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Hulti-ftbdal Information Processing for Visual

\iorkload ReHef

111chael W. Burke, Richard D. Gilson t and Richard J. Jagacinski

Human Performance Center and Aviation Psychology Laboratory

The Ohio State University

Columbus, Ohio

lf80-16131

onclas 11855

ARSTRACT

Subjects simultaneously performed two single-dimensional compensatory

track1na tasks, one with the left hand and one with the right hand. The

tracking perform;:!d with the left hand was considered the primtlry task and

was performed with a visual displ&y or a quickened kinesthetic-tactual (KT)

display. The right-handed tracking was considered the secondary-task and

\ias carried out only with a visual display. Although the two primary task

didplays had afforded equivalent performance in a critical tracking task

performed alone, in the dual-task situation the quickened KT primary

display resulted in superior secondary visual task performance. Comparisons

of various combinntions of prim.1rY ilnd second,try visual displays in integrated

or separated formats indicated that the superiority of the quickened KT display

was not Simply due to the elimination of visual scanning. In an additional

condition. a quickened signal obtained from an off-line KT display was used

to drive a primary visual display. Performance was equivalent to previous

dual visual task situations. indicating that quickening per se also was not

the immediate cause of the observed KT superiority. Results are discussed

in terms of S-R compatibility differences t competi tion for modal1ty-

dependent processing resources. task discriminnbility t and the role of

sensory buffers in maintaining multi-task frames of reference under conditions

of shifting attention.

1 NT 1t00>tJ<:'J'I ON

As man-machine systems have become more complex. faster, and more

preciae. the efficient monitoring nnd control of their operation has

necessitated the presentation of more illforllWtion to the system operator

at a much higher rate than ever before. Unfortunately. the quantity of

information is often greater than the operator can properly process. with

resulting reductions in operational efficiency or, at worst, accidents with

attendant possibilities of loss of life. nle phenomenon of system failure

precipitated by a high visual workload combined with high auditory task demands

has probably been most actively res~arched in the context of aircraft control.

However, the problem of visual overload is common to many systems. A great

deal of research has been conducted, therefore, on reducing the input process-

ing demands of command stimuli.

One technique available to systems designers for providing information

overload relief is to use mulci-modal presentation involving several sensory

modalities as opposed to primarily within-moda I tty presentation of all infor-

mation sources (Howell & Briggs, 1959). TIle assumption underlying this

approach is that presenting information for two tasks to two different

modalities will yield better overall performance than tf the information

for controlling both tasks is pres~~led to the same modality. This technique,

however, is little understood in terms of predicting which task structures

are amenable to such multi-modal treatment, and experimental investigations

have given highly inconsistent results (Treisman & Davies, 1973).

Being without adequate theoretical sUl'l>ort, multi-modal workload relief

techniques require strict empirical verification of their intended facilitory

effects, a fact of little comfort to a design engineer in the earl~ stages of

system development. Multi-modal presentation of i.nfom.1tion has tended in

OklQIHAl. PAGt: IS OF. POOR QUAlrrY

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. ~ of the baste proea.ses involved tn this phunoaenon 1s needed before it can be

.enerally utilized. With a properly developed theoretical base for its use.

~ltl-modal workload reltef techniques hold great promise for providing

solutions to the problems of increasing information rates encountered in many

areas of man-machine systems design.

Numerous alternatives to visual displays hnve been developed. There has

been some success in developing effective auditory displ~y configurations

(Vinje & Pitkin, 1972; Vinje. 1912; Mirchandani, 1972) and there are some

indications (but none conclusive) that such displ:lYs provid~ workload relief

for the visual modality. However, there is still a ma.lor constraint in their

widespread use; the auditory modality is uniquely suited for two critical

system functions. warning and communication. It would be difficult to justify

preempting these functions for presentation of control information. One

viable altemative is the use of tactile displays. Some sliccess has been

achieved with displays utilizing the sense of t01lch, but generally their

performance has been a poor second to the performance levels reached with

traditional visual displays (Hill, l~70). Tactile displays have generally

suffered from a major drawback --- difficulty in comfortably and effectively

maintaining a fixed proximity between the stimulation source and the skin

for adequate transfer of information. This problem has made most of these

displays inconvenient to use .'lIld impractical in most npplied situationll.

One particularly promising method of tacti Ie prNumt<ltion (~apitall?es

on both kinesthetic and tactual stinlUlntion by ml'UlH1 of. the operator's manipula-

+;10n t">i a s,erva-controlled slide embedded In a control handle (Fenton, 1966).

Unlike Qther tactile-based displays, this kinesthetic-tactual (KT) display

, does not assume that the op'crHtor 1s tI pa~siv(' rcceivl..'r of infonnation, but

3.

expl1c1tly assigns to the humltn an l1ctl~e 1'u lot! In gcnl.1rutJ,nR information from

the dllplay. Active perception oC an information source is u8ually more

.ffective (Gibson, 1962, 1919).

With the KT disp13y, the relationship between the position of the hand

and fingers can be voluntarily adjusted to achieve a high degree of sensitivity.

Extenlive research (reviewed by Gilson. Dunn, & Sun, 1977) has shown the ~

display to be an effective and pro!tically implemented means of displaying

information. Several studies have demonstrated its effectiveness in situations

as diverse as automobile (Fenton & Montano, 1968), aircraft (Gilson & Fenton,

197~). and helicopter control (Gilson et a1., 1977). Research reported in

Jagacinski. Miller, and Gilson (1979) has demonstrat~ that use of the KT

display with velocity quickening can result in performance equivalent to that

of an unquickened visual display for a critical tracking task. Additional

studies suggest that the use of this KT display can help alleviate the high

visual workload associated with such difficult tasks as landing a fixed-wing

aircraft (GllSOIl, 1976) or flying .:1 hcli.C'optcr ill .. hover or through nn ILS

approach (Gilson, Dunn, lie Sun, 1977). Still, tIll' fnctors causing the improve-

ment are at present largl;!],y unknown. It is possible that the use of nonvisual

displays may improve overall system' performance largely by eliminating the

peripheral·scanning interruptions necessarily present in the visual modality.

Alt,rnatively. improvements in ,performance may be due to more central factors,

such as an internal, cognitive scanning process. Switching between modalities

may be somehow morc efficient', less disruptive, or faster than switching

between information sources within the same modality.

1 Such the~retlcal questions must be resolved in order to utilize multi-modal

, . • presentation of information for workload r~lief. Verification of this apparent

_Jor que.u.on. were ~on.ldered:' (1) b ,.econlary tdk visual workloac1 ~"o'-O

81pUlca'ntly enhancecl by ua:lna a priaary quickened IT dl'Iliay rath.rthi";i~ ~-"" ~ ~ -- ~

prt.ar,visqal dt.play? (2) If so ~.tratedt 1a the effect prim.tily ,,-.... to the elimination 04 v!8ual scannlna? (3) Is the effect priaarlly,

due to velq,city quickening 01 the leT dupl,.,?

The measure of workload was dcriveacfrom a critical tracking taak(Jex. ~ f S

MCDonnell, & Phatak, 1966), which requires subjects to ~tabtll.ea first-order ~

unltable systea whose time con,tant- b made progressively slMller until the

tracker losell control. The inverse of the "critical" time constant at which

conttol is lost, Act provides a measure 01 tracking capability_ For visual

tasu. he is highly correlated with t e , the OpcTlltor's effective time delay

(Jex & Allen, 1972).

Within a dual-task fr.amework, for re,ulta to be meaningful it is necessary

to fir.t equate primary single task pe,rfol'1llance on the visual an~ leT di.playa,

80 that one display does not have an initial advantage over the other. BaleG -0'

on the results of Jagac1nski et a1. (1979), ~a velocity-quickened leT display

yielded approximately equivalent per~ormance to an unquiekened visual display.

Second. In order to maintain primary task performance matching near its

s1nl1e task level and to prevent oVl'remphasis of the secondary task, it Wa'S

further decided to cross-adal1ti vely couple the' twu tasks. .JC!x, Jewe 1..1., and

Allen (1972) had earlier developed the necessary algorithms, parameter values,

and automatic circuitry which were used in the present research.

Subjects perfonnod II primary compcnsntory traeklng task with their left:

hand, using information they recciwd from ld ther n visulll or a velocity

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quickened XT display. Concurrently. Hubjcct& performed a secondary visual

track!n, taak with their daht hand. The dynami('s of both the primary and

.econdary ""usb conaiated of Urat-order unstable (subcrlttcal) trackln,

5.

tub. The tiae constant for the primuy tracking task was fixed, whUe the

tt.e constant for the secondary task was coupled to the subjects' performance

on the prlury task. Cross-adaptive circuitry shortened the tiM eonstan~ of

the secondary task until primary task performance just began to deteriorate

from the level of performance obtained with minimal secondary loadlng.

The resultin. measure of secondary workload capability. As' was the inverse

of the ahortest time constant that subjects could control on the secondary

task while maintaining primary task pt~rfOrll\illw(, n('ar its minimally loaded

level.

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6.

METHOD

Subjects

Twenty pretested and selected subjects w~rc llssigned to one of the five

experimental' conditions and received a mOlletary payment nceording to II set

8ch¥dule and: their performance,

Apparatus

Displays. The primary task was controlled eJ ther by a quic\tened KT

display or one of four different visual displays. The KT diHplay was built

into the cylindrical lannule of the control :-;tlek, <tnd consisted of a servo-

controlled solid rectangular 8ect~H\ (1.25 em x 2.4 em x 4 em long) sliding

in and out of the h.andlc. ThetH,> positive and Ilcgat tv£' ex(:ursiOllS from the

flush surface of the control handle indicated tlH~ dir('ctic.m ilnd magnitude of

system error. The dynamic rang<' of the slide was + 1. 0 em from thl' handle

surface, with this full response down 3 dB nt 1.3 Hz. The phase lag for

frequencies below 1 Hz could be approximated 01:-; LI 0.12 s time delay, when

the display was driven to maximal displacement (set' UlJrke, 1979. for details).

The Ntactual-quickeneu (l'Q) group"used this KT displ ay with 501. velocity

quickening as the primary task display. AnntlH'r group of RubJects. the·visual-

" quickened (VQ) group, rcn!ivl·J "S!H'llti'llly equivill('nt display dynamic!> but as

a visual signal, by first j1nssillK tl'" vl'lol'itY-(luick('rll,'cl Hign.11 through an

off-line KT display hl·flll'l' Jrivillg ~IH' visual display. Tid" visu:ll contrul

condition would Lhlls haVl' bolll tlH' IH.'llcfjcj;rl l'I t!'d "f qlril'k"niug and till'

deleterious effect of servu-mot"r lag to approxim:ltl'ly t h,' ~;:1II11' cxt'Jnt itS the,

tactual display.

The primary taRk visual displays indicat(·u system otwr hy til\.' venit';ll

displacement of a grL'f!n targl't frnm the CC'lltcr of n TnktrOllix Type 602 CRT

',' ,

1.

display. Three different targl'l Ijizes were l~.wd: :t Hingle integrated dot

(2 DIll diameter) for the "visual intcHrllted (VI) group''. a short horizontal

Une (1 x 8.5 11IIIl) for the "visual 8hort-l1n(1 (VS) group", and a long horizontal

. Une (l mm x 8 cm) wLch nearly spanned the houndl1rieB of the CRT screen for

the "visual long-line (VL) group" <r'igu!'e 1). The subjects 1n the vq group

received the integrated dot visual display configuration.

Insert ngure 1 about hl're

The secondary task visual display used til(! !Hlme hasic display configurations,

but employed their vertically-oriented. horh:\lntal1y-moving counterparts: the

horizontal displacement of the singh! dot, " sl'parat(' short vertical line. ;md

a separate 10':h VI.'rt h-,ll 1 inc. TIlt' TQ group's seconda ry visual

display used the short vertical line. System error W.1S depicted as a horizontal

displacement with 11 dynamic range of ± 4.0 em. For slngle tasks the center

marker was 1 x 17 mm and for the dual tasks it wns 2 x 2 mm. The display-to-

viewpoint distance was 60 em. sub tending 4 visual Hngle of ± 3.So. In that

foveal viewing is typically regarded as :to.n° of visual angle, some extra-

foveal scanning would be expected fo~ the visual display consisting of the

two short lines. though not ncccRs.1rily for till' integrlll dot or the two long

intersecting lines.

Controls. Compatiblc with the vertical primary display orientation,

the primary task control stick moved in a V('rtical pl.ane at the left side of

the seated SUbjl'Ct. TIll' l'ontrol stick was a 57 em long unsprung isotonic: lever

arm, cu.tom-built to ~imlilaLe a helicopter ('01 1,-,'! ive control. R.:lOge of

angular travel W.1S i: lOo, wi th 20° above hod zllllla) represent lng: tht' neut ,'al

i

control position.

, -

,!,

'l'b. secondary task used a much allaUer wrist cuntroller (6 C1I x 0.3 em)

vith an angular left/right excursion of + 20° from its neutral posttion.

co.patlble with the secondary task's horizontal display orientation. the

isotonic lecondary control .tick moved from Hide to ddl" 1n n plane parallel

with the subjects' se~t back.

SYltem lmplenlt!ntatilm. The system dY~1.{"11{''': ,.rl'rC sImulated on an EAI

PACE TR-48 analog computer with hybrid digit;}l control. TIle! analog computer

8.

drove the visual display CRT directly, and the KT disl,lay indirectly through ..

lervo-amplifier interf:H~~. 111e actual posi tion of the KT display's sUde.

reaardle88 of the command signal applied. was given by a follower poten°t1ometer

attached to the drive motor. In addition to its function as feedback trans-

ducer tor the servomotor, the follower signlll serv(·d two other purposes. In

the KT display condition, this signal of lhe slide's actual positfon Wal

compared to where it should be (the command signal) in order to lenerate an

indication ~f impeded movement. When the subject grasped the display too

tightly, enough to override the servomotor, red wllrnlng lights were turned

on 1n both the subject 's ~'ubicle and the experimenter'. statilln. In aaother

role, when the KT display WilS not. lout"had by a subject but insteild was ulled

offline to simulate the KT dynamic" for the VQ ~ruup, t!lI~ 4111110g computer

drove the servomotor with il quickened signlll. lind the signal from the (ollow(·r

pot val amplified to driv(~ a viHual CRT JiRpl <ly.

The crittl~l,l tr<lcking task!> consisted of .1 ftnit-ord('r unstable syst('m

and a means of progressively shortening its t im(~ conRtllnt (Jcx, Me Donne 11.

& Phatak, 1966). 1'llI.' unstable plant WIlS contr"llcd by tht! angular potiitloll

'0

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.,

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of the approprlatu "fmt rol, whU" th~ tl1sh!m .. crtnr Will d1apll1ye.:l as 1\ : .t

di.placementof 1t. ,orrelponding display. No for~tnl function ~.s u.~ OJ ~L

.inca tho subjectK' Inh"rcnt vnri.,bll tty pruY ith.·d Huff1c1,,"t Inp~t. to.? !'

9' .-

excite the uri.tabl~ sYNte.. On ~nch t rial the tnt Unl 'ley('l of tnst.bOlty • ~ lilt

wal increased.lowly :It a constant rate of .05 r:ld/s'J. until it reached'~ .

"critical" level wher~ the operator could no lonr.er supply sufUcient control.;.

to Itabil1ze the system. . «-

1.088 of control WtlS defln('d as the diaplayed .yatell:

error exceedin. the previously 8pecifi~ diNpl"y excur.lon lillitl. Thl

critical level of 1nstabUity, ). , wnllthe dependent mea.url! taken on each; c: . !-

tdal. The initial level of 1n.tabiUty was preset by the experltnenter at c. "

the start of each trial such that each trial lasted approximately 30 I.

In orde" to equate s1ng!e-t .. sk perforl'Bitncc with the Visual and KT.

displays. it waR nen'HIMry tu qulcKl.n tll\' KT dfsl'l:lY. TIlI.! quickening ratio

of error yc>!oc:lty ( .~ ) to ('rror m'IKn lludl.' ( c:: ) W:IK 1: 1. In orcic>r to :make

the total dilplay rnn~"'R of tht:! quickc;tnt:!d lind IIn(lui(~kcned dhplnys mQrt

comparable, the effel'ttve quick,'n('d dispJay signol) walt ( ! + !.~)/2.: ;.

The circuitry used fOf the cross-adaptive dUoll-tosk pancH,a followed: .' .. the deaign of Jex, Jewell, and Allen (1972). nle dynaalc8 for both the pr¥mary . .-:;,.

and secondary taski consiited of " f~r.t-ordcr unstable eYRt .... The level'

of 1n.tability was fixed (or the primary task on nU dual-task Uials.· On \ t.

selected trials, the level of inlltabiUty on the secondary talk l!a& fixed:' ,. . ' . at a nominally low value of .1 r/s,and the error on the primary task under,

this minimal loading W3A measured. On the rcmllining triala, cro~.-ad8ptiv • ..

; ,

circuitry odju,;t~d the instability of lhl.' 1H'C'ond;lry tUk until the pdmary • I " ,_ .~

task error exccedL'd it" minim.111y londed v .. hH' hy 2"1.. ..

The cxpHrilllcnt l'lIlll!listctl of ch'ven sessioll:'. one-hour "er day, uver a

ORIGINAL PAGE IS ". POOR QUALITY

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ewo and one-balf week poriod. 11,e cxpe~n ... wnM

f ' 1 pr.e •• t, .1nlle-ta.k tra1nlnR, dual-t4.~performnncp, and powt-te.t.

i : •••• 1Oft. ~on.~ted of three blocks of tr'a18 Bep~rated by S minute reat

! - ;"t ;.. ,t: F

period •• For,_insle-talk 80.8ionl, each)block consisted of 15 critical

tr.ck1nl trla~ of approximately 30 s duration Nlt'h and a 10 Ii Intertrbl

interval. Th. performance mP.aaure was t_c m~dlAn !If the 15 ~ vnlues for , c "

ncb block.

For the dual-totsk !lllasiona, c.lch bl~ck cun .. iHled of one IIln11111111y

loaded trial aad five crou-adaptive trials, 311 of 100 8 dur.1tion. The ~-:. # ..

perfor.ance ~sures taken were the block Illedf~nH of pr1mary taak error ~~,

.. I

'. ... i; ,.

and aecondary'taak Instability. AS' alon, with the .1nlma11y loaded error '. i lev.l.

Pret.at. Five ,roups of approxlmat~)' 10 subjects each were pretested:· :.­

in a .1na1e-t.ak critical tracking parad1am using the •• condary visual t. __ · ..

with. ahort-llne target. No performanc; feedback was liven. Subjecta we,. ~

ranked on the b •• is of their median perf.r'III4nce ,;cores GO the l .. t two bl~ka~

The four highest Ncorin, 8ubjectfi in oacb J;r,'''p ,., .. ·r&! select\!d to cont:lnuc Oft t " i

for the full nl'llriment.

on each of the two t:lIlka Sl~P,lriltdy. Day" 2-'; cuns!:.terl (If trainillg on P.ilCh

feedback of their). S':UrL'fi. All Stlhjt .. ~tR lht'll Yt'('dvl'u mit' sessinn of . ('

trainin, (Day 6) on the '!bU.l1 St'('ond.1ry ttl~k wtth which tlu'v were alr,·.1dy"

familiar ~rOlll the pretest.

Oual-taak phn... On Day. 7-10. aubJecu controlled tlw primary ud

aecondary task~ aimultaneously. 1be firat twu sedlJlons were prlmarU.,. for

" " - _~.......-_=~_=~~ _______ ~~~=_~ ___ ~ iii!

11.

f.Ui.dlaclOt( and trllln!nl_ Subject ..... re·lnf.ned th. chey vera tq try ~ : r . '." .~ , ,

to pt .. low ... 1T0r &core •• 'baJ cov1cI on the vl._l or KT pd_r, taak, t "',.~

viall. OIlly noc:108lnl cOiltrot' of the vi."1 HCoDdafJ talk. the duratloa of t 0 ~_ • 4. ' ..

~ i!. the clual-ca" triab va. 100 Ii, al •• the a.Jeeta .r. not to loa.

'! -... ~ ~ ~ . ~

cODtl"olof .1,lIer t.ak. OIl .PP"'t.~ 6% of thea. crula aubJecta clid

loa. control. aad th ••• triala wen ~ted. Tiabt cOIltro1 of the pd_1"Y .' !!--

,uk vu alao ...... 1&_ to t,he aubJec'a' b, paylDl tho Oft 'ha but. of , "~

perforaaace OD~Da,., and 10 and .akIDl~vo-thtrd. Qf thalr perfor.anca pa,..at ';;! .

be decenained by thalr pl'l .. ry eftOr. .1), one-thin of ; " '~ J

decenain.d b)' their .econdary 'a8k In.c~11tt1 &Core ••

their payment va.

, .. In order to ue.rtaiR -.., IfhUt. in the level of primar,

, .. k pedoraance due to further practlcJ'vith it a. II c'lIIponent of the

dual-t •• t paradt .. , Mubjocta ~ere Ilven:e Hinglo-taat post-t.Rt. OQ)' 11 va.

identical In procedure to the prtBary-c"k critical tr.cktn~ paradia_ u •• d

• on Day 5. ~

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Stnale-Task Performance

Hean. ",ere calculai:ed from the block med1~n8 of the four subjects

serving in ~ach of the five display conditions. Their mean performance

for all blo;;ks over all 8ingl~-task seasions is shown in Figures 2 nnel 3. > • . .

Separate analyses of variance were conducted on each of the four single-

task phases~shown.

Insert Figures 2 and 3 about here

A two-way analysis of variance waS run on the pre-test data to examine

for possible biasing effects in the. assignment of subjects to experimental

conditions; only the last two blocks of Day I were analyzed. The between-

subject display-assignment variable indicated that there were no significant~ J

differences in the assignment: of subjects to display conditions, !(4,lS)=

• 51, ~>.l. There was a significant main effect superiority for the last

block, !(1,15)" 12.51, .E.<.01 but the effect accounted for only a small

percentage of the variance (Li .. 8%); this suggests little practical change

over these las t two blocks. The display-assignment by blocks interaction was

not Significant, f(4,15) = .53, p.>.l.

A similar mixed-design :lnalysis of varianCl~ was c.onduct ~d on the final

, .

., .

~

day of primary task training. Day 5. USing all three blocks. Performance in t.

the five between-subject display conditions did not differ significantly

from each other, X(!,,15) = .49, .\:>.1. The within-subject block factor again,

showed a significant main effect , .E(2,30) .. 9.07, £.<.01, but accounted for so

little of the variance (w2 :: 7%) as to be near asymptotic performance. Ag.lin,

<.

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the display by block interactl.on was no~ sigoificnnt t F(8,30) - 1.13, p>.l. .. , ?

An a~lalysis of the visual scc~ndary tr:lining seS8~Ont Day 6 :revealed .~

no significant effect of display, !(4,15) • .24, .2.>.1 t.; or of ." d~sP18y -r .... ~.:,

',,:

': by block 'interaction, !(8,30) - .6), ~.l. However, there was a~.18nificaQt

• '; J

" " ~ . effect of blocks, !(2,30) - 22.80,-~<.01, which accounte~ for a ,uff1c1ently

,. , i,

high propol\t1on of the variance (w 2 • 29%) to conclud~ that performance ~ . t

had not asym~oted yet. The last two blocks of the two $econdar, task "

sessions, Day.s 1 and b, were then compared and found'~ to .ign1flc~ntly differ '.

from each other, E(1,IS) = 88.16, .2.<.01; this factor:accounted f~r a major

portion of:: the variance (w2 = 62%). The display factor was not significant,

!(4,15) • ~44, .e.> .1 ,whereas the blocks did differ significantly from each

other, r(l,lS) :.: 9.02, .2.<.01. AI: interactions were not significant at

the ~.1 level or b~tt~r.

An analysis of variance also compared the post-test phase, Da)' 11,

with the final ses~ion of prim..1ry trainin?" Day 5. '!'here was no'. signif~ca~lI:

.'

difference between D<1Ys 5 and 11, I(l,lS) = .10, £>.1, and there' were no ,,' -".

significant ciifferenc~s amon~ the display conditiofts used, F(4,,15) • .49, - ") .

£.>.1. Likewise, all hi!?,her-order In~eract ions were not signifi.cant at -the

.2.>.1 level or better. The only sigl~ificant di£fet'en~e found wa~" in the . . . .

block factor, !(2.30) = 9.76 • .I!.<.Ol,bu~ this factor:, only accou~.ted for' a ,." ''I.

small amount of the variance (w2 .. 8%)., ,~

Dual-Task Performance

Because stahle, near-asyntptotic:performilnce was of more imporr..tnce than

acquisition, dual-task analyses were cortdm:led onty on the three blocks of

of Day 10. the fil)u1 session of dual ... task \wrform;lnce (J~tgures 4 and 5). The

statistical t('sts performed on the secondary task '\ values were repeated

.. -~-.-.-.~.- ---'-'->- - ---~---- ... --.". ~ ... -. -~ ._--.-.-.

~i 1

"~'T

ORIGINAl PAGE IS OF POoR OUALrry,

14.

for the prfury-task ('tror (e ) scores. ~'~1.The over~ll1 analysts str4'tesy was-' "'"P .' r J .. "', ,'I "

to analy.e the four tightly clustered vl,ual curves by themselves~and -~ f ~t

then to separately cOUll,are the KT display with the most nearly adjacent visual -, . ~y-

.~ * ~ cU.splay (1n this case, the VQ group). Cimpartng the KT display performance

~ ~ ~. -2' ~

aaa1nst the best performance among' the ~!sual dieplay groups al10~d the ,

moat conservative test of KT diSP~.y supiriority. ,,' ,. r 1

Analysis of the secondary-t~;k,As ,cores of the four visual~1splays ~ • *~ . ;-, "

alone revealed. a significant main .ffect~of both blocks, r(2,24) ~. 6.10, . ~ ~

.2.<.01, and display configuration, r(3,12) • 4.44, £.<.05. ..- ,

, The block factor

" accounted for 10% of the variance,~ while the display factor accoun:ted for

21%. The interaction of the tW() foctors,w;}s not significant, £:(6,24) • .8.

R.>'!. A DUnn's Test (or Bonfcrronl 1. with flEW = .05. 12 df) revealed no

significant differences'between adjacent visual display curves. but a

significant difference between the lowest and highest performance curves

(VQ and V~), and between the lowest and iecClnd highest performance curves,

(VI and VS). The VQ display condition aione was then compared to performance

with the quickened KT display. These two disl,lny conditions lfere found to be ~ ",,' .

>-

:~

significantly different:, !(1,6) 03 763.59, £.<.01, with this factor accounting ,t ~~ • -: 5. ; • 'A

for the majority of the; variancl' (Il. 72:0. nle blork factor was': also 'J t 0

.. ' significant, !(~,12) ... ~4.16. 1: <.01, but only [lccounted for 4% of' the

~ variance.' The 4tsplay ~y block interaction was not dgni.ficant, .(,(2,IZ>, so . . ~ .

h " ~ .. .29, R.>.l. , . Comp.ir1son~ conducted on the'prima~-t(1sk ('HOr data rev,ale~ no f

'

,.-~

'differences bet~een the, four visual conditions, 1:(3.12) = • 36, E.)~:l .• gOll1parison i

of the error'sccSres of the TQ and \'Q groups show(>d the error scores of'the TQ ~ ~

group were s~gn~'ficantlY lower. ,!:.<l.b) • 'S3.R6. 2.< .01, and this effect :accounted :.:.

for 51% of tbe v.~riance. Block f'l(~tors· wen' not signifi(';mt. nor ",ere any

"

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. ,~ f . -.~: ~ .' 4 ;. ~ : ..... interactions, the TQ group

thus ;rChit!'!'t sisuHicanUy kt~_r .econdary-t~.k ~ ~.:;J perfo....., •• while alao doing ~, b1'ter on 'he pru.ary tuk; . ; ... i.:

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The major finding of the prC'l-lt'nt st\ldy is that visual nod quickened KT

displays equllted for performance on a s4hglc dimensional critical tracking -::.

task do not show equivalent time-sharin$ performance with a secondary visual ',.

task. The quickened KT display Is mnrkJdly superi or in the dual-task situation;

the KT and visual displays produced abO\!t the same primary task error, but '.

differed greatly in terms of secondary ~ask capability. This result then .:.

answers the first question raised about ~the capacity of the quickened KT f. .~

" ,

display to provide significant visual w~rkload relief.

,'{ The next issue is the cause of the'';,:obscrved performance increase. Poulton;.

(1966) amor.g others deniOnstrated that w~en two simultaneous visual tracking.

~i' tasks are displayed on separate units, 4nd the displays are physically moved

;

", ",

closer together, performance is improved as a refllli t of the lessening of head '(

and eye movements. Such visual scannin •• then, is one possible source of

dual-task decren' .!nt, and the eliminatio~ of this Hcnnning decrement should

produce higher perform~nc~. Tlwt a sCa~ning factor is not the mnjor cause:,'~ of the observed KT display superiority is indicat('d by still-inferior perfor;mance

of subjects using 3n integrated visual 4isplay format, wliich presented the

two error. sighals as the combined horizontal an,l vertical movements of a

single target and th"r('by elill!lnall'd thl~ Il.l'('d for scanning. Thus, only a ~. .

small fraction of the KT superiority is '3pp.1relltly due to the elimination of., "

visual .scanning, as indic':ltcd by the slir,ht ly improved pnrformance with the .;~ ,',

integral dot' display rel;ltiv(~ to tracking the two s~ll separate lines. ": 0"

Two final p(1int~ should hl~ noted cOllel'rning th;;' app] ic;;hil ity of these '~~ ~~

, .. , . . .'

resultst~ scanning in general. Firflt,note that alihough the two small i .; .

~ .-:; ~

lines did:not permit: simultaneous foveal view of bot~ displays, 'the seannin" -~ -. <

range was.~still quite small (bc!ng limited to til(' 8'tm x 8 em display'range 'f:

~'G'NAl PQAiUGA~~ Cf. pooR

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display' a~rcin8el1lellt.~Contrary to these' expectations~ the large :line display

.';.'

~

produced slightly wor~e perform~~ce th~n the integra:. dot !; . :-:"!' • '1:

difference ~ not statistically~signit1cant). 1. ' 'l ~ .

. (althouth this

: ~.

SUbj'~ctive repot'i. su~e8t

.. }.

"~' .

that it is not an easy task to follow the intersecti6n of the t~~iine8 • jo ;' ." .: f.: ~-. -, *: .~

.~ ~-. . ~ ~ :' ~, ."..-+'

with contin~ou8 fovea~ view. laistea<l. ~:~here seems t.O be a type:~( pre.t~entlje· :. .: ' T.' ';-{ :~·.t"- .~ .• f.~. :. '.

, .:. _ .,:,.. ':1 :: I "'-'W~, i. ~', , "visual capture" occurring, where Ulovei4ent in one d1,laension see" :to c:iluse an'",

~;' " .: ,~" .r :~ ,~ ~. > :j; . involuntary :shift of attention to that )axis and to the detrimenf .of tbe .;

• \' f--: ,~2.' .:.. *. . 1 .ff { •. : ~,: . other axi' ': :., :,~ .~; ,;. ~ .

, If tbe:difference· between t;he quiEkened KT display and the ~'tsuai displaf~ t .} ,-,r. '. , •

\' .-'* . i· '.~ ~~. 3 . .~. ~ :". , ,~' is not a1;ply due toihe e1imin~tlon ot visual 8('ann;~ngt then Pt~aps :'there ..

'O...~ ~~:.. • .' - .!i. "

is some mbr~ central ~actor opetative.{ Three poss1~Uities are ~lfferences 1tl ;~ j ~ . '., :t~ 't ;~ ~ ..

inherent ~S-Il compatib!lity between the"jvisual anci Kf,displays, ~~~velocity- ? ~ , ~

quickenin~,sed with ~he KT display, 6r factors spe~1fic to the use of two t

; L separate ~e~sory mudalitl~s .

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s-a coajpatiblUty' is a ub lqu itou. ,.ehllv.to fa I " ,,.

of mnny cx~r Im('n tnl i

c:aus_ or confmmdtng aa the r~Ru1ts. ,

robult t ~

effeQ.'t. and ;; . is considered one ot; the most important factors determin!", Ji.

human per~oCmaqfe. .!,

." Compatibil ity is thpught to determine the complexity

. "-.. .

of the tranls"formation (number of {ccodfugs) between 11 stimulus and 1ts : ~., . ','~

response, t~ereby determing available resource demands and so becoming an ~ ~

1mportant'f~tor in workload considerations (Fitts, 1964; Rogers, 1979). I' .-

,. .. -' ... :-

f • With respec~ to' the present experimental rcsultR, it loIay be argued that the,~

~ 'l , "" ' KT display' 8 superiority is somehOW, due; to its having a higher degree of

J ~ The KT display may S-R compa~i~llity, hence reduc ing, proc~ssinr, demands.

:: be thought lio l!.ave a higher degree of SR compatibility because ()f its more ~ ~

.> f: '1 i ;

, , . . '!

, ,

"

intimate ~e~at1onship between thesourJe of Rtimulati~n, at the fingers 'II' " t \'

~ ~ , i ~Iovlng a display';'; ~,

~: -: _t

and halld,:mjd the reH{)onding nll'mb~r, ttl.e hand Rlimlllated. • T \ \

~ • : I~

. :! . " improve pcrfo,"manc~ (Hill t 197Qi." ,i.)

, ~'~

· 1 • ~

close to the' responding limb does:'not cilwnys " ' ~

However,~dJusting the position of 811mb on tl,,~ basis of kinesthetic-tactual , ' . ~~ ~ J

cues is a:':'c~('n daily activity. The present display design may ~fford a .; '.;:..

'J '

;' 01", .~ .. ~ ¥ ~ , ..,'

simple analqg to this highly comp~tible:llctivity. . :.t. ':, i.

Ther~ 4re several points which arlue against Ci compatibilityexplanatiori

in the pr~s8ht case. Fi rst, the via!Jal displays can also h(' argued to have "

• l ' high degrees of compatibility • though it is unknown to whllt degree relative

,; to the KT"display. Secondly, the present results indicated that '\1arying ~

~ ~

degrees of comr>~tihUity. at 11.!.lSt amo~g til<.' visual disp]ny confi~lIrations. i~ 1 .. :-..¥,. ~

had little ~ffect. Tbi rdly. for such" (actor to he the CilllSl' ot' the observ,!,d '~ ~

· KT superi~r~ty, one would llee_~ to expl~in wlty this proce:;si ng ad~~ntnge was :' L ~

not present in till! singll'-tns'k phal.Hl at1d yd 0lwrative in ;1 dual .. ~task sitUlltlOil. ~

One f1nnl;qUL1liticat1~n is tllpt an indOpl'n!\('l1l mC'lIsur<' of compatibllity is

·f

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,

, , ..

" •

I I

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nlc ••• ary before th,se arguments can be puraut'd in gl'C!ater detail. • i-_ ~ ..

Another po.atble reason for the superior perfo~ce of the kT~l,play • • ft.'" oi.."" ,".' "':" •

~ ":. ; 18 .the velqcity~qui~kenin8 used to equate the two ty(es of prt-.ry cfiaplays.

_. . l 1}" ~ E ~.:

8ln~. th1~ qul~~nl~a then become. ~ confoundina fac~r in int.~r.~tna the • • , (. , ~:. '"'t •

dual-task re.ults •. Therefore, a quickened lntearal~ot vlsua~dlapl.y . _.~ l '.' ~f:· .~>;. ~

wal .ubjec~8d to th~ same display dYnamlcl as the KT~illplay bY:"'8~ln' a • • . .. iI, 'j iii .• • " ~ ~ : ' •• -r

quickened ;;'1Ina1 thi-ouSh an offlin&' IT _chanbm befire viaual pre.int'ation ,.,.. , ;: . t~ it • .. , it ! :. < ': .

to the s"b)ect. lepults showed that viaual tracklns! wh." help.~ b~. q~lcken-.. , ." , .,' ~~ '. ina but alao h_p'~d by the same s~rvo lag as the K~ display, y~el;ed

...

approximat.ly equivalent performance in the single-task situatidn b~ " .

.ub.tantl~lly loWer~secondary perf~t.ance (as did the other vtstial ~.18play.) .. .. -t . i ;_~, ";,

t .. I ,. , · . in the dual-task sl~uation. The'lead'

'. .J provided by the velocity:~ulcken-

ing may simply be ~,eded to overcome the mechanical lag in the disp~~y

itself, or alternat~vely, to overcome an extra lag or longer cffectlve time '.

delay pre~ent in th~ KT perceptual system but not fo~nd in the visu,l system.

Perhaps the mo'st likely cause of the visual workload re~ief cap~lbllity

of the KT'display is its utilization of a different sens()ry madditY. ~.

observed superio.rlty could be due to, additional avallabil1t/ofpro¢essing , ,

"

~ '. '" .... ". ~. . . ' I " ' .. ,.'

~ '. ~ .'

t . .. " . It

i

resource.~ It *y ~e as some att~t1on theorists ha"e .pe~la~ed ~hat • i" ',' • ~ . ~

,'!! " .~

each .~ ~ '.

modality 'has .ite own reserve of processing c.1pacity independent of fnd'~ " -,,' .a •

... .. . uninfluenced by ·the; allocation r()l~ciea of other modalities (Koray/ 1967;

I . • , . : ) .

. -1. ',f" & Kniaht. 1974). :rreisman ~nd Da":ies (1973) have ar8ue~ that mul~~-lIOdal

. . ~ .' presentation aV~1d~.8tructural in~erference between

· . aval1ableadditiona'! stimulus proc_8sing mechanisms

two tasks by ~~in. , ~'~' .

rather than addtt10nal . ,. ·:l

.... ..;;, './

. ~ .,' 1;. , ' ..

Kantowi,tf .> ~ .... p ';.- .

freely allocatable ~apacity. n,eir experiments demonstrfted a cons~de~able ~

improvement 1n the'subj(>cts' ability to divide their att.nttan between two

J. r ., "

lQpvta ¥heR the" were

the present experiment

,; . , "

. '-'\

. ' .. ~

J .,' ~'

1n dlfferejt ~lltiea (viRUal and audito,,). In. T ' ~

the KT display ~y reduce visual workload ~y tapp1nl f

an unused eKtra pool of capacity 's8oc~ted with the tactual IIOdaUt.y.

In addition to l,erccptual anJlyzetil. there llre other modal1ty~speclfic

mechanisms which are candidates lOT atiuctural bottlenecks to withln-"

modaHty procesaing. It may take',less;t1111C to switch attention and then

become current Dn another task when the' two tasks are in different,' modalities

,.

• '!

,{

because of the presence l,f an extra se~ory huffer. Switching attention betwe~ I

modalities, the operator could maintai'}: the most recent state of the other ta8~

in such a buffer memory while,att~ndln~ to a different task. Given that the-

switcbing rate is not too slov and the:.ignals not chanalng too fas~. then -~

the contents of the buffer would be II good ('stim<ltc of the signal on the

first task. Returning to thaC' task could then be d9ne lIore quickly and .;: ,

to _

efficiently by simply updatin' the buffer' s contcnt8~ an lmpossibiUty ~f

* " -tbe two tasks used the same ~allty and hence the 8ame buffer. The exist-, '

f _ I,

enee of such buffer memories lave been -demonstrated :~n the visual ",odality .,

,

,. ,,, •

'i '\ .; :. ., l'<

" (Baddeley. 1976), tho auditor~ modality (Horton,

r 1970) and the tactual modalit~:

(B11ss. Crane. Mansfield. & T~sen~. 1966).

Increased stimulus discrtllinllbliity reduces pro¢essillg time (Lindsay. " j~

Cuddy, & Tulving. 1965i L1nds~y, Taylor & Forbe8~ 1968) and may have impUca-

" tions for multi-modal dua1-taik studies. Norc ('ffic~ent switching between two.

"

tasks in different modalities'may be due to reduced time dt.!lays stcnuning from

increlJaed task discr iminabll ity. One can cOflcC'ive of a s i ttl'l t ion where

capacity and stru~tural resou~ce8 arc equivnl~nt bot' within-nnd bctwcen­

modalities., but where p(.>rfo~nce ImproVl~H hCC.1UHC talolk informntion somcho~ ..

receives a aodality-sllCdfic "~tam~lng" (or fJulIlltnti\,c difference) rc!i.1tcd ;

.' ~

, :

,

: . , ','

1 t ~t ,f ~~ i~

'~.. ," :. .' : to the cj1annel structur~s it has po.sia through. Tb U8~ ~f W01icUff.~ent ~ .

. ' .', ·1'··.. ?;; :-!': '.' , "~ " modalities may provide sign~ls which 'erve~s cues ~p re~uce S~8~'con~~sion ;:

errors· by keeping the two lnformat1:m;i~aurcesd1stit\tt (~Piett C~rt1l. & i Webster. 1954; Mudd, 1963 i Shaffer .~lJ.'73) • ~ :;. ~, t.

~ ~ ~ ,,~,

The present rese~rch has demonstfated'the usefuines. of eheKT dt.pia, ! • ~ ! ~~ ?~ '.:. ~. ~

for, relieving visual workload. Resar61es8 af the eVe9tual an*wers cODcernlna ~ f ,_ '" • ~.: j- i,j·

the apecific locus and process of mul~i.modal workloa' relieft it i. interest- ;. , "., .': :~;. :. :.

ing to note that equating two displays in terllls of 81';sle c:ri,1c:ai task perfat1R-.i ' ~. . !- ~

~ .'~.

ance was not sufficient to produce equal dual-task ~e~formanc.. It has been

" " possible to conclusively establish that peripheral scanning w's not a ~jor

, -,

factor in the KT display's8uperiority, nor the veloclty quic~ning per se

~rovided the KT display. In addition, compatibility also doe, not appear "

to be a major factor. although the ev~dence fO,r thia conclusion is not'strong • . ,

At this time, tha most likl~ly cause of the ob • ..,rvt.'d visual workload reliof . ,"

would seem to be the modality factor. , Why using II ciifferent ~dality:' '~ \

should improve performance was not directly tested, although ~everal possible:, . "," ~t

.:~ .~ ~

mechanisms .. :ere suggested. It is hoped that theMe findings will stlm,,)ate' :? #

more research into the phenomenon of multi-modal workload relief.

ORIGINAL. r~GE IS OF POOR QUALITY

,r .,

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~' t " .. ., .. M t." rLISS. J. C.. CRANE. H. D.. MANSn!LD, P. K.. AND TOWNSFJID, J. ,;1' " 1966.

..... , l C ,~,

c . J~ f

J ' i ~ of " • ',' , . ~

The infonaation 'lY:l.t1able tn brief tat'tilc presentational ~ Percoptlon

!Ii P.JchophY81cs, 1. 273-283. '. ,fl. .. ~. t-

• ::. A ' . f f: BURKE, K. W., 1979, An lnve'tlaation ofv18ual/tnctual "ltl~al Infor.at1or' t i

Proc •• o1O&: .. IOI dual .ro .. -adapU"" .dUcal tal". llug.~ of lci ... • .. t : I i The,la ,. De~.rtaent of Induatrial and Syste.- Enllneer1nl~ ~::'l'be ·Ohlp Stat~~ . ~ l Unlver'lt'~ (HUIUl\ Perfonanc:e tenter/Aviation Pa,ehol0~ ta~r.tory .. :1·:!' f rec:hnlca1 Report No.2) ': :.~ ,: l 'r!

~. ~ J)'f, FElTON. i. E •• 1966, An lap roved un .... chlne Interface for the' d~1ver-veblc1et :t d,.

,", ' : ',: '; ,~, , " t l '. a,.tem. !!!! Tr~n8acUons !!!l .lli!!!!l Factora, !!!. Eleetronl~. 11,£-7. :t":.ll

150':'157. .. t;l> 1, ~ 't . r

FENTON, R. E., and MONTANO. W. B., 1968, An tntervehlcular 8P~1~~d18~lay flf'~ ~,

llIproved clr-r o!lovlng pcr r 0......... 1-R1:J! Tr 1!!'. ... ,.ct Ion. !!!!;. lIa.l-lt.chlne . i .; i , ~ ~

5,acellll, .-9. 29-35. ..~; ~ • .; ';" jr "

FItTS. P. ~I., 1964, Pen:ertual-lIOtor skUl lo4rnh\l;. In: Cat'e''''ies S!! l ~! ~ it

Acad.i~' • .,. .l i' . ~ 'S" . , . "" Psycholo&lcd." : Review • " i-.......-....... ~ ,::;"-rr.:;;:, :;:.:;or;' , ' ' i

t { , 11

~ ~':s . i .• :~' ,.;,' z.

~ Learning (EUited by A. Wo Heltml) (New York: .',

• <

CIBSON, J. J •• 1,962. Observlltions o~.acUve touch. . \ .

69. 477-49i. ~~: . "'I

CIBSON, 'J. J •• ),979. An ecological approac!'. ~ visual percept)otj~: .. ,,:; , ~ .' ", • : 'l " fJ

Nev 'otk?'~Roughton~Hiff11n. ':~' ; .': t GILSOJI, ~ D •• ~t76. A· tactual d1sPl~i,.td for prll1U1ry fURht~~r~~nlna:: ~ .; f':

. NaU.""l ~~on.Utic •. ond Space +""0""" Annu.1Re~~t~. ~2"'9~d: " CILSOII. I, D •• ~. I. S ..... dSUM •. ~l1977. ·A k!ne"het!'-~:~.~~al ~PlalL f

concept for hl!} h'opLl'r-pUot woru,.,d r,',h.ct fou. Pam 12.1l!! ll!! AnIl"1 t. , .' • " ",:; , . ". I • ~:'i "

NaUonal ~rllm of the AmeriCllIl. 1I.~t.eopt~r SC!,ci!tI. ~'!.shiaiat~n. DOieo: ',,~ .,

--~,-~ -~-~~--,~-- ---=~ - , .. ~-'~ -- -

~-~--~ .. ----. ,~-.

L~

I ~: 'of-.. ~

GILSON, R. D., and FENTON, R. E •• 1974, Klne.thetlc~taetu.l information ~.~ ~

Inf1ight ,~u~le.~ ~ Jr3n.~tlon. 2! Sy.te"t:~, '1 ;. !ru! Cybernetics. SMC-t. t 81-,0. ~i ',' _, fl

23:. ,

..'"l ':(. . HILL, J. W., 1970, Describing functloQtanalY81s of t,acklnl perfor.anr.e U81na

;~ '. -, ~.: :,~ ~ two tactile displays. !.I!§!~Tranyet1on8 ~ Mml:Mac:hlne Syatelll, ~-ll,

i i~ ,) .!

~. ( I. .'J

92-101. "\ ,.oJ

HOWELL, W. C., and BRWGS, r.. E.:i 195"" Inforna.1tion '''n~~ and procelllinl • *" . \. r',- "'-:!

varl~ble. ln man machine .y.te .. ~: A review of 'the ilterature. :.~}; ~ ..

Technlcal ReRo!:!. ~:~ VTRADEVCEN SOS:1, U. S. Nnval TfGiningDevlce Center, ... ' .!

Port W4shlnlton, ~". ,w York.', .1J

.!ACACINSKI, R. J' t MILLER, D. P/~ and tn .. C;ON. R. D., 1919, A comparison of : ~

kinesthetlc-tactual and visual display" via a critical tracking task.

.!!!!!!.!!. Factors, 21, 79-86.' ""

JEX. H. R •• and ~LEN, R. w •• 1970, ~.arch un II new human dynamic r:!8ponse •

test battery. ~e.£!~.!!S.! 'of tb.!. ~~I!!l f.nn_ferencl! 2!! ~f4nual Contr"l, ! . ;:

6, 743-717. ..i:~

,"~.

JEX, H. R., JEWELL,W. F., .1nd ALLEN, k. W •• 1972, Ueveloplllcut of tbe dual-ad. t 1

and croll-ccuplt>d crtticnltaak.; ~£l.'dl!~\t!. 'rt ~ ~ll\Ul\l Conference: :

.2!!. }>bnua~ Control, 8, 529-552.-

JEX, H. k., MCDONNELL.J. D., and PHATAlC. A. V •• 1966, A "critical" tracktna "' , 1

. 1n ElectronicM. tII~E-7. 138~14S. 1. - -.

KANTOWITZ. B. H., lind KNICIiT. J~'L •• 1974. T.'stinA tapping tillle.harin,.

~ournal ~ ExI)Crimental rfivchololl. 103. 331-336.

LINDSAY. P. H., CUDDY, I .. , and tl1LVINC!, E •• 1965, AbRolute lud_nt8 of

2, 211-212.

~ .

".

.. i ~ ;

-:. of. ~.: ; .;

a..;- { ,~- ;

., .

.i"'

~~'~. "" ...... """"= ...... ,_~~"---"_ ....... ____ , ... --_'''iiolI"~iOi''iii·.~iIiii.ii.'ii\i'-ilii-=-iiii· Iiii'.-"" -!ill!' 'il;!!' '.'0'.' -~"~'--_§_"'-'!liii-"_'--~'-!IlO''''''~;;;;!.!IiO-"",,,'' ----~,_: -----=·if~:a_~~£§II¥€~!3t.:i~.3== >'. ___ ~--- •• "'____ ~ !Iiiiii ~ =-

..

'I. .

. , LIIDIAY, P. "It TAYLOR, H. H., and FORIBS, S- 14., 1968. Attention and ., '. -

_ltW;-nliOUl dllcrlllination. l!!.c:eptlon!!!. PsychophYlicl. 4, ~

tIllCllAlDAlU .. P. 8 •• 1972, An auditory dilplay In a dual-axls tracklnl task.,,. .. i

Jill 'q_Iactions .2! Syat .... .!!!!.. !!!! Cyberne.s.!£!.. SMC-2. 375-380. f

MOIAY, M., 1.96~, Wher. ttl capacity UII1tad1 A surve, and a lIOde1. ~

~ P~ycholollca, 27. 84-92.

HORTON. J. ,;1970, A functional lftOdel for IIICIIKlry. tn: Mod..!].!'.!!!!!!!!!. MeIIorx " (Edit.~ by D. A. No1'1llan) (Nev York: Acadeudc). L

MUDD. S. A •• 1963, Spatial atereotypeao.f four dillenslona of pure tope.

Journal 2!~~erl.ental Paycholol1, 66,347-352 •

lIOULTON, E.,C., 1966, 'Engineerins p.yclaoIOIY· ~u,!ll. ~lew 2!. PaychololY, "

17, 177-200.

IDGEIS, S. ,., 1979, Stimulus-respona. coapatibillcy: Extra proc.s,ina . • tal.s:'versua respons. cOllpetition: ProcecdinSI!!.!!!!. Annual !!e.t1na .

I ' '

!L !!!!,:Huaan Factou Societl, 23, ~lS-419.

SPIlTH, V.,'CURTIS, J. F., and WEBST!!, 'J. C., 1954, ae.pendlna to on. of . ., two st_ltaneoul _s.aalls. Journal' !!. !!!!. Ac~1E.!!. Society !ll.

e ~ -

America, 26, 391-396.

TRElSMAR, A:, and DAVIES, A., 1973~ Divided attention to car oQG .ya.

Attention and rerformnnce, 4, 124-136. - or

....

VINJE, E. W~, 1972, PUght atmulnt iun .... luntfon of nud1n I FR d18p14Y. for ,

. I

rro('(!cdln@ ~2.! ,tlt!: ~n'p'u& f:2!!L~..,ce ~ Manunl

~ntrol, 2, 375-380.

VINJE. E. W~, and PITKIN, E. T., 1972, ~n oporator dyna.tc8 for aur.l " -i

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. ~, " ( , .. {'

~ r .'

i ~ , '. f "[

'.

compenaatory tucking. ~ Tran8*=tionH ~!!1. Systcma, ~. !!!!!. Cybemetic:a,

SMC .. 2,; 504-512.

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Pilure 1 -- Al~ ... natt •• vlauti elI.plo;: cunftcurllt tona. Vertlcal':..v •• nt i ... ~ , ' .. ,: .~ , ~ ,,' i .

1a uaad f~r the,rimary ~8'k dts~hY, and horl1Ont81 IIOV ... l'C 18 used

for the "condar, task d)aplay. . I , i

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,tlure 2 -- MelD arou, perforaance. ona 8ingle eritteal trackinlta.k with '=~~

• quick"ed tactual dlaptay and three unquicKened vltJud d1Iplay •. • J

F11ure 3 .. - Ke4D group pcrfol1lancca on Il Hingle "rtttc:a] tracklnl taak with " ,

a qul~kened tacty"] dhplay, an unquh'k<'tl~d visual (VI) dlaplay (both oj " .. ~ . .

repeated fr.OIIl Fi.ure 2) rt and 8 ~lckenr.d vill";,l display Mvl", ita .lpt~ :.. . j 'i t;",~

p ... ed through Af\ off-Unet8ct~1 diRpla)'. .i

'ilura 4 -- Me~ Ir~~ pedon..ncea ad' II dual ~. , ~ . ~. .

· ~ -dtapla),a are ther a8_ D'1n 'tlUte 2.

I • • \' :( .~ ).

'1aur~ 5 -- Keen Iroup perfomaancea o~ a dual ~ ! ~

d1.plays are the _._ 4a' 1n P1autjl 3. . .

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VISUAL DISPLAY CONFIGURATIONS

-•

·GROUP VS- SMALL LINE

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GROUP VL-LONG LINE

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··tROUPVI~INTEQRAL DOT

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DAY I'

PRETEST SECONCWn' TASK·

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SINGLE TASK PERFORMANCE

DAY 2 DAY 3

"6.-""

PRIMARY DISPLAYS

• • TACTUAL-QUICKENED (TO) ()o ..... O VISUAL-SMALL LINE (VS) .---.a VISUAL- LARGE LINE (VL) o '0 ~ISUAL-INTEGRAL DOTCV:U

DAY 4 DAY !S " w , ~: ".~ PR1MARY CRITICAL TASK

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DAY 6 DAY II TRAINING POST TEST SEC TASK PRIM QIT TASK

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2.0

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..... TACTUAL-QUICKENED (TQ' Oo-tO VISUAL-QUICKENED (VQ) o-c VISUAL-INTEGRAL DOT (V%)

DAY I DAY 2 DAY 3 DAY 4 DAY 5 DAY. DAY " PRETEST ' • ' TRAINING POIT TIlT

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SECONDARY TASK PRIMARY CRITICAL TASK SEC TASK ' .... CHIT TAR , '.

. ', ...... ,.,' '." ;.: ... ": .. ' ........... , ';: ,to; -:-1,1" ·,,. ... r .,.,~ ".\"~',~"~''''\. '~:.~t.If""·j. ...... ' •.. ~.,", .' ' ""',';'")i '~"". ~ ~ 'to';'

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DUAL TASK PERFORMANCE

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.13., ' . __ - _111;0-"-' .• 0 .6 ..... ::I!Jt'- ~. • • •• -0. • •

C' •• -; R::: .. .o ..••• ;S= .... a60-:::"'IIIf/ SECONDARY DISPLAYS

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DAY.7 .. DAY, 8, :, '.' 1·.,.· ... '., r:,".~ '. ('. :: .. ' •.. ~; ... ~ !~ •• "' .... " .. "1" .. <..: .... : ...... , "

.~ , ~.' . , " ........... , .. " ..... ~ .. " ... "-....... " ..

• • VISUAL- SMALL LINE (TO) 0 .. · .. 0 VISUAL- SMALL LINE (VS) A-- -6 VJSUAL- LARGE LINE (VL)

D VISUAL-INTEGRAL DOT (VI)

PRIMARY DISPLAYS

• • TACTUAL-QUICKENED (TO) 0·····0 VISUAL- SMALL LINE (VS) 60-- -6 VISUAL- LARGE LINE (VL)

D VISU~L- INTEGRAL DOT (VI)

,. ... ~. .' r •.

DAY,9 '. PA.Y 10 .. "', '. ~ .~ • ".'.'! "1: ,;.,.. . ""- .

,.--:. .11 .... ' ....... ".,11". • ..............

•• ' ~,.-' •. -" '., .. V .,,:j.' ...... ""'f""'''';~~ .'::;'\'~ ~~· •. :"(I,l; ..... : .... 1It.I'r!'.'""'....: ..

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DUAL TASK P~RNrANCE

DAY 7 DAY '8

.:

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SECONDARY DISPLAYS

• • VISUAl-SMALL LINE (TO) 00-0 VISUAL-INTEGRAL DOT (V

D VISUAL-INTEGRAL DOT (V '

PRIMARY DISPLAYS

• • TACTUAl-QUICKENED (rQ) , 0--0 VISUAL- QUICKENED (VQ) D a VISUAL-INTEGRAL DOT (VI

DAY 9 DAY 10

1 1 ~ .~ ~

1

L

l

This re;search WoIS S\lolHiI1rt'd in part hv tl1I' Ii. S. Army ,\lr Mobility ~~

Research an~: Development Laboratory, Hoffett Fil'ld, California, and in "

part by the :Avionics Laborntory, Electronics Command, Ft. MOllmout,h. New

,

... 26.

Jersey, and -Was monitored through NASA-Ames Grnnt NSG-2l79. The research ~ :"

"

reported he(ein was submitted by the first nuthor to the Department of

" Industrial ~nd Systems Engineering of The Ohio State University. in partial

fulfillment !of the requirements for a MS(~ IE Degree. The authors wish

~ especially ~o acknowledge the contributions of Professor Thomas H. Rockwell •

.-'. t

who served as thesis chairmnn. and Professor Kichard A. Hiller. Reprint ,~

requests sh~uld be addressed to Richard J. Jagncinsk1. Human Performance

Center, 404~B West 17th AVl'lluC'. ColllOlbml, Ohio, 4"l210 .

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