Difficulties in the Interpretation of Mental Tests? Types and Examples
- Author:
Frances Porter, A.B.,
Assistant Psychologist, Psychopathic Institute, Juvenile Court, Chicago. II Class II. Cases in whijh the Results on the Same Tests Differ when the Tests are Repeated 1. Results relatively better on retesting.
a. Individual first tested when in bad physical condition and retested after physical condition has improved. Case 18.* V. C. 16 years, 2 months. Boy. Summary: When this boy was first tested he was in bad physical condition; very poorly developed, undernourished, and very tired and listless. He had been smoking excessively. The tentative diagnosis was dull from physical causes. He was placed on a farm and was next tested after seven months of farm life. Although still very small for his age, he was then vastly better. His color was good and he had quite lost his listlessness. This time he. did well on the tests and would be diagnosed as of at least normal ability. The improvement is made, as one might perhaps expect, in those tests which require a more sustained effort and where there is not the stimulus of handling concrete material; the reason, undoubtedly, is that the boy’s former poor results on these tests were due, not to any lack of innate ability, but to a lack of sufficient vitality and energy to make use of his ability. This is one of the very important types of cases in court work where so large a proportion of the children come from ignorant and poverty stricken families, and consequently live under poor hygienic conditions and without the proper medical care. With such cases there is no other possible diagnosis than a tentative one. Mental tests: Introductory test?2m 453. Triangles?lm 48s. This is a decidedly poor result for a boy of 16. First Construction test?2m 16s, with 28 moves. This also is a poor result. Second construction test?lm 26s with 15 moves, a good record. First cross line test?done on first trial. Second cross line test?done on third trial. A normal child of eight generally does this on the third or * Case 10 in part I should have been case 9 under the heading “Individuals with poor powers of concentration” (p. 151); and case 9 should remain under its previous heading, but be called case 10.
fourth trial. Substitution test?3 errors in the reproduction from the model; 5 errors in the reproduction from.memory. This is noticeably poor. School work?reads fairly well. Arithmetic and writing both very poor.
Mental tests (seven months later): Binet tests?does all the 12 year tests correctly. First construction test?lm with 6 moves. Second construction test?2m 40s with 16 moves. Second cross line test (renumbered)?done correctly on first trial. Substitution test? done promptly with no errors in either reproduction. Completion test?3 errors, none illogical.
b. Individual tested when in an unfavorable emotional state, and retested in a favorable state.
Tested under unfavorable laboratory conditions.
Case 19. F. T. 17 years, 8 months. Girl. Summary: The interview with this girl, who came in with a prior diagnosis of feeblemindedness, was begun by way of a conversation about herself and her brother and their home life. The tests were introduced after talking to her about the kind of work she intended to do. When later the examiner praised her for doing well on the tests, she suddenly looked up and said in a very naive way: “Isn’t it funny that I’m not a bit afraid of you and I was so scared the other day with that other lady.” When asked why she had been so frightened she said, “Well, that doctor, you know, a large man, sat right there and stared at me. That made me nervous. I got so embarrassed I guess I really did act like a fool. I don’t know what I did say. Then two ladies came in and once when I answered some question I saw the lady that was talking to me look at them and laugh. After that I got mad and did not try. I just felt like I did not want to say anything.” After she had given 60 words in a little over 2m and had been told she had done well she said, ” I’m glad you think I can do something because I only gave 25 words the other day. Oh, I know because I saw her write it down. She had the paper right there where I could read it.”
She was greatly pleased at being told she had done quite well because at the end of her other examination her probation officer had told her that she had the mind of a little child.
Mental Tests: Binet tests?does all the 12 year tests easily. First construction test?203 with 8 moves. Second construction test? lm 18s with 14 moves, both good records. Second cross line test? done on first trial. Completion test?only two errors, both logical. School work?fairly well, only. All the results, except on school work, distinctly good.
(2) Tested when in a recalcitrant attitude. Case 20. W. A. 12 years, 4 months. Girl. Summary: This case illustrates how completely the results on mental tests may be distorted by the deliberate attitude of the person examined. In this case, the attitude was not induced by the experience of being examined, but was instead an anti-social attitude of long standing. The girl gave no sign of her frame of mind, so that it was not until she did so well on the later examination that it could be discovered that the first results were entirely worthless. Both times the girl’s physical condition was rather bad?poor nutrition, and vision only 20/60. The mother was said to have no control over this girl or over her subnormal older brother. This brother bullies W. at home and she, in turn, bullies the younger children at school. She has a very determined will and a fiery temper when she does not have her own way. She had got into a great deal of trouble at school, and, largely because of her unmanageableness, was put into the subnormal room. The first time we saw her she had been sent from the court to be tested before going to an institution; the second time was just after she had been released from it; released, not because of a court order but because she had successfully followed out her own plan of being so unruly and so stupid that she could not be kept. Naturally, she was in high spirits and very affable with the examiner. As a result her Binet age was changed from 9 3/5 years to 12 years in an interval of 5 months, and her work on other tests bears out her work on the Binet tests. A couple of months later she is reported as doing very well in the same school in which she had previously been so obstreperous.
Mental tests: Binet tests?failures; 10 years (1) arranging weights, (2) copying design, (3) detecting incongruities, (4) solving common sense problems; 12 years (1) using given words in one sentence, (4) defining abstract terms, (5) rearranging shuffled sentences. Introductory test?done poorly. School work?done very inaccurately.
Mental tests (five months later): Binet tests?does all the 10 year and all the 12 year tests quickly and easily. First construction test?she began this rather at random, then took out all the pieces and finished with good foresight in lm 243. Second construction test? 458 with 12 moves (11 being the minimum possible number of moves). Kraepelin test?here she shows poor mental control, making 3 errors in subtracting by sevens and later 7 errors in subtracting by threes. Opposites test?this, on the other hand, was done very well, with no error and the range was lm 2s. c. Undisciplined individual.
Case 21. A. J. 11 years, 3 months. Non-delinquent. Summary: Father and mother divorced. Earlier the father was very cruel to him. The mother has worked and the boy has been away from her in a number of institutions and on a homestead. She thinks that he has been to school, altogether, less than two years. A. J. shows many characteristics of the untrained child. He invariably wants to do some other test than the one given to him, or to use the material in a wrong way. He has to be reprimanded quite severely to make him obey instructions. If the problem is at all difficult for him he either loses his temper and pounds the material, or he becomes discouraged and begins to cry. Because of his lack of concentration he fails in tests which later prove to be within his ability. It is typical of his conduct that he has a visual memory span for five numbers, but will not try the test unless he reads the figures backwards.
This child represents very fairly the type of cases in which purely formal tests fail because of the child’s lack of previous training. This type is not to be confused with the uninformed child who fails in all the Binet questions involving information; here the lack of training shows itself in the child’s evident unfamiliarity with any mental problem, and his consequent inability to attack it calmly. On the first testing by the Binet scale, A. J. was 2 3/5 years retarded, but later he did 4 1/3 more tests which makes him not quite 2 years retarded. After this indication that we are not measuring his real ability, some tentative diagnosis seems the only course. We must certainly admit that a single trial is utterly inadequate and that the tests may even fail altogether. In this type of case (by no means uncommon among court children) the difficulties found in making a court recommendation from tests are equally great in working with other tests as with the Binet tests and the psychologist must not fail to take these difficulties into account if any useful recommendation is to be made from the results. Mental tests: Binet tests?failures; 7 years (4) giving value of stamps; 8 years (2) counting 20-0, (4) repeating numerals. (His memory span is 3 numbers); 9 years (1) making change, (4) naming months; 10 years (3) detecting incongruities, (4) solving common sense problems; 12 years, all. Binet age, 8 3/5. Introductory test? gave up after 4m 15s. He had done all except the triangles. First construction test?failed in 5m. Completion test?done in a very nonchalant manner with 25 moves (there are only 9 spaces to be filled), and with 5 final errors, 3 being illogical. Later he does this with only 2 illogical errors and no random moves. School work? does only the simplest concrete arithmetic and reads a first grade passage stumblingly with foolish comments. He was very restless and cried a good deal during these tests, but was easily cheered up. Mental tests (three days later): Binet tests?he succeeds in doing the following tests which he had previously failed; 10 years (4) Says at once that before taking part in an important affair he’d “sit down and think about it;” 12 years (1) comparing lines, (2) using given words in one sentence, (3) saying 60 words in 3m, (4) 1/3. He defines “charity” but cannot define “goodness” and “justice.” The sixty word test was only done after a great deal of urging. He had tried it before and always cried as soon as he could not think immediately of another word. He still fails on 8 years (2) and (4), 9 years (1) and (4), probably because these require information. First construction test?still fails on this. Second construction test? done in 4m, a slow record. First cross line test?done on second trial. School work?refuses to try any more arithmetic. Auditory memory span?3 numbers. Visual memory span?5 numerals.
2. Results relatively worse on retesting. Case of dulness from dementia. Case 22. B. U. 16 years, 9 months. Boy. Summary: Physical condition very good. The boy is clearly suffering from a mild mental upset, either an adolescent psychosis or the beginning of something more serious. Contrast the record of this boy with that of Case 5, the aberrational case given in Class I. In that case the Binet record is that of a normal individual, while in this case where the boy is known to have good ability, it is that of a defective: in the one case the Binet results do not tell the story, in the other they tell a false one. The very intelligent father of this boy tells us that until he was twelve years old he seemed entirely normal. At that time he passed examinations for the high school so that he is plainly at least up to the average in mental ability. When he began the high school course the teachers felt that he was peculiar and advised that he be examined. When we saw him he had already left school and had been working for sometime. This bright boy has a Binet age of just over 10 years and does equally poorly on other tests. The explanation is evident from his work on all tests involving mental control?note the atrocious results on the easy opposites test and on the Kraepelin tests. His conversation shows the same incoherence, he leaves his sentences unfinished and although he is not trying to defend himself he continually contradicts what he has just said. We certainly have no justification for accepting these negative results and no right to diagnose the boy as defective.
Mental tests: Binet tests?failures; 10 years (1) arranging weights, (2) copying drawings; 12 years (2) using given words in one sentence, (3) saying 60 words in 3m. Binet age 10 1/5. Second construction test?lm Is with 12 moves, a decidedly good record. Secorid cross line test?failed on fourth trial. Completion test?6 errors, 3 illogical, also an extremely poor result. School work?does long division with some careless errors. Tapping test?60 squares in 308 with 4 errors (first trial); 60 squares in 30s with 3 errors (second trial). Kraepelin test?subtracting by 7’s from 100 done in 2m 208 with 6 errors. Subtracting by 6’s done in lm 24s with 3 errors. Poor results. Opposites test?14 errors, 1 failure. Range 6.8a-23, average time 4s. This is an extremely bad record and the responses were very peculiar as well as slow.
Mental tests (repeated by another examiner): Second cross line test?renumbered, done on first trial. Completion test?7 errors. Tapping test?done much worse, only 39 squares tapped in 30s with 7 errors. Kraepelin test?subtracting by 7’s, 6 errors. Opposites test?9 errors.
It is quite unnecessary to give farther illustrations of cases which might come under this heading. Illness or physical weakness or depleting habits of many kinds, as well as dementia, per se, very obviously may cause a lessening of mental powers, either temporary or permanent.
Class III. Cases in which the Results on Tests are Noticeably Irregular. 1. Results on all types of tests irregular. a. Epileptic cases.
Case 23. J. M. 11 years, 7 months. Girl. Summary Physical condition, minor epilepsy. Her work on tests illustrates the peculiarities that are almost invariably found in the tests of the epileptic; though the epileptic is not the only type showing such records, hysterical cases and those addicted to bad habits showing the same reactions. These peculiarities are the variation from day to day, even from hour to hour, and the passing of more difficult and failing of less difficult tests; for instance, J. M. fails the second day in the first 12 year Binet test which she had previously passed, and does the completion test most atrociously, though later in the day she does this fairly well. The second peculiarity is shown in her work on the construction tests where she practically fails in the first test, which is generally considered the easier (56 moves, 17 of them impossible, for a test requiring 5 moves is practically a failure), while she does the second quite well.
Mental tests: Binet tests?failures; 12 years (3) saying 60 words in 3m, (5) rearranging shuffled sentences. School work? addition and long division done correctly.
Mental tests (four days later): Binet tests?failures; 12 years (1) comparing lines. She had done this correctly before, but persistently fails in it today. Does the others very easily. First construction test?4m 40s with 56 moves; 17 are placing of pieces in impossible situations. This is practically a failure. Second construction test? 2m 47s with 16 moves, only 5 more than the minimum.
Mental tests (next day): Completion test?done with 8 moves, 7 illogical, out of a possible 9 errors. This is a most unusually bad record. Later in the day she does it with 4 errors, 2 illogical. Case 24. V. T. 12 years, 11 months. Girl. Summary:
Physical condition good except for minor epileptic attacks. The girl has been truant from school a great deal and has been running away from home. Her tests results are true to the epileptic type, but she is subnormal as well, while with J. M. the poor results were due to epilepsy only. In this case the irregularities are shown in the Binet tests as well as in the performance tests. She does decidedly better on the second testing, her Binet age being changed from 8 2/5 to 9 1/5, but even at that the results are somewhat unusual; for she fails one of the 8 year tests yet succeeds in passing one of the 12 year group.
Mental tests: Binet tests?failures; 8 years (5) repeating numbers; 9 years (2) defining in terms superior to use, (4) naming months; 10 years (1) arranging weights, (2) copying drawings. Binet age, 8 2/5. First construction test?8s with 6 moves. That is very well done. Second construction test?3m 4s with 28 moves. This is a normally good performance. First cross line test?done on third trial. Second cross line test?done on fourth trial, but with great difficulty, a very poor attempt for her age. Completion test?3m 15s with 4 errors, 3 illogical. This also is poor. School work? writes very badly and cannot add three columns of figures. Mental tests (one week later): Binet tests?she still fails on 8 years (5); 9 years (2) and (4); but she now succeeds on 10 years (1) arranging weights, (2) 1/2 copying drawings, (5) using given words in two sentences; 12 years (2) using given words in one sentence, (3) saying 60 words in 3m. Binet age, 9 1/5. Second construction test?56s with 18 moves. Second cross line test?(renumbered) done easily on first trial; entirely different from her previous attempt. Completion test?2 errors, illogical. This also is very much better than her other effort. School work?done as poorly as before. b. Case of mental dulness from bad habits.
Case 25. N. L. 11 years, 10 months. Girl. Summary:
Very good physical condition. This case is significant as showing the effect on mental processes of a continued bad habit, even where this has not caused actual physical depletion. This little girl was brought to us because she had been through a series of bad sex experiences; which had not, however, involved any physical drain on her, but which at this time quite filled her mind. Mentally she is definitely not defective, but is at times dull and erratic in her work. She begins a test well, but her attention soon wavers; note her work on the second construction test and her attempt to do long division. She shows on the second testing that some of her failures were not due to inability, but to some temporary mental disturbance. The exact nature of this disturbance is doubtful, though it seems to involve a weakening of the powers of concentration. Perhaps this is due to intellectual debility, because of which the child lapses into a dreamy state or even one of mental vacuity, but it seems more probable that it is due to an obsessive recurrence of one system of ideas. Thus we have had girls tell us that “when a girl gets those ideas into her head, she can’t get in any others,” and children often stress the fact by stating that “those thoughts keep coming up in my mind in school.” Mental tests: Binet tests?failures; 10 years (2) 1/2 copying drawings, (3) detecting incongruities, (4) solving common sense problems. Does all the 12 year tests easily. First construction test? done fairly well. Second construction test?failed on first trial. Here she filled all but one space, and could not succeed in arranging those four pieces. Half an hour later does this quite normally in 3m 3s with 26 moves. First cross line test?done on second trial. Second cross line test?failed, clearly because she could not control her mental processes sufficiently. Completion test?1 illogical error, a normal result. School work?does arithmetic poorly. Other work fair. Mental tests (next day): Binet tests?does the 10 year tests she had failed. Second cross line test?she still fails on this. Says she can’t keep her mind on it. School work?she gets almost through a problem in long division without any errors, and then her attention weakens and she makes an error.
Results vary from time to time.
Case 26. I.K. 13 years, 6 months. Boy. Summary: Vision somewhat defective, but general physical condition good. Rather strong for age and size. This case illustrates rather strikingly the danger of making a diagnosis on a single examination where the results on Binet tests are poor. At the first interview this boy’s Binet age was just 9 years, one week later he passes every Binet test except giving 60 words in 3m. The boy was sent from an institution for dependent children, partly because he has done so poorly in school during the five years he has lived there, and partly because he has recently begun to steal small amounts from the home. When we first saw him he seemed very friendly and so far as we could tell was quite at his ease and willing to cooperate. Though his work on performance tests was rather irregular, he did nothing so poorly as to indicate that he was defective mentally, yet on the Binet tests he only succeeded in getting through 9 years. He seemed to have done the very best of which he was capable at the moment, and, of course, his school work was on a par with the Binet results; nevertheless we said at the time that we felt he might do better another day. This proved to be decidedly the case for the next week he did all the tests he had previously failed except the third of the 12 year tests. From the first testing we should have considered him feebleminded, perhaps with some specialized ability, and the only possible recommendation would have been a school for the feebleminded. After seeing him a second time we considered him a border-line case who might become very useful in some institution, although he probably could not make good outside of one. Nevertheless he scarcely needs the training of a school for the feebleminded.
Mental tests: Binet tests?failures; 8 years (2) counting 20-0; 9 years (2) defining in terms superior to use. (4) naming months; 10 years (2) copying drawings, (3) detecting incongruities; 12 years, all. First construction test?failed in 5m. Later did this in 55s. Second construction test?lm 27s. First cross line test?done on first trial. That is, these three performance tests are quite well done; the failure was probably due to being “rattled.” Second cross line test? done on fourth trial. This is a very poor result. Tapping test? done rather slowly but accurately. School work?he does only the simplest concrete additions, and can barely write.
Mental tests (a week later): Binet tests?does all the tests except 12 years (3) giving 60 words in 3m. Second cross line test (renumbered)?done on first trial. School work?no better than before.
3. Results on Binet tests show great irregularity. The first two records are those of feebleminded boys, but they differ from the common type in this great irregularity: Thus H. I. does better on the 7 year than on either the 5 or the 6 year tests, thus showing a small, but peculiarly distributed “area of irregularity.” C. M. fails on two of the 7 year, yet passes one of the 12 year tests. showing a large area of irregularity. Both of these boys come of pronouncedly neuropathic parents. In the third case, S. T., the boy fails on one 8 year and passes three 12 year tests, but all his failures except one are very distinctly questions of information. This was not true of the other cases where the failures included questions involving information, memory span, and reasoning, indiscriminately. The detailed record of these three cases is as follows: a. Defectives (not of the usual type) whose irregularities are the results of failures on all types of Binet tests.
Case 27. H. I. 7 years, 9 months. Boy. Summary: In this case, as in the following one, the heredity is bad. Both parents were alcoholic and the mother was probably insane. General physical condition is fair. The boy’s Binet record is very irregular. He fails on more of the 5 and 6 year than of the 7 year tests. Moreover his responses to the same situation are extremely variable, so that one is not at all sure how much he really knows and how many of his replies are random. He has much difficulty with anything involving language, and refuses even to try the memory tests. Mental tests: Binet tests?failures; 5 years (1) comparing weights, (3) repeating ten syllables, (4) counting pennies; 6 years (2) defining in terms of use, (3) drawing diamond, (4) counting pennies, (5) distinguishing pretty and ugly faces; 7 years (4) giving value of stamps, (5) naming colors. Binet age, 5 1/5. Case 28. C. M. 15 years, 11 months. Boy. Summary:
This boy shows a number of stigmata of degeneracy and is decidedly under nourished. No other physical defects. His heredity is bad. His father was neurasthenic and died in a detention hospital and one paternal aunt is insane. On the mother’s side the heredity is good. C. M. does most erratically on Binet tests, fails two of the 7 year, two of the 8 year, two of the 9 year and four of the 10 year tests, and yet does one of the 12 year group. His Binet age is just 8 and his work on other tests confirms this.
Mental tests: Binet tests?failures; 7 years (4) giving value of stamps, (5) naming colors; 8 years (1) comparing objects, (2) counting 20-0; 9 years (1) making change, (2) defining in terms superior to use; 10 years (1) arranging weights, (2) copying drawings, (3) detecting incongruities, (4) solving common sense problems; 12 years (3) saying 60 words in 3m; (12 years) (1), (4), (5) not tried.) Binet age, 8. First construction test?failed in 5m. First cross line test?failed. Completion test?done in very random fashion with 8 final errors, 6 being illogical. School work?fails to add 5 and 2, Reads a third grade passage with difficulty.
b. Normal children who fail on all the questions of one type. Case 29. S. T. 11 years, 4 months. Boy. Summary: This little boy is in rather poor physical condition because of a large infected cavity in the lower jaw. His home environment has been wretched. His father drinks heavily and does not support the family so that the mother is forced to work out all day. Consequently the boy has had almost no home control, and has been truant a good deal from school. Out of the six failures on Binet tests five are definitely due to lack of information. The fact that he does well on all performance tests which do not involve previous training proves that his poor record is due not to want of ability, but to lack of training.
Mental tests: Binet tests?failures; 8 years (4) date; 9 years (1) making change, (4) naming months; 10 years (1) arranging weights; 12 years (4) defining abstract terms, (5) rearranging shuffled sentences (boy cannot read these). Binet age, 9 4/5. First construction test?done in 17s with 7 moves. Second construction test? 2m 35s with 23 moves. First cross line test?correct on first trial. Second cross line test?correct on second trial. Completion test? done with only two logical errors. All these are decidedly good results. School work?does arithmetic very poorly and can barely read.
Case 30. P. D. Just 12 years. Boy. Summary: Physical condition, very defective vision; right eye 20/120, left eye 20/40. Attacks of vertigo. This case is given only to show that although lack of schooling frequently affects the results on Binet tests as in the case of S. T. (just cited) it may sometimes make no difference. In this case the boy has had probably less than three years schooling and no home training, yet he does all but one of the 12 year tests, including even the shuffled sentences, which he could read only with the greatest difficulty. P. D. is a little Italian boy who has always lived under miserable home conditions. His father and mother are separated and he lives with a younger brother and with the father who is away all day. The boys are locked out of the house in the morning and get their meals from neighbors. P. has just come from an institution where he thinks he was in the third grade. He has been in institutions twice before for a few months at a time; aside from that he has always “bummed most of the time after the first two years.”
Mental tests: Binet tests?only failure; 12 years (4) defining abstract terms. (Note that the boy is just 12.) First construction test?21s with 7 moves. Second construction test?lm 15” with 11 moves. Second cross line test?done on first trial. These three tests are excellently done. Code test?2 errors, 5 dots omitted. This also is done well for his age. Completion test?No errors. School work? this is of course very poor. He reads a second grade passage with difficulty.
Conclusions.
Class I includes nine types of cases, all indicating the need of more than the Binet-Simon system of tests for practical diagnosis. The inadequacy of these tests is due to a number of causes. The most obvious is the over-emphasis laid on language, the results depending so very largely on the individual’s ability to use spoken English. This distorts results, not only in the case of the foreign-born person, where, as we should expect, the difficulty with an unfamiliar tongue hides real ability, and in the case of individuals with a special disability for language, but in a quite different manner distortion occurs in the case of the verbalist type of defective whose language ability is out of all proportion to his other abilities. Here we get an exaggerated view of his mentality and may find ourselves diagnosing as normal some subnormals of a type which is often socially dangerous. Another cause of inadequacy of the Binet system is the fact that education and previous training very often, though not always, affect the results.
A third cause lies in the brevity of each separate task. The tests require only a series of spurts from the individual, instead of prolonged effort; consequently the tests give no indication of the person’s power to control his mental processes and voluntarily hold himself to one line of thought. Even where lack of this power is sufficient to class the person among the defective or the aberrational cases, the Binet tests may fail to show any indication of it.
The above criticisms apply, not only to the Binet 1911 series, but in the main to the various revisions of the Binet system which have been offered. Kuhlman made a slight attempt to introduce performance tests into the series, but others have rather increased the proportion of language tests after 8 or 9 years, and have done little to prolong the task set, or to avoid the over-valuation of formal training. The recently developed Yerkes-Bridges Point Scale does not help at all in these vital particulars. We chose the 1911 revision of Binet himself because it represents the mature views of the master, and has received more general sanction than any other revision. Then, there is the fact that the scale is satisfactory only up through 10 years. The tests above 12 years are now very generally realized to be of little value, and the want of any 11-year tests in Binet’s own latest revision greatly lessens the usefulness of the 12-year group. If a boy who has just completed his twelfth year passes all the 12-year tests, well and good, but if he passes only three? Surely one cannot count his mental age only 10 3/5 without positive proof that he would have failed on all the 11-year tests had there been any. On the other hand, why should each 12-year test penalize doubly? An analogous situation arises in the case of the child who passes all the 8-year, none of the 9-year, and three of the 10-year tests; his mental age is counted as only 8 3/5, although he has also passed three tests two years in advance of his basal age. If a child 13 years and 0 months failed on some of the 12-year tests, the fact would be significant, he would show somewhat retarded, but any Binet age as given between 10 5/5 and 12 5/5 means nothing exact. Since there are no valid Binet tests beyond 12 years, it follows that for all the cases over 12 years of age who are not feebleminded, there is no accurate gauge. We have never felt justified in accepting any group of tests for 11 and 13 years, first, because there is no agreement by clinical psychologists as to the respective values of any of the groups offered, and, secondly, because we believe that Binet was probably right in his opinion that it is not possible fairly to offer a common gauge for the mental growth of any single year above 10 years. Accretions at that age are comparatively small and show great individual variation. At our institute we have long ago concluded that the Binet tests in any revision have little validity for the establishment of accurate age norms above 10 years. During the last year from other careful sources there have come strong corroborations of this opinion. The above criticisms do not apply to the performance tests, which give us in these cases much information concerning the mentality of older persons, although not, of course, on an accretional age basis. Indeed we have found that the performance tests give us more adequate and more accurate information about all except tne very young children?not only for the reasons given above, but because they more easily arouse the interest of the individual who is being examined.
The cases of Class I suggest a criticism of Binet tests. Those in Class II show the pitfalls in all mental testing. The salient fact is this?that an individual does not always react in the same way to the same tests. The inevitable conclusion is that a single examination may not give us a fair measure of a case. Just now when there is such a move to make use of psychological tests in connection with the courts, a realization of the limitations of mental tests is indispensable if applied psychology is to contribute anything of value to social justice and not merely bring itself into deserved disrepute. If we find, and we most certainly do find, that many extraneous factors may enter into the examination, causing a normal individual to react temporarily as a subnormal one, then we must accept the fact, admit that we cannot safely diagnose every case in a single examination, and make sure by repeated trials that we have measured the actual mental ability of the individual and not his ability negatived by unfavorable emotional or physical conditions.
The common feature of the cases in the Class III is the irregularity shown on test results. Such results are of great diagnostic value, but only after the most careful interpretation. This uneven work will lead the examiner to suspect some one of a certain group of abnormal conditions?we get such results in the cases of epileptics, constitutional inferiors, hystericals and those mentally dull from bad habits. After the trouble has been determined, the tests cannot be taken at their face value as giving a quantitative measure of the individual’s mentality, except in the most general way, and after taking into account most carefully the probable effect of what may be a temporary abnormality.
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