Word identification in adults with mild mental retardation: does IQ influence reading achievement?

OBJECTIVE: To assess the relationship between word identification and intelligence in adults with mild mental retardation (IQ < 80). METHOD: A standardized evaluation was administered to 67 adults with mild mental retardation. The evaluation included a psychiatric interview, the WAIS-R, and a 2-h interview with a speech therapist and reading tests. RESULTS: Causes of mental retardation were diverse in the sample, and IQ scores ranged from 43 to 79 (mean score = 64). All subjects exhibited reading impairment, including 69% with severe impairment. No subject with an IQ score under 65 was able to perform adequately in the word identification tasks. Word identification was correlated with total and verbal IQ, but not with performance IQ. CONCLUSION: Our results suggest that, in contrast to subjects with normal intelligence, IQ score is correlated with reading in subjects with mild mental retardation. Finally, remediation should be preferentially implemented for subjects with IQ score greater than 65.     

Inspection time and intelligence in 7-yr-old children: A follow-up

Remeasures of inspection time (IT) were obtained from 30 of the 47 children reported in Nettelbeck and Young (Personality and Individual Differences, 10, 605–614, 1989). Ages ranged from 7 yr–0 months to 7–11 and Full Scale IQ (WISC-R) ranged from 93 to 142 (mean = 116.5 SD = 12.2). Correlations between IT and the WISC-R subtests, scales and factors used in the earlier study were generally statistically significant: and similar to those found earlier. The correlation between IT and Full Scale IQ was — 0.49, with those children whose IQs were below the median score of 116 again contributing more to this outcome. Similarly, the IT-IQ correlation was higher among children showing less well-directed attention in the IT task. Once again IT correlated better with Verbal IQ, supporting the hypothesis that IT is better associated with more general intellectual functioning than with specific cognitive abilities. Cross-lagged panel correlations between IT and IQ were —0.40, whether predicting IQ from IT or the reverse. Thus, there was no evidence for a causal relationship between these variables, although both may reflect a common cognitive ability factor.     

Intelligence and imagery in personality.

One hundred college undergraduates were administered the Richardson revision of the Gordon Test of Visual Imagery Control, the Betts-Sheehan Questionnaire Upon Mental Imagery, and the Shipley-Hartford Institute of Living Scale. The latter provided a conceptual quotient (CQ) score of intellectual impairment based upon a ratio between vocabulary and abstraction scores. Subjects with CQs above 100 had significantly higher control scores (p less than .02). High control subjects had significantly higher total IQ scores than did low control subjects (p less than .04). Subjects with high and medium range control had higher vocabulary scores than those with low control. This suggests possible assessment of proneness toward introverted and extraverted neuroticism based upon a combination type of imagery score and the ratio between abstract or vocabulary scores. The connection of imagery with dimensions of IQ may be a start toward a more refined measure of this aspect of personality. Problems and implications are discussed.     

Analysis of WAIS-IV index score scatter using significant deviation from the mean index score

The Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) does not include verbal IQ and performance IQ scores, as provided in previous editions of the scale; rather, this edition provides comparisons among four index scores, allowing analysis of an individual's WAIS-IV performance in more discrete domains of cognitive ability. To supplement the pairwise index score comparisons included in the WAIS-IV manuals, this article describes the use of the mean of the four index scores (the average index score) as a baseline for analyzing index score variability and as a method for identifying strengths and weaknesses within an individual's index score pattern. Davis's formula was used to calculate critical values for the identification of index scores with a statistically significant difference from the average index score. Subsequent analysis of the WAIS-IV normative sample indicates that variability in performance at the index score level is not uncommon in the general population. More than 70% of individuals in the normative sample have at least one index score that differs significantly from their mean index score. This variability in index score performance appears to have little relationship to age or gender, but it is strongly related to the full-scale IQ.     

Interictal and postictal performances on dichotic listening test in children with focal epilepsy

Dichotic listening test (DL) is an important tool to disclose speech dominance in healthy subjects and in clinical cases. The aim of this study was to probe if focal epilepsy in children reveals a corresponding suppression of the ear reports contralateral to seizure onset site. Thus, 15 children and adolescents with clinically and electroencephalographically diagnosed focal epilepsy selected for left-hemisphere speech dominance without mental retardation were compared to matched controls according to age, gender, IQ and handedness. All children were assessed with DL for three times: Interictally (t(0)), postictally 5' (t(1)) and 1h (t(2)). At t(0), all groups revealed a right ear advantage (REA), indicating a left-hemisphere speech dominance. There was a continuous increase in right correct score (REC) over the trials for normal controls. Five minutes postictally, there was an abrupt decrease in REC with a sustained left ear correct score (LEC) for children with epilepsy, independent of which side suffered from seizures. This effect was maintained even after 1h. Thus, in children with left-hemisphere speech dominance the epileptic discharges caused a suppression of REC regardless of origin. The seizures may have a prolonged impact on attention and auditory perception for a considerable time after consciousness has been regained.     

Achievement and adjustment correlates of the matching familiar figures test

To help clarify the relationship between the Matching Familiar Figures (MFF) Test and measures of school achievement and adjustment, 450 children from kindergarten, second, and fifth grades were tested and achievement scores and teacher's ratings of classroom and personal adjustment were obtained. Regardless of grades, MFF latency in most instances did not predict achievement or adjustment. At the kindergarten level the correlations between MFF errors and both achievement and adjustment were significant for most subscales but at second grade correlations were lower and generally nonsignificant except for a few adjustment items. At the fifth grade level the correlations were moderately high but when IQ was partialled out the correlations with achievement and school adjustment dropped to near zero; however, partialling out IQ did not affect the moderate correlations between errors and personal adjustment. The errors score evidencedmore important relationships than the latency scores. The relationship between the MFF and ratings of social and emotional adjustment was consistently higher than the correlations between the MFF and achievement. These results suggest that MFF errors are personalogically relevant and that MFF performance is generally more related to adjustment than achievement.     

Sex Differences in Self-Estimates on Two Validated IQ Test Subscale Scores

Two related studies investigated sex differences in self- and parental estimates of IQ scores on specific scales derived from standardized and validated IQ tests. In the first study 210 participants were asked to estimate their scores on the 11 WAIS-R subtests as well as their overall general IQ. Results showed males estimated their overall score, plus their total WAIS score, significantly higher than females, with effect sizes around 0.5. Factor analysis showed participants did differentiate between verbal and performance subscale scores on this test. In the second study 117 participants performed a similar task, but this time on the 12 subscales of the Stanford-Binet test. Males estimated their overall score higher than females. Factor analysis also showed 2 clear factors that reflected exactly the verbal and performance subscale scores.     

The relationship between IQ, social class and EEG findings in healthy children investigated by child-psychiatric methods

Abstract.— 222 children aged between 4.5 and 16.5 years. who were found to be normal by strict somato-neuro-logical criteria, were investigated by EEG and by child-psychiatric methods. Intelligence tests were performed according to WISC. The mean intelligence quotient amounted to 116.3± 12.4 in boys and 116.6± 14.1 in girls. Child-psychiatric findings deviating from the strictly normal occurred in 30 children significantly more frequently in social class III compared to I and 11. There was no relationship of significance between IQ and social group. No relevant relationship was found between IQ and psychiatric variables, nor between IQ and EEG-findings. The absence of the normal fixed relationship between IQ and social group is a notable finding, as is also the high average IQ. The strict normal criteria may have contributed to the exclusion of individuals with lesions and thus diminished factors having an inhibitory effect of the development of intelligence.     

The Relationship Between Diverse Components of Intelligence and Creativity

Intelligence and creativity are accounted for in terms of two different mental operations referred to as ‘convergent thinking’ and ‘divergent thinking’, respectively. Nevertheless, psychometric evidence on the relationship between intelligence and creativity has been controversial. To clarify their relationship, we characterized the relationship between diverse components of intelligence and creativity through the administration of psychometric tests on a large sample (WAIS, RPM, and TTCT‐figural: n = 215; TTCT‐verbal: n = 137). The general intelligence factor (g) score showed significant correlations with both TTCT‐figural and TTCT‐verbal scores. However, sub‐dimensional analysis demonstrated that their association was attributable to the specific components of both TTCTs (TTCT‐figural: Abstractness of Titles, Elaboration, and Resistance to Premature Closure; TTCT‐verbal: Flexibility) rather than to their common components (Fluency and Originality). Among the intelligence sub‐dimensions, crystallized intelligence (gC) played a pivotal role in the association between g and the specific components of both TTCTs. When the total sample was divided into two IQ groups, these phenomena were more evident in the average IQ group than in the high IQ group. These results suggest that the mental operation of creativity may be different from that of intelligence, but gC may be used as a resource for the mental operation of creativity.     

Gender and its contribution to the prediction of cognitive abilities at 5 years

Gender-related differences in the prediction of five year-olds' cognitive abilities from measures of distal environment, proximal environment and infant test scores were examined in a random sample of 93 boys and 90 girls. Distal environmental data included maternal IQ, maternal and paternal education. Proximal environmental data included two variables derived from the Home Screening Questionnaire: the Home Questions and the Toy Checklist. The Bayley MDI was administered at age 13 months, whereas WPPSI-R was used as cognitive outcome measure at age 5 years. The relationship between paternal education and child IQ, and between proximal environmental variables and child IQ was significantly stronger for boys than for girls. The associations between proximal environment and IQ in boys, were accounted for by the distal environmental variables. Bayley MDI correlated significantly higher with girls' IQ compared to boys' IQ. Findings are discussed in terms of parental gender-differentiated socialization processes.     

Mitochondrial DNA marker EST00083 is not associated with high vs. average IQ in a German sample

In a recent report in this journal (Plomin & Petrill, 1997), a mitochondrial DNA marker (EST00083) yielded significant associations with high vs. low IQ in two population-based samples of children in the U.S. The present study tested this allelic association for German adults with high vs. average IQ scores. The high IQ adults (N=47) were members of Mensa, an organization whose membership criterion is an IQ score above 130. Their EST00083 allelic frequencies were compared to the allelic frequencies for a control group of adults (N=77) whose IQ scores were less than 110 as estimated from short-term memory and speed-of information-processing tests. Although the differences between the two studies are considerable, the present results do not provide support for the hypothesis that EST00083 is associated with high IQ.     

Intelligence and selective attrition in a nationally representative and longitudinal sample of Americans

Selective attrition is a potentially serious problem that can bias the findings that are generated from longitudinal samples. Although the extent to which IQ might be involved in selective attrition has been studied, the results from these studies have been decidedly mixed. The current study adds to the literature examining the link between IQ and selective attrition by examining four waves of data from the National Longitudinal Study of Adolescent Health. Analysis of these data revealed that IQ is related to attrition, with lower IQ respondents more likely to drop out of the study when compared against higher IQ respondents. The evidence suggests that dropouts score about 4.5 IQ points lower than subjects who did not drop out. Limitations of the study are noted and directions for future research are discussed.     

WAIS test-retest reliability for a clinical out-patient sample.

WAIS test-retest reliabilities were calculated for a clinical out-patient sample with testing intervals varying from 1 to 10 yr. There was no relationship between test-retest interval and the stability of test scores and the correlations between IQs were quite satisfactory (Full Scale IQ = .897, Verbal IQ = .906, Performance IQ = .876). Reliabilities remained high even when the sample was divided by diagnosis into organic, neurotic, personality disorder, and schizophrenic subgroups.     

Raising the IQ: The Ramey and Haskins study

The Ramey and Haskins intervention experiment succeeded in producing IQ gains at three years of age averaging about one standard deviation in young children who were selected for being at risk for subnormal intellectual development. The study is examined in terms of its consistency with other findings, the heritability of IQ, the g aspect of IQ, the simplex pattern of longitudinal interage mental test score correlations, mother-child IQ correlations, and criteria for establishing educationally and socially significant gains in intelligence defined as g rather than as a score on a particular test. Narrow transfer of training from cognitive intervention techniques to IQ test performance in early childhood, rather than enhancement of the g factor itself, is hypothesized as a cause of the typical fadeout of early IQ gains in later childhood.     

The secular rise in IQs in the Netherlands: Is the Flynn effect on g?

IQ scores have been increasing over the last half century, a phenomenon known as the Flynn effect. In this study, we focused on the question to what extent these secular gains are on the g factor. Two IQ batteries: the Interest-School achievement-Intelligence Test (ISI) and the Groningen Final Examination Primary Education (GALO) yielded small and modest negative correlations between standardized gains and g loadings. As these studies employ large samples this suggests that the combined literature now shows a modest negative relationship between d (the secular change in test score) and g.     

Influence of IQ in interpreting MMSE scores in patients with multiple sclerosis

The Mini-Mental State Examination (MMSE) and Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) were administered to 46 outpatients diagnosed with multiple sclerosis (MS). MMSE total raw score was significantly and positively correlated with all WAIS-IV indexes, even when controlling for the effects of participant educational level, with the strongest relationship being with Full Scale IQ. These results suggest that clinicians consider patient intellectual functioning, in particular Full Scale IQ, when diagnosing neurocognitive impairment based on screening with the MMSE in individuals with MS.     

Dichotic listening and left-right confusion

The present study examined the relationship between individual differences in dichotic listening (DL) and the susceptibility to left-right confusion (LRC). Thirty-six men and 59 women completed a consonant-vowel DL test, a behavioral LRC task, and an LRC self-rating questionnaire. Significant negative correlations between overall DL accuracy and LRC rates in men (behavioral task) and self-ratings in women, indicated that the more participants struggled with left-right discrimination, the fewer DL syllables they reported correctly. However, there was no relationship between LRC and the typical right ear advantage. Thus, there is a sex- and task-dependent relationship between LRC and overall DL accuracy, but not between LRC and ear asymmetry. It is concluded that (a) atypical ear asymmetries, as in certain clinical populations, cannot be explained by associated deficits in left-right discrimination, and (b) LRC can negatively affect task performance, even when participants do not have to make explicit "left" versus "right" decisions.     

The Gordon Diagnostic System and WISC-III Freedom from Distractibility Index: validity in identifying clinic-referred children with and without ADHD

Gordon Diagnostic System and WISC-III scores for clinic-referred 6- to 16-yr.-olds (184 with ADHD Combined Type and 46 without ADHD) were analyzed to evaluate the combination of scores and cutpoints that maximized diagnostic accuracy. Using an "ADHD cutpoint" of IQ minus the GDS Composite score > or = 13, 87.8% of the children were correctly identified as having or not having ADHD. IQ minus Freedom from Distractibility > 0 yielded 73.5% accuracy. When the two meaures were combined to create new criteria (IQ minus GDS Composite > or = 13 or IQ minus Freedom from Distractibility > or = 11), diagnostic accuracy increased to 90.9% and negative predictive power improved substantially. Diagnostic agreement between the Gordon Diagnostic System and Freedom from Distractibility was 70%, suggesting that the two tests measure both similar and unique traits.     

Validity of the Wechsler abbreviated scale of intelligence and other very short forms of estimating intellectual functioning

Performance on the Wechsler Adult Intelligence Scale-III (WAIS-III) was compared to performance on the Wechsler Abbreviated Scale of Intelligence (WASI), as well as short form estimations of intellectual functioning derived from WAIS-III performance, in a mixed clinical sample of 72 participants. The WASI verbal IQ (VIQ) score was significantly higher than the WAIS-III VIQ, whereas performance IQ (PIQ) estimates all differed from actual WAIS-III PIQ and full scale IQ (FSIQ). Correlations of WAIS-III scores with WASI scores were consistently lower than were correlations between the WASI-III and all other short forms. Although maintaining administration times of 15 minutesfor a two-subtest FSIQ and 30 minutes for a four-subtest FSIQ, the WASI did not consistently demonstrate desirable accuracy in predicting scores obtained from the WAIS-III. The results suggest that clinicians should use the WASI cautiously if at all, especially when accurate estimates of individuals' WAIS-III results are needed.     

Substituing supplementary subtests for core subtests on reliability of WISC-IV Indexes and Full Scale IQ

The effects of replacing core subtests with supplementary subtests on composite score reliabilities were evaluated for the WISC-IV Indexes and Full Scale IQ. When Wechsler's guidelines are followed, i.e., only one substitution for each Index; no more than two substitutions from different Indexes when assessing the Full Scale IQ, summary score reliabilities remain high, and measurement error, as defined by confidence intervals around obtained scores, never increases by more than 1 index score point. In three instances, substitution of a supplementary subtest for a core subtest actually increased the reliabilities and decreased the amount of associated measurement error.