance. Tests with variations of steering ratio and steering torque produced little change in driver performance, although there was a weak minimum in cone scores at a steering ratio G = 24. In some of the experiments reported here, spare mental capacity was measured during the test period. For this indirect measurement of task difficulty, changes in the spare mental capacity of the driver were found to have the same sensitivity to changes in the vehicle, as did the change in the number of cones touched by the vehicle.
Panel Layout for Rectilinear Instruments
Authors: Bauer Robert W. , Cassatt Robert K. , Corona Bernard M. , Warhurst Frank
Published: July 2017

Rectilinear dials on a typical cockpit display were arranged in parallel, both horizontally and vertically, and also in a mixed, orthogonal arrangement. Although, intuitively, the parallel layouts appeared advantageous, the mixed layout yielded the best detection accuracy and the shortest detection times. Increasing the spacing between groups within a parallel, vertical array did not significantly improve performances. Uniform scales in any arrangement proved superior to non-uniform scales in readout accuracy. Thirty-six pilots and sixteen technical and scientific laboratory personnel participated in the study. Performances of pilots and non-pilots were very similar.
Perceptual Narrowing in Novice Divers
Authors: Weltman Gershon , Egstrom Glen H.
Published: July 2017

It was hypothesized that in diving, danger-induced stress may contribute to performance decrement by narrowing perceptual scope. A study was conducted to examine the effect of task load and type of underwater exposure on response time to a signal light in the visual periphery. Novice divers monitored a peripheral light alone, or while simultaneously performing a central addition or dial-watching task. Each subject was tested on the surface, in a diving tank, and in the open ocean. It was found that the central tasks did not interfere with peripheral vigilance on the surface. During diving, a distinct subgroup of the dual-task subjects exhibited markedly increased response times to the peripheral light while maintaining near constant performance on the central tasks. Their behavior appeared more closely related to diving risk than to other environmental factors. The remaining dual-task subjects, and the light alone group, were almost uneffected by underwater exposure. The hypothesis was considered partially validated.
Evaluation of a Fault Localization Job-Aid for a Navy Transceiver
Authors: Rigney J. W. , Fromer R.
Published: July 2017

The assessment of corrective maintenance performance of Navy technicians has revealed that they have difficulty with the problem-solving aspects of this task. This difficulty is due partly to the large amount of information concerning the relationships between symptoms and malfunctions (S-M relations) that must be available for efficient problem-solving behavior. The sheer bulk of this information almost precludes memorization, especially if the technician is responsible for the maintenance of several different types of equipment. A job-aid which contains S-M relations in an accessible form, should greatly assist the electronics technician in fault localization.

A fault locater (XFL) was developed for the AN/URC-32 transceiver. The XFL contains S-M relations for AN-URC-32 circuits and front-panel indications. It accomplishes three things: I) it leads the electronics technician through an appropriate sequence of front-panel tests, 2) it indexes the technician to the smallest possible fault area, and 3) it describes the fault area in terms of equipment circuitry.

Two studies were performed to evaluate the effectiveness of the XFL. The results showed that both maintenance and non-maintenance personnel can quickly learn to use the job-aid, and that it may be useful in supporting corrective maintenance performance.
Biomedical Considerations of Possible Decompression Effects in a Supersonic Transport
Authors: Emery Jerry A. , Burrows Alan A. , Collier Douglas R.
Published: July 2017

The possible consequences of the event of a supersonic transport cabin decompression are discussed in terms of biomedical considerations for passengers. Recent data concerning health and age-sex distributions are reviewed in an effort to derive a model group likely to be encountered among future supersonic transport flights along both transcontinental and transatlantic routes. Further consideration is directed to an analysis of various disease groups in terms of functional impairment as a means of anticipating passenger safety during cabin decompression. The results have been used to establish a basis for safety equipment design recommendations. Finally, attention is directed to research areas and methodology by which usable statistics might be obtained to provide further clarification of the tolerance ranges of debilitated humans.
Independent Effects of Error Magnification and Field of View on Compensatory Tracking Performance
Authors: Smith Russell L. , Garfinkle David R. , Lyman John
Published: July 2017

This experiment evaluated the independent effects of error magnification and field of view on compensatory tracking performance. Both display and optical magnification were investigated. In general, the results demonstrated that: (1) the facilitative effect on performance of display magnification was primarily due to the concomitant field of view reduction and not magnification per se; (2) optical magnification facilitated performance but subsequent display gain increases had no further affect; (3) regardless of visual mode employed, optimum performance levels on a complex trajectory converged at approximately the same field of view. In was suggested that increasing the optical gain or decreasing the field of view resulted in subjects reducing their reaction times to target movements. No evidence was found which indicated that magnification facilitated visual perception.
The Influence of an Intermittent Visual Stimulus on Perceptual Motor Skills in Aviation
Authors: Ailslieger Ross E. , Dick R. Dale
Published: July 2017

The effect of a light flashing at 5 fps on performance of tasks representative of those required of a pilot was studied. The tasks were digit span, pursuit rotor, reaction time, and a combination of all three. Reaction time was longer in the combined task, and pursuit rotor performance was degraded by the flashing light. It was concluded that the longer reaction times were due to lowered vigilance, and the degradation of pursuit rotor performance was attributed to interference in the central processes by the flashing light.
Status of Human Factors and Biotechnology in 1968-1969
Authors: Kraft Jack A.
Published: July 2017

A survey was conducted of 503 business, industrial, consulting, governmental, nonprofit research, and educational organizations to determine the current status of activities, programs, and characteristics of the human factors and biotechnology professions. Of the organizations surveyed, more than 77% responded and provided such information on their human factors and biotechnology operations as size, reporting level, professional specialties, termination rates, salaries, professional society activities, sources and amounts of funding, computer use, publications, facilities and facility investments, and program activities. Comments were received concerning problems facing the profession, means for increasing effectiveness of the profession, trends, and growth projections.
Human Factors in the Long Run
Authors: Ritchie Malcolm L.
Published: July 2017

Some fundamental questions are raised in such a way that planning for the future of the Human Factors Society may be stimulated. These questions deal with the nature of the field and of the society.
Trends in Human Factors Research for Military Information Systems
Authors: Mayer Sylvia R.
Published: July 2017

Military information systems are surveyed in an historical context starting with the SAGE system of the 1950's and projecting to the anticipated supersystems of the 1970's. Human functions in development, operation, and use of these systems are considered from a human factors point of view. This evolutionary overview shows how hardware and software design impact on human performance and how this impact has focused and expanded research in the computer sciences and in the behavioral sciences. The evolving human functions in military information systems are described. These descriptions serve as a basis for defining and researching critical human factors opportunities and problems. Paralleling this analysis is a review of several past, current, and future trends in human factors research for future military information systems.
Experimental Analysis of Man-Computer Problem-Solving
Authors: Sackmanh H.
Published: July 2017

Experimental methods and findings in human problem-solving using on-line and off-line computer systems are reviewed. For historical and technical reasons the field of applied man-computer communication has not been the subject of extensive scientific study. The advent of time-sharing systems in the last decade produced an initial body of empirical data from user statistics and experimental studies comparing time-sharing with batch-processing. This body of data is reviewed for its implications to the controversy over batch and time-sharing systems and to the understanding of human behavior in the man-computer setting. Although the available experimental data are meager and tentative, it is already apparent that behavioral principles of human problem-solving and learning theory can account for many of the trends observed. In turn, the theories can be enriched by new leads stemming from studies of man-computer dialog. A plea is made for interdisciplinary cross-fertilization between behavioral and computer sciences to bridge the humanistic lag in man-computer communication.
Time-Sharing and Self-Tutoring: An Exploratory Case History
Authors: Sackman Harold
Published: July 2017

This study is concerned with the effectiveness of individual user performance for an extended self-tutoring task in a time-shared computing facility. The investigation is an experimental case history of one individual (the author) following the TINT self-tutoring user manual from beginning to end in the SDC Q-32 Time-Sharing System at a Teletype console. (TINT is a user-oriented dialect of JOVIAL, an interpretive language adapted to time-sharing with many self-teaching features.) The methodology featured measurement of natural user behavior in which the user served as his own control in successive console sessions. The sample included 1,861 user input commands collected over 18 hours at the teletypewriter terminal.

The quantitative results revealed some evidence for systematic learning and reinforcement effects; there were progressive tendencies toward higher productivity and lower error rates with increasing TINT experience. The qualitative findings revealed that the numerous and diversified exercises facilitated familiarity with the elements and the varied services of the TINT system. The chief drawback was exclusive reliance of the tutoring method on literal reproduction of the text by the user at his console. The paper concludes with recommendations for more genuine interactive involvement between the user, the central system, and self-tutoring aids.
The Design of Microfiche Systems
Authors: Teplitz Arthur
Published: July 2017

The use of microfiche is limited because user requirements and standards are poorly defined. Problem areas include: film polarity, reduction and blowback ratios, equipment design, identification and numbering, content arrangement, application areas, and competitive media. The evidence is in conflict as to what is acceptable to the user. This evidence is discussed, key references are cited, and problem areas are defined for human factors and systems-engineering-oriented practitioners interested in applying their knowledge and skills to the design of microfiche systems.
The Forgetting of Instrument Flying Skills
Authors: Mengelkoch Robert F. , Adams Jack A. , Gainer Charles A.
Published: July 2017

A laboratory study of forgetting was conducted, using an aircraft simulator as the research device. Two groups of subjects were used, with one group receiving twice the amount of original training as the other. The retention interval was four months for both groups. The principal result was that discrete procedural response sequences had statistically and practically significant loss over the retention interval, but proficiency in controlling flight parameters (tracking) and statistically significant losses in only some instances and never in operationally significant amounts.
Optimal Flash Rate and Duty Cycle for Flashing Visual Indicators
Authors: Markowitz Joseph
Published: July 2017

This experiment examined the ability of observers to determine, as quickly as possible, whether a visual indicator was steadily on or flashing. Six flash rates (periods) were combined factorially with three duty cycles (on-off ratios) to define 18 “types” of intermittent signals. Experimental sessions were divided into six runs of 100 trials, each run utilizing one of the six flash rates. On any given trial in a run, the probability of a steady signal occurring was 0.5 and the probability of a flashing. signal occurring was 0.5. A different duty cycle was employed daily for each experimental session. In all, 400 trials were devoted to each of the flash rates at each duty cycle. Accuracy and latency of response were the dependent variables of interest. The results show that the observers view the light for an interval of time appropriate to the expected flash rate and duty cycle; whether they judge the light to be steady or intermittent depends upon whether the light is extinguished during the predetermined waiting period. Adoption of this temporal criterion delays responding in comparison to those tasks involving responses to light onset. The decision or response criteria held by the observers are also sensitive to the parameters of the flashing light: observers become increasingly willing to call a flashing light “steady” as flash duration increases.
Star Magnitude and Manual Navigation Sighting Accuracy Using the Apollo T2 Sextant
Authors: Haines Richard F. , Mayhew Lewis B.
Published: July 2017

This laboratory study investigated the effect of four star magnitudes (0, +1, +2, +3) upon the angular sighting accuracy attainable between a star and a lunar limb using a space-rated sextant with an 8-power telescope. Four males were tested. The results indicated that over a series of daily sightings sighting accuracy increases as star magnitude decreases; i.e., the angle between the actual lunar limb and the perceived lunar limb decreases as the intensity of the star increases. The significant subject and day main effects that were found indicate that each individual must be calibrated against himself and that extreme care must be taken to center the various images correctly within the sextant's field of view each time the instrument is set up. These findings are discussed in relation to further refinement of a graphic model of the distribution of energy on the retina. A discussion is also presented on the differences between sextant sighting research conducted in the laboratory and in the real, high-altitude or space environment.
Foot Forces Exerted at Various Aircraft Brake-Pedal Angles
Authors: Hertzberg H. T. E. , Burke Francis E.
Published: July 2017

This study reports the forces (means and standards deviations) exerted by the foot at various angles of extension about its ankle. A sample of 100 rated pilots was selected by height and weight. The forces were measured in a cockpit mock-up constructed around a specially instrumented F-80 rudder-pedal assembly. The right rudder pedal (hinged on the rudder bar) could be rigidly set to any desired angle between vertical and 75° forward of vertical. Foot forces were measured at 11 positions of the instrumented brake pedal in both neutral and extended positions of the right leg, and in three cockpit sizes (37 in., 39¼ in., and 41 in.)–66 measures on each man. In all three conditions, maximal forces were exerted within a 20° zone between 15 and 35° forward of vertical. Subjective comfort preferences, expressed by 86 pilots, closely paralleled the force findings. It is concluded that aircraft brake-pedal systems should be designed to maximize the effectiveness of the foot in that optimal zone, and that the same zone should be considered for other foot-operated controls, like automobile accelerator pedals.
Auxiliary Heating of the Hands during Cold Exposure and Manual Performance
Authors: Lockhart John M. , Kiess Harold O.
Published: July 2017

Twenty subjects performed five manual tasks barehanded during exposure to a 60°-F ambient temperature control condition, a 0°-F condition, and three ambient temperature conditions of 20°, 0°, and −20° F, in which auxiliary heat was applied to the hands. The tasks consisted of the Purdue Pegboard assembly, block-stringing, Minnesota Rate of Manipulation placing, knot-tying, and screw-tightening tasks and were performed after exposure durations of 0, 60, 120, and 180 min. Exposure to the 0°-F condition without auxiliary heat resulted in significant performance decrements on all tasks. The application of auxiliary heat to the hands resulted in the avoidance or alleviation of impaired performance during cold exposure depending upon the task, ambient temperature condition, and duration of exposure. The differential effects of auxiliary heat during cold exposure across manual performance tasks were related to the effects of auxiliary heat on hand skin temperature. These effects are discussed in terms of differential hand and finger dexterity, strength, and speed of movement requirements across tasks.
The Effects of Age and Physique on Continuous-Work Capacity
Authors: Snook S. H.
Published: July 2017

The following hypotheses were investigated: (1) continuous-work capacity does not decrease with increasing age, and (2) physique has a greater effect on continuous-work capacity during slower, heavier tasks than during faster, lighter tasks. Twenty-eight, healthy male subjects, 14 between 25 and 35 years of age, and 14 between 45 and 60, performed 54 manual handling tasks for a duration of 40 min. Three lifting, three lowering, four pushing, one pulling, and six carrying tasks were performed at three different rates of work. Three replications of a walking task were also performed. The continuous-work capacity of each subject for each task was measured by a psychophysical technique which required subjects to adjust their work loads to the maximum amount that they could perform without strain or discomfort, and without becoming tired, weakened, overheated, or out of breath. Heart rates were monitored continuously during task performance. The age hypothesis was tested by subjecting both work-load and heart-rate data to analyses of variance. The physique hypothesis was tested by correlating work-load data with each of 41 anthropometric measurements obtained from each subject. The results supported the age hypothesis. The physique hypothesis, however, was supported only by the results of the younger group of subjects.
The Value of an Accelerator Release Signal
Authors: Mortimer Rudolf G.
Published: July 2017

The value of a signal shown on the rear of an automobile when the accelerator is released was investigated by measuring (1) the magnitude of decelerations in coasting passenger cars, (2) the ability of drivers to detect coasting of a vehicle they are following, and (3) coasting periods used by a number of drivers on various trips. Coasting decelerations of a sample of passenger vehicles did not exceed 3 ft/sec 2. The driver's sensitivity (ΔH), the change in spacing necessary to detect coasting of a lead vehicle, was a direct function of the initial headway (H) with a median value ΔH = 0.12H. Instrumentation of a motor-pool automobile showed that most coasting durations were between 0.5 and 5 sec. with speed reductions of less than 4 mph. Release of the accelerator pedal was followed by braking on less than 50% of the coasting occasions. It was concluded that a coasting signal could not reliably indicate that braking would follow and was largely unnecessary for detection of coasting, but could aid in reducing the development of critical conditions when coasting periods exceed about 5 sec. A signal given only when coasting duration exceeds 5 sec. would not occur frequently and would provide valid information on most occasions.