Technical Paper 374 LEVEIL

SIMULATING VARIOUS MOON ILLUMINATION

LEVELS WITH LIGHT ATTENUATING

DEVICES (LADS)

Paul R. Bleda

ENGAGEMENT SIMULATION TECHNICAL AREA

U. S. Army

Research lnst,tute for the 04’h wioral and Social Sciences

July 1979

Approv.d for public rele.se; distribution unlimited.

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FOR THE BEHAVIORAL AND SOCIAL SCIENCES

A Fiel d Operating A gency under t he Jurisdiction of thc

Deputy Chief of Staff for Personnel

WILLIAM L. HAUSER

JOSEPH ZEIDNER Co lon •I . U S A ,n. y

T•chn ic.l Dir.ctor Commandsr

NOTICIS

DIST~ ISUTI ON Pr’msry d,str,bul,on of this report has been mid, by AAI. PI..ge sddrsss correspon(1en .

concerning dsstribuft on of reports to U. S. Army ~iSiircft Institute for the Sih.~ior.l and Social $c*ncc’

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QIL TM findings in this report ar. not to bi Construed is in OffIcial DIpartment Of the Army position

nIIss so designated by Othsr .utPiOrifld documents

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c

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SIM ULATING ~~RIOUS OON~~~ LUMINAT1ON LEVELS WITh

~iGHT-~~TE~~~TING ICES (LADs) g - ___________________________

~~~~~ ‘~~~~~~~ j S PERF0RMING 0RG. REPORT NUMBER

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MENT . PROJECT . TASK AR EA a WORK UNIT NUMBERS

Army Research Institute for the Behavioral and _

Social Sciences (/ )

5001 Eisenhower Ave., Alexandria , VA 22333 “-

~~ L 2Q162722A765 L

It. CONTROLLING OFFICE NAME AND ADDRESS ,

.“

Deputy Chief of Staff for Personnel 

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Washington , DC 203 10 • ~

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IS. SUPPLEME NTARY NOTES

IS. KEY WORDS (Contfnu. on r.v.r as .Sd. It n.c.a.ary ond fdenff If by block .umb.r)

Light-attenuating devices Continuous operations

Simulated darkness Welder ’s goggle faceinask

Night training Bidensity filters

Rifle marksmanship

SQ. k~J15AC’I (c~~f~~ a. revere. aide IC n,~~~ s.,y ~~d 14.nSIfr by bloei m i*er)

‘

~~ o reduce the problems of safety, logistics, and evaluation inherent in training at night , the Army Research Institute has developed experimental

light—attenuating devices (LADs) that simulate niqht v i ’~

ual conditions durin (1

the day . Single—density or bidensity lenses can be fitted to existinq facemaoks and used to conduct certain night training operations durinq the day

with little reduction in effectiveness .

DO ~~~~~~, 1473 EDITION OF I 

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20.

LADs were used experimentally in training and testing night rifle

marksmanrhip during basic Army training at Fort Jackson , S.C. Filter

densities effec tively approximated night illumination with a full moon ,

a quar ter moon, and a new moon; trainees using LADs performed as well

as trainees performing under actual night conditions .

Ic

ACCESSION for

NTIS White SectIon~~ ~

DOC Buff Sectiosi ~ INA IN~

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Dish. AVAIL and/or SPEC1M

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Technical Paper 374

‘V

SIMULATING VARIOUS MOON ILLUMINATION

LEVELS WITH LIGHT-ATTENUATING

DEVICES (LA DS)

Paul A . Bleda

Angelo Mirabe lla , Team Chief

Submitted by: Frank J. Harris, Chief

ENGAGEMENT SIMULATION TECHNICAL AREA

Approved By:

A. H. Birnbaum, Acting Director

ORGANIZATIONS AND SYSTEMS

RESEARCH LABORATORY

Joseph Zeidner

TECHNICAL DIRECTOR

U.S. ARMY RESEARCH INSTITUTE FOR THE BEHAVIORAL AND SOCIAL SCIENCES

j 5001 Eisenhower Avenue, Alexandria, Virginia 22333

Office, Deputy Chief of Staff for Personnel

Department of the Army

July 1979

Army Project Number Training and Ev*luatIon

20162722A755

Approrisd fo, public release; dIstribution unlimited.

iii 

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ARI Research Reports and Technical Papers are intended for sponsors of

R&O tasks and other research and military agencies. Any findings ready for

implementation at the time of publication are presented in the latter part of

the Brief. Upon completion of a major phase of the task, formal recommen~ dations for official action normally are conveyed to appropriate military

agencies by briefing or Disposition Form.

1
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FOREWORD ______________________

Since 1973, the U.S. Army Research Institute for the Behavioral and

Social Sciences (ARI) has been investiqatinq the concept of using simulated darkness for night training during daylight. Light-attenuating devices (LADS) that reproduce the essen tial fea tures of night feasibil ity

have been developed .

Three types of LADs have been developed on an experimental basis: a

filter to fit on a standard Army sun/wind/dust goggle , used in research

in nap-of--the-earth flight at Fort Rucker , Ala. , in 1974 ; outser t lenses

to fit over the Ml7 protective mask , used for land navigation research at

For t Lewis , Wash., early in 1977 ; and inser t lenses to fit a conventional

welder ’s goggle , as described in this report.

This report documents a field experimental evaluation of LADs as applied to training and testing night rifle marksmanship. The evaluation

was conducted by the Basic Training Committee Group at Fort Jackson , S.C.,

in 1977 and 1978.

The LADs project has been accomplished jointly by ARI and Gentex

Corporation (Omn j.tech Division) under contracts DA}1C19-77-M-0077, monitored by J. Douglas Dressel , and DAJ (C1.9-77—M—0049, monitored by Paul R.

Bleda. Work was done by the Human Factors in Tactical Operations Technical Area under the direction of Aaron Hyman , in response to the objectives

of Army Project 2Q162722A765.

4

~~~ PH LINER

chnical Director

IL 

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SIMULATING VARIOUS MOON ILLUMINATION LEVELS WITH LIGHT-ATTENUATING

DEVICES (LADs)

BRIEF

Requirement:

To investigate whether use of light-attenuating devices (LADs) could

permit night rifle marksmanship training to be conducted during the day ,

and specifically to determine how well the LADs filters could simulate

illumination levels from different phases of the moon as judged by their

effect on marksmanship performance .

Procedure :

Prototype LADs goggles used lens filters of varying densities fitted

in a welder ’s goggle facemask . The different optical filters reduced daylight to the perceived amounts of light given by the new moon , quarter

moon, and full moon.

Soldiers learning night rifle marksmanship in Basic Training at Fort

Jackson , S.C., were divided into three groups . One group was trained and

tested during the day , wearing LADs goggles. The other two groups were

trained and tested at night during the three phases of the moon , one by

moonlight alone and the other with targets illuminated briefly by intermittant flashes of light. About a fourth of the 1,556 trainees were women .

Results :

Trainees using the prototype LADs performed as well as those training

and testing du’ actual night .

Qualifying scor~~ fired with either LADs or during actual night were

essentially the same for full and quarter moon illumina tion, noticeably

poorer under new moon illumination alone . Flashes of light behind the

targets enabled trainees to do equally well under all lighting conditions .

Men qualified with higher scores than women regardless of illumination .

Both male and female soldiers using LADs fired fewer rounds to qualify , on the average , than soldiers during actual night.

vii

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Utilization of Findings:

• LADs can potentially enable many night training exercises to be conducted during the day , alleviating problems of scheduling , logistics , and

safety . The lenses tested appear able to reproduce different levels of

moonlight illumination for night rifle marksmanship training . Their use - could save a great deal of training time and ammunition .

I

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SIMULATING VARI OUS MOON ILLUMINATION LEVELS WITH LIGHT-ATTENUATING

DEVICES ( LADs)

CONTENTS _______________________________

• Page

INTRODUCTION 1

METHOD 2

Design 2

Subjects 4

Equipment 4

Procedure 4

RESULTS 5

Qualifications 5

Number of Rounds Fired 8

DISCUSSION 8

REFERENCES 11

DISTRIBUT ION 13

LIST OF TABLES

Table 1. Welder ’s goggle version of LADs 3

2. Night rifle marksmanship performance 6

3. Analysis of variance of qualification scores 7

ix 

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SIM ULATING VARIOUS MOON ILLUMINATI ON LEVELS

WITH LIGHT-ATTENUATING DEVICES (LADS)

INTRODUCT ION

Mili tary personnel mus t be trained to rely on reduced visual cues

when performing combat tasks during darkness. The conduct of field exercises at nigh t , however , poses numerous problems relating to safety,

logistics, and performance evaluation . To circumvent the problems inherent in nigh t training , the Army Research Institute (ARI ) has developed

light-attenuating devices (LADS) that provide the essential features of

night visibility during daylight (Farrell, 1975). The LADs are worn over

the eyes and simulate night darkness by reducing the amount of illumination available to users. The level of reduced illumination can be changed

to correspond to different phases of the moon .

The use of simulated night illumination for training has been evaluated with three prototype versions of the LADs . These versions have been

fabricated with filters that attach as (a) a s3ndwich on the standard Army

sun/wind/dus t goggle , (b) outsert lenses on the Ml7 protective mask , and

(C) inserts in a conventional welder ’s goggle.

The sandwich version was field tested for infantry tasks such as distance estimation , target detection , and terrain walking and also for napof-the--earth helicopter maneuvers (3600 and 450 bank turns , hovering ,

obstacle avoidance and detection , etc .). Because performances with the

LADs appeared to be degraded in the same way as performances at nigh t,

results of the field tests were encouraging .

Outser t lenses that fi t on the Ml7 protective mask were field tested

for navigation tasks. A bidensity lens with less attenuation in the lower

portion than in the upper portion was used for safety reasons ; navigators

walking on rough terrain could verify their footing more easily. The results indicated that , compared to daylight , actual night performances degraded significantly in terms of navigation speed and accuracy . Performances obtained with the LADs were intermediate to those found in daylight

and at night. It appeared that the bidensity feature allowed navigators

using LADs to travel faster than navigators who performed at night (Peters

et al., 1978) .

The welder ’s goggle version of the LADs was developed in response to

a field request from a basic training (BT) center in the Army . The BT

center sometimes faced administrative problems due to scheduling anomalies

• (for example , paydays , holidays) that made it necessary to conduct night

rifle marksmanship training on a given night with more than one company .

When two companies underwent training on the same night , the night-fire

range was required to operate for extended periods , creating hardships

for both trainees and cadre .

-

. . . 
The advan tage of the welder ’s goggle facemask was that it could be

used by trainees who wore helmets and corrective lenses. The welder ’s

shade plates (lenses) were made of polycarbonate plastic filters that

contained an organic dye ; one pair of the lenses had a metallic gold coating to filter out potentially harmful infrared and ultraviolet rays. Because the compartment holding the filters could be disassembled easily or

removed intact , different fil ter combina tions to produ ce differe nt optical

densiti~~

, could readily be obtained or interchanged . Table 1 shows the

technical specifications of welder ’s goggle LADs .

A potential limitation of the welder ’s goggle LAD is that the face-

• mask restr icts the user ’s field of view to about 500; normal day or night

vision is abou t 1700. This characteristic raises a number of issues , such

as the extent to which a relatively narrow field of view limits depth perception , which in turn might reduce rifle-fire accuracy . This type of

concern was not addressed directly in the research , because the immediate

goal was no t to specify the na ture of the rela tionshi p be tween f ield of

view and rifle-fire accuracy; rather , the main objec tive was to validate

the behavioral correspondence between the various simulated and actual

moonlight illumination levels in terms of their impact on marksmanship

performance .

• Levels of simulated darkness were produced with optical filters that

attenua ted the existing day ligh t by ~~~~~~~ l0 5.0, or l0~~~~ order of

magnitude . Since the luminance level of a bright earth day is about lO~ foot-candles (a standard measure of illumination) , the percentage of apparent light for these LAD wearers was 0.005, 0.01 , or 0.03, respectively .

These percentages correspond closely to actual physical measurements of

ni gh t illumination levels during the new , quar ter , and full moon phases

• (Van Cott & Kinkade , 1972).

It was predicted that performances obtained with the various densities of the LADs would not differ from performances during the corresponding phases of the moon. That is, the ni ght rifle-fire accuracy found

during daylight with the 5.3, 5.0, and 4.5 optical density filters would

approximate accuracy obtained at night during the new , quar ter , and full moon phases, respectively. It was anticipated , however , that performance

would fall off as a linear function of the degree of darkness.

METHOD

Design

The overall design of the experiment was a 2 x 3 x 3 between-groups

factorial. The factors were (a) sex of trainee , (b) level of illumination , and (C) type of darkness attenuation . The illumination level varied

the degrees of simu lated da rkness to corr espond to the new , quar ter , and

f ull moon phases. The type of darkness factor included one experimental

2
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I

Table 1

Welder ’s Goggle Version of LADs

Characteristics Characteristics

of filter of facemask Limitations

Standard welder ’s #12 or #13 Commercial welder ’s goggle face— Restricted field of view

molded shade plate lens made of mask (American Optics product

organically dyed polycarbonate #488) made of soft green vinyl Not completely light-tight

plastic material

Uncomfortable for some users

Evaporated hard metallic (gold Indirect ventilation through with relatively small head

alloy) coating on one side of plastic louvers that eliminate sizes

the plate to f’~

icer out poten- light leakage by creating light

tially harmful infrared and traps

ultraviolet light

Lens compartment can be easily

Acetate sheet shade lens with disassembled or removed for

tinted gray base exchange of filter combinations

Clear cover plate made of poly— Foam urethene pads have been

carbonate plastic with scratch- added as temple flaps and along

resistant coating the edges that come in contact

with the cheekbones , forehead ,

Hydrosorb coating to reduce and nose to increase light tightfogging on inside of lens ness . Composition gasket of

trenolic—impregnated fiber and

plastic serves as seal between

facepiece and frame . Metal

spring separates lens

________ ___ _______________________
group in which trainees performed with LADs during daylight (simulated

darkness) and two control conditions that involved actual night

illumination.

One of the two control groups was exposed to targets with flashing

lights that showed the target silhouette , while the other fired without

such visual cues. The flashing-lights condition was included because it

reflected the standard operating procedure at the installation where the

• field test was conducted . The two primary dependent measures were the

percentage of trainees who qualified for record by passing the qualification test and the number of rounds of ammunition fired .

Subjects

The participants were selected from 15 integrated training companies

that underwent the night rifle marksmanship portion of BT at Fort Jackson ,

S.C., in December 1977. Five companies were arbitrarily assigned to the

various moon phases. About 75% of the 1,556 trainees participating in the

field test were males.

Equipment

The night-fire range was equipped with a Disappearing Automatic Retaliatory Target System (DARTS) that allowed automatic recording of the

exact number of hits scored by trainees . This system featured two banks

of targets located at distances of 25 m and 50 m with 30 “E” -type silhouette targets on each bank . The targets were roughly the size of a

man ’s head and torso. Each trainee was exposed to 20 targets : 10 at

each of the two banks for every phase of the training program . Ancillary

DARTS equipment included target silhouette illumination devices and variably timed “enemy ” muzzle flashes . A prepunched tape permitted full automatic control of the range, including the electronic recording of each hit

or miss.

Procedure

When they arrived at the night-fire range , trainees already had completed the day portion of the Basic Rifle Marksmanship (BRM) program . The

night segment involved 6 hours of instruction, practice , and testing . The

segment began with a 45-minute bleacher presentation that included a walkthrough demonstration of the entire night program . Following this presentation , each company of about 100 trainees was divided into five fire

orders of about 20 trainees each, who were assigned individually to the

firing points on the range.

4
All f i ring was ~ ot formed with t he Mlt~

A1 r i tie , the standard mi ~ it at y

weapon used by rifl emen in infantry squads . Preloaded n tq.i.~ I iss; 1⁄4OS t .1 i S—

j ug the appropriate number 01 rounds to hi’ fi rod in the semiautomatic mode

were issued to each trainee .

The MI6AI has a roar sight with an aperture ot only .

‘ mm; one ~

.-

~innot

see th rough it during darkness to align (or point) the front post sight

onto the tar get. Consequently, trainees are taught a special ni ght—f ir e

technique that does not use the sights for firing during darkness. This

technique differs from its day counterparts in two ways. Fiis t , t h e mat-k sman raises his or her head so tha t the chin rests on the quit butt , not

against its side . Second , both eyes (not just one) remain ope n when the

weapon is sighted ; this is done by aligning the end of the batrel out o the

target rather than by coordinatinq the front and tear :;iglt ts .

Practice Fire. Each trainee initiall y fired 32 rounds using the itight

rifle—fir e technique during daylight . After completion of the day phase ,

trainees fired an additional 40 pract jOt’ round s in eit her simulated or actua l darkness. All research groups received identical instruct jolts , except

that trainees wearing the 5.3 , 5.0, or 4.5 LAD filters performed their

practice and testing during daylight . For the two control groups , these

activities were conducted at night either wi th or without f lashing l ight s

that ill uminatud the target silhouct to . Trainees assigned to the LADs

condition were allowed 30 minutes for dark adaptation while those in the

control groups waited for darkness.

Record Fire. Trainees were issued 60 rounds of ammunition for the

test phase of the night BRN program . Current requirements for qualification at Fort Jackson stipulate 10 hits out of the 20 target exposures

with at least 3 hits recorded against 50—rn targets. in addition to qual—

• ifications, the number of hits obtained at the 2~~

—m and SO—rn targets and

the n umber of rounds expended were also determined .

RESULTS

Table 2 shows mean performances along each of the f ive relevant dimensions. The pattern of results for the percentage of qualifications

also was found for three of the remaining measures (i.e., hits at ~~~~ in

and 50 in and total hits) , and differed onl y for the number of rounds

fired . In view of this pattern , results are given only for the qual iiications and rounds fired .

Qualifications

Sex of Trainee. A 2 x 3 x 3 weighted-means analysis of variance was

performed on the percentage of qualifications . A weighted-means analysis

was used because there was no even distribution by sex in the sample and

the trainee population at large . Accordingly, this analysis is appropriate5
Table 2

Night Rifle Marksmanship Performance

Type of attenuation

Optical density Moonlight without Moonlight Performance .

of L~~ target lights with lights dimensions (n = 985) (n = 281) (n = 290)

5.3 5.0 4.5 New Qtr Full New Qtr Full

Qualifications 36% 52% 57% 33% 60% 52% 65% 60% 53%

Hits at 25 m 5.5 6.4 6.4 5.6 7.0 6.9 6.3 6.6 6.7

Hits at 50 m 2.8 3.7 3.9 2.6 4.0 3.4 4.3 4.3 4.4

Total hits 8.3 10.1 10.4 8.2 11.0 10.3 10.6 10.9 11.1

Rounds fired 44.1 41.7 41.2 48.5 45.1 47.3 40.4 40.0 42.7

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~ ~~~~~~~ - •
only for assessing the effects of a trainee ’s sex on the likelihood of

qualifying for record . The results indicated that the only significant

main effect due to the sex of the trainee was on qualification scores

(F(1 , 1,538) 36.50, p < .001); females were less likely to qualify than

were males (36% vs. 55%). No remaining effect involving the sex of a

trainee approached significance (p > .05 in all cases) . Since no interactive effects involved this factor , scores were collapsed across sex in

all subsequent analyses .

Simulated vs. Actual Night Illumination. A 2 x 3 unweighted-means

was performed that included two types of attenuation (LADS and actual

night without target lights) and three levels of illumination. The night

condi tion with targe t ligh ts wa s omi tted so tha t more direct comparisons

could be made between simulated and actual illumination levels.

The resul ts, shown in Table 3, indica ted only a significant main

effect due to illumination level on qualifications . Subsequent Newman—

Keul s analyses revealed that qualifications obtained in the full and

quarter moon phases did no t differ from each other (p > .05) but were

significantly higher than those evidenced during the new moon pha se

(p .05 in both cases). The absence of either a main or interactive

effect due to the type of attenuation factor strongly supports the idea

that performances with LADs correspond to performances obtained at night.

Table 3

Analysis of Variance of Qualification Scores

Source df MS F

Type of attenuation (A) 1 .00 .00

Level of illumination (B) 2 4.11 17.02***

AxB 2 .36 1.47

Error 1260 .24

‘- .001

Moonlight With Target Lights. A separate analysis was performed on

qualifications evidenced when target lights were used at night. The results of a one-way unweighted—means analysis of variance indicated that

the effects of illumination level did not reach significance (F(2 , 287) =

1.29, p > .05). Apparently the flashing target lights eliminated the

performance degradation characteristic of the new moon phase .

7

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Number of Rounds Fired

Sex of Trainee. A 2 x 3 x 3 weighted—means analysis o t variance was

performed to assess the effects due to the sex of the t rainee on the amount

of ammunition used . Since none of the effects involvinq this variable approached significance (p > .05 in all cases), scores across the sex variable were combined in all subsequent analyses.

Simulated vs. Actual Night Illumination. The results of a 2 x 3

unweighted-means analysis of variance indicated signifi cant main effects

on the n umber of rounds fired due to the type of attenuat ion (F(l, 1,260) =

45. 17 , p .001) and to the level of illumination (F(2 , 1, 260) 6.15 ,

p .01). Specifically , the mean rounds fired were fewer with the LADs

(42.34) than during actual night (46.97) across all illumination levels.

Also , more rounds were fired during the new moon phase (45.04) than during

the quarter moon (42.52) and full moon (42.49) phases.

Moonlight With Target Lights. The main effect of illumination level

on the n umber of rounds fired was significant (F (2 , 287) = 3.47 , p ‘- .05)

according to a one-way unweighted—means analysis. Newman-Kculs analyses

indicated that significantly fewer rounds (p < .05 in all cases) were

fired during the full moon phase than during either the quarter or new

moon phases, which did not differ from each other (p > .05).

DISCU SSION

Along most of the performance indexes , male trainees scored significantly higher than did females. This sex difference was evident across

the various illumination levels (both simulated and actual) . Perhaps because of their shorter arms, women experienced more difficulty than men

in aligning a rifle on target . That is, when trying to maintain a Line

of sight whi le firing, women could not rest their heads as comfortably on

top of the rifle stock as men could . To accou~

nodate sex differences in

physical stature , shorter rifle stocks, new sighting systems, or different

night-fire procedures need to be developed .

As expected , the level of illumination affected marksmanship performance during both simulated and actual moonlight conditions (without target

lights). In particular , fewer quali fications were evidenced during the

new moon , as compared to the quarter and full moon phases, which did not

differ.

In accordance with existing literature (e.g., Van Cott & Kinkade ,

1

~

) 72 , p. 49) , these findings suggest that predominantly photopic (cone)

vision was involved during the full moon (4.5) and quarter moon (5.0)

phases. However , the sharp degradation evidenced in the new moon phase

suggests tha t predominantly scotopic vision was used at this level . Tar-

• get l ights at night , however , eliminated differences across the various

8

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~~~~~~~~~~~

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moon phases . Apparently the use of flashing lights that silhouette the

• target for 1 second eliminates the performance decline resulting from the

reduced illumination of the new moon phase.

The major finding of this research was that performances obtained

• with the 5.3- , 5.0- , and 4.5-density LADS closely approxi”tited performance~

;

during the new , quar ter , and full moon phases, respectively. Results validated the behavioral correspondence between the various optical. densi ty

LADs and actual moonlight in the specific training environment of the Fort

Jackson night-fire range . The results suggest that the LADs may he used

as an effective adjunct to , or as a substitute for , training at night . As

such, LADS provide the user with a great deal of control over the imm ediate

training situation and eliminate the handicap of firing during the new

moon , when the likelihood of qualifying for record is substantially lowei .

Using the LADS during daylight affords at least two major advantages

over actual night training with regard to savings in both ammunition and

time. Specifically , LAD wearers used an average of 4.6 fewer rounds of

ammunition than did trainees who fired during actual night . Since about

50 ,000 recruits undergo BT each year at Fort Jackson , this saves roughl y

231,500 rounds (estimated cost, $18,520) for the testing phase alone .

This fi gure does not include the potential savings derived from prac tice

sessions and refires (i.e., failures to qualify that require the trainee

to fire again for record) .

The use of LADs can save time as well as ammunition expenditures .

Six hours is allotted for the instruc tion , practice , and ~vsting of night

rifle marksmanship skills. Before the night session , however , an average

of 3 additional hours usually is spent waiting for suitable levels of

darkness to fall. This “dead” time can be reduced if trainees fire for

record with the LADs immediately after receiving instruction and practice .

The saving is estimated to be about 178,000 workhours per year (Bleda ~ Labrozzi , 1979), including both the training company personnel and the

cadre responsible for operating the night-fire range . Use of LADs translates into a financial savings of about $500,000 a year .

There are other advantages to using simulated rather than actual

levels of darkness . Specifically, many safety problems in night training would be alleviated by the LADs , because individual and group performances would be monitored by observers with full vision . Moreover , LADs

training allows instructors to make more accurate observations , evaluations , and corrective feedback of trainee performance than they could at

night ; this increased precision could improve training effectiveness.

Finally, LADs provide administrative flexibility so that trainees and

cadre do not have to perform late at night .

The potential military applications of the LADs are much broader

than the specific rifle marksmanship example. In particular, the increased range , lethality, and accuracy of modern weapons systems has led

to tactics and doctrine that emphasize the concept of continuous operations. The continuous operations concept requires that combat and

9

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~~~~•-

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support functions be conducted around the clock and under all illumination levels to reduce the effectiveness of modern weapons in the hands

of the enemy . Accordingly, comba t personnel mu st be tra ined to rely on reduced visual cues to perform continuous operations successfully. The LADs provide a safe , convenient , and effective means to achieve this objective.

10

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~~~~~~~~ • -

REFERENCES

Bleda, P. K. , & Johnson , T. M. Goggles That Turn Of f the Sun.

Ma rch 1978 , 28 , 36-39.

Bleda , P. K ., & Labrozzi , A. In the Dark of the Day. Infantry, MarchApril 1979, 69(2), 32—34 .

Farrell , 3. P. Simulating Night Visual Conditions During the Day With

Light Attenuating Devices . Behavior Research Methods and Instrumentation, 1975, 1, 539—54 1.

Peters, 3. I., Bleda , P. R., & Finebe rg , M. L. Effects of Illumination

Level and Sense of Direction on Land Navigation Performance . ARI

Technical Paper 362, May 1979.

Van Cott , H. P. , & Kinkade , R. G . Human Engineering Guide to Egu ij *nent

Design. New York : McGraw-Hill Inc., 1972.

11

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