CONCEPT IDENTIFICATION BY SCHIZOPHRENIC AND NORMAL SUBJECTS AS A FUNCTION OF PROBLEM COMPLEXITY AND RELEVANCE OF SOCIAL CUES 1

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1 Journl»/ Abnorml Psychology 1969, Vol. 74, o. 3, COCEPT IDETIFICATIO BY CHIZOPHREIC AD ORMAL UBJECT A A FUCTIO OF PROBLEM COMPLEXITY AD RELEVACE OF OCIAL CUE 1 VLADIMIR PIHKI 2 Veterns' Administrtion Hospitl, Oklhom City AD LYLE E. BOURE, JR. University of Colordo chizophrenic nd norml 5s (# = 230) solved concept-identifiction (CI) problems vrying in stimulus complexity, simultneously with either norml or schizophrenic stooge providing relevnt or irrelevnt cues. Mjor results were () CI performnce ws negtive function of stimulus complexity, (b) socil cues from norml stooge hd greter effects on problem solving thn socil cues from schizophrenic stooge, nd (c) schizophrenics demonstrted deficit in problem solving connected primrily with the use of socil cues. Comprisons of these dt with expecttions bsed on mthemticl model of CI reveled severl significnt discrepncies, ttributble primrily to the fct tht normls re more sensitive to socil cues thn re schizophrenics. Pishkin nd Blnchrd (1963) reported preliminry evlution of the bility of schizophrenic nd norml 5s to use socil (i.e., from nother person) nd nonsocil (i.e., from vritions in physicl stimulus) sources of informtion in solving concept-identifiction (CI) problems. Generlly, their results indicted tht, in ddition to being poorer problem solvers, schizophrenics showed reltive inbility to profit from solution-relevnt informtion provided by nother person (ctully, confederte of E cting s nother 5). These results, nd others like them (Dvis & Hrrington, 1957; Johnnsen, 199), re consistent with Cmeron's (1947) "socil disrticultion" chrcteriztion of schizophrenic behvior. Moreover, s shown by Pishkin nd Blnchrd, they re describble in quntittive detil by mthemticl model of CI performnce (Bourne & Restle, 199). The present study is, in severl respects, n extension of the Pishkin-Blnchrd work. First, in the erlier experiment, socil cues (when they were vilble) were supplied by 1 The uthors re indebted to Hrold L. Willims for criticl reding of the mnuscript. This reserch ws supported in prt by Veterns' Administrtion Medicl Reserch Funds. 2 Requests for reprints should be directed to Vldimir Pishkin, Veterns' Administrtion Hospitl, 921 orthest 13th treet, Oklhom City, Oklhom peer confederte (C) (i.e., schizophrenic 5s were pired with schizophrenic Cs nd norml 5s with norml Cs). An issue, just s importnt s the difference between norml nd schizophrenic bility to use socil nd nonsocil cues in problem solving (but not nerly s thoroughly explored), concerns the reltive sliency of cues provided by norml nd schizophrenic prtners. Recent findings (Pishkin, 1966) indicte tht, in generl, 5s fil to use s much informtion from schizophrenic s from norml person when mking perceptul judgments. The present experiment, studying the four possible dyds formed with schizophrenic nd norml 5s nd Cs, sought to determine whether similr performnce trends re evident in complex problemsolving tsk. econd, in the preceding study ll experimentl problems were chrcterized by single level of stimulus complexity. It is well known tht stimulus complexity not only governs the difficulty of CI tsk (e.g., Bourne, 1957) but lso tends to interct with other significnt vribles (e.g., Bourne & Restle, 1959; Pishkin, I960). The Pishkin- Blnchrd results might, therefore, be severely limited in generlity, with greter (lesser or reversed) differences between norml nd schizophrenic performnces existing in problems of other complexity levels. Accordingly, tsks of three different complexities (the

2 COCEPT IDETIFICATIO 315 intermedite of which ws used by Pishkin nd Blnchrd) were employed in the present experiment to study the possible moderting influence of this vrible on norml-schizophrenic differences. Thus, the mjor purpose of this work ws to collect more extensive evidence on the bility of schizophrenic nd norml s to solve conceptul problems of vrying levels of difficulty using informtion provided by either or both socil nd nonsocil sources. In ddition, n ttempt ws mde to describe these dt quntittively within the frmework of mthemticl model used by Pishkin nd Blnchrd. The ccurcy of tht description reflects one mjor ssumption tht ll sources of informtion, socil nd nonsocil, re dditive nd thus serves s minor test of the model. ubjects METHOD The 5s were 115 schizophrenics nd 115 normls. They consisted of mle ptients nd ides from Veterns' Administrtion europsychitric Hospitls t Oklhom City, Oklhom; Little Rock, Arknss; Tuskegee, Albm; Tomh, Wisconsin, nd Centrl tte Hospitl, ormn, Oklhom; ll ptients hd current dignosis of schizophrenic rection, chronicundifferentited type. All ptients () who were below 20 or bove 45 yr. of ge, (6) who hd hd electroshock or insulin therpy or psychosurgery, or (c) who were suffering from neurologicl, uditory, or visul disorders s indicted by the dmissions' physicl exmintion were not included in the smple. one of the ptients were on psychotropic drug regimen which exceeded dily dose of 100 mg. of chlorpromzine. The schizophrenic s were firstpsychitric-dmission ptients with n verge length of hospitliztion of 4.14 dys. The norml popultion consisted of mle psychitric ides in corresponding institutions who were lso yr. of ge. All 5s were dministered the vocbulry portion of the hipley Institute of Living cle prior to the experiment. schizophrenic nd five norml 5s were ssigned to ech of 46 experimentl tretment conditions. The 5s were mtched cross ll conditions for ge nd intelligence (hipley vocbulry score). The schizophrenic ptients were mtched for length of hospitliztion in ech of the experimentl conditions. All mtching ws to the extent tht no significnt difference ws reched between ny pir of groups in ge, intelligence, or hospitliztion. In those conditions where C ws required, chronic-undifferentited, schizophrenic ptients in good contct, ides, nd technicins were used. The Cs were dressed either in Veterns' Administrtion ide or ptient uniforms s pproprite nd were strngers to 5s. Aides lwys wore ide uniforms nd ptients lwys wore Veterns' Administrtion ptient uniforms. A totl of 1 schizophrenic ptients nd 14 ides prticipted s Cs. Procedure All 5s were dministered two-choice CI problem wherein they were required to lern to mtch their responses with the relevnt dimension of geometric ptterns. The correct nd incorrect responses were not so defined to 5s. Form of figure ws the relevnt dimension; tht is, 5s were required to respond by sying "A" or "B" for squres or tringles, respectively, regrdless of the other (irrelevnt) chrcteristics of the ptterns. levels of complexity were estblished by vrying one (color), three (color, size, nd number) or five (color, size, number, verticl position, nd orienttion) irrelevnt dimensions of the stimuli. The ptterns were presented by mle on 3 X 5 crds mounted in slot bove T-shped structure. Below the stimulus slot t 5's eye level were mounted two mber feedbck lights which were positioned below the blocked letters, A nd B. The feedbck ws provided simultneously to 5 nd C immeditely following 5's response. The long rm of the T structure prevented 5 nd C from viewing ech other, lthough both were ble to view the stimulus nd the feedbck lights simultneously. Design The design ws 5X3X2X2 fctoril with five stimulus-socil cue conditions (two of which hd either stimulus or socil cues only), three degrees of problem complexity, two 5 popultions, nd two types of Cs. All 5s performed on the tsk for 192 trils or until 16 consecutively correct responses were mde. All ptterns ppered eqully often but with the restriction tht the sme pttern never ppered on successive trils; otherwise the order of presenttion ws rndom. In conditions where C prticipted he lwys responded before 5 in ccordnce with sequence of responses progrmmed on slip of pper. The T structure prevented 5 from viewing the C's progrm. The 5 ws introduced to C s ptient or n ide, but ws not wre tht C ws stooge. Both 5 nd C were given the sme instructions. The 5 ws informed tht becuse C hppened to rrive t the lbortory erlier he would lwys respond first nd tht the sme feedbck would be provided to C nd 5. A more detiled description of the tsk nd instructions ppered in n erlier pper (Pishkin & Blnchrd, 1963). The five bsic conditions used hi this experiment were designed in order to test the effects of vilbility of stimulus nd socil cues by combining relevnt nd irrelevnt spects of the two types of informtion. Tble 1 summrizes these conditions long with the theoreticl equtions (developed in Pishkin & Blnchrd, 1963) for predicting performnce within ech. As noted bove, the bsic CI conditions were elborted to include three levels of tsk complexity. In

3 316 VLADIMIR PIHKI AD LYLE E. BOURE, JR. TABLE 1 MAI EXPERIMETAL CODITIO AD THEIR CORREPODIG THEORETICAL EQUATIO Condition r TV Criticl solution-relevnt informtion Eqution kr R + I + B I "~ B+ hr + l 0 R+I+B+ kr R+I+B+ I " R+I+B+ ote. st=stlmulus informtion, soc=socil Informtion, 0 =lerning rte, k = proportion of vilble stimulus informtion used, f=proportion of vilble socil informtion used, K=number of relevnt stimulus dimensions, /=number of irrelevnt stimulus dimensions, B=weight of bckground cues, 5 =weight of socil informtion. Conditions (Cond.),,, nd V, where socil informtion ws vilble, either schizophrenic (C) or norml (C) stooge prticipted, with n equl number of schizophrenic nd norml 5s pired with the two types of C. To summrize, the tsks over the five conditions were s follows: Condition I. The s performed individully on CI problem nd C ws not present. Condition. CI ptterns were not vilble nd s were required to guess which feedbck light would go on fter C hd responded. The mximum number of "correct" guesses could be reched only by imitting C. Condition. A CI problem ws presented on which C ws correct on every tril. Thus, correct responses could be mde by either responding to relevnt stimulus dimensions or imitting C; both the stimulus nd C cues were relevnt. Condition. This ws CI problem on which C responded rndomly. olution could only be reched by ignoring C nd by identifying the relevnt CI dimension. Condition V. The C ws rbitrrily correct on every tril nd the pttern of guesses clled correct hd no reltionship to the CI ptterns, so tht CI ptterns would hve to be ignored nd solution could be reched only by imitting C. REULT AD DICUIO Anlysis of vrince ws performed on errors to criterion nd is summrized in Tble 2. It indictes tht the min effects of complexity, C type, nd stimulus conditions were sttisticlly significnt, wheres there ws no overll influence upon CI performnce of type. Consistent with previous results, it ws 10 9A fio f.f\ f\n demonstrted tht s complexity incresed the number of errors lso incresed linerly (Pishkin, 1960). The men number of errors when 5s, Cs, nd conditions were pooled were 11.44, 25.45, nd 37.2 for problems with one, three, nd five irrelevnt dimensions, respectively. The min effect of C showed tht more errors were mde when the origin of socil cues ws schizophrenic stooge, s cn be seen in Figure 1. This effect, coupled with the insignificnt vrince ssocited with 5 type, suggests tht Pishkin nd Blnchrd's observtion of n overll difference in problem solving between normls nd schizophrenics is t lest prtly ttributble to the confounding of type nd C type in their experiment. Figure 1 lso indictes tht the min effect of stimulus conditions is probbly result of fewer errors occurring in Cond. I,, nd thn in Cond. nd V. This result suggests tht the conflict in socil nd stimulus cues, which rises only in Cond. nd V, is significnt inhibitor of problem solving. The C type min effect is further elborted by certin interctions. First, significnt Complexity X C Type interction indictes tht s complexity incresed from one to five irrelevnt dimensions comprtively poorer performnce resulted in the conditions where C ws schizophrenic s compred to norml. The significnt X C Type interc- TABLE 2 AALYI OF VARIACE OF ERROR TO CRITERIO ource of vrince Complexity (A) ubject type (B) Confederte type (C) timulus conditions (D) AXB AXC AXD B XC B X D CXD A X B X C B X C X D AXCXD AXBXD AXBXCXD Error *f b umber in prentheses =error men squre. * <.O. ** <.01. ***i><.001. F.34*** 14.16*** 7.9*** 3.4* 4.0** 4.05** 3.19* ( ) b

4 COCEPT IDETIFICATIO C C 50 CHIZOPHREIC C ORMAL C C CODITIO FIG. 1. Men errors produced by schizophrenic (crosshtched) nd norml (blnk) 5s in the five conditions. tion indictes, moreover, tht the potency of norml Cs ws significntly greter thn tht of schizophrenic Cs in fcilitting or inhibiting CI performnce of normls; schizophrenic 5s, on the other hnd, demonstrted tendency to be less differentilly influenced by two types of stooges, regrdless of whether they provided relevnt or irrelevnt informtion. The significnt C Type X timulus Condition interction clerly demonstrtes tht the number of errors committed by both 5 popultions ws function of whether C nd/ or stimulus cues were relevnt or irrelevnt to the solution of the problem; for exmple, s seen in Figure 1, performnce in Cond. Ill, where both C nd stimulus were relevnt, ws mrkedly superior to tht of the Cond. where the socil cues were irrelevnt to the solution. An interction involving complexity,, nd C types emphsizes the significnt trends found in the Complexity X C Type nd 5 X C Type terms. It is noteworthy tht performnce becme progressively poorer when complexity incresed, especilly by schizophrenic 5s with schizophrenic Cs, wheres performnce of norml 5s t the lowest level of complexity (one irrelevnt dimension) with relevnt norml C ws superior to ll other groups. In order to evlute the between-group differences with both 5 popultions nd C types, series of difference scores plus the "criterion difference" (Lindquist, 1953) required to rech sttisticl significnce (p <.05) ws computed for ech pir of group scores, nd these re presented in Tble 3. With pooled popultions it is cler tht there were no significnt differences in errors between ny pirs of combintions in Cond. I,, nd. However, s seen in Figure 1, significntly greter number of errors ws pro-

5 31 VLADIMIR PIHKI AD LYLE E. BOURE, JR. Condition TABLE 3 COMPARIO OF MEA ERROR BETWEE CODITIO chizophrenic 5 orml 5 A. Difference between schizophrenic C nd norml C for two popultions, CD" = * -14.5* V 24.1*.* * 10.9* B. Difference between 5 popultions mtched with different Cs, CD = * V 30.5* 17.2* * 17.3* C. Difference between men errors of schizophrenic nd norml 5s, CD = 9.19 I V V * * D. Pooled 5 popultions: Difference in men errors, CD = I * -14.0* Criterion difference. Condition * -21.2* ill -32.2* -22.3* 9.9 duced in Cond. nd V s compred to Cond. I,, nd (Tble 3, ection D). ection A of Tble 3 represents differences in men errors for schizophrenic nd norml 5s between dyds performing with schizophrenic nd norml Cs. A positive score indictes greter number of errors with schizophrenic Cs. ignificnt differences for Cond. Ill,, nd V indicte tht the influence of schizophrenic Cs on performnce of schizophrenic s ws significntly less thn tht of the norml Cs. With norml s it is lso cler tht schizophrenic Cs hd less fcilitting influence upon performnce thn norml Cs. However, it is noteworthy tht in Cond. Ill, where both stimulus nd socil cues were relevnt, there were no differences in the performnces of norml s s function of C type; this finding is most likely due to the fct tht the problem ws sufficiently simple for norml 5s tht it msked the effect of C type. ection B of Tble 3 represents differences between the two popultions due to C type. A positive score in this section indictes greter number of errors produced by schizophrenic 5s thn by norml 5s. It is pprent tht when Cs were used in Cond. nd V, significntly greter number of errors ws produced by schizophrenic 5s thn by norml 5s. These dt re consistent with other findings tht schizophrenics re not ble to gin relevnt informtion from socil source to the sme degree s norml 5s. Poorer performnce by normls ws evident in Cond., however, where the function of C ws to interfere with solution. ection C of Tble 3 shows differences between the two 5 popultions for ech condition. The only significnt differences ppered in Cond. nd V, gin demonstrting deficiency of schizophrenic 5s in using socil informtion, regrdless of the source. The fct tht no differences were found between the two popultions in Cond. Ill is probbly ttributble to the simplicity of the problem. In Cond. the interference effect of C for norml 5s might hve been sufficient to overcome their typicl dvntge over schizophrenics, since norml Cs negtively influenced performnce of norml s to greter degree thn tht of schizophrenic s. Theoreticl Anlysis Clibrtion of theoreticl prmeters in Tble 1 ws ccomplished using Equtions 1, 2, nd 5 (derived in Pishkin & Blnchrd, 1963). Clibrtion dt were tken from two subgroups of Cond. I (one nd five irrelevnt dimensions), Cond., nd one subgroup of Cond. V (five irrelevnt dimensions). These prmeters were derived by use of simultneous equtions nd pplied in predicting performnces for the remining groups. The clibrted vlues re summrized in Tble 4. Consistent trends re pprent: The rte of

6 COCEPT IDETIFICATIO 319 stimulus-cue usge, the rte of socil-cue usge (from schizophrenic or norml source), s well s the weights of socil-stooge cues ll of which re quntittive prmeters, estimted from the dt nd required for n ccurte fit between model nd dt were smller for schizophrenic thn norml 5s. In ddition, it is cler tht the vlue of norml socil cues ws pproximtely twice s gret s the vlue of schizophrenic socil cues for both the norml nd schizophrenic 5 popultions. Tble 5 shows the predicted men errors for conditions which were not included in the clibrtion of constnts. It is pprent tht the two predictions in conditions with stimulus cues only were dequte. Also the prediction of combined nd redundnt stimulus nd socil cues (Cond. Ill) ws firly close, t TABLE 4 CALIBRATIO OF THEORETICAL PARAMETER Group ormls chizophrenics k B I s In.39.15, ote. k ^proportion of vilble stimulus informtion used ; J3=welght of bckground cues; It = proportion of cues from schizophrenic stooge used by 5; In = proportion of cues from norml stooge used by 5; 5<=weight of schizophrenic C; * =weight of norml C. lest for norml 5s. However, there were severe discrepncies when stimulus nd socil informtion conflicted (Cond. nd V), result which reflects primrily the fct tht norml 5s were significntly more sensitive thn schizophrenics to socil cues. The ssumption of equivlent reltive sensitivity mde by the model is simply inpproprite for description of these dt. TABLE 5 OUTCOME or THEORETICAL AALYI TO CRITERIO Group Condition nd no. irrelevnt dimension g 0 Predicted chizophrenic Error Predicted Obtined e Predicted orml Error Predicted Obtined I. timulus only. ocil only one. timulus + socil. timulus-socil V. ocil-stimulus (.111)0.07 (.05)" (.074)" (.09)'' (.02)" (.031)" (11.4) (19.) (31.6) (1.6) (14.) (4.) (3.) (14.2) (6.0) (31.) (14.2) (14.6) (16.0) (36.2) (41.4) (49.4) (6.2) (21.4) (10.2) (52.0) (30.4) (9.2) (56.) (.132)0.03 (.061)" (.137)" (.255)" (.02)" (.171)" (.) (16.2) (23.6) (.4) (3.6) (5.) (3.4) (7.4) (6.) (15.4) (10.4) (12.) (24.6) (32.2) (51.) (46.4) (96.4) (16.4) (6.2) (24.2) (17.) (37.6) (21.6) Confederte type; =schizophrenic, norml. b Estimted from dt.

7 320 VLADIMIR PIHKI AD LYLE E. BOURE, JR. ome generl conclusions mde from this theoreticl nlysis include () normls used more of the relevnt stimulus informtion thn schizophrenics, (b) since the B prmeter represented irrelevnt, bckground stimultion rising from sources other thn the stimulus pttern, it is pprent tht normls were more sensitive to bckground cues thn were schizophrenic s, (c) normls were more sensitive to socil cues thn schizophrenics whether those cues cme from schizophrenic or norml Cs, (d) both normls nd schizophrenics used more cues from norml C thn from schizophrenic C, (e) the performnce of normls working with both stimulus nd socil cues followed theoreticl predictions dequtely, thus giving some support to the dditivity of cues ssumption of the model, though the sme conclusion obviously does not hold for schizophrenics, (/) discrepncies between model nd dt resulted lrgely from the fct tht schizophrenics did not use cues from norml Cs s effectively s predicted, nd (g) the model ssumes tht schizophrenic s would use C (norml or schizophrenic) in the sme wy tht the norml used C. The significnt interction X C type indictes tht this prticulr ssumption is untenble. Present findings clerly demonstrte schizophrenics' deficit in processing of informtion from socil source, especilly when such source is peer, schizophrenic ptient. REFERECE BOURE, L. E., JR. Effects of dely of informtion feedbck nd tsk complexity on the identifiction of concepts. Journl of Experimentl Psychology, 1957, 54, BOURE, L. E., JR., & REILE, F. Mthemticl theory of concept identifiction. Psychologicl Review, 1959, 66, CAMERO,. The psychology of behvior disorders: A bio socil interprettion. Boston: Houghton Mifflin, DAVI, R. H., & HARRIGTO, R. W. The effect of stimulus clss on the problem-solving behvior of schizophrenics nd normls. Journl of Abnorml nd ocil Psychology, 1957, 54, JOHAE, W. J. Responsiveness of schizophrenics nd normls to socil nd non-socil feedbck. Unpublished doctorl disserttion, University of Wisconsin, LIDQUIT, E. F. Design nd nlysis of experiments in psychology nd eduction. Boston: Houghton Mifflin, PIHKI, V. Effects of probbility of misinformtion nd number of irrelevnt dimensions upon concept identifiction. Journl of Experimentl Psychology, 1960, 59, PIHKI, V. Perceptul judgment of schizophrenics nd normls s function of socil cues nd symbolic stimuli. Journl of Clinicl Psychology, 1966, 22, PIHKI, V., & BLACHARD, R. J. timulus nd socil cues in concept identifiction of schizophrenics nd normls. Journl of Abnorml nd ocil Psychology, 1963, 67, (Received ovember 20, 1967)