Dimensional preference and shift option

NANCY WRAY DAHLEM and LYNNJAMES McLAUGHLIN, St. LouisUniversity,St. Louis, Mo. 63103

Dimensional preference of first gradechildren was determined by one of fourmodifications ofamatching type preferencetest. The data suggested that contradictoryconclusions regarding the relationshipbetween dimensional preference and shiftperformance reported in paststudies arenotdue to use ofa matching, as opposed to adiscrimination type preference test, per se.Further study of the matching typepreference test wasrecommended.

In 1966, Smiley and Weir reported thatpreference for a particular stimulusdimension was related to performance on anoptional-shift problem. The Ss assigned totheir preferred stimulus dimension chose tomake reversal (R) shifts more often than Ssassigned to their nonpreferred dimension.They also required fewer trials to criterionon Phase 1 ofan optional-shift task.

Two more recent studies have indicatedthat dimensional preference had no effecton shift option. The Ss assigned to theirpreferred dimension did, however, requirefewer trials to criterion than Ss assigned totheir nonpreferred dimension (O'Brien,1966; James, O'Brien, & Brinley, 1969).

The major methodological differencebetween the Smiley & Weir study (1966)and the two others concerned the preferencetest used. Specifically, Smiley and Weiruseda discrimination type of preference testwhich required the S to respond to acompound stimulus-red circle, forexample. Later the S indicated whetherresponse had been to the color or to theform aspect of the compound.Approximately 20 stimulus exposures wererequired to determine the dimensionalpreference of the average S. The preferencetest stimuli were not used in theoptional- shift task which folIowed.

In contrast, O'Brien (1966) and James etal (1969) used a matching type of preferencetest. On each of six trials, the S was requiredto indicate which two of the stimuli in thetriad presented "looked most alike." Someof the preference test stimuli were used inthe optional-shift task which folIowed asothers were not.

The aim of the present study was todetermine whether failure to find arelationship between dimensionalpreference and shift option would persist ifamatching type of preference test were used,but modified. Specifically, would theO'Brien (1966) and the James etal(1969)

Psychon. Sci., 1969, Vol. 16 (6)

findings persist if a matching type of testwere used but (I) number of stimulusexposures was 6 for some Ss and 18 forothers, and (2) stimuli used in thepreference test were either all identical or allnonidentical to those used in the optionalshift problem which folIowed?

SUBJECTSThe Ss were 90 first-grade children.! Each

S was randomly assigned to one of fourpreference tests and to either his preferredor to his nonpreferred stimulus dimensionbefore beginning an optional shift task.

APPARATUSThe modified Wisconsin General Test

Apparatus used consisted of a one-wayvision screen which separated the E and theS, and a sliding tray on which moveablestimulus panels were positioned over rewardreceptacles. The sliding tray could be movedeither to the S's or to the E's side of theapparatus through a hinged door positionedimmediately below the one-way screen.During intertrial intervals, the tray was onthe E's side of the screen to allow forstimulus changes and for placing of tokenrewards used during the optional-shift task.The stimulus objects, glued to the moveablestimulus panels, were wooden figuresvarying in color (red, blue, orange, andgreen) and in form (circle, triangle, cross,and square).

PROCEDUREEach S was given a preference test I day

before beginning the optional-shift task.Two of the tests used stimuli identical tothose used later in the shift task (red andblue, circle and triangle). The other twoconsisted of nonidentical stimuli, or stimulinot to be used in the shift task (orange andgreen, cross and square). Half of the Ssassigned to each preference test wereexposed to the stimuli on 6 trials and halfwere exposed to the stimuli on 18 trials.Thus, each S was assigned to one of thefolIowing preference tests: 6 exposures toidentical stimuli (6-NI), 6 exposures tononidentical stimuli (n-NI), 18 exposures toidentical stimuli (18·1) or 18 exposures tononidentical stimuli (18-Nl).

On each preference test trial, triads ofstimuli showed a selected color and form intwo stimulus positions. Positioning of thestimuli across trials guaranteed that adimensional preference could not be afunction of position preference. Forexample, red circle, red triangle, and bluetriangle might be presented in thosepositions on one trial. On another trial, redtriangle, blue triangle and red circle or bluecircle, red triangle and red circle might bepresented.

During preference testing, each S was toldto slide back the two stimuli in the triadwhich "looked most alike." Any S matchingon the basis of color or on the basisofformon five of the first six preference test trialswas considered to show a consistentdimensional preference. No reinforcementwas givenduring preference testing.

When each S came to the experimentalroom to begin the optional-shift task onDay 2, he was told to slide back the "correctthing." He was also told to take the pennythat would always be in the rewardreceptacle under the "correct thing." Thesepennies he could trade for a candy bar at theend of the game. A correction procedure wasused in Phases I and 2 of the task whichforced the S to slide back the correctstimulus folIowing every incorrect choice.No S was allowed to take the hidden pennyif he had made an error on his first choice.

The optional-shift task used wasdescribed in detail in Kendler, Kendler, &Learnard (1962). Briefly, the task consistedof three phases. In Phase I, two pairs ofstimuli were presented from trial to trial (redcross and blue triangle; blue cross and redtriangle). Position of the stimuli wascounterbalanced so that consistentresponses to a cue were not confoundedwith position preferences. During this phase,the S was consistently reinforced forresponding to single cue either on hispreferred or on his nonpreferred dimension.When the S reached a criterion of 9 of 10correct responses, he was shifted to Phase 2of the task in which only one stimulus pairwas used. In Phase 2, the S was neverreinforced for response to the stimulusbearing the cue that had been positive inPhase I. Upon reaching a criterion of9 of 10correct responses in Phase 2, the S beganPhase 3. Phase 3 consisted of 10 Phase 2trials interspersed among 10 test trials. Theformer trials were aimed at keeping the Sresponding as he had responded in Phase 2.The latter trials used the stimulus pair notused in Phase 2. They were aimed atdetermining whether the S had chosen toreverse or to nonreverse during Phase 2. AlISswho made eight responses to a single cueduring the 10 test trials were labeled eitherreversers or nonreversers, depending on thecue to which they had responded. Other Sswere called inconsistent.

RESULTSRegardless of the type of preference test

used, all 90 Ss showed a preference for formover color. The Ss were not, however, soconsistent in their Phase I performance.During Phase I, 27 Ss failed to reachcriterion in spite ofthe correction procedureused. Twenty-four of these had beenassigned to their nonpreferred dimension(NP Ss) and only three to their preferreddimension (P S5). All three P Ss who failed

279

Table IShift Choices of P and NP Ss Assigned to the Four Preference Tests

Preferred Nonpreferred

Preference Test N R % N NR % N R % N NR %6-1 8 100 0 0 3 50 3 506-Nl 7 86 I 14 4 57 3 43

18-1 7 100 0 0 1 14 6 8618-Nl 8 100 0 0 6 75 2 25Overall 30 97 I 3 14 50 14 50

worked on the variouspreference tests failedto reach significance at the .05 level. Thesame finding held when comparisons weremade among NP Ss who had worked on thefour types of preference test.

The analyses of the Phase 2 overall dataindicated no significant difference in thetrials to Phase 2 criterion required by P andby NP Ss. Also, NP reversers and NPnonreversers did not differ in trials toPhase 2 criterion. When U tests comparedtrials to criterion required for Phase 2learning by Ss who had worked under eachof the four preference tests, only the 18-1 vsthe 18-NI difference for NP Ss wassignificant (U = 6; p < .010). The 18-NISs,predominantly reversers, required fewertrials to criterion (median = 10) than the18-1 Ss who were predominantlynonreversers(median = 16).

to reach criterion were in Preference Test18-1. The failing NP Ss were in all fourpreference tests (6-1= 4; 6-NI = 6; 18-1 = 6;and 18-NI= 8). These 27 Ss,along with fourPhase 3 inconsistent Ss, were dropped fromthe data to be discussed.

In order to determine the effect ofdimensional preference on shift option, theoverall data and the data for each preferencetest shown in Table I were analyzed. The chisquare test of the overall data indicated asignificant effect of preference on shiftoption (X2 = 14.60, df= I, P < .001). TheP Ss elected to make the R shift almostexclusively(97%), whereas only 50% of theNP Ss elected to make the R shift.Consideration of the data for eachpreference test, however, suggests that this isan oversimplification. One hundred per centof 18-1 P Ss elected to make the R shift as86% of NP Ss in this preference test electedthe NR shift (Fisher's exact p = .010). DISCUSSIONAlthough none of the other Fisher tests The data reported here suggest thatreached significance at the .05 leve. the failure to fmd a relationship between18-NI data suggest that the R shift was dimensional preference and shift option ispreferred by both P and NP Ss (100% and not a universal fmding when preference is75%, respectively). The 6-1 and 6-NI data assessedby a matching type of test. In fact,suggest that most P Ss (100% and 86%, the 18-1 data indicated a significant effectrespectively) elected the R shift as about that one might expect from the Heal,50%ofNP Sselected this shift. Bransky, and Mankinen data which showed

Mann-Whitney U tests were used to that in a forced-shift problem an R shift wascompare the performance of P and NP Ss easier than an NR shift for P Ss, as theduring Phase I learning. The data indicated conversewas true for NP Ss(1966).that P Ss required fewer trials to criterion Although the small Ns used in this study(median = 13.0) than NP Ss(median = 24.5, indicated trends rather than significantz = 3.31, P < .0(05). These P Ss, reversers fmdings for three of the four preferencewith one exception, were faster learners tests used, the data suggest that thethan the combinations of reversers and matching type of preference test will yieldnonreversers which made up the NP group. different types of data under different testA U test comparing trials to criterion ofNP conditions. Data like that of Smiley andreversers and NP nonreversers, however, I Weir (the 6-1 and 6-NI data), like that ofindicated that reversers were not' O'Brien and James et al (the 18-NI data),significantly faster learners than and like the Heal et al data (the 18-1 data) allnonreversers (R median = 24.5, NR median seem plausible. But, whether all of these= 28.0; z=.95, p<.I71). The Utest trends are reliable or not must becomparison of trials to criterion for P Ss determined by future research which useswho reversed and for NP Ss who reversed larger Ns.indicated that P reversers required fewer Even though our data dearly indicate thetrials to criterion than NP reversers need for further study using the matching(P median = 12.0, NP median = 24.5; type of preference test, they indicate onez = 3.17, P < .0(08). finding consistent across the test

Type of preference test appeared to have modifications studied. Regardlessof the testno effect on trials to criterion in Phase 1 modification used to assesspreference, an Rlearning. All of the U tests which compared shift was the predominant choice of P Ss.trials to criterion required by P Ss who had Similar confidence in ability to predict shift

280

choice of NPSs isnot warranted on the basisof our data.

The data reported agree, in general, withdata reported in other studies in suggestingthat dimensional preference may be acritical determinant of speed of Phase 1learning. Not only did NP reversers requiremore trials to Phase I criterion than Preversers but NP reversers and NPnonreversers required about the samenumber of trials to criterion. The P reversersdid, however, require fewer trials to Phase Icriterion than NP reversers. The onlyevidence that could be construed asevidencethat reversers are faster learners thannonreversers came from the comparison ofthe Phase 2 scores contributed by the 15 NPSs. The dimensional preference of these Sswas assessedby the 18-1 and 18-NI tests.

In summary, the data reported heresuggest that differences in the relationshipbetween dimensional preference and shiftoption reported in past studies is not due touse of a matching type, or a discriminationtype, of preference test per se. They alsosuggest that, regardless of the matchingmodification used, R shifts are the choice ofmost P Ss. The shift choice of NP Ss,however, seems to vary with the preferencetest modification used to assessdimensionalpreference. Since the matching type ofpreference test is more quickly and easilyadministered than the discrimination typeof test, further study of the matchingpreference test seemswarranted.

REFERENCESHEAL, L. W., BRANSKY, M. L., & MANKlNEN,

R. L. The role of dimension preference inreversal and nonreversal shifts of retardates.Psychonomic Science, 1966,6,509-510.

JAMES, L.M.,O'BRIEN, T.G.,& BRINLEY,J. F.The effect of dimensional preference on reversalshift behavior of young children. PsychonomicScience, 1969, 14,56-58.

KENDLER, T. S., KENDLER, H. H., &LEARNARD, B. Mediated responses to size andbrightness as a function of age. AmericanJournal of Psychology,1962,75,571-586.

O'BRIEN, T. Dimensional preference effect onreversal shifts of first and second graders.Unpublished Master's thesis, St. LouisUniversity, 1966.

SMILEY, S. S., & WEIR, M. W. Role ofdimensional dominance in reversal andn onreversal shift behavior. Journal ofExperimental Child Psychology, 1966, 4,296-307.

NOTE1. The authors wish to express their

appreciation to Dr. Robert L. Henley, AssistantSuperintendent of Teaching Personnel of theMehlvilleR-9 School District, and to the principaland teachers of Bierbaum School, Mehlville,Missouri, for making this study possible.

Psychon. Sci., 1969, Vol. 16 (6)