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Froure 7. TMT-I problem-solving task, block diagram.

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Wroure 8 Serial-performance task.

Appendix 1



Taste 1. Eight-cam subtask program
Cam No. 1 2 3 4 5 6 7 8
Time of event (sec) 13 | 21 | 39 | 60 | 69 | 81 | 96 101
1 L+ Ww L- R-
2 R- R+ w L-
3 | L+ R+ L-
4 R- L- | W L-
Stepper 5 R-| W L— R-
position
6 | L+ R+ Ww L—
7 R- L- R-
8 | L+ WwW | R+ L-
9 | L+ R+ WwW | R-
10 R-| W L- R-

Code: L=left meter; R=right meter; W=warning light; (+-)=needle moves upward; (—)=needle moves downward.

of the CRT target is practiced to compensate for
oscilloscope amplifier drift.

Approximately 21% hours of training appear to
be required on the TMT task for subjects to reach
a relatively stable baseline of performance and
demonstrate subtask integration. Figure 4 indi-
cates the performance means for a group of 30
Agency test pilots. On Day 1 they received 45
minutes practice, followed on Day 2 by 150
minutes of continuous practice with knowledge
of performance given about every five trials (15
minutes). Following initial training, college
students typically show small, but steady, im-
provement with 15 to 30 hours experience at the
task.

Experience with the TMT-I indicated some
desirable modifications that have been incorpo-
rated in a new model, the TMT-II, shown in
Figure 5. The display in this case is provided by
a Hewlett-Packard Model 130B oscilloscope

equipped with P-7 phosphor. Vertical-move-
ment, edgewise-type, panel meters are used, and
detections of needle movements are acknowledged
by illumination of the associated push-button that
must be depressed. The TMT-II does not provide
for the mental-arithmetic auxiliary task. A con-
trol has been added at the experimenter’s station
to allow selection of three variations in speed of
the motors driving the tracking-target function
cams. This provides two faster forcing functions
for more stressful task loading.

Stop clocks in the new TMT-II scoring console
(Figure 6) are Standard Electric Co. Model S-1
with manual, lever reset. Analog-computer cir-
cuitry is being assembled, at the time of this
writing, from three Philbrick Model MP solid-
state operational amplifier manifolds containing
as a system ten P65AU and two P25A amplifiers,
two PSQ Quadratic Transconductors, and power

supply.



w

=e

REFERENCES

. Frost, G. G.: A review of scoring methods for tracking

tasks, USAF, Aerospace Medical Research Labora-
tories Memorandum P-14, Wright-Patterson AFB,
Ohio, October 1962.

Wetrorp, A, T.: An apparatus for use in studying
serial performance. Amer. J. Psychol., 65: 91-97,
1952,

. Kay, H.: The effects of position in a display upon

problem solving. Quart. J. Exp. Psychol., 6: 155-169,
1954.

Krvoman, A. D., Ross, §., Vicrno, F. L., and Ciype,
D.J.: A research note: effects of dextro-amphetamine
and meprobamate on problem solving and mood of
aged subjects. J. Gerontal., 15: 419-420, 1960.
Buckner, D. N., and MoGratn, J. J., eds: Vigilance:
@ symposium, New York: McGraw-Hill, 1963.

Bakan, P.: Extraversion-introversion and improve-

ment in an auditory task. Brit. J. Psychol., 50: 325-
382, 1959.

7. O'Connor, W. F.: A twenty-station behavioral com-
munications laboratory with flexible networks and
on-line digital logging. FAA Office of Aviation Medi-
cine Report, in press.

8 Pearson, R. G., Hunter, C. E., and Nuat, G. L.:
Development and evaluation of a radar air traffic
control research task. FAA Office of Aviation Medi-
cine Report, in press.

9, Pearson, R. G.: Scale analysis of a fatigue checklist.
J, Appl. Psychol., 41 : 186-191, 1957.

10, Pearson, R. G., and Byars, G. E., Jr.: The develop-
ment and validation of a checklist for measuring sub-
jective fatigue. School of Aviation Medicine, USAF,
Report No, 56-115, Randolph AFB, Texas, December
1956.



a series stops the clock and ‘is signalled by red
indicator lamps on both the experimenter’s con-
sole and the subject’s display panel. Data are
obtained from measures of incorrect responses and
of time to attain error-free performance; i.e., to
learn the “code.” With the above paradigm, both
age of the subject and degree of practice appear,
in our experience, to be critical variables during
early exposure to the task. Typically, 8 or 9 trials
per problem are required to reach criterion with
initial practice, while subjects who have had expe-
rience with 15 to 20 problems require only 2 or 3
trials per problem.

The flexibility of the apparatus has prompted
its use by other investigators in studies of aging
effects on skill, display-control relationships,
short-term memory store, prefrontal brain injury,
aircrew fatigue, and drug effects?*

VI. Vigilance.

Vigilance is defined here as a form of continu-
ous, prolonged monitoring behavior in which the
operator must detect a critical signal that occurs
infrequently and unpredictably. The task may
vary in terms of absolute signal rate, critical sig-
nal to noncritical signal ratio (or contrast), or
signal to background contrast. According to Me-
Grath, “The signal to be detected may be either
a discrete stimulus added to or taken away from
the environment, or a change in a continuously or
intermittently presented stimulus.”*® Typically,
detection efficiency can be demonstrated to decline
in tasks of 30 minutes to 1 hour, and consequently
frequent rest periods for observers are recom-
mended. .

A. Bakan Task, A tape-recorded copy of this
auditory task has been made available to us by
Bakan.* The task requires the subject. to listen
to a voice repeating a series of digits recorded
at the rate of one per second. The critical signal
is a set of three successive odd numbers, all of
which are different; e.g., 5-3-7, 9-1-5, etc. Upon
hearing such a set, the subject writes them down
in a column on an answer sheet. During a 64-
minute “watch,” 40 critical signals occur. Data
normally consist of the number of correct signal
detections and of “false positives” (i.e, subject
responds to a nonsignal) for a 16-minute sub-
period.

Although we have used the Bakan task success-
fully in one experiment, certain considerations
led us to develop the new auditory vigilance task

described below. Since the Bakan task is a popu-
lar one, some subjects anticipate a relationship
between their responses and the space provided
on the answer sheet; ie., they are familiar with
the task or compare notes with others regarding
the number of signals. Difficulty has been encoun-
tered with some older (age 45 to 65) noncollege
subjects in indoctrinating them on the task; in-
deed, some showed no evidence of being able to
detect a critical signal with 4 to 5 hours of train-
ing. Finally, we decided to use a task that in-
volved a purer element of signal detection and
that did not imply a requirement in it for mem-
ory; ie, a Bakan subject’s response requires both
recall and recording of all three digits correctly.

B. “Beep” Task. This task was developed by
recording 1,000 cps tones at 3-second intervals.
Nonsignals are of 1.0 second duration, while sig-
nals are 1.4 seconds long. The difference in length
between the two tones appears to avoid any prob-
lem involving the difference threshhold; expe-
rience indicates subjects have no problem identi-
fying which of two tones, 1.0 and 1.4 seconds, is
the longer. With prolonged listening to the tone,
however, the traditional characteristics of the vigi-
lance task become evident. Thirty-six signals
occur during a 60-minute watch, 9 every 15
minutes.

In a typical experiment, the subject listens to
the recording through a headphone set and indi-
cates detections by depressing a push-button.
This produces a stylus deflection on a-20-channel
Esterline-Angus event recorder. With this equip-
ment it is possible to obtain data on several sub-
jects concurrently. A communications-systems
laboratory, described in detail elsewhere by its
developer,” has enabled us to test concurrently up
to 20 subjects, each located in a separate sound-
proof booth. The subject station shown in Fig-
ure 10 includes Telex headphones with micro-
phone, a volume control, lamp, a response key,
and a communication link to the experimenter.

VII. Radar Air Traffic Control.

A simulator complex, described in considerable
detail elsewhere,’ provides a capability for assess-
ing a number of operator functions that charac-
terize the enroute radar air traffic controller's task.
These include vigilance, problem solving, moni-
toring, and reaction time. Programming of dis-
play conditions is accomplished by punched tape
and relay circuitry. Task events are thereby pre-



IH. Choice Reaction Time.

This task, located at the subject’s station of both
the TMT-I and TMT-II, is the traditional two-
choice reaction time. It requires the subject to
respond as rapidly as possible to the onset of a red
or green signal by hitting the telegraph key lo-
cated immediately below the associated indicator
light (see Figures 1 and 5). For a given trial, the
subject must rest his right hand on a small metal
plate imbedded (over a small, sensitive miscro-
switch) in the console-table surface. This illumi-
nates a “ready” indicator light at the experiment-
er’s control console. The experimenter then gives
a “ready” command (usually over a microphone-
headset hookup) and, following a delay of 2, 3, or
4 seconds (selected at random by the experiment-
er), depresses a push-button switch that triggers
the signal light and scoring circuitry. Circuitry
is depicted in the block diagram (Figure 3). In
the TMT-I, two measures are obtained directly,
total RT, and decision RT, which is the time it
takes for the subject’s hand to leave the ready pad.
This latter time may be presumed to reflect the
time required for sensory reception, central identi-
fication, and neuromuscular command. A third
measure, motor RT, is derived from the difference
between total and decision RT’s, and reflects the
hand-movement time required to bridge the 9-inch
gap from pad to response key. The stop clocks
involved are those employed in the TMT subtasks.
In the TMT-II, all three measures are obtained on
separate clocks.

Three RT trials can normally be obtained dur-
ing a 1-minute period. We have followed the
practice of obtaining our RT data from two suc-
cessive rest periods during a 15-minute period of
performance (five trials) at the TMT apparatus,
and use the median of six scores as the index of
behavioral efficiency.

IV. Mental Arithmetic.

This task is located at only the TMT-I subject’s
station. It requires short-term memory store and
involves addition of two 2-digit numbers and sub-
traction of a third 2-digit number (eg.,
22 + 19 — 17) that appear in succession on ad-
jacent visual readouts (TEEE Series 10,000) on the
panel (Figure 1). The subject “accepts” each of
the first two temporally separate inputs by de-
pressing the associated push-button as each read-
out is illuminated in succession. With the

appearance of the third input, the subject is then
required to punch his answer as rapidly as possi-
ble on the panel-mounted keyboard and indicate
the certainty of his response by depressing a
“check-off” push-button. As indicated by the
block diagram of the circuitry (Figure 7), scoring
begins with presentation of the third input and
ends with the “check-off” response. Use of the
check-off button avoids the problem encountered
with many subjects who treat the task in the man-
ner of a reaction-time problem and, accordingly,
make frequent errors in punching the keys.

In practice, the experimenter advises the subject
of the start of a series, usually giving four prob-
lems during a 1-minute “rest” period. A buzzer
sounds with the appearance of each number and
ceases with the subject’s response. Both response
errors and speed are scored.

The digital readouts for this application have a
range of 12 numbers, 11 to 22, which provides a
relatively simple task. With undergraduate col-
lege students, however, considerable individual dif-
ferences have been observed, and so to date the
sensitivity of the task to experimental treatment
has not been demonstrated. Paper-and-pencil
practice tests, incidentally, have confirmed this
problem. For some subjects a strong practice (re-
learning) effect is evident.

V. Problem Solving.

Circuitry described by A. T. Welford * was fol-
lowed in the construction of the apparatus shown
in Figures 8 and 9. Basically, the task requires the
subject to make a key-pressing response (from 1
of 12 keys) to a light appearing in a bank of 12
indicators. A correct response extinguishes the
stimulus light, a new one appears, the process is
repeated, ete., for any given number of lights up
to 12. The plugboard (Figure 9) permits the ex-
perimenter to select and vary both the sequence in
which the lights come on and their relationship to
the response keys, so that an infinite number of
series combinations are possible. For any given
pattern that is wired, selection of both starting
and ending points within a series can also be con-
trolled by two 12-position switches.

We have used a serial learning paradigm in
which the subject must find the sequence of keys
that will cause six lights to change in series. Pres-
entation of the first stimulus light is controlled
by a switch on the experimenter’s panel that also
starts a stop clock. The final correct response in


ca

om

=

REFERENCES

Frost, G. G.: A review of scoring methods for tracking
tasks. USAF, Aerospace Medical Research Labora-
tories Memorandum P-14, Wright-Patterson AFB,
Ohio, October 1962.

Wetrorp, A. T.: An apparatus for use in studying
serial performance. Amer. J. Psychoi., 65: 91-97,
1952.

Kay, H.: The effects of position in a display upon
problem solving. Quart. J. Exp. Psychol., 6: 155-169,
1954.

Krveman, A. D., Ross, 8., Victno, F. L., and Cry,
D. J.: A research note: effects of dextro-amphetamine
and meprobamate on problem solving and mood of
aged subjects. J. Gerontal., 15: 419-420, 1960.
Buoxner, D. N., and McGraru, J. J., eds: Vigilance:
@ symposium, New York: McGraw-Hill, 1963,

Baxan, P.: Hxtraversion-introversion and improve-

nm

2

10.

ment in an auditory task. Brit, J. Psychol., 50; 325-
332, 1959.

O'Connor, W. F.: A twenty-station behavioral com-
munications laboratory with flexible networks and
on-line digital logging. FAA Office of Aviation Medi-
cine Report, in press.

Pearson, R. G., Hunrer, C. E., and Near, G. L.:
Development and evaluation of a radar air traffic
control research task. FAA Office of Aviation Medi-
cine Report, in press.

Pearson, R. G.; Scale analysis of a fatigue checklist.
J. Appl. Psychol, 41 : 186-191, 1957.

Pearson, R. G., and Byars, @. E., Jr.: The develop-
ment and validation of a checklist for measuring sub-
jective fatigue. School of Aviation Medicine, USAF,
Report No. 56-115, Randolph AFB, Texas, December
1956,



AM 66-19

PERFORMANCE TASKS FOR OPERATOR-SKILLS
RESEARCH

Richard G. Pearson, Ph. D.

Approved by Released by
4
J. Rosert Ditis, M.D. P. V. Srzezn, M.D.
Carer, Civ Anromepicay InstrTuTE Fretp Arr Suranon
June 1966

FEDERAL AVIATION AGENCY

Office of Aviation Medicine



LEGEND -

FEDERAL AVIATION” AGEN
FAR DEPOT

TMT-1

TRACKING 8 REACTION TIME

‘BLOCK DIAGRAM

“AAD-C-181-1

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Appendix

15 30 45 30

60

90

MINUTES OF PRACTICE

Ficure 4, TMT-I skill acquisition with practice.

9



APPENDIX

Fieure 1. Tracking and monitoring task, Model I.

Ficure 2. TMT-I programing and scoring complex.

8


sented repeatedly, reliably, and concurrently to
each of six experimental subjects seated at sepa-
rate task consoles (Figure 11). Radar targets are
presented by filmstrips made from an animated
display. Hypothetical pilot communications and
flightstrip information are played concurrently
from prerecorded tapes. Responses to critical
events are measured automatically with electronic
counters, and periodically, the data are typed out
by a Friden Flexowriter and punched on paper
tape for computer analysis. Duration and fre-
quency of subject radio transmissions are also
scored. Monitoring of system operation and data
collection requires only a single experimenter.

A unique photographie technique provides
identical target workloads for each of several
1-hour tests; yet the subject perceives these as
different task programs. This permits day-to-day
comparison of performance under comparable
environmental and task conditions while con-
trolling for possible memory effects.

Initial experimentation indicates that approxi-
mately 8 hours of practice are required for subjects
(ATC instructors) to integrate effectively all
subtasks and to achieve a stable level of profi-
ciency. A new flightstrip format has been de-
veloped to be commensurate with system design,
and, currently, closed-circuit television is being

installed for radar target display. Research
applications include studies of drug effects on pro-
ficiency, fatigue, stress, aging, automated training,
target and display characteristics, workload, and
control techniques.

VIII. Assessment of Affective State.

To supplement and complement the perform-
ance data derived from the operator tasks de-
scribed, two affective-state checklists have been
used in our research. A fatigue checklist with two,
13-item, equivalent forms is described in detail
elsewhere.” #° An extension and elaboration of
this, developed by the author in 1956 at the USAF
School of Aviation Medicine, is identified as the
SAM Affective Checklist, Form X, and includes
81 items as listed in Table 2. The clustering is
based on item sorts made by psychologists working
in stress, drug, and sensory-deprivation research.
A unique feature of the items (in contrast to many
mood checklists in use) is that they are under-
standable by low-vocabulary individuals. Screen-
ing trials included individuals with as low as
seventh grade education and from wide geographi-
cal, racial, and ethnic backgrounds. Typical
checklist format requires the subject to check those
items that describe his mood or feelings as of a
given moment.

Tasie 2. SAM affective-checklist items

Cluster Polarity Items
1. Anxiety _ (+) Quiet; easy going; peaceful; calm, cool, and collected.
(-) Anxious; worried; disturbed; excited; uneasy; tense.
2. Alertness. _--..-----.- (+) Alert; careful; cautious; wide-awake; clear-headed.
(-) Careless; reckless.
3. General morale..-..-_- (+) Agreeable; sociable; witty; talkative.
(-) Irritable; unfriendly.
4, Elation-depression..____ (4) Cheerful; carefree; happy; daredevil; happy-go-lucky.
(-) Moody; sad; depressed; serious.
5. Cooperation__--------- (+) Cooperative; eager.
(-) Indifferent.
6. Organic. ._..--.------- (4) Dreamy; light-headed.
(-) Drowsy ; dizzy; headache; weak; feverish; heavy-headed; hot; cold; numb.
7. Work attitude..._..- (+4) Energetic; industrious; strong; raring-to-go; fit-as-a-fiddle; ambitious.
(-) Lazy; dull; sluggish; stale; lifeless; run-down; slowed-down.
8. Relaxation...-..-.-_.- (4) Relaxed; patient.
(-) Nervous; jittery; restless.
9. Persistence.____-__-__- (+) Self-confident; on the ball; steady; tireless.
(-) Unsure; unsteady; confused; disorganized; useless, timid.
10. Boredom___.-.-------- (+) Interested.
(-) Bored; uninterested.
11. Fatigue... ----------- (4+) Quite fresh; extremely peppy.
(-) Tuckered out; dead tired.



dication of the control position coordinates. Ini-
tially, voltage to the control system was supplied
by two 1.4-volt mercury cells, later superceded by
asmall regulated DC power supply.

C. Subtasks. The meter-monitoring subtask
requires the operator to detect needle deflections
of each of two panel meters, one located on each
side of the CRT display. Tips of the needle
pointers are located 5 inches from the center of the
CRT display. Ifa movement of a needle from a
null position on either meter is observed, the op-
erator must respond with his left hand by press-
ing the appropriate push-button (Micro Switch
Series 2) located at the lower left of the panel.
Timely responses null the needle; if, however, the
deflection goes undetected, the needle is auto-
matically nulled within the time frame of the cam
program described below. Detections within this
time frame are “rewarded” by the onset of an
amber lamp located above each meter.

The warning-light monitoring subtask requires
the operator to detect the onset of a yellow visual
indicator located at the extreme lower left-hand
corner of the panel, 14 inches from the center of
the CRT display. Operator response, which ex-
tinguishes the light, requires depression of a push-
button located in the top of the control stick. As
in the case of the meter subtask, the cam program
automatically extinguishes the light after a period
of time if the event goes undetected.

To provide for variety in the occurrence of sub-
task events, a combination of cam-timer and step-
ping-switch circuitry was designed involving 10
different subtask schedules, or test trials, as shown
in Table 1. With each new trial, the advance of
the stepping switch selects a different combina-
tion of cams to control the pattern of events occur-
ring over time. The program shown provides for
3 meter events and either 0 or 1 warning-light
events for a given trial. Trial events are pro-
grammed to occur at irregular intervals during a
2-minute task trial. Allowing for a 1-minute rest
period between trials (which has been our prac-
tice) a specific pattern of subtask events does not
repeat itself within 30 minutes.

D. Task Load. The task load provided by the
subtasks is, of course, secondary to that of the
forcing function input to the central tracking task.
This latter input is provided by movement of two
target function cams that vary the voltage input
to the X and Y terminals of the oscilloscope by
electromechanical means, thereby determining the

position of the target on the CRT display. The
two irregular cams functionally represent, respec-
tively, the mixture of sine waves of 3, 5, and 8
cycles per minute and 3, 8, and 10 cycles per
minute. The motors driving the cams operate at
different speeds, however, so that the former cam
pattern runs its course in 120 seconds, the latter in
160 seconds. Maximum target excursion on the
display was set at 4 cm from center; limiters pre-
vent the target from disappearing off the display
in the event of an inappropriate control response.

E. Scoring. For the tracking task, voltages de-
fining the position of the target on the display
(i.e, input function minus joystick voltages) are
fed into a PACE TR-20 analog computer, which
integrates the absolute error over the task trial.
Readout appears on a Non-Linear Systems Model
4700 digital voltmeter. Computer wiring is in
accord with the recommendations of Frost.’
Scoring of performance by the computer is initi-
ated 10 seconds following the start of a trial (to
allow for operator warm-up effects) and ceases 5
seconds before the end of a trial. Subtask re-
sponses are timed with Industrial Timer Corpora-
tion Model SC-100 stop clocks in 0.01-second units.
Clock reset is push-button, solenoid-actuated.

F. Typical Operation. Figure 2 shows the ex-
perimenter’s station, which includes a task-pro-
gramming and scoring control console (left), the
analog computer, and digital voltmeter and 48-
volt DC power supply (right). A 20-cam Indus-
trial Timer Corporation Model RC timer lo-
cated inside the control console accomplishes sev-
eral functions: (a) Activation of buzzers that in-
dicate “ready,” “start,” and “cease” tracking-task
status, (b) control of analog computer “hold,”
“integrate,” and “reset” modes; (c) blanking out
of the CRT target during rest periods; (d) opera-
tion of tracking-target function cams; and (e) ac-
tivation of the monitoring subtasks and associated
stop clocks. Separate circuits permit recycling of
the tracking-target function cams and resetting of
the stepping switch that controls the subtask event
program. Figure 3 is a block diagram depicting
more clearly the circuitry involved in task control
and scoring.

Checkout procedure prior to daily testing in-
cludes balancing of the analog computer and cen-
tering of the CRT target on the cross-hairs of the
display with all inputs balanced. With extended
testing of 2 to 10 hours, routine hourly calibration


Appendix

)

Y

Ficure 9. Serial-performance programing unit.

Ficure 10, Communication-laboratory subject station.

12




PERFORMANCE TASKS FOR OPERATOR-SKILLS RESEARCH

I. Introduction.

Engineering psychology as a discipline is con-
cerned with the efficient and optimal combination
of men and machines in both normal and unusual
operator environments. In civil aviation, the
focus of its interest is upon pilots, other airborne
personnel, air traffic controllers, and other ground
personnel—taking into account the capabilities
and limitations of the skilled operator, the equip-
ment with which he must interact, and the environ-
ment in which he must work. With the establish-
ment of a new research facility and its associated
mission, there existed a need for performance
tasks that would permit study of problems asso-
ciated with maintenance of operator proficiency,
whether these problems reside in the operator, the
task, or the work environment. This report de-
scribes the selection, development, and operation
of several tasks that, in support of these needs,
are now part of the engineering-psychology re-
search capability of the Office of Aviation
Medicine.

The tasks described are intended, collectively,
to sample a broad spectrum of abilities required
by complex operator systems and, individually, to
be 4 challenge to the experimental subject. Some
were developed to simulate closely real-life tasks,
while others are of a more abstract nature. The
tasks also vary to the extent with which demands
are placed upon various levels of functioning of
the human organism; e.g., attentional, sensory
input, central processing and decision, and motor
output.

Il. Tracking and: Monitoring.

The tracking and monitoring task (TMT-I)
was developed to simulate, in part, some of the
functions associated with flying skill. Figure 1
(all figures are in the appendix) shows the sub-
ject’s station, which includes, in addition to the
main tracking-monitoring task, a capability for
assessing either choice reaction time or simple
mental-arithmetic ability during rest periods.

These auxiliary tasks will be described.in follow-
ing sections. The principal (central) task in-
volves two-dimensional, compensatory tracking of
a, randomly moving target appearing on a 5-inch
diameter display. Specifically, the operator's task
requires centering a target spot on cross-hairs by
moving a small spring-loaded joystick. Concur-
rently with the tracking task, two subtasks, meter
and warning-light monitoring, can be programmed
to occur at irregular intervals during a given trial.
The purpose of these subtasks is to introduce some
complexity into the test situation by requiring the
operator to time-share his visual tracking, scan-
ning, and peripheral-vigilance activities.

Taken together with the auxiliary tasks, the
attraction of the TMT-I system for operator-
skills research is that a number of diverse human
functions—simple motor responses, psychomotor
coordination, monitoring, peripheral attention,
and problem-solving—can be evaluated quickly
and repeatedly at a single station. Consequently,
a profile of performance effects can be obtained as
a function of time on the task under the experi-
mental treatments of interest, °

A. Display. The tracking-task display is pro-
vided by a Hewlett-Packard Model 120B oscillo-
scope equipped with P** phosphor and an internal
graticule to eliminate parallax. For testing under
dark conditions, the face of the CRT can be illu-
minated with black light. The table surface is
271% inches above the floor, and the center of the
CRT is 13 inches above this. The display panel
is situated 12 inches back from the front edge of
the table.

B. Control. The joystick assembly is Raytheon
Type FA-7553, obtained as surplus RBDE-5
equipment. Handle length is 444 inches and diam-
eter is 1 inch. Maximum stick displacement is
thru an are of approximately 100°. As noted in
Figure 1, the control is offset 3 inches to the right
of a line through the center of the CRT. Poten-
tiometers attached at the point of rotation of the
X and Y axes of the joystick yield a voltage in-



FOREWORD

This report describes the characteristics and uses of several research tasks
developed as part of a capability for conducting experiments involving skilled-
operator performance. In this context, the success of the project. scientist’s
efforts at times depends greatly upon the design and reliability of the equip-
ment with which he and his subjects are involved. The author has been fortu-
nate in this regard to have at his disposal commendable engineering, electronics,
mechanical, and shop services, involving consultation, design, development,
maintenance, and fabrication. Development of the tasks described was a prod-
uct of these services and the individuals who rendered them deserve recognition :
Marion C. Oviatt, Harlie W. Huffman, Francis E. Anderson, and Armand C.
Schmidt, all from CAMI’s Research Engineering Service; and Clifton E.
Hunter and Don P. Harris, from the FAA Depot.

Qualified requestors may obtain Aviation Medical Reports from Defense Documentation
Center. The general public may purchase from Clearinghouse for Federal Scientific and
Technical Information, U.S. Dept. of Commerce, Springfield, Va. 22151


Ficure 6, 'TMT-II programing and scoring unit.

Appendix 10


Appendix

18

USS. GOVERNMENT PRINTING OFFICE:1968 O—224-074

Ficure li, Radar ATC task console.