WorldCat Identities

Mertens, Henry W.

Works: 53 works in 159 publications in 1 language and 5,443 library holdings
Roles: Author
Classifications: RC1054.U5,
Publication Timeline
Most widely held works by Henry W Mertens
Predictive validity of the aviation lights test for testing pilots with color vision deficiencies by Nelda J Milburn( )

4 editions published between 1996 and 2004 in English and held by 237 WorldCat member libraries worldwide

The color filters of the Farnsworth Lantern (FALANT) were changed to meet the Federal Aviation Administration s signal color specifications, thereby creating a job-sample color vision test called the Aviation Lights Test (ALT) that is used for secondary screening of air traffic control specialist applicants in the terminal option. The purpose of this experiment was two-fold: to determine whether the ALT could be used in place of the FALANT for testing pilots and whether the altered filters in the ALT (primarily, a more highly saturated red) improved its predictive validity with the criterion instrument called the signal light gun (SLG). The SLG is used by air traffic controllers to communicate with pilots in aircraft experiencing radio failure within the airport terminal area. Method. Participants were 145 individuals with moderate to strong red-green color vision deficiency, 10 individuals with minimal color vision anomalies, and 227 individuals with normal color vision, as classified by a Nagel anomaloscope. Participants identified 3 series of 9 pairs of colored lights of the FALANT and the ALT. A subset of 82 participants also identified the color-coded signals of the signal light gun test (SLGT). Results. The frequency of confusing white and green lights was similar for all tests; however, as predicted, errors involving red targets were reduced for the color deficient sample for the ALT relative to the FALANT. Compared with the FALANT, the use of signal colors in the ALT had little effect on cross-tabulated pass/fail outcomes with the SLGT, K(82)= .70 and .675. Conclusions. Results suggest that if the ALT is administered and scored with procedures identical to the FALANT, the incidence of passes and failures for pilots with color vision deficiencies will be essentially the same for the two tests
Age, alcohol, and simulated altitude : effects on performance and breathalyzer scores by William Edward Collins( Book )

6 editions published in 1988 in English and held by 237 WorldCat member libraries worldwide

Trained men in two groups, 30-39 (n=12) and 60-69 (n=13), each performed at the Multiple Task Performance Battery (MTPB) in four separate full-day sessions with and without alcohol (2.2 mL of 100-proof vodka per kg of body weight) at ground level and at a simulated altitude of 12,500 ft (3810 m). Subjects breathed appropriate gas mixtures through oxygen masks at both ground level and altitude. Mean breathalyzer readings peaked near 88 mg % and did not differ between age groups or altitude conditions. Younger subjects performed better than older subjects; performance of both age groups was significantly impaired by alcohol, but these adverse effects were greater for the older subjects. No significant effects on performance were obtained due to altitude or to the interaction of altitude with alcohol. These results and those from several other studies suggest that prevalent views regarding the nature of the combined effects of alcohol and altitude on blood levels and on performance need to be redefined. Keywords: Intoxication, Performance(Human)
Evaluation of functional color vision requirements and current color vision screening tests for air traffic control specialists by Henry W Mertens( Book )

4 editions published in 1990 in English and held by 222 WorldCat member libraries worldwide

Effects of color vision deficiency on detection of color-highlighted targets in a simulated air traffic control display by Henry W Mertens( Book )

4 editions published in 1992 in English and held by 219 WorldCat member libraries worldwide

Age, altitude, and workload effects on complex performance by Henry W Mertens( Book )

5 editions published in 1983 in English and held by 219 WorldCat member libraries worldwide

Fifteen healthy men in each of three age groups, 20-29 yrs, 40-49 yrs, and 60-69 yrs, were evaluated regarding complex performance in two altitude conditions (ground level vs. 3,810 m) which were administered during performance testing. Performance was measured during a 3-h test session with the Multiple Task Performance Battery (MTPB) which involved time-shared performance of several flight-related tasks presented in different combinations to vary workload. MTPB tasks consisted of monitoring of warning lights and meters, mental arithmetic, problem solving, visual target identification, and tracking. Heart rate decreased slightly at the 3,810 m altitude in the 60-69 yr group, but increased significantly at altitude in the two younger groups. Both epinephrine and norepinephrine excretion rates were highest in the 20-29 yr group and lowest in the 40-49 yr group. Age related decrements occurred in monitoring tasks, information-processing tasks, and a tracking task involving psychomotor- coordination. Performance differences occurring as a function of age were evident predominantly at moderate and high workload levels. There were no important effects of altitude on performance. Physiological and biochemical responses had little relation to performance. Implications of these findings for future research relating age to pilot performance are discussed
Two-flash thresholds as a function of comparison stimulus duration by Mark F Lewis( Book )

4 editions published in 1970 in English and held by 213 WorldCat member libraries worldwide

The proposal that two-flash thresholds may be used as direct measures of the critical duration (tc) of Bloch's law was tested. Two-flash threshold was found to be an increasing function of comparison stimulus duration for durations of 3 to 22 msec. indicating that two-flash threshold does not measure tc. Increasing luminance in the range of 1.0 to 3.0 log mL. enhanced the effect. Application of these data to specifications for strobe lights used as anticollision devices is discussed. (Author)
Reaction time as a function of flash luminance and duration by Mark F Lewis( Book )

4 editions published in 1967 in English and held by 212 WorldCat member libraries worldwide

As a consequence of the high speeds of modern aircraft, pilots must respond quickly to signal lights from the ground or other aircraft during night flight. The present study was concerned with the relation of reaction time to flash luminance and duration. Reaction time was a decreasing, negatively accelerated function of flash luminance. Flash duration had no clear effect upon reaction time. (Author)
Perceived depth between familiar objects by Walter C Gogel( Book )

4 editions published in 1967 in English and held by 211 WorldCat member libraries worldwide

In aviation, size cues are frequently used in a pilot's evaluation of depth or distance. In the study, the hypothesis was examined that the essential factor in the size cue to depth from familiar objects is the perceived size S' per unit of retinal size theta of each of the objects, with the object having the largest value of S'/theta appearing to be the more distant object. Five familiar objects (a box of cough drops, a half dollar, a tape dispenser, a door key, and a tube of toothpaste) were simulated. The objects were presented in pairs and the Os indicated their perceived width (S'), the perceived distance (D') of each from himself, and the perceived depth (d') between the objects in each pair. In agreement with the above hypothesis, the results indicate that the perceived depth between the objects was a monotonic function of the difference between the values of S'/theta. The average values of d' and D' were similar to the simulated values for distances up to approximately three feet from the observer. For greater distances the error in the average d' and D' values increased with an increase in the simulated distances. The study supports the notion that the familiar size cue to depth can occur between objects of dissimilar shape whenever these objects have perceived sizes. The concept of S'/theta as the significant factor in the familiar size cue to depth permits this cue system to be of significance in a wide variety of naturally occurring situations. (Author)
Behavioral changes from chronic exposure to pesticides used in aerial application : effects of Phosdrin on the performance of monkeys and pigeons on variable interval reinforcement schedules by Mark F Lewis( Book )

5 editions published in 1972 in English and held by 209 WorldCat member libraries worldwide

The need for study of behavioral difficulties resulting from exposure to pesticides is based upon reports of behavioral difficulties in aerial applicators following organophosphate poisoning and is underscored by a recent plane crash of a cropduster pilot in which prior exposure to several organophosphate pesticides was implicated. The present study examines effects on performance of pigeons and squirrel monkeys of Phosdrin (mevinphos), a cholinesterase-inhibiting pesticide not previously studied in the laboratory. Variable interval schedules of reinforcement were used with both food and water as rewards. A dose related decrease in response rate was observed with all animals. Decrements in behavior were observed at doses below which external symptoms of Phosdrin poisoning occurred, indicating the need for further investigation of the behavioral actions of pesticides
Assessment of the Broca-Sulzer phenomenon via inter- and intra-modality matching procedures : studies of signal-light brightness by Mark F Lewis( Book )

4 editions published in 1968 in English and held by 207 WorldCat member libraries worldwide

Signal lights are presented to an observer as flashes with finite duration; thus, the effect of flash duration on the apparent brightness of the signal is important. The relation of effective signal brightness to flash duration and luminance finds expression in the Broca-Sulzer phenomenon. This study was concerned with the effect of method of measuring brightness and with the effect of adaptive state of the eye on the Broca-Sulzer phenomenon. Subjects adjusted the luminance of test flashes 1 to 1000 msec. in duration to match either the loudness of a 500 msec. comparison tone (1000 Hz) or the brightness of a 500 msec. comparison flash. Comparison tone loudness were 75, 86, and 97 dB. Comparison flash luminances were 10, 100, and 1000 mL. In the light-adapted condition, a 1.5 sec. adapting flash was presented 2.5 sec. before the comparison flash. No adapting flash was presented in the dark-adapted condition. The Broca-Sulzer effect appeared only with the highest comparison stimulus intensities in both crossmodality matching and brightness matching conditions. This finding conflicts with the hypothesis that the Broca-Sulzer effect is obtained only when the procedure for measuring brightness involves a visual comparison stimulus. An interaction found between method of measuring brightness and adaptive state was also discussed. The findings are pertinent to the prediction of effective brightness of a signal since, under some conditions, apparent brightness does not increase steadily with increased duration but, rather, evidences a peaking effect. (Author)
Discrimination of short-duration (two-pulse) flashes as a function of signal luminance and method of measurement by Henry W Mertens( Book )

4 editions published in 1971 in English and held by 207 WorldCat member libraries worldwide

The recent introduction of strobe lights for anticollision purposes raises the possibility of using temporal patterns of short duration flashes as information carrying signals. The current experiments are concerned with the detection of the minimum duration dark interval between signal light pulses as a function of signal luminance and the psychophysical method of measurement. Experiment I tested the theory of signal detectability (TSD) prediction that observer sensitivity is independent of the psychophysical method used in measurement. Discrimination of a constant duration stimulus (three msec) and a variable duration test stimulus (seven to 32 msec) was measured with a two- alternative Forced-Choice (FC) procedure and a Yes-No procedure. Sensitivity was comparable under the two psychophysical procedures, thus supporting the application of TSD to the sensory processes involved in discrimination of two- pulse stimuli. Experiment II measured discrimination with the FC procedure at three luminance levels: 31.8, 318, and 3183 candelas per square meter. Discriminability increased with luminance. Thus, pulses separated by a dark interval short enough so that only a single flash is seen over the entire scotopic intensity range may, however, be seen at photopic intensities as two pulses, or appear to flicker, or otherwise appear to be of different character
Problems in depth perception : a method of simulating objects moving in depth by Walter C Gogel( Book )

2 editions published in 1965 in English and held by 199 WorldCat member libraries worldwide

Problems in depth perception : perceived size and distance of familiar objects by Walter C Gogel( Book )

2 editions published in 1966 in English and held by 197 WorldCat member libraries worldwide

A homogeneous field for light adaptation by Henry W Mertens( Book )

2 editions published in 1966 in English and held by 194 WorldCat member libraries worldwide

Optimizing blink parameters for highlighting an air traffic control situation display by Nelda J Milburn( Book )

5 editions published in 1999 in English and held by 157 WorldCat member libraries worldwide

Research suggests blinking targets are more alerting than steady targets; however, several factors can interact with blinking to either improve or degrade its attention-getting value. Those factors include target size, color, brightness contrast, frequency of blink, and the time the blink is at maximum brightness relative to the time it is off or dim during the blink cycle. No guidelines were found for determining the optimal attention-getting blink amplitude (the percentage of decrease in target brightness from a standard) and the interaction of blink amplitude with the other blink characteristics mentioned above. Thirty-six participants were asked to locate and select blinking blocks of text on a simulated air traffic control display to examine the interaction of blink frequencies, amplitudes, and duration with size of text. Our results support the use of amplitudes 75% or greater combined with frequencies from 2 to 4 Hertz and text size 0.15 inch or greater for optimum highlighting value in visual search tasks
Evaluation of a range of target blink amplitudes for attention-getting value in a simulated air traffic control display by Nelda J Milburn( Book )

3 editions published in 1997 in English and held by 156 WorldCat member libraries worldwide

Several sources suggest that blinking targets are more alerting than steady targets. Those sources recommend target size, color, shape, brightness contrast, frequency of blink, and parameters for the ratio of time the blink should be 'on, ' relative to the time it is 'off' However, no guidelines were found for an effective, attention-getting blink amplitude (the percentage of decrease in target brightness from a standard). Ten participants located and selected the blinking information data blocks (targets) from 16 data blocks on a Simulated Air Traffic Control Display. Seven blink amplitudes, ranging from 12.5% to 100%, were evaluated. Error and response time performance were near optimum for conditions involving a 75% to 100% decrease in brightness. For the standard luminance (51.4 Cd/m2), frequency (2 HZ), and duration (.10 sec) used in this experiment, a decrease in brightness of at least 75% was necessary for maximum attention-getting value of a blinking target
A further validation of the practical color vision test for en route air traffic control applicants by Henry W Mertens( Book )

4 editions published in 1996 in English and held by 152 WorldCat member libraries worldwide

The Flight Progress Strips Test (FPST) is currently used for secondary color vision screening of applicants for air traffic control jobs at en route centers. The test provides a practical, job-specific color vision selection criterion involving use of color coding in the most important color task of en route radar contollers, i.e., discrimination of the non-redundant color coding in flight progress strips (FPSs). This experiment provides a further, independent validation of the FPST using a new criterion test. Prediction by the FPST of performance on the new and old criterion tests was compared. Subjects were classified as normal or deficient based on anomaloscope readings. The pass/fail cutoff score for all tests was 'pass with no more than one error.' All people with normal color vision passed. Over all, for participants with both normal and abnormal color vision, the correlations between error scores on the FPST and both criterion tests were greater than r=.93, and error scores tended to increase with degree of color vision deficiency. The validity of the FPST was Kappa=.86 for prediction of performance on the new criterion test, as compared to .91 for prediction of performance on the original criterion test. Part of that small decrease in validity may be because of application of the same pass/fail cutoff score to the new criterion test, which contains a larger number of items than the FPST. The predictive validity of the FPST was shown to be acceptably high in this further validation with a new, independent set of actual flight progress strips as the criterion test
Validity of FAA-approved color vision tests for Class II and Class III aeromedical screening : final report by Henry W Mertens( Book )

6 editions published in 1993 in English and held by 148 WorldCat member libraries worldwide

All clinical color vision tests currently used in the medical examination of pilots were studied regarding validity for prediction of performance on practical tests of ability to discriminate the aviation signal colors, red, green, and white given under both day and night conditions. Those same practical tests are given to pilots with color vision deficiency who apply for a waiver of the Class II or Class III color vision standards. Subjects with varying type and degree of color vision deficiency (n=122) and subjects with normal color vision (n=120) were classified with the anomaloscope and given both practical and clinical tests. The clinical color vision tests included the American Optical Company plates (1965 and 1940 Editions), AOCHRR plates (2nd Edition), Ishihara plates (14-, 16-, 24-, and 38-plate tests), Dvorine plates, Richmond plates, Farnsworth Lantern, School of Aviation Medicine Color Threshold Tester, Titmus Tester, Titmus II Tester, OPTEC 2000 Tester, and Keystone Orthoscope/Telebinocular test. The criterion tests required naming the colors of actual signals produced by the Aviation Signal Light, with the same test procedures and viewing distances used in actual practical tests. The Farnsworth Lantern and several plate tests were the best clinical tests for predicting ability to identify the colors of aviation signals. Individuals with color vision deficiency identified signal colors better at night than during the day. Recommendations for improving the disposition criteria of some clinical tests, and for discontinuing several obsolete tests are discussed. Aviation signal lights, Color vision screening, Color vision deficiency
Practical color vision tests for air traffic control applicants : en route center and terminal facilities : final report by Henry W Mertens( Book )

5 editions published in 1995 in English and held by 147 WorldCat member libraries worldwide

Two practical color vision tests were developed and validated for use in screening Air Traffic Control Specialist (ATCS) applicants for work at en route center or terminal facilities. The development of the tests involved careful reproduction/simulation of color-coded materials from the most demanding, safety critical color task performed in each type of facility. The tests were evaluated using 106 subjects with normal color vision and 85 with color vision deficiency. The en route center test, named the Flight Progress Strips Test (FPST), required the identification of critical red/black coding in computer printing and handwriting on flight progress strips. The terminal option test, named the Aviation Lights Test (ALT), simulated red/green/white aircraft lights that must be identified in night ATC tower operations. Color coding is a non-redundant source of safety-critical information in both tasks. The FPST was validated by direct comparison of responses to strip reproductions with responses to the original flight progress strips. Validity was high; Kappa=. 91. The light point stimuli of the ALT were validated physically with a spectroradiometer. The test lights met the FAA and ICAO standards for colors of aircraft and aviation signal lights. The reliabilities of the FPST and ALT were estimated with Chronbach's alpha and were .93 and .98, respectively. The high job-relevance, validity, and reliability of these tests increases the effectiveness and fairness of ATCS color vision testing
Validation of an inexpensive illuminant for aeromedical color vision screening : final report by Nelda J Milburn( Book )

5 editions published in 1993 in English and held by 144 WorldCat member libraries worldwide

An inexpensive illuminant for color vision screening suggested by the NRC-NAS Committee on Vision was evaluated as a substitute for the Macbeth Easel Lamp. The Macbeth Easel Lamp is the recommended illuminant for pseudoisochromatic plate tests used in aeromedical color vision screening, but is no longer in production. Subjects included both normal trichromats (P=145) and persons with varying degrees and types of color vision deficiencies (p=152) as diagnosed with the Nagel Type I anomaloscope. Subjects were given the Dvorine Pseudo-Isochromatic Plate Test illuminated by each of the two light sources. One Verilux True Color Light tube (Fl5T8VLX) was installed in an adjustable fluorescent desk lamp and position at a height of 24 in above the center of the Dvorine test book to give a 270 lux illumination to match the illumination produced by the Macbeth light source. The two presentations of the Dvorine were separated by several other color vision tests. Each subject was given a different random order of plates 2-15 for each light source. Pass/Fail performance with the Dvorine test was virtually the same with the two light sources when criterion for failure was 3 or more errors. The Verilux True Color Light obtained a Kappa value of .97, and very low false positive (.021) and false negative (.006) rates when compared to the Macbeth Easel Lamp. Performance and possible applications of the Verilux True Color Light in aeromedical color vision screening are discussed
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