Age and Experience Effects on the Interpretation

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Psychologyand Aging
t991. Vol. 6. No. 3. 426-433
Age and ExperienceEffectson the Interpretation
of OrthographicDrawingsof Three-DimensionalObjects
Timothy A. Salthouse
School of Psychology, Georgia Institute of Technology
Adults of differentagesand experiencelevelsattemptedto recognizewire-framedrawingsof 3-dimensionalobjectsoriginally displayedin orthographic views. Although only slight age relations
wereevidenton a measureofdecision accuracyin the criterion task, increasedagewasassociated
with poorer performanceon severaltaskshypothesizedto assesscomponentprocesses.Furthermore,therewasno significantalterationin anyofthe performancemeasuresby statisticallycontrolling for amount o[relevant experience,and there wasno evidencethat peopleofdifferent ages,or
different levelsof experience,relied on differcnt abilities to perform the criterion task. These
resultsseem to imply that experienceneither mediatesnor moderatesage-relatedinfluenceson
certain measuresof relativelybasiccognitiveprocesses.
In severalrecentprojects,my colleaguesand I (e.g.,Salthouse,
Babcock,Skovronek,Mitchell, & Palmon, 1990;Salthouse&
Mitchell, 1990)found that age-relatedinfluenceson me:rsures
of spatial visualizationability were largelyindependentof the
amount of experiencethe researchparticipants had received
with relevantactivities.This wastrue in comparisonsrestricted
to practicingarchitectsin the Salthouseet al. study and when
the researchparticipantswere categorizedwith respectto the
amountofexperiencethey reportedwith activitiespresumedto
requirespatialabilitiesin the Salthouseand Mitchell study.The
apparentimplication of theseresultsis that experienceneither
mediatesnor moderatesage-relateddiferencesin certain measuresof spatial ability. However,a potential limitation of the
earlier studies is that the measuresof spatial ability were not
deliberatelyselectedto be similar to any particular occupational or leisureactivity.Instead, the measureswere basedon
conventionalpsychometrictestsor computer-controlledvariantsofthose tests.The primary purposeofthe presentproject
was to examine interrelationsof age and experienceon measuresofspatial ability derivedfrom speciallycreatedtaskspostulated to be very similar to activitiesperformedby many engineers.
The criterion task in this projectconsistedofthe recognition
of three-dimensionalobjectsportrayedinitially assetsof three
orthographicdrawingsand, subsequently,
assingle,wire-frame
drawings(seethe top panel of Figure I for an illustration). A
strong argumentcan be made that the interpretation of these
kinds of technical drawingsof three-dimensionalobjectsis a
critical skill for many engineersbecausetechnicaldrawingsare
This researchwas supportedby National Institute on Aging Grant
AG06858.The enormousassistanceofJennifer Shawin all phasesof
this project is gratefullyacknowledged,as are the advice and suggestions of WalterRodriguezand the assistanceof MichaelCox and Shane
McWhorter in the preparationof materialsand computer programs.
Correspondence
concerningthis article shouldbeaddressedto Timothy A. Salthouse,SchoolofPsychology,GeorgiaInstitute ofTechnology,Atlanta, Georgia30332.
necessaryfor the transition from the designto the construction
ofnearly all objects.Moreover,accuracyin both producingand
interpreting drawingsis extremelyimportant in the engineering professionbecausethe drawingsfrequently function as a
legal document specifyingexactly what is to be constructed,
and a failure of either representationor interpretation could
result in time-consumingdelaysor possiblyevenexpensivelitigation.
Although engineersmay not be requiredto producedrawings
at all stagesof their careers,graphicalcomprehensionis likely
to be important throughout one'sprofessionallife. Giesecke,
Mitchell, Spencer,Hill, and Loving (1969,p. 7) haveevenasserted that an engineerdeficient in the ability to understand
technicaldrawingsis "professionallyilliterate."A further indication of the importanceof technicaldrawingsin engineering
is evident in the fact that nearly all engineeringcurricula includeat leastone courseon mechanicaldrawingor engineering
graphicsand that items relatedto the interpretationof technical drawingsare often included in examsfor the professional
certification or licensingofengineers.Theseconsiderationsall
suggestthat the interpretationoftechnical drawingsis an activity with considerablerelevanceto the practicingengineer.
The most widely usedmethod of representingthree-dimensional objectsis the orthographic projection systemin which
the object is portrayed by two-dimensionalviews of the top,
front, and right surfacesofthe object.The strategyoften recommended in textbooks (e9., Gieseckeet al., 1969; Hoelscher,
Springer, & Dobrovolny, 1968; Luzadder, 1968; Rodriguez,
1990), and preferred by instructors of engineeringgraphics
courses(Salthouse& Rodriguez, 1990), for determining the
three-dimensional object representedby the three orthographicviewsis to project eachsurfaceonto an outline box and
then to mentally cut out the extraneousregions.For example,
applicationofthis strategyto the setoforthographic drawings
in the top left panel of Figure I would involve folding the top
view down and back along its front horizontal axis into the
picture planeand folding the right view back alongits left vertical axis into the picture plane.This shouldresult in a three-di-
426
427
AGE AND EXPERIENCEEFFECTS
Orthographic
Screen1
l
Scresn2
r
[]E
Perspective
Screen 2
affil\
Recognition-after-Rotation
Scr6€n1
t;
'?#
Scre€n2
U]
Screen 3
Assemble
Scre€n 2
[lt l
r-1
L_l
D
S
FigureI . Illustration of displaysin successive
screensof trials in the four experimentaltasks.(The labels
ofthe screennumber werenot presentedin the actual tasks,and the lettersD and S in the bottom ofthe
screenswere replacedby the words diferent and,same in the actual tasksas remindersofthe response
assignment.S = starting viewing point; F: final viewing point)
mensional representationresemblingthe object portrayed in
Screen2.
Analysis of this recommendedstrategysuggeststhat it involvesat leastthree distinct components.The fint is deciding
how an object or surfacewould look when viewed from a different perspective;the secondis preservingthe altered perspective
ofone surfacewhile transforminganotherobjectorsurface;and
the third is the coordination and assemblyof the information
from the different perspectivesinto a coherentthree-dimensional object. The tasks createdto assessthese hypothesized
componentsare illustrated in the bottom panel of Figure l.
The task labeledperspectivewasdesignedto evaluatethe ability to recognizean object after it had been rotated or spatially
transformeda specifiedamount. The first displayon a trial in
this task illustrated the object that was to be rotated and also
contained a display of the starting (S) and final (F) viewing
poins of the object. Instructions indicated that the respondent
should imagine that the obj€ct wasviewed from the position on
the circle marked S and that he or she then walked around to
the point marked fl The task wasto decide,with a same-different response,whether the object representedin the seconddisplay correspondedto how the object in the initial display would
appear ifviewed from the new perspective.
The task labeledrecognition-after-rotationinvolved three successivedisplays. The first and third displays were of a single
orthographic view ofan object, which the respondentwas to
judge aseither the same-differentwith respectto one another.
The secondscreenin the trial containeda wire-frameview of a
diff€rentobjectand a referencecircle indicatingthe S and the F
perspectivesfor viewing the object. The respondentwas instructed to try to rotate the object on the screen such that it
would appearthe sameas if it wereviewedfrom PositionF on
the referencecircle. As much time and rotation manipulations
as neededwere allowed for this rotation process.Note that this
task really involvestwo distinct activities-the primary requirement of making a same-differentjudgmentto the orthographic
drawing in the third display, and the interpolated activity of
rotating the different wire-frame object in the seconddisplay.
The task labeledassembleinvolvedtwo displaysand required
a same-different decision regarding whether the orthographic
views in the fint screenand the three-dimensional drawing in
the secondscreencould r€pr€sentthe same object. Familiar
symbols on the facesof a cube were usedas the stimulus material in thistaskto emphasizethe integrationorassemblycomponent, rather than the ability to deal with potentially novel spatial materials.
Two independent studies were conducted with different
groups of participants. Only collegestudentsparticipated in the
first study becauseits primary goal was to examine the relations betweenthe experimental measuresand measuresof per-
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428
TIMOTHY A. SALTHOUSE
formance on standardized tests of three potentially relevant
cognitive abilities. The second study involved adults of different
ages and experience levels to investigate the interrelations of
age and experience on the performance of the experimental
tasks. Because the experimental tasks were identical in both
studies, the general method is described first.
Method
All participants performed the four tasks illustrated in Figure I in
the following order: (a)orthographic,(b) perspective,(c) recognitionafter-rotation,and (d) assemble.Each ofthe taskswas presentedon a
microcomputer,with the first screendisplayedfor 4.5 s,and the second
(or third in the recognition-after-rotationtask)screendisplayedfor an
unlimited time to allow the subjectto respond.Responses
weredepressionsofthe "slash"(/) key on the keyboardforsameand ofthe Zkey for
different.Rotationofthe wire-frameobject in the secondscreenofthe
recognition-after-rotationtask was carried out by depressionsof the
left and right arrow keyson the keyboard.
The stimulusmaterialsusedin the taskswereorthographicand wireframedrawingsof relativelysimplethree-dimensionalobjects.Approximately I 50 pairs of similar objectswere identified, and complete(orthographic and wire-frame) sets of drawings were created for each
memberof the pair. Selectionof the drawingseventuallyincluded in
the experimentaltaskswasbasedon severalsuccessive
pilot testsand
accompanyingitem analyses.Pairs ofsimilar objectswere neededso
that the correspondingdrawingsfor the other memberofa given pair
could be usedasthe incorrect or asthe differentalternative(for 5ogoof
the trials) in the orthographic,perspective,and recognition-after-rotation tasks.The different alternatives(alsoon 50%ofthe trials) in the
assembletask were createdby altering the orientation of one of the
lettersfrom a correct set of drawings.
Eachtaskwasprecededby a briefdescription ofthe instructionsand
the examiner'soffer to answerany questionsleft unclearby the instructions. The participant then performed a set of five practice trials as
many times asdesired(with feedbackon accuracyafter eachset)until
he or she felt comfortableabout the nature ofthe task. A total of30
different experimentaltrials were presented,with accuracyfeedback
provided after eachresponse.The accuracyfeedbackconsistedof the
wordscorrector incorrectfor the same-differentdecisions.Additional
feedbacklor the rotation componentin the recognition-after-rotation
taskconsistedofa displayofthe referencecircle with portrayalofthe S,
desired f, and actual F viewing positions. The averageaccuracy
achievedacrossthe 30 experimentaltrials wasalsodisplayedaftereach
task.
Immediatelybeforethe first task, eachparticipant answereda setof
questionsabout his or her recentexperiencewith severalactivitiesand
rated his or her ability with eachactivity.The experienceinformation
wasreportedin termsofthe averagenumber ofhours per month spent
performingthe activity during the last 6 months,and the ability ratings
wereon a 5-point scaleranging froml (high relativeto the averageadult)
to 5 (low relativeto the averageadult).The activities included in the
questionnaireare listed in Tablel, along with the meansand standard
deviationsof the responsesin the two samples.Severalactivities assumedto be unrelatedto proficiencywith spatial taskswere included
to allow generalresponsetendenciesto be differentiatedfrom reports
of specificexperienceand abilities.
After completing the experimental tasks, the participants were
askedto rate how familiar the tasksand stimulus materialsappeared.
Ratingswere madeon a 5-point rating scaleranging froml (veryunfamiliar) to 5 (veryfamilia).
markers of spatial visualization, inductive reasoning, and percaptual speed abilities. The purpose of these additional measures was to allow a determination of the factorJoading pattern
ofthe n€w measures by reference to established abilities.
Method
Subjects. Participants in the study were I 2 I collegeundergraduates,
82 women and 39 men, with a mean ageof 20.0 years.(No significant
genderdifferenceswereevident in any ofthe experimentalmeasures,
and consequentlythis classificationvariablewas ignored in all subsequent analyses)Compensationfor participation in the 2-hr session
consistedofcredit toward a courserequirement.
Procedure. Before performing the experimental tasks, the participantsin Study I wereadministeredsix paper-and-penciltests.The six
tests,and their respectivetime limits, wereasfollows:paper-folding(3
min), surfacedevelopment(6 min), lettersets(7 min), seriescompletion
(5 min), numbercomparison(l .5 min), and finding As (2 min). All tests
werefrom the EducationalTestingServiceKit of CognitiveReference
Tests(Ekstrom, French,Harman, & Dermen, 1976),exceptthe series
completion test, that was from the Shipley Institute of Living Scale
(Shipley,1986).Eachtest wasadministeredaccordingto the published
guidelines,and performancewas rcpresentedby the number of items
answeredcorrectly.
Resultsand Discussion
Means and correlationsamong the experimentalmeasures
aresummarizedin Table2. Threepointsshouldbe notedabout
the values in this table. The fint is that the mean levelsof
performanceare near the middle of the effectiveperformance
range(i.e.,chanceis 507owith a two-alternative,same-different
decision),indicating that most scoreswereprobablynot limited
by floor or ceiling restrictions. The second point is that although the estimatedreliabilitiesare not as high as one might
hope,they arenevertheless
acceptablefor the presentpurposes.
And third, althoughall the correlationsbetweentheexperimental measureswere positive,none of them was very large,This
suggeststhat the measureswere not all assessingexactly the
sam€construct.
Table 3 contains the resultsof the factor analysiswith varimax rotation conductedon the data from the six paper-andpencil psychometric tasks and from the four experim€ntal
tasks.Three factorshad eigenvaluesgreaterthan 1.0and were
retained in the final factor solution. The loading patterns for
thesefactorssuggestthat the first factor correspondsto spatial
visualizationability and that the third factor reflectsperceptual
speed.The secondfactorcan probablybe interpretedasreflecting reasoning,but it is more complex than the other factors
becausethe reasoningtestsload nearlyequallyon all three factors.
The most interestingaspectof the resultsin Table3 is that the
experimentalmeasuresload exclusivelyon the first 2 factors,
with measures from the orthographic and perspective tasks
loading on the SpatialVisualizationfactor and measuresfrom
the recognition-after-rotationand assembletasks loading on
the mixed factor,which probablyconsistsmainly of Reasoning.
It can therefore be inferred that the experimental measuresare
assessing
abilitiesrelatedto spatialvisualizationand inductive
Study I
reasoning,but independentof perceptualspe€d.
Participants
in theinitial studyperformedtheexperimental
Meansand standarddeviationsof the responses
to the experitasksjustdescribed
andsixpaper-and-pencil
testsoftenusedas enc€and self-ratedability questionsaresummarizedin Tablel.
429
AGE AND EXPERIENCEEFFECTS
Table I
Means and Standard Deviations of Experience-Ability QuestionnaireResponses
Ability rating
Study I
Activity
Reading books, magazines,or newspapers
Managing or supervisingother people
Developingand implementinglong-term plans
Considering how an object or building would
look from a differcnt viewing position
Producing or interpreting technical drawings
(e.g.,blueprints)or 3dimensional objects
Using computer-assisteddesign or computerassistedmanufacturing computer programs
Recent experience
Study 2
Study I
Study 2
M
SD
M
SD
SD
2.t
2.5
2.4
1.0
1.0
0.9
1.8
2.4
2.3
0.9
1.0
1.0
39.4
t7.9
13.0
35.0
33.2
18.2
47.O
42.9
18.2
54.9
63.4
29.7
2.6
l.l
2.4
t.2
7.0
15.7
Il.l
24.0
2.6
l.l
2.6
1.3
t0.2
22.2
15.4
36.3
2.8
l.l
3.3
t.4
7.1
l8.E
ll.l
34.1
M
SD
Note. For ability ratings,I = high and 5 = low.Recentexperiencewasmeasuredin termsof the averagenumberof hoursper month that werespenl
performing the activity in the last 6 months.
Thesedatawerealsosubjectedto a factoranalysiswith varimax
rotation to identify meaningfulconstellationsof responses.
Resultsof the factor analysisare summarizedin Table4.
The factor analysis yielded five factors with eigenvalues
greaterthan 1.0.The loading patternssuggestthat the factors
represent Subjective Ability With Relevant Activities, Subjective Ability With Other Activities, Experience With Relevant
Activities, ExperienceWith Other Activities, and Experience
With Computer-Assisted Design-Computer-Assisted Manufacturing(CAD-CAM) Activities.The bottom portion of Table
4 contains the correlationsbetweeneachofthese factorsand
the experimentalmeasures.The most noteworthyaspectof the
correlations is that only the negativerelations between the factor representingself-ratedability with relevant spatial activities
and performance in the orthographic and penpective tasks
were significantlydifferent from zero.This indicatesthat people who rate their abilities as higher than average(i.e., lower
numbers on the rating scale)perform somewhatbetter in these
tasksthan peoplewho rate their abilities lower.
The averagerating to the postexperimentalquestion concerning the familiarity of the tasksand stimulus materialswas
2.3.The familiarity rating wasnot significantlycorrelatedwith
Study 2
Table 2
Correlation Matrix-for Study I (N = 121)
Variable
l.
2.
3.
4.
5,
Age
ORTHO
PERS
REC.ROT
ASSEM
M
SD
20.0
L6
-.01
.60
-.10
.50*
.78
72.5
l 1.8
75.3
t4.6
any of the factors from the experience-ability questionnaire
responses,
but it waspositivelycorrelatedwith eachofthe experimental measures.The correlationswerelow (i.e.,the rangewas
.13 to .27), however,and only that (r = .27) with the measureof
accuracyin the orthographic task was significantly(p < .01)
greater than zero.
The resultsof this initial study wereencouragingin at least
four respects.First, the experimentaltasksseemedto be understood by all participants and yielded measureswith averages
near the middle of the measurementscaleand with acceptable
levelsof reliability.Second,the variousmeasureswerenot simply alternative reflections of the same construct becausethe
correlationsbetweenthem werenot very high, and they did not
all load on the samefactor.Third, the factor analysisrevealed
that the measureswere related to Spatial Visualization and Inductive Reasoningabilities, but not to PerceptualSpeedability
And fourth, the experience-abilityresponses
could be grouped
into meaningful clusters reflecting Experience or Subjective
Ability with RelevantActivities or with Other Activities. In light
ofthese satisfactoryresultsfrom the initial study,I decidedto
proceedwith the major investigationof the relationsof Ageand
Experienceon thesemeasures.
.l I
.25*
.29*
.79
87.1
13.2
-.02
.16
.20
.25'
.60
83.6
9.0
Note. Boldfacednumbers indicate estimated reliabilities computed
by boosting the odd-even correlation by the Spearman-Brownformula. ORTHO = accuracyin the orthographictask; PERS= accuracy
in the perspectivetask;REC-ROT: accuracyin the rccognition-afterrotation task; ASSEM : accuracyin the assembletask.
t p <.01.
As mentioned in the introduction, the primary goal of this
researchwasto examinethe effectsofexperienceasa potential
mediatoror moderatorofperformanceontaskspresumedto be
relevant to the occupational activities of engineers.The researchparticipants in this study therefore ranged from 2 I to 80
yearsof age,and attempts were made to solicit the participation
of individuals with widely varying levelsof experienceinterpreting technicaldrawingsof three-dimensionalobjects.
Method
Subjects.Specialeffortsweremadeto recruit participantslikely to
with thegeneration
havehadexperience
andinterpretation
oftechnicaldrawings
ofthree-dimensional
objects,in additionto participants
with littleor no experience
of thistype.Theseeffortsincludednumer-
I
I
430
TIMOTHY A. SALTHOUSE
Table 3
Factor Analysis for Study 1: Experimennl and PsychometricMeasures
Measure
I
I
I
Factor I
(Spatial
Visualization)
Paper folding
Surfacedevelopment
.736
.8t2
.150
.152
lrtter sets
Seriescompletion
. 3 1I
.27|
.449
.562
.054
-.089
-.183
.295
.782
. 75 7
.132
.t62
.148
.1 9 8
.786
.628
3.388
|.542
Finding As
Number comparison
Orthographic
Penpective
Recognition-Rotation
Assemble
Eigenvalue
ous letters and phone calls to local engineeringcompanies;CADCAM organizations;faculty membersin mechanical,civil, and aerospaceengineeringdepartments;and letterssent to 1,800graduatesof
the GeorgiaInstitute of Technologywith degreesin mechanicalengineering.The final sampleconsistedofl32 men between2l and 80
years of age. (Only men were included in the final sample because
women made up a very small proportion of the relevantpopulation,
and consequentlynot enoughwomen volunteeredto allow meaningful
analysesofpossible gender,Gender X Age, or Gender X Experience
Factor 3
(Perceptual
Speed)
Factor 2
(Reasoning)
h2
.573
. 71 6
.37|
.442
.436
.584
.654
.612
.638
.421
1.021
effects) Although most participants had engineeringbackgrounds,
level of experiencewas evaluatedby responsesto the experienceability questionnaireand wasnot basedon occupationalclassification.
The meanlevelofhealth, asratedby the participantson a 5-pointscale,
ranging from (l ) excellentto (5) poor , was| .40, with an agecorrelation
of .25. The mean number of yearsof educationwas 16.2,with an age
correlationof . 12.Compensationfor the approximatelyI .5-hr session
was$10.
Procedure, All participantscompletedthe experience-abilityques-
Table 4
(Study l)
Factor Analysis of Experience-Ability Responses
Variable
I
Self-ratedability
Reading
Managing
Planning
Perspective
Technicaldrawing
CAD-CAM
Hours per month
Reading
Managing
Planning
Perspective
Technical drawing
CAD-CAM
Eigenvalue
Factor I
(Relevant
Subjective
Ability)
.149
.169
.038
.760
.803
.655
Factor 2
(Other
Subjective
Ability)
.628
.792
.775
. 1 74
.093
.108
-.t21
.362
-.010
-.196
.014
.286
2.497
- . 1I I
.05
-.38*
-.30r
-.18
-.1I
-.02
.03
-.01
.06
.05
-.081
.036
.094
-.t34
t.770
Factor 3
Factor 4
Factor5
(Relevant
(Other
(cAD-cAM
Experience) Experience) Experience)
-.t21
.155
.1 5 5
-.077
-.164
.057
-.103
.109
-.3r9
-.020
.018
-.206
.034
.344
-.041
.822
.836
.260
1.450
.795
.067
.789
-.001
-.023
.030
1.229
h2
.468
;137
.728
.633
.692
.537
-.116
-.627
.106
-.020
.072
.74t
t.otz
.673
.698
.642
.7t7
;tt4
.7t 8
Correlations
Age
ORTHO
PERS
REC-ROT
ASSEM
.08
.16
.20
.06
-.05
.05
.02
.t4
.00
.05
.04
.06
.02
-.07
-.00
Note. ORTHO = accuracyin the orthographic task; PERS = accuracyin the perspectivetask; RECROT : accuracyin the recognition-after-rotationtask; ASSEM = accuracyin the assembletask; CADmanufacturing.
CAM = computer-assisted
designor computer-assisted
t p<.01.
AGE AND EXPERIENCEEFFECTS
431
ence-ability questionnaireare summarizedin Table3 and the
results of the varimax rotation factor analysis perfiormed on
these data are summarized in Table 6. The factor pattern in
Table 6 is generallysimilar to that from Study l, with the excep
tion that the CAD-CAM experiencemeasurenow loadson the
RelevantExperiencefactor instead of combining with the managing experiencemeasureto form a separate,fifth factor.
Correlations of these factors with age and the experimental
measuresare displayedin the bottom of Table 6. Only two
correlations were significantly different from zerq and both
Results and Discussion
were negative. That is, increased age was associated with
The correlation matrix illustrating the correlationsbetween
smaller amountsof relevantexperience,and higher ratings of
the ageof the researchparticipant and the experimentalmearelevantability (i.e.,lower scoreson the scale)were associated
suresis presentedin Table5. As in Study1,the reliabilitiesof the
with a higher levelof performanceon the orthographictask.
measuresare in the moderaterange,and the correlationsbeThe absenceofsignificant correlationsbetweenthe Relevant
tween measuresare low to moderate.However, the greater
Experiencefactor and any of the experimentalmeasuresraises
rangeofparticipant agesin Study2 resultedin significantnegaconcerns that the experiential variation may have been too
tive correlationsbetweenageand the recognition-after-rotation small to haverevealedthe expectedmain effectsof experience.
and assemblemeasures.Perhapsbecauseof lower reliabilities,
To explore this possibility,the researchparticipants were dithe agecorrelationswith the orthographicand perspectivemeavided into quartileson the basisoftheir scoreson the Relevant
sureswere not significantlydifferent from zero,although they
Experiencefactor,and then the absoluteamount ofexperience
were in the samedirection as the correlationswith the other
contrastedfor the 33 individuals in the top 25Voand for the 32
measures.Controlling amount of education or self-reported individuals in the bottom 25Vo.Thepeoplein the bottom 257o
health statushad relativelylittle effecton the agerelations,as
reported an averageof only 4.7 total hr per month devoted to
the agecorrelationsafter partialing educationwere-. 17,-. 18,
the three relevantactivities(i.e.,consideringhow an object or
-.41, and - .26, for the orthographic,perspective,recognitionbuilding would look from a differentviewing position,producafter-rotation,and assembletasks,respectively;and thoseafter
ing or interpretingtechnicaldrawingsof three-dimensionalobpartialinghealthstatuswere-.12, -.1 5, -.35, and-.27,respec- jects, and using CAD-CAM programs),compared with an
tively.
averageof 120.5total hr per month for peoplein the top 25vo.
Although the instructionsin eachtask emphasizedaccuracy, Assumingthesereportsare valid, therefore,the individuals in
and not speed,of the decisions,the time participantstook to
the lowest25Voof the scoreson the RelevantExperiencefactor
make decisionsin eachtask wasalsoanalyzed.Thesedecision
were spendingan averageofa little overone halfofa working
times averaged
between2.05 and 3.15s acrossthe four tasks, day per month using relevantspatialabilities,whereasthosein
and all weresignificantly(p < .01) correlatedwith chronologithe highest25Vowercspendingan averageof about l5 working
cal age(i.e.,the correlationsrangedfrom .32 to .48). Angular
daysper month using theseabilities.Despitethesesubstantial
task
error in the rotation phaseofthe recognition-after-rotation
differencesin amount of experience,the two groups did not
wasalsoanalyzedand wasfoundto correlate(.34,p <.01) with
differ significantlyin any of the experimentalmeasures.These
chronologicalageofthe researchparticipant.Theseresultsindiresultsmake it unlikely that the relationsbetweenexperience
catethat, in eachtask,increasedagewasassociatedwith signifiand performanceon the experimentaltaskswereattenuatedby
cantly slowerdecisions,in addition to somewhatlessaccurate a restrictedrangeofrelevantexperience.
decisions.
The responsesto the postexperimentalquestionconcerning
Means and standarddeviationsof responsesto the experithe familiarity of the tasksand materialsare also informative
about the validity of the experienceratings.The mean rating
was2.3 (,SD: 1.1),and it wassignificantly(p <.01) correlated
with the RelevantExperiencefactor (r: .26)and with performTable 5
ancein the orthographic(r: .3 I ) and perspective(r: .29)tasks.
Correlation Matix for Study 2 (N = 132)
Thesepatternsindicate that peoplerating the tasksand mateVariable
I
rials as more familiar report more experiencewith presumably
relevantactivities,and alsoperform betteron two ofthe experi-.t6
-.39*
-.26*
-.16
l. Age
.40*
.33*
.26* mental tasks,than peoplerating the tasksand materialsas less
2. ORTHO
.63
.66
.29*
.34? familiar. The only other significantcorrelationswith the famil3. PERS
.81
.39* iarity ratingswerewith ageI : -.24\ andthe RelevantSubjec4. REC-ROT
.79
5. ASSEM
tive Ability factor (r = -.25). Older participants,and thoserat't9.6
79.9
78.7
M
46.4
71.8
ing their abilities with relevantactivitiesto be lower than averl 1.5
13.0
15.6
12.0
14.5
SD
age(i.e.,higher valueson the rating scale),thereforerated the
Note. Boldfacednumbers indicate estimated reliabilities computed
tasksandmaterialslower in familiarity than did youngerparticby boosting the odd-even correlation by the Spearman-Brown foripantsor participantswith averageor high ratingsof their own
mula. ORTHO = accuracyin the orthographictask; PERS: accuracy
ability
on relevanlactivities.
in the perspectivetask; REC-ROT = accuracyin the recognition-afterTwo setsof multiple regressionanalyseswere conductedon
rotation task; ASSEM = accuracyin the assembletask.
* p < .01.
the experimentalmeasureswith ageand the RelevantExperi-
tionnaire, performed the four experimental tasks,and answeredthe
postexperimentalquestionconcerningthe familiarity ofthe tasksand
stimulus materials.In addition, approximately5 min at the end of the
sessionrryasdevoted to the performance of two computer-controlled
versionsofa digit-symbolsubstitution task. Resultsfrom thesetasks
arenot describedherebecauseofplans to report them in the contextof
a largerstudyexplicitly concernedwith agedifferencesin digit-symbol
substitution performance.
432
TIMOTHY A. SALTHOUSE
Table 6
Factor Analysis of Experimce-Abiliry Responses(Study 2)
Variable
Self-ratedability
Reading
Managing
Planning
Perspective
Technicaldrawing
CAD-CAM
Houn per month
Reading
Managing
Planning
Perspective
Technicaldrawing
CAD-CAM
Eigenvalue
Factor I
(Relevant
Experience)
Factor 2
(Relevant
Subjective
Ability)
Factor 3
(Other
Subjective
Ability)
.104
.244
-.016
-.018
-. 128
-.318
-.009
.303
.067
.855
.90r
.522
.6t7
.441
.89r
.138
.044
-.151
- . 1 9r
-.449
.042
-.098
.014
.291
.429
.547
.801
.759
.830
.481
-.058
.270
.512
.638
.848
.7'79
2.749
.233
-.t54
-.002
-.229
-.169
.009
2.146
-.t20
-.053
-.45'l
.282
-.057
.088
1.575
.684
. 7t 5
.190
.218
.025
* . 1 II
1.000
.540
.61I
.507
.587
. 75 l
.62E
-.08
.0'l
.04
-.10
.08
.t2
.10
.03
-.14
-.09
Factor 4
(Other
Experience)
h'
Correlations
Age
ORTHO
PERS
REC-ROT
ASSEM
-.29r
.06
.ll
-.01
.18
.07
_.29r
-.21
-.l0
Note. ORTHO = accuracyin the orthographic task; PERS = accuracyin the perspectivetask; RECROT = accuracyin the recognition-after-rotationtask; ASSEM = accuracyin the assembletask; CADCAM = computer-assisted
designor computer-assisted
manufacturing.
t p <.01.
ence factor as predictors.The first analyseswere intended to
determinethe extentto which the age-related
effectsmight have
been mediated,or possiblyobscured,by age-relatedvariations
in experience.Theseanalysesthereforeexaminedthe influence
ofage after partialing the varianceassociatedwith experience.
The resultsrevealedthat the ageeffectswerevery similar before
and after control of the RelevantExperiencefactor. To illustrate, the squaredmultiple correlationsfor agebeforeand after
enteringthe RelevantExperiencefactor in the regressionequation were as follows:orthographic,R2 : .026 beforeand .023
after; perspective,R2: .026beforeand .018after; recognitionafter-rotation,
R2: .l5l beforeand.166after;andassemble,
R2
= .069beforeand.048 after.Becausethe attenuationofthe age
relationsafter control ofa variablereflectingamount ofexperiencewasvery small, it can apparentlybe inferred that most of
thoserelationsare not mediatedby experientialvariations.
The secondsetofregressionanalysesconsistedofexamining
interactionsofage and the RelevantExperiencefactor to determine whetherexperiencemight moderatethe agerelationson
the experimentalmeasures.Theseanalysesthereforeinvolved
enteringthe Age X RelevantExperiencecross-productinteraction terms after both the ageand RelevantExperienceterms in
the multiple regressionequations.None of the interactions
weresignificant-that is, F(l, 128)<2.28, p <.l0-with anyof
the experimentalmeasures,implying that the agerelationswere
also not moderatedby amount of experience.
A final setof multiple regressionanalyseswascarried out to
examine the possibility that the manner in which proficiency
wasachievedin the criterion orthographictask varied according to the individual's age or amount of relevantexperience.
Three multiple regressionequations were therefore created to
predict performanceon the orthographic task: the first with
only the measuresfrom the perspective,recognition-after-rotation, and assembletasksas predictors;the secondwith the experimental n{easuresplus ageand interactionsofage and the
experimental measuresas predictors;and the third with the
experimental measuresplus the Relevant Experiencefactor
scoresand interactionsof those scoreswith the experimental
measuresas predictors.
The R2 valuesincreasedacrossthe three equationswith valuesof .210,.238,and .252,respectively.
However,only the perspectivemeasurewasa significant(p < .01) predictorof orthographic performance,and none of the Age x Experimental
Measuresor RelevantExperienceX Experimental Measures
interactionswere significant.The absenceofsignificant interactionsindicatesthat there is no evidencethat peopleofdifferent ages,or with differentamountsof experience,rely on different combinationsof componentabilitiesto achievea givenlevel
ofproficiency on the criterion taskofrecognizingthree-dimensionalobjectsin wire-frameviewsfrom orthographicdrawings.
General Discussion
The major purposeof the researchreported in this article
was to investigatethe interrelationsofage and experienceon
taskscreatedto resemblean activity performedby many engi-
433
AGE AND EXPERIENCE EFFECTS
neers-interpretation of two-dimensional drawings of threedimensional objects. Results from the first study established
that the tasks yielded suitable measuresof performance in
terms of averagesin the middle of the performance scale,reasonablereliability, and loading patternson Spatial Visualization and Inductive Reasoningfactors.The first study also demto questionsaboutexperienceand abilonstratedthat responses
ity on specific activities could be grouped into meaningful
clusters.Participants in the secondstudy wereselectedto representa wide rangeof agesand levelsof experiencewith presumably relevant activities. The major finding of Study 2 was that
the age relations on the experimental measureswere neither
mediatednor moderatedby variationsin relevantexperience.
That is, the age-relatedinfluences were not substantially attenuatedafter partialing out the varianceassociatedwith relevant
experience,and there were no significant interactionsof age
and experienceon any ofthe experimentalmeasures.
Becausethree of the experimental tasks were designedto
assesscomponentshypothesizedto be important in the criterion orthographictask,analyseswerealsoconductedto investigate the possibility that the composition of performance
changedwith ageor experience.Theseanalysescan be viewed
as an extensionof the molar equivalence-molecular decompositionstrategyusedby Charness(l 98 I ) and Salthouse(l 984).
The primary expectation,ifincreasesin ageor experienceare
associatedwith changesin the relativeimportanceof the molecular componentsof a molar task, is that significantinteractions
shouldbe evidentbetweenthe componentpredictorsand either
age or experience.None of the interactionswere statistically
significant, and thus there is no evidencein these data that
people of different ages,or with different amounts of experience,relied on different combinationsof abilities to perform
the orthographictask.
The resultsof this project are consistentwith those of two
earlier projects (Salthouseet al., 1990; Salthouse& Mitchell,
1990) in suggestingthat the relations betweenadult age and
performanceon severalmeasuresof spatialvisualizationability
arelargelyindependentoftheamountofexperiencethe individuals have receivedwith relevantactivities.As in the previous
reports,this absenceof a mediatingor moderatinginfluenceof
experiencedoesnot appearto be attributableto a limited range
ofexperiencebecauseconsiderablevariation wasevidentin the
number ofhours reported to be devotedto relevantactivities.
Moreover,unlike the previousstudies,the experimentaltasks
in the presentproject were speciallydesignedto resemblea
common occupationalactivity of engineerswho comprised a
substantialproportion ofthe currentsampleofresearchparticipants.It is, ofcourse,true that noneofthe participantsactually
hadexperiencewith the specifictasksinvestigatedin thesestudies, and wire-frame representationsof three-dimensionalobjects are probably lesscommon than axonometric(three-surface)or solid-modelrepresentations.The current procedures
and materialsneverthelessseemreasonablebecauseperformance on the criterion orthographic task loaded on a Spatial
Visualizationfactor in StudyI and was positivelycorrelatedin
ability in presumablyrelevant
StudiesI and 2 with self-assessed
activities and with ratings of the familiarity of the tasks and
materials.
It is important to be explicit about what the resultsof this
project, and thoseofthe earlier projects,seemto imply about
the joint effectsofage and experienceon cognitive functioning.
Becausethe age relations were generally independent of the
amount of experience the research participants had received
with presumably relevant activities, these findings provide no
support for the idea that the age-relateddeclines in at least
certain measuresof cognitive functioning are attributable to
disuseor lack ofexperience. Ifthe disuseinterpretation were
valid, one would have expected the age relations to be greatly
attenuated,and perhapseveneliminated, after the experiential
variations werecontrolled. That this did not occur in any ofthe
studiesthereforesuggeststhatthe disuseinterpretationis probably insufficient to account for the observeddifferencesin these
measures.
However, neither the present results, nor the results of the
previousstudies,are necessarilyinformativeabout the relation
betweenageand either generalcognitivefunctioning or levelof
competencein one'soccupationalactivities.All of the studies
concernedwith spatial visualizationabilities havefocusedon
relativelybasiccognitiveprocessesand havedeliberatelyminimized the contribution of knowledgefactorson cognitive functioning. Becauseproficiency in many activities probably deof
pendsasmuch or more on knowledgeason the effectiveness
increase
processes,
is
likely
to
knowledge
and
because
basic
with experienceand with age,the resultsof thesestudiesmay
not be generalizableto more complex measuresof cognitive
functioning. Examinationof the interrelationsofage and experience on more complex aspectsof cognition should therefore
be an important goal for future research.
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ReceivedSeptember14, 1990
RevisionreceivedJanuary3l,l99l
AcceptedRbruary 1, l99l r
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