"Constancy" of the IQ.

Thorndike, Robert L.

doi:10.1037/h0061268

Cited by 55 publications

(15 citation statements)

References 84 publications

(69 reference statements)

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“…( 4 ) Variation in the rate of intellectual growth. In general, as the interval between tests lengthens, so the retest correlation decreases, often steadily (Nemzek, 1933; Thorndike, 1940;Eysenck, 1953). There is no reason to suppose that errors of measurement (whether arising from personal fluctuations in respect of subject or tester, or standardization errors) are likely to be steadily cumulative, and thus a decreasing correlation coeficient must be primarily a reflexion of some real change of status of members of the group.…”

Section: Third Studymentioning

confidence: 99%

Cognitive and Social Changes in the Feebleminded—three Further Studies

Clarke¹,

Clarke²,

Reiman³

1958

British J of Psychology

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Earlier papers have described researches showing that i.q. increments in adolescent and young adult persons certified as feebleminded occur not infrequently, cannot be explained as artefacts, and appear to be linked with early very adverse environmental experiences. The present three studies indicate that i.q. increments can be large over long periods of time, are correlated with changes in social adjustment, but cannot be shown to be induced by special environmental stimulation; in the present age range and type of subject, they tend to occur in any reasonable environment. Results imply that a necessarily poor outcome cannot be predicted for children with i.q.'s in the 50's, 60's or 70's if they also come from very adverse conditions. Test reliability, statistical regression, and a review of some relevant literature are discussed; theoretical problems concerning intellectual development are presented; and attention is directed to individual differences in susceptibility to environmental damage and to the whole problem of human resilience.

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Section: Third Studymentioning

confidence: 99%

Cognitive and Social Changes in the Feebleminded—three Further Studies

Clarke¹,

Clarke²,

Reiman³

1958

British J of Psychology

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“…(3) The fact that test-retest correlations tend progressively to diminish with time. Below the age of 20, this diminution is in the order of 0.04 per year, excluding children under 5 years of age, where it is larger (see Thorndike, 1933Thorndike, , 1940Eysenck, 1953).…”

Section: Statement Of the Problemmentioning

confidence: 99%

“…In general it is found that the longer the time interval the greater the tendency to individual change and hence the lower the correlation coefficient. Eysenck (1953), for example, calculated from Thorndike's (1933Thorndike's ( , 1940 data that the fall-off in correlation tended to be linear, averaging 0.04 per year; since there is no reason to suppose that errors of measurement are cumulative, this must be due to other factors.…”

Section: Present Use Of the Conceptmentioning

confidence: 99%

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Regression to the Mean—a Confused Concept

Clarke

Brown

1960

British J of Psychology

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It is suggested that psychologists, like other people, are not entirely immune from the tendency to ‘blind themselves with science’. Statistics in particular provide a convenient mystique and thus an encouragement to use catch‐phrases in describing events we do not fully understand. One typical example is the phrase ‘regression to the mean’, often used to explain changes in extreme test score and usually regarded as a wholly statistical problem without psychological implications. This paper, however, by reference to physical and psychological data, attempts to indicate its primarily behavioural bases and to show why groups chosen for study on the basis of extreme test score will tend to regress towards the mean of the general population, while regression of extreme scores in groups not so selected will be towards the mean of their own specific population. There appear to be two main factors at work. (i) The effects of fleeting, inconstant personal alterations in response to the test (the so‐called ‘errors of measurement’ which are more complex than they sound). (2) The essentially non‐linear nature of most individual physical or psychological growth. To say without further qualification that test scores have changed ‘because of regression’ gives no greater information than to state that they have changed because they have changed.

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“…The Stanford-Binet, a verbal intelligence test that requires individual administration, is the only test on which the stability of the IQ has been extensively investigated (Bloom, 1963;Thorndike, 1933Thorndike, , 1940. Although the intelligence of perhaps ninety-five percent of the population is measured only with group tests, no previous study has investigated the stability of group IQ tests over the ten-year interval mentioned in the Bloom (1963) quote.…”

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confidence: 99%

Ten-Year Stability of Verbal and Nonverbal IQ Scores

Hopkins

Bracht

1975

American Educational Research Journal

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Intelligence tests continue to be the most widely used measures of cognitive aptitudes. Performance on such measures is usually expressed as an IQ score. Popular opinion to the contrary, relatively little is known about the long term measuring of IQ scores from group verbal and non-verbal intelligence tests, especially the latter. This study shows that, below ten years of age, stability in IQ scores from group verbal tests is considerably below that for the Stanford-Binet. Non-verbal IQ scores were found to have substantially less stability than Verbal IQs.

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"Constancy" of the IQ.

Cited by 55 publications

References 84 publications

Cognitive and Social Changes in the Feebleminded—three Further Studies

Cognitive and Social Changes in the Feebleminded—three Further Studies

Regression to the Mean—a Confused Concept

Ten-Year Stability of Verbal and Nonverbal IQ Scores

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