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A comparison of the Stanford-Binet (1937 revision, form L) and Wechsler intelligence scale for children… Powell, Joan Anne 1951

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/fa  A COMPARISON OF THE STANFCRD-BINET (1937 REVISION, FORM L) AND WECHSLER INTELLIGENCE SCALE FOR CHILDREN AT DIFFERENT AGE AND INTELLECTUAL LEVELS  by JOAN ANNE POWELL  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS i n the Department of PHILOSOPHY AND PSYCHOLOGY  We accept t h i s thesis as conforming t o the standard required from candidates f o r the degree of MASTER OF ARTS  Members of the Department of Philosophy and Psychology.  THE UNIVERSITY OF BRITISH COLUMBIA August, 1951  A COMPARISON OF THE STANFORD-BINET (1937 REVISION, FORM L) AND WECHSLER INTELLIGENCE SCALE FOR CHILDREN AT DIFFERENT AGE AND INTELLECTUAL LEVELS Abstract This study was designed t o i n v e s t i g a t e the r e l a t i o n s h i p between the i n t e l l i g e n c e quotients yielded by two widely used i n d i v i d u a l tests o f i n t e l l i g e n c e f o r children, namely, the Stanford-Binet, Form L, (1937 Revision) and the Wechsler I n t e l l i g e n c e Scale f o r Children (WISC). U n t i l recently, the Binet has been used almost e x c l u s i v e l y to ascertain the i n t e l l i g e n c e of the school-age c h i l d but, with the publication of the WISC i n 1949, there has been an increasing trend toward using the tests either interchangeably or i n conjunction with one another. In view of t h i s development, an attempt t o discover the r e l a t i o n s h i p between the two scales would seem to be of much p r a c t i c a l value. Although the two scales agree i n assuming a "g" f a c t o r of i n t e l l i g e n c e , they d i f f e r as t o the nature of t h e i r content and construction. The Stanford-Binet does not include any t e s t items designated as measuring a p a r t i c u l a r s k i l l , whereas the WISC i s composed of twelve subtests, each supposed t o tap a s p e c i f i c a b i l i t y , and i t y i e l d s a separate v e r b a l and performance i n t e l l i g e n c e quotient. The two scales also d i f f e r i n the manner o f computing an i n t e l l i g e n c e quotient; the Binet scale depends upon a Mental Age concept of i n t e l l i g e n c e , whereas the Wechsler I n t e l l i g e n c e Scale for Children i s a point scale. This study attempted to a s c e r t a i n t o what extent the Stanford-Binet correlates with each of the WISC scales (Verbal, Performance and F u l l Scale) at three d i f f e r e n t age l e v e l s and three l e v e l s of i n t e l l i g e n c e , i . e . , with subjects of Superior, Average and Retarded i n t e l l i g e n c e . I t also attempted to f i n d out what differences, i f any, might occur between the Mean i n t e l l i g e n c e quotients yielded by the two tests i n the above age and i n t e l l e c t u a l categories, and what d i r e c t i o n these differences might take. Wechsler has objected to the Stanford-Binet deviations, which vary i n s i z e at difference age l e v e l s . At 6 years, the Binet standard deviation i s unusually small, and at 12 years of age i t i s unusually large: the WISC standard deviations are the same size at  each age l e v e l . I t was hypothesized, therefore, that at the extremes of the i n t e l l i g e n c e d i s t r i b u t i o n at ages 6 and 12 years, there should be differences between the Mean i n t e l l i g e n c e quotients yielded by the two tests i n the d i r e c t i o n of the s i z e o f the Binet standard deviations at these two age l e v e l s - a smaller Mean Binet than Mean WISC i n t e l l i g e n c e quotient a t age 6 years, with a higher Mean i n t e l l i g e n c e quotient on the Binet at age 12 years. Subjects of these two ages, 6 and 12 years, were included i n the experimental group i n order t o t e s t t h i s hypothesis, while the use of subjects o f superior and retarded i n t e l l i g e n c e insured that extreme scores would occur. The sample o f subjects of average i n t e l l i g e n c e , plus a group o f 9-year-olds, were included f o r control and comparison i n t e s t i n g t h i s hypothesis but also f o r t h e i r own research value. The sample was composed o f 85 subjects - ten children i n each age category of the Superior and Average i n t e l l i g e n c e groups; and i n the Defective group, fourteen 12-year-olds, nine 9-year-olds, and four 6-year-olds. The p o s i t i v e correlations which occurred may be summarized as follows : 1.  In the 9-year-old Superior group, the Stanford-Binet IQ correlated s i g n i f i c a n t l y with (a) the WISC Verbal IQ a t the 1% l e v e l o f confidence; (b) the WISC Performance Scale IQ a t the 5% l e v e l o f confidence; (c) the WISC F u l l Scale IQ at the 1% l e v e l of confidence.  2.  In the 9-year-old Average group, the Stanford-Binet IQ correlated s i g n i f i c a n t l y with (a) the WISC. Verbal Scale IQ at the 1% l e v e l of confidence; (b) the WISC F u l l Scale a t the 5% l e v e l of confidence.  S i g n i f i c a n t differences between the Mean 10s of the two tests may be summarized as follows : 1.  In the group of Superior 9-year-olds, the StanfordBinet IQs were s i g n i f i c a n t l y higher (at the 1$ l e v e l of confidence) than the WISC Verbal, Performance, and F u l l Scale IQs.  2.  In the.group of Superior 12-year-olds, the StanfordBinet IQs were s i g n i f i c a n t l y higher at the 1$ l e v e l of confidence f o r the WISC F u l l and Verbal Scale IQs.  3-  In the group of Average 12-year-olds, the StanfordBinet i s s i g n i f i c a n t l y higher at the 5$ l e v e l of confidence than the WISC Verbal IQ.  The major conclusions o f t h i s study are : 1.  The obtained results are i n e s s e n t i a l agreement with the studies comparing the Wechsler adult scale and the Stanford-Binet.  2.  There seems to be a consistent tendency i n t h i s study and others reviewed previously f o r lower correlations between the Stanford-Binet and WISC Performance Scale, than between the StanfordBinet and WISC Verbal and Performance Scales.  3.  There seems to be no support f o r the hypothesis that the difference between the Mean Stanford-Binet and the Mean WISC IQs at the Superior l e v e l w i l l d i f f e r i n d i r e c t i o n according to the size^ o f the Binet standard deviation at the age l e v e l i n question.  4.  The WISC appears to be an u n s a t i s f a c t o r y t e s t f o r measuring the markedly retarded children. Both i n terms of construction, and i n t e r e s t value to subjects, the Stanford-Binet seems t o be a better scale f o r the measurement of the lower l e v e l s of intelligence.  5.  Keeping i n mind the l i m i t e d sample upon which t h i s study was based, the two scales do not seem to be interchangeable. The p r a c t i c a l import o f t h i s conclusion i s that c l i n i c i a n s , s o c i a l workers, p s y c h i a t r i s t s , school teachers, and so on, should be f u l l y aware that the c h i l d given both the tests may well y i e l d widely d i f f e r e n t IQs on the respective t e s t s .  Suggestions  for future research have been included.  C O N T E N T S  CHAPTER I  PAGE INTRODUCTION Statement o f the Problem H i s t o r i c a l Background Review of the Literature  II  PROCEDURE Selection o f Subjects Administration of the Intelligence Scales  III  TREATMENT OF DATA AND RESULTS Treatment o f Data Results : -(a) Obtained Correlations between Scales (b) Comparison o f Mean IQs (c) The Performance of the Defective Group  IV  DISCUSSION OF RESULTS Theoretical Expectations and Obtained Results Obtained Results compared with the Literature Consistent Trends emerging from the Data Suggestions for Future Research  V  1 1 1 3  13 13 16 22 22 22 28 41  47 47 56 58 58  SUMMARY  60  BIBLIOGRAPHY  64  T A B L E S  O r i g i n a l Plan f o r s e l e c t i o n o f Sample  Obtained Sample represented as t o Age and Intelligence Level Groups  Correlations between Stanford-Binet and WISC Verbal, Performance, and F u l l Scales  Correlations between Stanford-Binet and WISC Verbal, Performance, and F u l l Scales  Mean WISC Verbal Scale IQs compared with Mean Stanford-Binet IQs  Mean WISC Performance Scale IQs compared with Mean Stanford-Binet IQs  Mean WISC F u l l Scale IQs compared with Mean Stanford-Binet IQs  Mean WISC Verbal Scale IQs compared with Mean Stanford-Binet IQs  Mean WISC Performance Scale IQs compared with Mean Stanford-Binet IQs  Mean WISC F u l l Scale IQs compared with Mean Stanford-Binet IQs  Performance o f 12-year-old Mental Defectives on WISC Verbal, Performance, and F u l l Scales, and on Stanford-Binet Performance of 9-year-old Mental Defectives on WISC Verbal, Performance, and F u l l Scales, and on Stanford-Binet Performance of 6-year-old Mental Defectives on WISC Verbal, Performance, and F u l l Scales, and on Stanford-Binet  ACKNOWLEDGEMENTS  The author i s most grateful t o her Facultyadviser, Mrs. D. T. Kenny, f o r her continued encouragement and many h e l p f u l suggestions and criticisms.  The author i s indebted to Dr. R. F. Sharpe, Acting Assistant Superintendent and Inspector of Secondary Schools, f o r permission to t e s t i n the Vancouver Elementary Schools.  She i s also grate-  f u l t o Dr. L. L. S a u r i o l , Superintendent o f The Woodlands School, New Westminster,  B.C., and to  Dr. T. D. Barber, Superintendent o f The Rainier State School, Buckley, Washington, U.S.A., f o r making available the retarded subjects used i n t h i s study.  CHAPTER I INTRODUCTION  Statement of the Problem  The purpose of t h i s study i s t o investigate the r e l a t ionship between the i n t e l l i g e n c e quotients yielded by two widely used standard i n t e l l i g e n c e scales, namely the Stanford-Binet Form L (1937 Revision), and the Wechsler Intelligence Scale f o r Children (WISC). U n t i l recently, aside from group i n t e l l i g e n c e tests, the Binet  scale  has been used almost exclusively to ascertain the i n t e l l i g e n c e o f the school-age c h i l d .  With the emergence of the WISC i n 1949, there has  been an increasing s h i f t toward the use of t h i s scale either i n conjunction with, or i n place of, the Binet scale.  In view of t h i s trend,  a comparison o f the two scales, such as i s proposed i n t h i s study, i s of much p r a c t i c a l value.  That i s , i f the tests are t o be used i n t e r -  changeably, some attempt t o demonstrate the relationship between the two scales i s urgently  needed.  H i s t o r i c a l Background Although the authors o f both o f these scales follow  2 Spearman i n assuming a global f a c t o r o f i n t e l l i g e n c e , the two scales are quite d i f f e r e n t i n the nature o f t h e i r construction.  No attempt  i s made i n the Binet scale t o group the items i n terms o f the kinds of s k i l l s involved, whereas the Wechsler Intelligence Scale f o r C h i l d ren i s composed o f twelve subtests, each o f which involves a p a r t i c u l a r s k i l l , and the scale y i e l d s a separate Verbal and Performance i n t e l l i g e n c e quotient.  In t h i s respect, the Wechsler scale i s some-  times thought t o lean toward Thurstone's approach t o i n t e l l i g e n c e i n terms of s p e c i a l a b i l i t i e s .  Wechsler himself, however, i s c a r e f u l  to point out that he i s p r i m a r i l y interested i n a r r i v i n g a t a general measure o f i n t e l l i g e n c e and that the subtests are not "...a series of t e s t s that measure primary a b i l i t i e s , " (p.5, 20).  Besides d i f f e r i n g as t o the type o f material and i t s arrangement, the two tests show sharp differences i n the method o f a r r i v i n g a t the i n t e l l i g e n c e quotient.  The Binet scale depends on  a Mental Age concept o f i n t e l l i g e n c e , whereas the Wechsler scale f a l l s i n t o the category o f a point scale. objections to the Stanford-Binet'  Wechsler has voiced strong = IQ formula for several reasons,  CA t o be discussed l a t e r i n t h i s paper.  Both the adult, and the more  recent Wechsler Intelligence Scale f o r Children, y i e l d an i n t e l l i g e n c e quotient r e s u l t i n g from a comparison o f the subject's performance with that o f others o f his own age, rather than the equating o f the performance with a c e r t a i n Mental Age l e v e l . on several grounds.  Wechsler j u s t i f i e s t h i s move  F i r s t l y , he points out that a Mental Age o f %  3 years i s not at a l l the same i n t e l l e c t u a l capacity i n a 10-year o l d or a 5-year o l d as i t i s i n a 7-year old, as i s implied by the construction of the Binet scale.  Secondly, he questions  the assumption, innate i n  the Stanford-Binet, that i n t e l l e c t u a l growth stops at 16 years. method of computing the IQ makes any such assumption unnecessary;  His it  a l s o makes allowances f o r the slowed-up i n t e l l e c t u a l development of puberty and the e a r l y teens, and f o r the decrease i n i n t e l l e c t u a l a b i l i t y which occurs with age.  Whether or not t h i s method, which i s  more lenient to older subjects, i s better depends upon the use to which the score w i l l be put.  Thirdly, Wechsler's chief objection to the  Stanford-Binet i s to the s i z e of the standard deviations at d i f f e r e n t age-levels. (CTLIQ =  The greatest deviations occur at age 12  20.00), and  at  6  years (CTLIQ =  12.50).  years  He points out (p.26,  19) that a c h i l d 2 sigma away from the Mean at age 6 years w i l l have an IQ of 75, IQ of 60.  whereas a c h i l d s i m i l a r l y placed at 12 years w i l l have an Hence the scale y i e l d s a rather u n r e l i a b l e estimate of the  subject's i n t e l l i g e n c e .  Review of the Literature E a r l y attempts to investigate the r e l a t i o n s h i p between i n t e l l i g e n c e quotients derived from Mental Ages and those derived from point scales have been based on comparisons of the Stanford-Binet the Wechsler-Bellevue Adult Intelligence Scales.  with  Since the Wechsler  Intelligence Scale f o r Children, used i n t h i s study, has grown out of  4 and c l o s e l y p a r a l l e l s the Adult Scale, a review o f the above mentioned studies seems i n order at t h i s point.  A number o f these studies were done with adolescents since i t i s i n t h i s age range t h a t both scales are widely used. Sartain (13) compared IQs obtained on the Stanford-Binet with those obtained on the Wechsler-Bellevue by f i f t y adolescent college freshmen. He found that the Stanford-Binet correlated with the F u l l Scale, .774; with the Verbal Scale, .802; and with the Performance Scale, .510. He estimates that the Stanford-Binet y i e l d s an IQ approximately 5 points higher than does the Wechsler-Bellevue;  The Mean Binet IQ was 129-44,  and the Mean Wechsler IQ was 117.44 with a c r i t i c a l r a t i o of 5«55No d e f i n i t e conclusions are stated by the author and the results are ambiguous because one cannot be sure which of the variables, (a) adolescence, (b) superior i n t e l l i g e n c e , or, (c) both, accounts f o r the results.  Goldfarb (6) used a sample o f s i x t y adolescents i n foster homes, with Mean Age equal to 14*6 years. was highest f o r 62$ of the subjects.  The Mean Verbal IQ  The F u l l Scale Wechsler c o r r e l a t -  ed with the Stanford-Binet to produce a c o e f f i c i e n t o f .86; the Verbal, a c o e f f i c i e n t of .80; and the Performance, a c o e f f i c i e n t o f .67.  The  author claims that bright subjects t e s t higher on the Revised StanfordBinet than on the Wechsler, while the advantages are reversed f o r the d u l l subjects. and " d u l l " .  The author does not q u a l i f y what he means by "bright"  He further states that younger children get higher  5 Stanford-Binet IQs and older subjects higher Wechsler IQs, but again does not specify as t o what these categories encompass.  He a l s o  maintains that the Wechsler does not discriminate very w e l l amongst groups o f superior adolescents.  The fact that these subjects were i n  foster homes does not appear t o have produced r e s u l t s d i f f e r e n t from those that might have been expected from a comparable sample not having this characteristic.  Guertin (7) refers t o an unpublished study of his own with a sample o f feebleminded subjects with IQs between 51 and 75, and between the ages of 15 and 22 years.  He found that the Wechsler-  Bellevue EQ for these subjects was 5.33 points above the Binet IQ, although he does not state whether or not t h i s difference was s i g n i f i c a n t .  From these studies i t appears that adolescents of superior i n t e l l i g e n c e achieve higher IQs on the Stanford-Binet, and that d u l l adolescents achieve higher IQs on the Wechsler.  Younger adoles-  cents seem t o get higher Binet than Wechsler IQs, and older adolescents seem t o get higher Wechsler IQs.  Kutash (10) used a sample composed o f f i f t y adult mental defectives.  He found that  (a) the Wechsler-Bellevue y i e l d e d higher  IQs i n BU% o f the cases, (b) the Mean Wechsler IQ was 11 points higher than the Mean Stanford-Binet IQ, the difference s i g n i f i c a n t at the 1$ l e v e l o f confidence, (c) the s i z e of the difference i n IQs v a r i e s d i r e c t l y with the chronological age o f the subject, and (d) the two  6  scales correlated, r = .77'  He concludes that differences i n the IQs  obtained on the two scales are due to differences i n norms and p r i n c i p l e s of standardization.  The standardization and norms o f the Wechsler take  i n t o account the normal deterioration with age which the Binet does not do.  Rabin (12) and Guertin (7) point out that the r e s u l t s o f t h i s  study may not be v a l i d owing t o the l a c k of homogeneity as t o age i n the group selected.  Halpern (9) conducted a study using one-hundred-andt h i r t y - t h r e e patients at a mental hygiene c l i n i c .  The subjects were  a l l c l a s s i f i e d as having d u l l normal i n t e l l i g e n c e , and were divided i n t o four age groups.  For ages 15 to 34 years, the t e s t s yielded  similar measures, although Halpern prefers the Wechsler f o r several t e c h n i c a l reasons.  I t was found that from ages 10 to 14 years,  higher IQs are consistently yielded by the Stanford-Binet.  Halpern  believes that f o r subjects who are 13 years and younger, and f o r 14-year-olds who are o f low i n t e l l i g e n c e , the Binet i s the preferable instrument.  He suggests that the Binet IQs are too high and that the  Wechsler IQs are too low.  When he took a group o f subjects and d i v i d -  ed them according t o i n t e l l i g e n c e , the highest c o r r e l a t i o n s were at. the extremes.  In spite of t h i s fact, the greatest differences occurred  with the superior subjects, and the l e a s t with the retarded subjects. He would postulate that "...both scales tap the defective's l i m i t e d capacity equally well, but that the range of the superior subject's i s reached equally by a l l t o o l s , " (p.210, 9).  Because the Wechsler norms  7 take the d e t e r i o r a t i o n o f i n t e l l e c t u a l a b i l i t y with age i n t o account, he says that differences between the IQs i n those over 34 years are generall y accountable f o r i n terms of differences i n t e s t construction.  He  believes that the introduction of the non-verbal tasks i n the WechslerBellevue makes for further t e s t differences.  Balinskyj I s r a e l and Wechsler (2) tested the r e l a t i v e effectiveness of the Wechsler-Bellevue and the Stanford-Binet i n diagnosing mental deficiency.  The c r i t e r i o n was p s y c h i a t r i c diagnosis.  The best predictions were made i n t h i s order : the Wechsler F u l l Scale, the Wechsler Verbal Scale, the Stanford-Binet, Performance Scale.  and, l a s t , the Wechsler  Using b i - s e r r i a l r ' s , the authors computed the  forecasting a b i l i t y o f the Wechsler t o be 4C#, and that o f the Binet t o be 5%.  The sample was of patients i n the Bellevue Hospital.  the Wechsler-Bellevue was validated c l i n i c a l l y i n the Bellevue  Since Hospital  (p.127, 19), and, presumably, according t o the standards o f that i n s t i t u t i o n , and since t h i s study was c a r r i e d out i n the same i n s t i t u t i o n , i t i s not s u r p r i s i n g that Wechsler scores of a subsequent sample should agree more c l o s e l y with those standards than scores on a t e s t validated on other c r i t e r i a .  In summary, i t would appear that retarded subjects a t t a i n higher IQs on the Wechsler-Bellevue than on t h e Stanford-Binet.  This  could r e s u l t from the f a c t that, as Wechsler points out (p.157, 19), the feebleminded generally do better on the Performance than on the Verbal Scale.  Differences would be expected a t t h i s l e v e l o f i n t e l l i g e n c e ,  8 since, of a l l the three Wechsler scales, the Performance Scale correlates lowest with the Binet, and a higher IQ would be expected because a better Performance index would n a t u r a l l y tend to r a i s e the F u l l Scale IQ. Benton, Weider and Bleauvelt (3) studied a sample of s i x t y subjects described as "mental cases" who were cooperative.  The  subjects ranged i n age from 16 t o 59 years, with a Mean Age o f 35 years. The c o r r e l a t i o n s were a l l high, although, as usual, the Performance Scale showed the lowest agreement.  The c o e f f i c i e n t s were as follows :  F u l l Scale, .93; Verbal Scale, .92; and Performance Scale, .73. A l though the Mean scores are s i m i l a r , the d i s t r i b u t i o n s d i f f e r g r e a t l y  ,  the standard deviation of the Stanford-Binet f a r exceeding that of the Wechsler.  The authors f e e l that these d i s p a r i t i e s do not i n d i c a t e a  r e a l difference i n what the t e s t s measure because widely diverse scores on the Binet and Wechsler may i n d i c a t e s i m i l a r positions i n r e l a t i o n t o the Means. bered.  This becomes obvious when the high c o r r e l a t i o n s are remem-  The difference i s , again, due t o the Wechsler norms; the  authors express the opinion that the scores would be comparable i f converted i n t o p e r c e n t i l e ranks or standard scores.  This study must be  regarded as inconclusive since the nature o f the sample i s so i l l defined.  M i t c h e l l (11) used a sample o f two-hundred-and-sixtyeight subjects, mostly delinquents and chronic a l c o h o l i c s without psychosis, and cooperative psychotics.  He found that a l l three parts  of the Wechsler correlated s i g n i f i c a n t l y with the Binet;  tx>renty-one  9 of his subjects showed a d i f f e r e n c e of more than 20 IQ points between t h e i r scores on the two scales; on the Wechsler.  o f these, sixteen showed a higher IQ  The ages o f these subjects (M  c  48.2 years) was nearly  double that o f the f i v e subjects who scored 20 points higher on the Stanford-Binet.  Since the sample i s heterogeneous, any c h a r a c t e r i s t i c s  which might have accrued t o one c l i n i c a l group may have been obscured by the opposite tendencies i n another group;  no j u s t i f i c a t i o n i s given  by the author f o r the sample selected.  On the basis o f these studies, i t appears that superior subjects do better on the Stanford-Binet than on the Wechsler, and that retarded subjects do better on the Wechsler than on the Binet.  Up t o  the e a r l y teens, higher scores are found on the Binet, and, a f t e r t h i s age l e v e l , higher scores are found on the Wechsler.  In a l l studies,  the Wechsler Performance Scale correlates lower with the Stanford-Binet than do the Verbal or F u l l Scales.  With the exception o f those  studies i n v o l v i n g adolescents, a l l these comparisons are at a disadvantage. was  They are attempting to compare IQs on two t e s t s , one o f which  standardized on adults and the other on children.  Literature on the Wechsler Intelligence Scale f o r C h i l d ren has been scant t o date.  Of the four a r t i c l e s published on i t ,  two bear on t h i s i n v e s t i g a t i o n . Doppelt  only  The f i r s t , by Seashore, Wesman and  (14), i s concerned c h i e f l y with describing the standardization  of the WISC, a matter which i s not of great i n t e r e s t here.  The authors  do point out, however, that i t i s u n l i k e l y that there w i l l be very  10 extreme scores because the range o f IQs on a point scale such as the WISC i s quite a r b i t r a r y .  I f the standard deviation had been set at  20 IQ points rather than the 15 points a c t u a l l y used, extreme scores might be expected. The only other study that i s r e l a t e d t o t h i s i n v e s t i g a t i o n was that done by Frandsen and Higginson (5), who compared IQs on the WISC with those on the Stanford-Binet.  The scales were also  tested f o r v a l i d i t y i n p r e d i c t i n g school success.  The sample included  f i f t y - f o u r Fourth Grade children between the ages of 9-years-and-l-month and 10-years-and-3-monthsj average achievement.  the subjects were o f average a b i l i t y and  The F u l l Scale WISC and Stanford-Binet c o r r e l a t -  ed t o y i e l d a c o e f f i c i e n t , r = .80, and the Verbal and Performance Scales yielded c o e f f i c i e n t s of .71 and .76 respectively.  The v a l i d i t y  of the Binet f o r p r e d i c t i n g school success as measured by the Standard Achievement Test was found t o be .63, and that o f the WISC to be .76. Only i n the Language Achievement subtest d i d the Stanford-Binet predict better than the WISC.  Unlike the studies reviewed comparing the Stanford-Binet and Wechsler-Bellevue,  t h i s study by Frandsen and Higginson answers  l i t t l e concerning test differences i n any except the average i n t e l l e c t u a l group.  As indicated by the l i t e r a t u r e on Wechsler-Bellevue and  Stanford-Binet studies, large differences do not occur i n the groups of average subjects, but do occur with the superior subjects and with the retarded ones, and with the older subjects and with the younger  11  ones.  On the basis of these same studies, f o r instance, one might  expect that retarded subjects would achieve higher WISC than Binet IQs, and that the superior subjects would have lower WISC than Binet IQs. In the present i n v e s t i g a t i o n , an attempt w i l l be made to compare the performance of subjects of superior and defective i n t e l l i g e n c e , as w e l l as those of average i n t e l l i g e n c e .  In the s e l e c t i o n o f age l e v e l s t o be used, t h i s studyhas an advantage over the studies comparing the Wechsler-Bellevue  with  the Stanford-Binet, i n that both o f the present tests have been standardized on children.  The WISC i s a point scale with a set standard deviation, while the s i z e of the Stanford-Binet standard deviation varies, being unusually small at age 6 years and unusually large at age 12 years. As was discussed e a r l i e r , Wechsler argues that t h i s c h a r a c t e r i s t i c o f the Binet produces u n r e l i a b l e r e s u l t s , since subjects a t the top and bottom parts o f the normal curve show a d i f f e r e n t IQ at d i f f e r e n t age levels.  At the extremes o f the normal curve, i . e . , with the retarded  and the superior subjects at these ages, therefore, there should be a Mean difference between the IQs produced by the two scales.  Since  the WISC has a set standard deviation, the same a t each age l e v e l , the Mean Differences should be i n the d i r e c t i o n corresponding t o the s i z e of the Binet deviation at that l e v e l .  These ages, 6 and 12 years,  w i l l be included i n the sample, therefore, i n order to t e s t t h i s hypothesis.  The i n c l u s i o n o f samples of superior and retarded  12  children w i l l insure that extreme scores ( i . e . , a t either end o f the normal curve) w i l l occur.  This w i l l give information omitted by  Frandsen and Higginson, f o r , although they report high correlations, they do not say whether the scores are comparable as to s i z e .  It will  also give information as to whether the high agreement they report also holds f o r other age l e v e l s . Besides the 6 and 12-year-olds, the sample w i l l include a group of 9-year-olds, since the Binet standard deviation at age 9 i s not only near the average f o r that t e s t  ( i t i s equal t o 16.4 IQ points  and the average i s 16 points) but i t also approximates the WISC deviation of 15 IQ points.  The 9-year-olds, plus a sampling of average  children, will, be included f o r t h e i r own research value, but mainly f o r purposes o f control and comparison.  In b r i e f , t h i s investigation i s planned to f i n d out to what extent the three indices o f i n t e l l i g e n c e yielded by the WISC cn the F u l l , Verbal and Performance Scales, correlate with those yielded by the Stanford-Binet a t ages 6, 9 and 12 years, using superior, average and defective children.  I t w i l l endeavor t o ascer-  t a i n whether the Mean scores i n these groups show r e a l differences i n average IQs yielded by the two t e s t s , and, i f so, i n what d i r e c t i o n these differences do occur.  CHAPTER I I PROCEDURE  In order t o determine the extent t o which i n t e l l i g e n c e quotients by the Binet scale (1937, Revised edition) and the Wechsler Intelligence Scale f o r Children are comparable, the following method o f investigation was  employed.  Selection of Subjects  The study was planned so that the sample should include t h i r t y children of superior i n t e l l i g e n c e , t h i r t y of average i n t e l l i gence, and t h i r t y retarded children.  Each group of t h i r t y would  include ten children aged 12 years, ten aged 9 years, and ten aged 6 years.  Thus, the sample should include t h i r t y children at each age  level.  In t h i s way,  varying i n t e l l i g e n c e and varying age l e v e l s  were represented i n the sample used i n t h i s study. should equal ninety. I,  The t o t a l sample  The planned selection i s represented i n Table  (p- 14).  The 9 and 12-year-old Superior subjects were obtained from various elementary schools throughout Vancouver.  They were  14  TABLE I  ORIGINAL PLAN FOR SELECTION OF SAMPLE N = 90  Age  I n t e l l e c t u a l Level  Superior  Average  Defective  Total  6 years  N = 1 0  N = 1 0  N = 1 0  =  3  0  9 years  N = 1 0  N = 1 0  N - 1 0  =  3  0  1 2 years  N = 1 0  N • 1 0  N = 1 0  =  3  0  Total  = 30  =30  =30  = 90  15 selected on the basis o f scores on either the Detroit F i r s t Grade Exami n a t i o n , or Otis Score, or scores on the National I n t e l l i g e n c e Scale, or on a l l of them, depending upon what tests the c h i l d had taken.  The  sample does not include any subject whose academic standing i s a t variance with the l e v e l of a b i l i t y indicated by the i n t e l l i g e n c e t e s t s , nor does i t include any subjects f o r whom the r e s u l t s of d i f f e r e n t tests were equivocal.  Some of the 6-year-old Superior subjects were selected  on the basis o f teachers' reports:  these evaluations proved u n r e l i a b l e ,  however, and additional subjects had t o be tested i n order to obtain the required number of subjects a t t h i s l e v e l . The subjects i n the Average category were selected on much the same basis as the Superior group, that i s , scores on previous i n t e l l i g e n c e t e s t s , grades and marks and class standing.  No  difficul-  t y was encountered i n obtaining the required subjects i n t h i s  category.  The sample of feebleminded  subjects was obtained from  the Woodlands School, New Westminster, B.C., and the Rainier State School, Buckley, Washington, U.S.A. requirements,  Besides f u l f i l l i n g the age  these children had to be defectives c l a s s i f i e d as  " f a m i l i a l " , and an attempt was made t o use only the brighter children within the "moron" or "borderline" c l a s s i f i c a t i o n .  However, several  problems presented themselves i n the work a t t h i s l e v e l .  In the  f i r s t place, neither o f the two schools had a s u f f i c i e n t number of children at these age l e v e l s who were c l a s s i f i e d as " f a m i l i a l ' , and, 1  i n the second place, of those obtainable few were s u f f i c i e n t l y  16 i n t e l l i g e n t to meet the requirements o f the study.  These requirements  were set up because Wechsler included i n the retarded sample of h i s standardization group "...cases of the required ages who were rated as having IQs under 70 and not below 50,"  (p.8,  20).  The t h i r d and  l a r g e s t problem occurred with the 6-year-old Retarded group.  Except  i n unusual instances, such as cases of p h y s i c a l damage and mongolism, children are not admitted to the Woodlands School u n t i l they are 6 years of age.  Few 6-year-olds were obtainable, therefore^ and those  who were showed very low i n t e l l i g e n c e .  The reason f o r the great  d i f f i c u l t y i n obtaining subjects at t h i s l e v e l may be i n the ages selected.  In other words, e a r l y committal to an i n s t i t u t i o n  may,  generally speaking, be confined to cases of physical d i s a b i l i t y , mongolism and very great retardation.  For these reasons, the sample  of Retarded children has been c u r t a i l e d , e s p e c i a l l y i n the 6-year-old group. I I , (p.  The obtained sample used i n t h i s study i s indicated i n Table  17)-  Administration of the Intelligence Scales  A l l the t e s t i n g was done by the investigator who  had  been trained i n the administration and scoring o f both of the scales used i n t h i s study.  Every e f f o r t was made t o follow the standard  procedures recommended i n the test manuals.  The records were scored  f i r s t by the examiner and then the scoring was checked by a trained worker i n the f i e l d .  17  TABLE I I  OBTAINED SAMPLE REPRESENTED AS TO AGE AND INTELLIGENCE LEVEL GROUPS N = 85  Age  Intelligence Level Superior  Average  Defective  Total  6 years  N = 10  N = 10  N =  4  = 24  9 years  N = 10  N = 10  N =  9  =29  12 years  N = 10  N = 10  N = 12  =32  = 30  = 30  = 25  = 85  Total  18 Half the subjects i n each a g e - i n t e l l e c t u a l group were given the Stanford-Binet f i r s t , and the other h a l f were given the WISC f i r s t , i n order t o nrinimize and even out the effects of p r a c t i c e . The second t e s t was given within a week, but never immediately a f t e r the f i r s t i n order t o avoid f a t i g u i n g the subject.  The two t e s t s were  given as nearly as possible under the same conditions, and care was taken to prevent the t e s t i n g running through any preferred a c t i v i t y of the c h i l d , e.g., recess or a school concert, or when the children were i n a state o f excitement, f o r instance, before Sports' Day.  In general, a high l e v e l of cooperation was obtained from the subjects. most eagerly.  The school children, especially, p a r t i c i p a t e d  In the case of the 6-year-olds, the examiner was  introduced t o the c l a s s and i t was then explained that some of the children were t o "play some games" with her.  In t h i s way, the t e s t i n g  became a most desirable and pleasurable t h i n g t o these  youngsters.  I n i t i a l l y , these c h i l d r e n were asked not to t e l l friends the contents o f the t e s t s .  their  However, t h i s seemed t o impart to  the whole a f f a i r the atmosphere of a "secret" which the youngsters found most d i f f i c u l t t o keep, so that a f t e r a while t h i s practice was dropped.  On the whole, whether o r not the subjects were asked not to  t e l l , very l i t t l e evidence was shown of subjects knowing the test material beforehand.  Some of the subjects were asked t o name the t e s t they  19 preferred, but, i n general, there did not seem to be a preference f o r either t e s t . More d i f f i c u l t y was encountered i n establishing rapport with the feebleminded  children, e s p e c i a l l y the very young ones.  These children were u s u a l l y more cooperative, however, when they were brought a second time a f t e r the f i r s t attempted interview had been abandoned.  Occasionally, i t seemed better to allow the attendant to  remain i n the room throughout the t e s t i n g i f the c h i l d were very shy. In these cases, the attendants were asked not to help the c h i l d i n any way,  and t h i s request was honored without exception.  It was the impression of the investigator that, i n the main, the WISC was much more d i f f i c u l t f o r the Retarded c h i l d than was the Binet.  Such a d i s t i n c t i o n can e a s i l y be made simply i n terms o f  e s t a b l i s h i n g rapport and engaging the subject's a t t e n t i o n .  The  l i t t l e toys of the Stanford-Binet are immediately a t t r a c t i v e to subj e c t s of low mental age, but the WISC equipment does not have a vestige of t h i s attractiveness.  The statement - "These pieces, i f  put together correctly, w i l l make a boy.  Go ahead and put them  together." - was, apparently, meaningless to most o f the Retarded subjects. of  Obviously, i f the subject f a i l s to comprehend the nature  the task, he can not successfully complete i t .  Differences  between the two t e s t s i n the p r a c t i c a l value of a score at t h i s l e v e l are i l l u s t r a t e d very well i n the Picture Completion  Test.  Instructions  to t e l l what was missing only occasionally evinced a s u i t a b l e response  20  from the subject, but most of these children could and d i d spontaneously name the pictures.  This a b i l i t y would add t o the subject's score on  the Binet, but, so f a r as a WISC score i s concerned, i t makes no difference whether the subject d i d name the pictures or merely sat i n d u l l silence.  For these reasons, the Stanford-Binet seems more s u i t -  able f o r use with Retarded children, and also because i t does y i e l d IQs at a lower l e v e l than does the WISC, although i t d i d f a i l with most of the Retarded 6-year-olds and with some of the 9-year-olds i n t h i s study.  In administering the WISC to subjects of $ years and older, not suspected mental defectives, the examiner i s permitted t o omit the f i r s t few items i n each subtest and t o s t a r t at a designated point of d i f f i c u l t y along the scale.  I f the subject does not achieve  a certain number of consecutive correct responses, however, the examiner must work back from the designated point u n t i l the required number of consecutive correct responses has been given.  While t h i s  technique i s at times undoubtedly time-saving i n t e s t i n g older and brighter subjects, i t i s also somewhat awkward, e s p e c i a l l y i f i t i s constantly necessary t o move backwards to easier items.  Also, some  subjects notice the marked change i n the l e v e l of d i f f i c u l t y of the items, and, i n t h i s way, become aware o f having f a i l e d the more d i f f i c u l t items.  F i n a l l y , the administration of the easier items i n  the Performance scale seems excessively complicated;  f o r instance,  d i f f e r e n t directions and examples are given with each of the f i r s t  four items i n the Block Design and Picture Arrangement t e s t s .  CHAPTER I I I TREATMENT OF DATA AND RESULTS  Treatment o f Data In order t o f i n d out to what degree the three indices of i n t e l l i g e n c e , yielded by the WISC on the Verbal, Performance, and F u l l Scales, correlate with those yielded by the Stanford-Bine ^ at -  ages 6, 9 and 12 years, using Superior and Average subjects, Pearson Product Moment correlations were computed i n each a g e - i n t e l l e c t u a l group between each Wechsler scale and the Stanford-Binet.  An attempt  i s made t o ascertain the nature of IQ differences yielded by the two tests by computing Mean Differences between the Stanford-Binet and Verbal, Performance, and F u l l Scales o f the WISC i n each a g e - i n t e l l e c t u a l group, and then using the t - t e s t t o t e s t f o r s i g n i f i c a n c e o f the difference.  Results  (a) Obtained correlations between scales : Superior Subjects The obtained c o e f f i c i e n t s of correlations between these  two measuring instruments based on the Superior subjects are shown i n  23 Table I I I , (p. 24). With the 6-year-old Superior subjects, the Verbal Scale c o r r e l a t i o n with the Binet was the lowest i n t h i s  age-intellectual  group, and the t h i r d lowest i n the entire Superior category; correlation was not s i g n i f i c a n t .  The Performance Scale  c o e f f i c i e n t i s the highest i n t h i s a g e - i n t e l l e c t u a l significant.  the  correlation  group, but i s not  The F u l l Scale correlation i s s l i g h t l y smaller than  that of the Performance Scale; i n t e l l e c t u a l category.  i t i s the median value for t h i s  entire  In the 9-year-old Superior group, the Verbal  Scale correlation i s s i g n i f i c a n t at the 1% l e v e l of confidence, and i s the highest i n the entire study.  While the Performance Scale  c o e f f i c i e n t i s the lowest i n t h i s a g e - i n t e l l e c t u a l s i g n i f i c a n t at the %  l e v e l of confidence.  group, i t i s  The F u l l Scale c o r r e l a t -  i o n i s the second highest i n the whole i n t e l l e c t u a l category, and i s s i g n i f i c a n t at the 1% l e v e l of confidence.  The Verbal Scale  correlat-  ion i s the highest i n the 12-year-old Superior group, and the  correlat-  i o n next to, but lower than, the median value f o r the entire i n t e l l e c t u a l category;  the value, however, i s not s i g n i f i c a n t .  The Superior  12-year-old Performance Scale correlation i s the lowest i n the study.  The F u l l Scale c o r r e l a t i o n i s the second lowest i n the  i n t e l l e c t u a l category;  entire entire  the c o e f f i c i e n t i s not s i g n i f i c a n t .  Average Subjects  The correlations  (  based on Average subjects are found  TABLE I I I CORRELATIONS BETWEEN STANFORD-BINET AND WISC VERBAL, PERFORMANCE, AND FULL SCALES  Superior Subjects  Age  Verbal Scale  Performance Scale  Full Scale  6 years  .34  .53  •5.2  9 years  .93  .67  • 91  .50  .01  .33  12 years  .05  =  .602  .01  =  .735  25 i n Table IV, (p.26). In the 6-year-old Average group, the Verbal Scale correl a t i o n i s not s i g n i f i c a n t and i s the lowest i n the group, and the t h i r d lowest i n the average i n t e l l e c t u a l group.  The Performance Scale shows  the highest correlation i n t h i s a g e - i n t e l l e c t u a l group, although the c o e f f i c i e n t i s not s i g n i f i c a n t .  The F u l l Scale correlation i s s l i g h t -  l y lower than the Performance Scale correlation;  i t i s the median  value f o r the entire Average i n t e l l i g e n c e group.  The Verbal Scale  correlation a t the average 9-year-old l e v e l i s the highest f o r the entire Average group, and i s s i g n i f i c a n t at the l $ l e v e l o f confidence. The Performance Scale c o e f f i c i e n t i s the lowest i n t h i s a g e - i n t e l l e c t u a l group, and the second lowest i n the entire Average category; significant.  i t i s not  The F u l l Scale correlation i s second highest i n t h i s age-  i n t e l l e c t u a l group and i n the entire Average category; cant at the 5$ l e v e l of confidence.  i t i s signifi-  In the 12-year-old Average group,  the Verbal Scale shows the highest correlation;  i t i s the same as the  Average 6-year-old F u l l Scale c o e f f i c i e n t , and i s also the median value for the Average group;  the value i s not s i g n i f i c a n t .  The Performance  Scale correlation i s the lowest f o r t h i s a g e - i n t e l l e c t u a l group and f o r t h i s entire i n t e l l e c t u a l category.  The F u l l Scale correlation f o r t h i s  a g e - i n t e l l e c t u a l group i s the medium one and i s not s i g n i f i c a n t .  Summarizing the r e s u l t s of Tables I I I and IV, i t i s immediately apparent that i n both i n t e l l e c t u a l groups, the rank order of the correlations i s the same at the same ages.  The highest, second  TABLE IV CORRELATIONS BETWEEN STANFORD-BINET AND WISC VERBAL, PERFORMANCE, AND FULL SCALES Average Subjects  Age  Verbal Scale  Performance Scale  Full Scale  6 years  .31  .52  .50  9 years  • 77  .28  • 73  12 years  • 50  .24  .46  .05  =  .602  .01  =  .735  A l l quantities are rounded o f f t o second decimal place. When worked to t h i r d decimal place, r = .727«  +  27 highest, median, t h i r d  lowest, and lowest correlations f o r each i n t e l -  l e c t u a l group occur with the same WISC scales ( i . e . , ance, or P u l l Scales) at t h e same age l e v e l s .  Verbal, Perform-  In each a g e - i n t e l l e c t u a l  group, the F u l l Scale correlation i s the middle value, and i n both 6year groups the rank order of the Verbal and Performance Scales i s the reverse o f what i t i s i n both o f the 9-year and both of the 12-year groups. The rank order o f the Verbal correlations i s the same i n both i n t e l l i g e n c e groups, with the 9-year-olds showing the highest c o e f f i c i e n t s , the 12-year-olds the next highest, and the 6-year-olds, the lowest.  The rank order of the F u l l Scale correlations i s also the  same i n both i n t e l l i g e n c e groups, but the order i s not the same as f o r the Verbal Scale correlations.  In t h i s case, the 9-year-olds show  the highest c o e f f i c i e n t , but the 6-year-olds are second highest i n t h i s case, with the 12-year-olds l a s t .  With the exception o f the f a c t that  the 12-year-olds both show the lowest c o e f f i c i e n t s , there i s no rank order agreement between the two i n t e l l e c t u a l groups f o r the Performance Scale c o r r e l a t i o n s .  Defective Subjects  The f a i l u r e to obtain a s u f f i c i e n t number of the more i n t e l l i g e n t defectives (described i n Chapter II) resulted i n only f i v e of this group achieving WISC F u l l Scale i n t e l l i g e n c e quotients. a r e s u l t no correlations were run i n t h i s sample.  As  The a c t u a l r e s u l t s  28  w i l l be discussed l a t e r , under a separate heading.  (b) Comparison of Mean IQs : Superior Subjects The comparison of the Mean i n t e l l i g e n c e quotients between the two tests f o r the Superior subjects are shown i n Tables V, VI, and VII, (pp.29, 30 and 31)In the Superior group, a l l the Mean WISC IQs are smaller than the Mean Binet IQs with which they are being compared. In the Superior 6-year-old group, the Stanford-Binet IQs range from 110 to 154, a difference o f 44 IQ points, the l a r g e s t range i n this a g e - i n t e l l e c t u a l group;  the Binet standard deviation i s s l i g h t -  l y l a r g e r than those of the Wechsler I n t e l l i g e n c e Scale f o r Children i n t h i s a g e - i n t e l l e c t u a l group.  The WISC Verbal Mean IQ f o r the Superior  6-year-olds d i f f e r s by only a small amount from the Binet Mean IQ f o r the same group and the d i f f e r e n c e i s not s i g n i f i c a n t ;  the range o f IQs  on the Verbal Scale i n t h i s a g e - i n t e l l e c t u a l category i s from 105 t o 131, a range o f 26 IQ points;  t h i s scale a l s o shows the smallest  standard deviation i n t h i s a g e - i n t e l l e c t u a l group.  The Mean Perform-  ance IQ f o r the Superior 6-year-olds d i f f e r s from the Mean Binet IQ by the same amount as does the Verbal Scale; significant.  again, the d i f f e r e n c e i s not  The IQs range from 106 t o 138, a range o f 32 IQ points,  the largest range o f any WISC scale i n t h i s a g e - i n t e l l e c t u a l group;  TABLE V  MEAN WISC VERBAL SCALE IQs COMPARED WITH MEAN STANFORD-BINET IQs  Superior Subjects  Age  Stanford-Binet  WISC Verbal Scale  M. IQ  S.D.  6 years  122.80  11.73  3.91  119.30  7«87  2.62  3*50  9 years  137.90  17-00  5-66  125.20  11.86  3.95  12.70  5.16  12 years  131.90  8.75  2.92  113.20  8.07  2.69  18.70  6.65  S  * ' E  +  M M  .05 .01  = =  - I  2.26 3-25  Q  S  ' ' D  S  - « E  M M  - Diff-  t  +  . 90  TABLE VI  MEAN WISC PERFORMANCE SCALE IQs COMPARED WITH MEAN STANFORD-BINET IQs  Superior Subjects  M. IQ  S.D.  years  122.80  11.73  9 years  137.90  12 years  131.90  6  S.E.  M. IQ  S.D.  3.91  119.30  10.56  3.52  3.50  .97  17.00  5.66  119.10  10.62  3.54  18,80  4«47  8.75  2.92  123.90  10.67  3-56  8.00  1.75  M  .05 = 2.26 .01 = 3.25  +  S.E.  M  M.  Diff.  t  +  TABLE VII  MEAN WISC FULL SCALE IQs COMPARED WITH MEAN STANFORD-BINET IQs  Superior Subjects  Age  Stanford-Binet  WISC F u l l Scale  M. IQ  S.D.  S.E.  M. IQ  S.D.  6 years  122.80  11.73  3.91  121.10  9.03  3.01  1.70  9 years  137.90  17-00  5.66  124*40  11.00  3.66  13.50  4.86  12 years  131.90  8.75  2.92  120.20  7-33  2.44  11.70  3-74  +  M  .05 .01  » 2.26 = 3.25  S.E»  M  M. D i f f .  t  +  .49  32  the standard deviation i s s l i g h t l y larger than i n the Verbal Scale. The Mean F u l l Scale IQ f o r the Superior 6-year-olds d i f f e r s from the Mean Binet IQ by a much smaller amount than do the Verbal and Performance Scales;  the difference i s not s i g n i f i c a n t .  108 t o 13<3 points, a difference o f 30 IQ points;  The IQs range from the standard  deviation i s smaller than that o f the Performance Scale, and l a r g e r than that of the Verbal Scale.  A l l the WISC scale standard deviations i n  t h i s a g e - i n t e l l e c t u a l group are smaller than the Binet standard deviation, but there i s not a great difference between any o f them.  In the group o f Superior 9-year-olds, the Stanford-Binet IQs range from 119 t o 168, a range o f 49 IQ points, the l a r g e s t i n the entire study;  t h i s group of IQs also shows the l a r g e s t standard  deviation i n the study;  i t shows a considerable difference from the  next l a r g e s t standard deviation.  The Mean Verbal IQ i n the Superior  9-year-old group shows the fourth greatest difference from the Mean Binet IQ i n the entire study, although i t i s the smallest difference i n t h i s a g e - i n t e l l e c t u a l group; l e v e l o f confidence.  the difference i s s i g n i f i c a n t a t the 1%  The IQs range from 110 t o 148, a difference o f  38 points, and the largest WISC range i n t h i s a g e - i n t e l l e c t u a l group; i t also shows the l a r g e s t WISC standard deviation a t t h i s a g e - i n t e l l e c t ual level.  The Mean Performance IQ d i f f e r s from the Mean Binet IQ by  the l a r g e s t amount i n the study; 1$ l e v e l o f confidence.  the difference i s s i g n i f i c a n t at the  The IQs range from 104 t o 136, a range of 32  points, the smallest range i n t h i s a g e - i n t e l l e c t u a l group; the  33 standard deviation i s also the smallest i n the a g e - i n t e l l e c t u a l group. The Mean F u l l Scale IQ f o r the Superior 9-year-old group shows the t h i r d largest difference from the Mean Binet IQ i n the entire study; the difference i s s i g n i f i c a n t at the 1% l e v e l of confidence. range from 112 t o 146, a difference o f 34 points.  The IQs  The range o f the  sizes of the standard deviations i s smaller i n t h i s a g e - i n t e l l e c t u a l group than f o r the Superior 6-year-old group, but the values are a l l larger. In the Superior 12-year-old group, the Stanford-Binet IQs range from 118 to 146, a difference of 28 IQ points, the smallest Binet range i n t h i s i n t e l l e c t u a l group.  The Superior 12-year-old  group also shows the smallest Binet standard deviation i n t h i s i n t e l l e c t u a l group.  The Mean Verbal Scale IQ sho\re the second largest  difference from the Mean Binet IQ i n the whole study, and the largest i n t h i s a g e - i n t e l l e c t u a l group;  the difference i s s i g n i f i c a n t at the 1  1% l e v e l of confidence, showing the largest c r i t i c a l r a t i o obtained i n the entire study. IQ points.  The IQs range from 104 t o 130, a difference of 26  The Mean Performance IQ shows the largest non-significant  difference from the Mean Binet IQ i n the e n t i r e study; smallest Mean Difference i n t h i s a g e - i n t e l l e c t u a l group.  i t i s the The range of  IQs i s from 100 t o 140, a difference o f 40 IQ points, and the largest range i n t h i s a g e - i n t e l l e c t u a l group; largest i n t h i s same group.  the standard deviation i s the  The Mean F u l l Scale IQ f o r the Superior  12-year o l d subjects d i f f e r s from the Mean Binet IQ by the smallest  34 s i g n i f i c a n t difference a t t h i s i n t e l l e c t u a l l e v e l j s i g n i f i c a n t at the 1$ l e v e l o f confidence.  the difference i s  The IQs range from 108 t o  133. a range o f 25 IQ points which i s the smallest range f o r t h i s i n t e l l e c t u a l group;  the standard deviation i s a l s o the smallest f o r the  i n t e l l e c t u a l group. The 6-year l e v e l has the smallest Mean Differences within each WISC scale;  i n the Verbal Scale, the 12-year l e v e l shows the  largest difference, with the 9-year l e v e l coming next. reversed f o r the Performance and F u l l Scales.  This order i s  In the Stanford-Binet,  the largest standard deviation occurs at the 9-year l e v e l , the smallest at the 12-year l e v e l , and the middle value a t 6 years. a l s o f o r the WISC F u l l Scale.  This order holds  In the WISC Verbal Scale the l a r g e s t  deviation occurs at the 9-year l e v e l , the next largest at 12 years, and the smallest at 6 years;  i n the Performance Scale, the-largest deviat-  ion i s at 12 years, the next largest a t 9 years, and the smallest at 6 years.  The range of s i z e for these deviations i s only .11 IQ points.  In the Stanford-Binet, the largest Mean IQ occurs a t 9 years, the next largest at 12 years, and the smallest a t 6 years.  In the WISC F u l l  and Verbal Scales, the highest Mean IQ occurs at 9 years, the next largest a t 6 years, and the smallest at 12 years.  In the Performance  Scale, the highest Mean IQ occurs at the 12-year l e v e l , the next largest at the 6-year l e v e l , and the smallest a t 9 years.  Average Subjects The comparison o f the Mean i n t e l l i g e n c e quotients  35 between the two tests f o r the Average subjects are shown i n Tables VIII,  IX and X (pp.36, 37 and 38). In the average 6-year-old group, the Stanford-Binet IQs range from 89 to 112, a difference o f 23 IQ points, which i s the smallest range i n the entire study;  the standard deviation i s smaller than  any i n the Superior group, and i s the smallest i n t h i s a g e - i n t e l l e c t u a l group.  The Mean Verbal Scale IQ f o r the Average 6-year-olds does not  d i f f e r s i g n i f i c a n t l y from the Mean Binet IQ, but i t i s s t i l l the largest difference at t h i s a g e - i n t e l l e c t u a l l e v e l .  The IQs range from 90 to  109, a difference of 19 IQ points, the smallest range i n the study, and the standard deviation i s the largest i n t h i s a g e - i n t e l l e c t u a l group. The Mean Performance Scale IQ d i f f e r s from t h e Mean Binet IQ by the smallest amount o f any of the WISC scales i n t h i s a g e - i n t e l l e c t u a l group;  the difference i s not s i g n i f i c a n t .  114, making a difference of 25 IQ points;  The IQs range from 89 to the standard deviation i s  the middle value deviation f o r the WISC scales at t h i s a g e - i n t e l l e c t u a l level.  The Mean F u l l Scale IQ d i f f e r s from the Mean Binet IQ by a  small amount which does not constitute a s i g n i f i c a n t d i f f e r e n c e .  The  IQs range from 91 t o 113, a difference o f 22 IQ points, and the standard deviation i s t h e smallest WISC deviation i n t h i s a g e - i n t l l e c t u a l group. A l l the WISC Mean i n t e l l i g e n c e quotients at t h i s l e v e l are smaller than the Mean Binet i n t e l l i g e n c e quotient.  At the average 9-year-old l e v e l , the Stanford-Binet IQs range from 84 to 113, a difference of 29 IQ points, and the standard  TABLE VIII  MEAN WISC VERBAL SCALE IQs COMPARED WITH MEAN STANFORD-BINET IQs  Average Subjects  Age  Stanford-Binet  M. IQ  S.D.  6 years  105.00  9 years  99.40  12 years  101.30  WISC Verbal Scale  S.E.  M  M. IQ  S.D.  6.56  2.19  101.30  7.71  2.57  3*70  1.32  8.08  2.69  101.60  6.39  2.13  2.20  1.28  8.03  2.68  95*20  6.73  2.24  6.10  2.45  +  .05 = 2.26 .01 = 3.25  S.E.  M  M. D i f f .  t  +  ,  TABLE IX  MEAN WISC PERFORMANCE SCALE IQs COMPARED WITH MEAN STANFORD-BINET IQs  Average Subjects  Age  Stanford-Binet  WISC Performance Scale  M. IQ  S.D.  S.E.  M. IQ  S.D.  S.E-  6 years  105.00  6.56  2.19  102.00  7*24  2.41  3.00  1.33  9 years  99.40  8.08  2.69  98.20  7-.ll  2.37  1.20  .35  12 years  101-30  8.03  2.68  99-90  7-93  2.64  L40  .43  +  M  .05 .01  = 2.26 = 3.25  M  M. D i f f .  t  +  TABLE X  MEAN WISC FULL SCALE IQs COMPARED WITH MEAN STANFORD-BINET IQs Average Subjects  Age  Stanford-Binet  WISC F u l l Scale  years  105.00  6.56  2.19  101.60  6.59  2.20  3.40  9 years  99.40  8.08  2.69  99.90  5-11  1..70  . 50  12 years  101.30  8.03  2.68  97.10  6.69  2.23  M  M. IQ  .05 = 2.26 .01 - 3.25  +  S.D.  M. D i f f .  S.D.,  6  S.E.  S.E.  M. IQ  M  4.20  t  +  1.55 . 27 1.63  39 deviation i s the largest i n t h i s i n t e l l e c t u a l group.  The Mean D i f f e r -  ence between the Mean Verbal IQ f o r Average 9-year-olds and the Mean Binet IQ i s not s i g n i f i c a n t , but i t i s the largest i n t h i s a g e - i n t e l l e c t u a l group.  The IQs range from 89 t o 113, making a difference  points, the standard deviation i s small.  o f 24 IQ  The Mean Performance IQ  d i f f e r s from the Mean Binet IQ by the second largest amount f o r t h i s age-intellectual  group;  again, the difference  i s not s i g n i f i c a n t .  The IQs range from 89 to 110, the smallest range i n t h i s u a l group; u a l group.  the standard deviation i s the largest i n t h i s  age-intellectage-intellect-  The Mean F u l l Scale IQ d i f f e r s from the Mean Binet IQ by  the smallest amount i n the study;  the difference  i s not s i g n i f i c a n t .  The IQs range from 88 to 109, making a difference  o f 21 IQ points, the  same s i z e as the range of the Performance Scale, a t t h i s level;  age-intellectual  the standard deviation i s the smallest i n the entire study.  A l l the Mean Differences at t h i s age-intellectual  l e v e l are smaller  than those a t the Average 6-year-old l e v e l , and a l l the WISC scales show higher Mean i n t e l l i g e n c e quotients than does the Stanford-Binet.  In the Average 12-year-old group, the IQs range from 82 to 118, a difference  of 36 IQ points, the largest range i n t h i s  i n t e l l e c t u a l group;  the standard deviation i s only the second largest  Binet deviation i n t h i s i n t e l l e c t u a l group, but i t i s the l a r g e s t i n the age-intellectual  group.  The Mean Verbal IQ d i f f e r s from the Mean  Binet IQ by the largest amount i n t h i s i n t e l l e c t u a l group, although the difference  i s not as large as the largest i n s i g n i f i c a n t  difference;  40 the difference i s s i g n i f i c a n t at the 5% l e v e l of confidence, and i s the only s i g n i f i c a n t difference i n t h i s i n t e l l e c t u a l group. from 85 t o 108, a difference o f 23 IQ points.  The IQs range  The Mean Performance  IQ d i f f e r s by the smallest amount i n t h i s a g e - i n t e l l e c t u a l group from the Mean Binet IQ; the difference i s not s i g n i f i c a n t .  The IQs range  from 89 t o 110, a d i f f e r e n c e o f 21 IQ points, the smallest range i n t h i s a g e - i n t e l l e c t u a l group;  the standard deviation i s the l a r g e s t f o r  t h i s a g e - i n t e l l e c t u a l group.  The Mean P u l l Scale IQ d i f f e r s from the  Mean Binet IQ by an amount which i s not s i g n i f i c a n t . from 86 t o 109, a difference o f 23 IQ points;  The IQs range  the standard deviation  i s the smallest f o r t h i s age i n t e l l e c t u a l group.  A l l the Mean WISC  s c a l e IQs are smaller than the Mean Binet IQ at t h i s a g e - i n t e l l e c t u a l level.  In the Verbal and F u l l Scales, the l a r g e s t differences occur a t 12 years, then 6 years, then 9 years.  In the Performance  Scale, the l a r g e s t difference i s at age 6 years, then 12 years, then 9 years;  the smallest difference i s always at the 9-year l e v e l .  The  l a r g e s t Verbal standard deviation occurred a t 6 years, the next l a r g e s t at 12 years, and the smallest a t 9 years;  i n the Performance Scale,  the largest standard deviation occurred at 12 years, the next largest at 6 years, and the smallest at 9 years; was the same.  i n the F u l l Scale, the order  In a l l the WISC scales, the 9-year l e v e l shows the  smallest standard deviation.  In the Stanford-Binet a t t h i s i n t e l l e c t -  u a l l e v e l , the 9-year l e v e l shows the l a r g e s t standard deviation; the  41 12-year l e v e l , the next largest;  and the 6-year l e v e l , the smallest.  In the Stanford-Binet, the 6-year l e v e l shows the highest Mean IQ;  the 12-year l e v e l , the next highest;  l e v e l , the lowest. at 9 years;  and the 9-year  For the Verbal Scale, the highest Mean IQ occurs  the next highest, at 6 years;  and the lowest at 12 years.  For the Performance Scale, the highest Mean IQ occurs a t the 6-year l e v e l , the next highest a t the 12-year level,- and the lowest at the 9-year l e v e l .  For the F u l l Scale, the highest Mean IQ occurred at the  6-year l e v e l , the next highest a t the 9-year l e v e l , and the lowest at the 12-year l e v e l .  (c) The performance o f the Defective Group :  Of the twelve Retarded 12-year-olds, a l l twelye obtained i n t e l l i g e n c e quotients on the Stanford-Binet; to 68, a difference of 40 IQ points. obtained WISC F u l l Scale IQs; of 12 IQ points.  the IQs ranged from 28  Of these twelve, only three  these ranged from 55 to 67, a difference  Of the remaining nine, one subject achieved an IQ  on both the Verbal and Performance Scales, and two subjects obtained IQs on the Verbal Scale alone.  Of the remaining s i x subjects, one  achieved no scaled score at a l l , and the others achieved scaled scores only on the Verbal and F u l l Scales. In the group of Retarded 9-year olds, only f i v e of the nine subjects achieved Stanford-Binet IQs; these IQs ranged from 26  42 to 60, a difference of 34 IQ points.  Of these five, the two subjects,  who achieved the highest Binet IQs for this group, also achieved Full Scale WISC IQs of 49 and 53•  A l l the subjects i n this age group  achieved scaled scores on the WISC Full, Verbal and Performance Scales, because, due to the system of standard scores, i t i s possible for a subject at this, and lower age levels, to achieve scaled scores without having given a single correct response.  However, two of the subjects  did achieve scaled scores (but no IQs) because they had given some correct responses. Of the group of four 6-year-old defectives, only one achieved a Stanford-Binet IQ (46) and none achieved a WISC Full Scale IQ.  The three subjects who did not achieve Binet IQs, a l l achieved  Verbal and Performance IQs, and the subject who achieved the StanfordBinet IQ achieved a Verbal IQ but no Performance IQ, although he did obtain a scaled score on that section of the test. achieved Full Scale scaled scores.  A l l the subjects  The achievement of Verbal and  Performance IQs by three of the subjects i s due to the construction of the test, as outlined before, and no correct responses were actually given. In the case of the 12-year-olds, the WISC Full Scale IQs were of a size comparable to those on the Binet, and this i s true of a l l the Verbal and Performance IQs obtained at this age level.  In  the 9-year old group, the WISC Full Scale: IQs are both smaller than the accompanying Binet IQs.  43 The actual scores obtained by these subjects are shown i n Tables, XI, XII and XIII, (pp. 44, 45 and 46).  44 TABLE XI PERFORMANCE OF 12-YEAR OLD MENTAL DEFECTIVES ON WISC VERBAL, PERFORMANCE, AND FULL SCALES, AND ON STANFORD-BINET  Subject Number  StanfordBinet IQ  WISC Verbal  Performance  F u l l Scale  Scaled Score  IQ  Scaled Score  IQ  Scaled Score  IQ  71  54  67  0  -  16  -  1  68  25  69  29  2  36  0  -  0  3  47  8  47  8  4  57  5  5  37  1  6  32  2  -  7  41  1  -  0  8  28  3  -  9  46  12  10  52  11 12  -  0  -  1  -  0  -  2  -  1  -  0  5  0  -  3  52  8  -  20  -  11  51  27  68  38  55  43  9  48  12  47  21  -  53  11  51  28  69  39  56  TABLE XII  PERFORMANCE OF 9-YEAR-OLD MENTAL DEFECTIVES ON WISC VERBAL, PERFORMANCE, AND FULL SCALES, AND ON STANFORD-BINET  Subject Number  StanfordBinet IQ  WISC Verbal Scaled Score  Performance  IQ  Scaled Score  IQ  F u l l Scale Scaled Score  IQ  1  26  2  1  3  2  +  2  5  7  3  +  2  -  2  4  4  60  14  55  21  60  35  53  5  52  12  52  18  55  30  49  6  +  2  1  3  7  41  3  7  10  8  25  2  1  3  9  +  2  1  3  Impossible t o compute an IQ because no basal age could be found.  46  TABLE XIII  PERFORMANCE OF 6-YEAR-OLD MENTAL DEFECTIVES ON WISC VERBAL, PERFORMANCE, AND FULL SCALES, AND ON STANFORD-BINET  Subject Number  StanfordBinet IQ  WISC Verbal Scaled Score  Performance IQ  Scaled Score  Full, Scale  IQ  Scaled Score  1  +  11  51  12  47  23  2  +  11  51  12  47  23  3  +  4  46  11 12  +  51 52  12  47  9  Impossible t o compute an IQ because no basal age could be found.  -  23 21  IQ  CHAPTER IV DISCUSSION OF RESULTS  Theoretical Expectations and Obtained Results As has been previously pointed out, since the StanfordBinet has a standard deviation smaller at age 6 years, larger at 12 years, and approximately the same size a t age 9 years, than that of the Wechsler Intelligence Scale f o r Children, there should be c e r t a i n d i f ferences i n the Mean IQs yielded by the two t e s t s when t e s t i n g i n t e l ligence at the extremes of the normal curve.  At the 6-year l e v e l ,  f o r instance, the Mean Stanford-Binet IQ f o r superior subjects should be lower than the Mean WISC IQs; at the 12-year l e v e l , the Binet IQ for superior subjects should be higher than the Mean WISC i n t e l l i g e n c e quotients;  and, at age 9 years, the Mean IQs on the two tests should  be approximately the same. These expectations are a c t u a l l y f u l f i l l e d at the Superior 12-year l e v e l where the Binet Mean IQ i s considerably higher than the WISC Mean IQs, although the Mean Difference between the Binet and Performance Scale i s not s i g n i f i c a n t .  The differences are f a r  l a r g e r , however, than might be expected i n terms of the sizes o f the  48  standard deviations f o r the two scales.  Furthermore, inspection o f the  differences obtained i n the Superior groups a t the other two l e v e l s tend to n u l l i f y the r e s u l t s of the Superior 12-year-old group of any s i g n i f i cance as f a r as the theory about the standard deviations i s concerned. Although none of the differences between the Mean Binet and the WISC Scale IQs at the 6-year l e v e l i s s i g n i f i c a n t , a l l the WISC scale Mean IQs are smaller than the Mean Binet IQ with which they are being compared-  Moreover, i n the Superior 9-year-old group, where the closest  agreement should be expected, there occur three of the four largest Mean Differences i n the study, a l l s i g n i f i c a n t a t the 1% l e v e l of confidence; again, the Mean Binet IQ i s higher than any of the Mean WISC i n t e l l i g e n c e quotients.  In general, these r e s u l t s are f u l l y substantiated by the s i z e o f the obtained standard deviations.  With one exception, the  Stanford-Binet standard deviations are larger than the deviations obtained by the same group on the WISC scales.  The exception occurs i n  the Superior 12-year-old group where the Performance Scale standard deviation i s larger than that of the Stanford Binet.  I t w i l l be  remembered that although the Mean Difference here was large, i t was not significant.  I t i s d i f f i c u l t t o say, therefore, whether or not  Wechsler's objections to the unusual sizes o f the Stanford-Binet standard deviations at ages 6 and 12 years are j u s t i f i e d on p r a c t i c a l grounds. Within the l i m i t s of t h i s study and compared with h i s own point scale with i t s set deviations, they c e r t a i n l y are not j u s t i f i e d .  49 In general, the Average group appears to have achieved s i m i l a r IQs on both the Stanford-Bine-^ and Wechsler Intelligence Scale for Children, Verbal, Performance and F u l l Scales.  There i s one  exception to t h i s trend, and that i s when the 12-year-old Mean Binet IQ i s compared with the Mean Verbal IQ.  This difference i s s i g n i f i -  cant at the 5% l e v e l of confidence. The nature of the obtained standard deviations i s not always the same as those which occurred i n the standardization groups of the two scales.  I t i s rather i n t e r e s t i n g to note that i n neither  the Superior nor the Average groups do the Stanford-Binet standard deviations, obtained at the three age l e v e l s , rank i n s i z e i n the same order, as do the standard deviations obtained with the o r i g i n a l Binet standardization group.  According t o the l a t t e r , the 12-year-old group  should show the largest standard deviation, the 9-year group the next largest, and the 6-year group the smallest.  In the Superior group i n  t h i s study, the 9-year group shows the largest standard deviation; the 6-year group the next largest;  and the 12-year group the smallest.  In the Average group, the 9-year group again shows the l a r g e s t standard deviation, the 12-year group the next l a r g e s t , and the 6-year group the smallest.  On the other hand, within the results f o r each WISC  s c a l e o f the Average group, and i n the Superior group's Performance Scale, the standard deviations at a l l ages show considerable s i m i l a r i t y , as would be expected by the f i x e d nature of the WISC standard deviations. Such s i m i l a r i t y does not occur, however, i n the results o f the Superior  X  50  group for the Verbal and Performance Scales.  The d i s s i m i l a r i t y of  these scales i n t h i s matter must be regarded as mere chance v a r i a t i o n s , since no explanation can be found i n terms of unusual ranges. one instance, which occurs i n the Superior 9-year-old  In only  Stanford-Binet  r e s u l t s , are the obtained standard deviations as large as those reported by the authors of the two s c a l e s .  The f a c t that the s i z e of the obtained Stanford-Binet deviations at the three age l e v e l s do not rank i n the same order as do those i n the o r i g i n a l standardization group, i s probably due to sampling errors, and could be explained by the differences i n the range of obtained IQs.  A sample of ten i s much more subject to influence by a s i n g l e  extraordinary score than i s a l a r g e r group.  The larger s i z e of the  Binet standard deviations as compared with those of the WISC could be explained i n terms of the point scale nature of the WISC with i t s set deviations, a matter to be discussed l a t e r i n t h i s s e c t i o n .  The smallness of the obtained standard deviations compared with those on the standardization groups of the two tests can probably be explained by the presence of factors i n t r i n s i c i n the present experimental design.  The l i m i t e d s i z e of the sample would  make f o r a considerable r e s t r i c t i o n i n the range of talent i n any group, that i s , the homogeneous nature o f the samples probably best f o r the small s i z e of the standard deviations;  one  accounts  the ranges of the  Average and Superior groups are n e c e s s a r i l y smaller than those of the standardization groups which encompass not one, but a l l ,  intellectual  51 levels.  The exception which occurs in the results of the Superior 9-  year-old group on the Stanford-Binet, is probably the result of chance influence.  The possible range in the Superior group is necessarily  less restricted than in the Average group, and i t so happens that this group contains two exceptionally high intelligence quotients of 164 and 168. These differences between the two scales with regard to obtained Means and standard deviations are probably best explained in terms of differences in test construction.  The study by Seashore,  Wesraan and Doppelt (14), described in the introduction, i t will be recalled points out that the range of IQs on a point scale is quite arbitrary.  Since the range of IQs and standard deviations on the WISC  is quite narrow, extreme scores are not to be expected.  Thus, the  range of IQs, which it is possible for a subject to achieve, is much more restricted.  The obtained results, i.e., lower Mean WISC IQs for  the Superior subjects, and smaller WISC standard deviations is, therefore, to be expected on the basis of the construction of the test. The approximate equality of the Mean IQs in the Average group is also to be expected, since a difference in test construction, such as we are concerned with here, manifests itself only at the extremes of the normal curve. Since the WISC does not yield an IQ below 45, only five of the defective populations achieved Full Scale IQs.  The apparent  equality between the IQs at the 12-year level, with a slight lowering of  52 the WISC IQs at age 9, i s not i n accordance with the v e r i f y i n g Binet standard deviations, or the r e s t r i c t e d IQ range o f the WISC.  The sample  i s f a r too small, however, t o permit any safe generalizations. For reasons outlined i n Chapter I I and because i t y i e l d s an IQ below 45, the Stanford-Binet does appear to be the preferable i n strument a t t h i s l e v e l .  In terms o f the many objections t o the Mental Age concept, there i s undoubtedly much t o be s a i d for the point scale, and a "conservative" one, such as the WISC which sets i t s scale so that extreme scores are rare, i s u s e f u l because, for example, a Superior score i s f a i r l y c e r t a i n t o indicate superior a b i l i t y .  I t i s possible, however,  that the "compression" of the values eliminates certain shadings o f quantity, e s p e c i a l l y at that point between the average and the extremes. These shadings are obtainable on a scale l i k e the Stanford-Binet, where the subject and his performance set the index to a f a r greater degree. Here the subject's age i s set t o the month, rather than within four months, and there i s a c t u a l l y no IQ which he cannot a t t a i n .  Whether  the r e l i a b i l i t y and v a l i d i t y of the Binet, or o f any i n t e l l i g e n c e test, warrants such p r e c i s i o n i s another question.  One rather confusing  c h a r a c t e r i s t i c manifested by the point s c a l e nature of the WISC i s the fact that, at the upper age and i n t e l l i g e n c e l e v e l s , a subject may make a perfect performance on a subtest and not achieve a perfect scaled score f o r i t , or, even more, confusing, a t the lower age and i n t e l l e c t u a l l e v e l , the subject may give no correct responses whatever, and s t i l l achieve a  53 scaled score. Of the eighteen correlations computed, only f i v e were s i g n i f i c a n t , and a l l of these occurred at the 9-year l e v e l .  I t would  appear then that, except at one age l e v e l , these two tests are not measuring the same thing.  There are two major explanations as to why  this may appear to be so.  The f i r s t one could be i n terms of the motivational and i n t e l l e c t u a l development of the c h i l d during these years.  A 6-year  old c h i l d i n Grade I does not have a l l the desirable attitudes and attentiveness more common i n an older c h i l d ;  one encounters, i n l e s s e r  degree, a l l the motivational problems of t e s t i n g a very young c h i l d . As Anderson ( l ) points out, the younger the c h i l d , the l e s s r e l i a b l e the r e s u l t ;  v a r i a t i o n i n motivation could account f o r the low c o r r e l a t -  ions at t h i s age.  With a few exceptions, t h i s problem i s not a serious  one i n t e s t i n g the 9-year-old;  by t h i s age, the c h i l d has been i n  school f o r three or four years and has, presumably, acquired the d e s i r able attitudes and motivation.  According to Thurstone (p.206, 18), a  c h i l d of t h i s age has no manifest s p e c i a l a b i l i t i e s due to a maturational factor, thus giving the impression of global i n t e l l i g e n c e ;  on the basis  of t h i s theory, the high correlations which occur at t h i s age l e v e l would be expected. abilities;  As the c h i l d grows older, he tends to develop s p e c i a l i z e d thus, the 12-year-old correlations are low due, presumably,  to the f a c t that a good Performance Scale IQ does not always mean a good Verbal Scale IQ at t h i s age l e v e l .  54 There are several objections t o t h i s explanation. Although the correlations at the 9-year l e v e l are higher than at other ages, the Performance Scales i n both i n t e l l e c t u a l groups correlate lowest at t h i s age - evidence that a high IQ on one WISC scale does not n e c e s s a r i l y mean a high IQ on the other.  A study by Swineford  (16)  gives evidence contrary t o the r e s u l t s suggested by t h i s present i n vestigation that there are s p e c i a l a b i l i t i e s at 9 or 12 years of age. Students i n Grades VIII and IX (who would be older than 12 years of age) showed no change i n f a c t o r i a l composition from one year to the next, and Swineford concludes that with increasing maturity, the general factor (presumably, whether f a c t u a l or a r t i factual) plays a less important part.  The second explanation could be purely i n terms of chance.  The influence of chance factors i n a sample of ten i s bound to  be much more d i s t o r t i v e than i n a larger sample.  Presumably, the action  of Probable Errors of the IQ w i t h i n a small and homogeneous group tends to obscure any true r e l a t i o n s h i p which might e x i s t .  In a large sample,  a few reversals i n rank order would be hidden by the general trend, whatever i t might be .  Whatever the true explanation, keeping i n mind the l i m i t e d sample upon which t h i s study was based, the two scales do not seem to be interchangeable.  I t does seem possible that a c h i l d given  both of these tests might w e l l y i e l d widely d i f f e r e n t i n t e l l i g e n c e quotients on the respective t e s t s .  55 The high correlations with large Mean differences within the Superior 9-year-old range are r e a d i l y explainable.  The high  correlations i n d i c a t e that the tests are c e r t a i n l y measuring the same a b i l i t y i n t h i s group, and the differences i n scores are a t t r i b u t a b l e to differences i n t e s t construction.  The WISC i s a s c a l e with a set  standard deviation, i n which the range has been comparatively r e s t r i c t ed so that lower scores i n t h i s i n d i c a t e much higher a b i l i t y than the same score i n the Stanford-Binet;  f o r instance, an IQ o f 130 amongst  a group o f Superior children, such as those encompassed by t h i s study, i s quite usual on the Stanford-Binet, but i s much rarer on the WISC.  The d i s s i m i l a r i t y of i n t e l l i g e n c e quotients yielded by the two tests i s e s p e c i a l l y noticeable i n the Superior group:  12-year-old  correlations are a l l low and the Verbal and F u l l Scale IQs show  a s i g n i f i c a n t difference from the Mean Binet IQ at t h i s a g e - i n t e l l e c t u a l level.  Inspection of the a c t u a l scores reveals extreme differences  and, with rare exceptions, these differences are i n the direction of a lower WISC score.  Such a s i t u a t i o n i s bound t o be confusing i n some  degree to the c l i n i c i a n ;  he cannot be sure, f o r instance, when a  subject receives a slightly-above-average IQ on the WISC, whether he would have made a comparable showing on the Stanford-Binet, or whether, as happened several times i n t h i s group of Superior 12-year-olds, he might have made a Superior showing i n the Stanford-Binet.  This l a t t e r  does not constitute a fixed c r i t e r i o n by any means, but i t c e r t a i n l y i s a c r i t e r i o n of some sort, i f only through long use, and one which cannot  56  be e n t i r e l y ignored. I t i s i n t e r e s t i n g t o note that i n both i n t e l l e c t u a l groups, the rank order of the three correlations (Binet with Verbal, Performance, and F u l l Scales) i s the same f o r the same age, i . e . , the rank order o f the correlations i s the same f o r the Superior 6-year-olds as f o r the Average 6-year-oldsj  the same f o r the Superior 9-year-olds as f o r the  Average 9-year-olds;  and the same f o r the Superior 12-year-olds as f o r  the Average 12-year-olds.  Any s i m i l a r i t y i n rank order o f these  correlations, within each i n t e l l e c t u a l group, i s robbed o f i t s s i g n i f i cance by the fact that both i n t e l l e c t u a l groups display exactly the same rank order at each age. median, t h i r d  Furthermore, the highest, second highest,  lowest and lowest correlations, i n both i n t e l l e c t u a l  groups, occur i n p r e c i s e l y the same correlations, i . e . , with the same WISC scales (Verbal, Performance or F u l l ) and at the same age l e v e l s . These r e s u l t s give some suggestion that age l e v e l influences much more the degree t o which the Stanford-Binet and Wechsler Intelligence Scales for Children measure the same thing, than does i n t e l l e c t u a l l e v e l .  Obtained Results compared with the L i t e r a t u r e  As has been previously pointed out, these r e s u l t s agree very l a r g e l y with the predictions made by Seashore, Wesman and Doppelt (14).  The findings also agree, i n the main, with the r e s u l t s published  by Frandsen and Higginson:  the correlations at the 9-year l e v e l are  high (sometimes s l i g h t l y higher than those reported by Frandsen and  57 Higginson) with the Performance Scale c o r r e l a t i n g the lowest.  This  study d i d not f i n d , however, that such high correlations occur also a t other ages as i s implied by the Frandsen and Higginson study, (5)' The r e s u l t s agree with the findings o f Sartain (13), on the Stanford-Binet and Wechsler-Bellevue, that Superior subjects score higher on the Binet, although most o f the differences found on t h i s study are greater than the 5 IQ points suggested by him;  similar  findings were made by Goldfarb (6). The r e s u l t s f o r the Retarded group are simply not adequate t o permit a comparison o f the findings with those o f the l i t e r a t u r e . In agreement with Wechsler  (p.157, 19), however, there does appear t o be  some trend toward the Performance i n t e l l i g e n c e quotient being higher than either the Verbal or F u l l Scale IQs.  The results o f t h i s study agree very c l o s e l y with the findings o f Halpern (9)*  She found that the highest  correlations  between the Stanford-Binet and Wechsler-Bellevue occurred at the extremes of the normal curve, and that, i n s p i t e of t h i s f a c t , the greatest d i f ferences occurred with the Superior subjects and the l e a s t with the Defectives. In general, this study agrees with the l i t e r a t u r e of the Stanford-Binet and Wechsler-Bellevue, i n showing lower correlations between the Binet and WISC Performance Scale, than between the Binet and WISC Verbal or F u l l Scales.  58 Consistent Trends emerging from the Data The Superior 9 - y e a r - o l d w i l l probably score much higher on the Stanford-Binet than on the WISC, but h i s p o s i t i o n r e l a t i v e t o the Mean i s probably s i m i l a r on both scales.  The r e s u l t s f o r the  Superior 1 2 - y e a r - o l d are a great deal more confusing;  the two t e s t s  do not appear t o be measuring the same phenomenon at t h i s a g e - i n t e l l e c t ual level.  Much more research should be done a t t h i s , and surrounding,  a g e - i n t e l l e c t u a l l e v e l s to ascertain whether or not the r e s u l t s o f t h i s investigation are due merely t o chance influences, or whether they are due t o some difference i n subject matter i n the two t e s t s , or t o the influence o f some maturational factor.  One should also remember that the WISC does not y i e l d an IQ below 45, and that, therefore, the Binet i s much more u s e f u l i n t e s t ing at t h i s l e v e l o f i n t e l l i g e n c e . The fact that age influences the degree o f c o r r e l a t i o n between the Binet and each of the three WISC scales, much more than does i n t e l l e c t u a l l e v e l , may be i n agreement with some theories of general or s p e c i a l a b i l i t i e s and the influence o f maturation.  As was  pointed out previously, however, the trend i s not c l e a r l y towards either s p e c i f i c or general a b i l i t i e s .  Suggestions f o r future Research This study should be repeated to ascertain whether or not  59 the trends discerned i n i t are a c t u a l or merely the r e s u l t of various chance influences;  such a study would probably be rendered more  r e l i a b l e by the use of a l a r g e r sample.  Since the r e s u l t s o f t h i s  investigation suggest that the use of the WISC at very low l e v e l s of i n t e l l i g e n c e i s not e n t i r e l y s a t i s f a c t o r y , future studies might u t i l i z e a l e s s extreme group of defectives.  As outlined i n a previous section, a future i n v e s t i g a t i o n might be directed toward ascertaining whether or not the wide d i f f e r ences i n i n t e l l i g e n c e quotients, yielded by the two t e s t s at the Superior 12-year-old l e v e l , are a manifestation special a b i l i t i e s .  of the development o f  This purpose could, perhaps, be accomplished by  t e s t i n g above and below the 12-year age l e v e l , and noting  consistent  trends toward smaller correlations and wider s i g n i f i c a n t differences with increasing  age.  SUMMARY  The purpose o f t h i s study was t o investigate the r e l a t i o n s h i p between IQs yielded by the 1937 Revised Stanford-Binet, Form L, and the Wechsler Intelligence Scale f o r Children (WISC) at d i f f e r e n t age l e v e l s and d i f f e r e n t l e v e l s of i n t e l l i g e n c e .  The  i n v e s t i g a t i o n endeavored t o f i n d out t o what extent the Stanford-Binet correlates with each o f the WISC Verbal, Performance and F u l l Scales at ages 6, 9 and 12 years, and with superior, average and defective children.  I t attempted t o ascertain whether the Mean scores i n  t h i s group show r e a l differences i n average IQs yielded by the two t e s t s , and, i f so, i n which d i r e c t i o n these differences occur.  The WISC i s a point scale with a s e t standard deviation, while the s i z e o f the Stanford-Binet v a r i e s , being unusually small at age 6 years, and unusually large at age 12 years.  I t was hypothesized  that a t the extremes of the i n t e l l i g e n c e d i s t r i b u t i o n a t these ages, there should be a difference between the Mean IQs of the two scales i n the d i r e c t i o n corresponding t o the s i z e o f the standard deviation a t the age i n question.  To insure that extreme scores would occur, the  sample included superior subjects and mental defectives.  Besides the  6 and 12-year-olds necessary to t e s t t h i s hypothesis, the sample also  61  included 9-year-olds, whose Stanford-Binet standard deviation approximates that of the WISC.  These 9-year-olds, plus a sampling o f average c h i l d -  ren, were included f o r purposes of control and comparison but also f o r t h e i r own research value. The sample was composed o f eighty-five subjects - t e n children i n each age category i n the Superior and Average groups; and i n the group of Defectives, fourteen 12-year-olds, nine 9-year-olds, and four 6-year olds.  The Average and Superior subjects were obtained  i n the elementary schools throughout  Greater Vancouver, and were chosen  on the basis of past records o f a b i l i t y and achievement.  The group of  Defectives was obtained from the Woodlands School, New Westminster, B.C., and from the Rainier State School, Buckley, Washington, U.S.A.:  a l l the  feebleminded subjects had been diagnosed as " f a m i l i a l " defectives.  The p o s i t i v e correlations which occurred may be summarized as follows :  1.  In the 9-year-old Superior group, the StanfordBinet IQ correlated s i g n i f i c a n t l y with (a) the WISC Verbal IQ at the 1% l e v e l o f confidence; (b) the WISC Performance Scale IQ a t the 5$ l e v e l o f confidence; (c) the WISC F u l l Scale IQ a t the 1# l e v e l of confidence.  2.  In the 9-year-old Average group, the StanfordBinet IQ correlated s i g n i f i c a n t l y with -  62 (a) the WISC Verbal Scale IQ at the 1% l e v e l o f confidence; (b) the WISC F u l l Scale IQ at the 5% l e v e l of confidence.  Significant  differences between the Mean IQs o f the two  t e s t s may be summarized as follows :  1.  In the group of Superior 9-year-olds, the Stanford-Binet IQs were s i g n i f i c a n t l y higher (at the 1$ l e v e l of confidence) than the WISC Verbal, Performance and F u l l Scale IQs.  2.  In the group o f Superior 12-year-olds, the Stanford-Binet IQs were s i g n i f i c a n t l y higher at the 1$ l e v e l o f confidence f o r the WISC F u l l and Verbal Scale IQs.  3»  In the group of Average 12-year-olds, the Stanford-Binet i s s i g n i f i c a n t l y higher a t the 5% l e v e l o f confidence than the WISC Verbal Scale IQ.  The major conclusions o f this study are :  1.  The obtained r e s u l t s are i n e s s e n t i a l agreement with the studies comparing the Wechsler adult scale and the Stanford-Binet.  2.  There seems to be a consistent tendency i n t h i s study and others reviewed previously, toward lower correlations between the Stanford-Binet and WISC Performance Scale, than between the . Stanford-Binet and WISC Verbal and F u l l Scales.  3'  There seems t o be no support f o r the hypothesis that the differences between the Mean Binet and  63 Mean WISC IQs at the Superior l e v e l w i l l d i f f e r i n d i r e c t i o n according t o the s i z e o f the Stanford-Binet at the age l e v e l i n question. 4«  The WISC appears t o be an u n s a t i s f a c t o r y test for the markedly retarded children. Both i n terms of construction and i n t e r e s t value to subjects, the Stanford-Binet seems t o be a better scale f o r the measurement of the lower l e v e l s of i n t e l l i g e n c e .  5.  Keeping i n mind the l i m i t e d sample upon which this study was based, the two scales do not seem t o be interchangeable. The p r a c t i c a l import o f t h i s conclusion i s that c l i n i c i a n s , s o c i a l workers, p s y c h i a t r i s t s , school teachers, and so on, should be f u l l y aware that the c h i l d given both tests may well y i e l d widely d i f f e r ent IQs on the respective t e s t s .  BIBLIOGRAPHY  ANDERSON, John E. The l i m i t a t i o n s of i n f a n t and preschool tests i n the measurement of i n t e l l i g e n c e . J . Psychol., 1939, 8,  351-379BALINSKY, B., ISRAEL, H., and WECHSLER, D. Relative e f f e c t i v e ness o f the Stanford-Binet and Bellevue i n t e l l i g e n c e scales i n diagnosing mental deficiency. Amer. J . Orthopsychiat.,  1939, 9, 798-801.  BENTON, Arthur L., WELDER, Arthur, and BLEAUVELT, Jean. Performance of adult patients on the Bellevue i n t e l l i g e n c e scales and revised Stanford-Binet. Psychiat. Quart., 1941, 15,  802-806.  BURT, C y r i l . C r i t i c a l notice o f Thurstone's "Multiple Factor Analysis." B r i t . J . educ. Psychol., 1947, 17, 163-169. FRANDSEN, Arden N., and HIGGINSON, Jay B. The Stanford-Binet and the Wechsler I n t e l l i g e n c e Scale f o r Children. J . cons u l t . Psychol.. 1951, 15, 236-238.  GOLDFARB, William. Adolescent performance i n the WechslerBellevue i n t e l l i g e n c e scale and the r e v i s e d Stanford-Binet examination, Form L. J . educ Psychol.. 1944, 35, 503-507. GUERTIN, Wilson H. Mental growth i n pseudo-feeblemindedness. J . c l i n . Psychol.. 1949, 5, 414-418. GUILFORD, J . P.  367-394-  Human a b i l i t i e s .  Psychol. Rev.. 1940, 47,  65 9.  HALPERN, Florence. A comparison of the revised Stanford-Binet, Form L, and the Bellevue adult i n t e l l i g e n c e t e s t as c l i n i c a l instruments. Psychiat. Quart. Suppl. 1942, 16, 206211. t  10.  KUTASH, S. B. A comparison of the Wechsler-Bellevue and the revised Stanford-Binet scales f o r adult defective d e l i n quents. Psychiat. Quart., 1945, 19, 677-685-  11.  MITCHELL, M. Performance o f mental h o s p i t a l patients on the Wechsler-Bellevue and the r e v i s e d Stanford-Binet, Form L. J. educ. Psychol.. 1942, 33, 538-545-  12.  RABIN, Albert I., and GUERTIN, Wilson H. Research with the Wechsler-Bellevue t e s t : 1945-50. Psychol. B u l l . , 1951, 48, 211-248.  13-  SARTAIN A. A comparison of the new r e v i s e d Stanford-Binet, the Bellevue scale and c e r t a i n group tests of i n t e l l i g e n c e . J- s o c Psychol.. 1946, 23, 237-239-  14-  SEASHORE, Harold, WESMAN, Alexander, and DOPPELT, Jerome. The standardization of the Wechsler I n t e l l i g e n c e Scale f o r Children. J . consult. Psychol.. 1950, 14, 99-110.  15-  SPEARMAN, C. Theory of general factor. 1946, 36, 117-131-  16.  SWINEFORD, Frances. Growth i n the general and verbal b i - f a c t o r from Grade VII t o Grade IX. J . educ. Psychol., 1947, 38, 257-272.  17-  TERMAN, Lewis M., and MERRILL, Maud A. Measuring IntelligenceLondon: George G. Harrap and Co. Ltd., 1937-  18.  THURSTONE, L. L. Current issues i n factor a n a l y s i s . B u l l . , 1940, 37, 189-237-  19.  WECHSLER, David. The Measurement of Adult Intelligence. Baltimore: The Williams and Wilkins Company, 1944.  B r i t . J . Psychol.,  Psychol.  66 20.  WECHSLER, David. Wechsler I n t e l l i g e n c e Scale f o r Children Manual. New York: The Psychological Corporation, 1949.  

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