Education and Intelligence: Pity the Poor Teacher because Student Characteristics are more Significant than Teachers or Schools.

Education has not changed from the beginning of recorded history. The problem is that focus has been on schools and teachers and not students. Here is a simple thought experiment with two conditions: 1) 50 teachers are assigned by their teaching quality to randomly composed classes of 20 students, 2) 50 classes of 20 each are composed by selecting the most able students to fill each class in order and teachers are assigned randomly to classes.

Scholastic Assessment or g? The relationship between the Scholastic Assessment Test and general cognitive ability.

There is little evidence showing the relationship between the Scholastic Assessment Test (SAT) and g (general intelligence). This research established the relationship between SAT and g, as well as the appropriateness of the SAT as a measure of g, and examined the SAT as a premorbid measure of intelligence. In Study 1, we used the National Longitudinal Survey of Youth 1979.

Phenotypic and behavioral genetic covariation between elemental cognitive components and scholastic measures.

The study subjected nine elementary cognitive task variables from the Cognitive Assessment Tasks (CAT) and three scholastic measures from the Metropolitan Achievement Test (MAT) to phenotypic and behavioral genetic structural equation modeling based on data for 277 pairs of same sex monozygotic (MZ) and dizygotic (DZ) twins from the Western Reserve Twin Project. Phenotypic and behavioral genetic covariation between certain elemental cognitive components and scholastic performance was examined to determine (a) whether these elemental cognitive components contribute substantially to the variance of scholastic performance; (b) whether such contributions vary across different domains of school knowledge or from specific domains to a general aptitude; (c) the behavioral genetic composition of the elemental cognitive components and the scholastic variables; and (d) how the association between the cognitive components and scholastic performance is genetically and environmentally mediated. The results of the study showed that as much as 30% of the phenotypic variance of scholastic performance was accounted for by the CAT general factor, which was presumably related to mental speed.

General intelligence and the definition of phenotypes.

From Spearman's famous 1904 paper to Carroll's recent book on factor analytic results from a multitude of studies, there has been one consistent conclusion: 'g', or general intelligence, is the factor that defines the phenotype for intellectual functioning. It is no overstatement to say that g is undoubtedly the most important psychological construct discovered in this century. It predicts more and is implicated in a wider range of behaviour than any other psychological construct.

Dopamine markers and general cognitive ability.

Because general cognitive ability (g) is among the most heritable behavioural traits, it is a reasonable target for a search for quantitative trait loci (QTLs). We used a selected-extremes design to test candidate genes for allelic association with g. Polymorphisms in four genes in the dopamine system (DRD2, DRD3, DRD4, DAT1) were genotyped for 51 high g children with IQ scores > 130 and for 51 average g control children.

What is so special about special education?

There is nothing special about special education. Educational methods have not changed significantly in at least 2,500 years. IQ tests were developed to identify those in need of special education, with the intention of developing appropriate educational methods.

No association between general cognitive ability and the A1 allele of the D2 dopamine receptor gene.

Berman and Noble (1995) reported significantly reduced visuospatial performance in children with the TAQI A1 allele of the D2 dopamine receptor (DRD2) gene. Given that visuospatial performance loads highly on an unrotated principal component indexing general cognitive ability, we tested the association between DRD2 and WISC-R IQ comparing 51 high-IQ, 51 average-IQ, and 35 low-IQ children in the IQ Quantitative Trait Loci (QTL) Project. No statistically significant association between the TAQI A DRD2 alleles and IQ was found.

The independent prediction of general intelligence by elementary cognitive tasks: genetic and environmental influences.

Current theories of intelligence have, in some cases, begun to include elementary cognitive tasks. Behavioral genetic studies of intelligence have not taken these theories into account. The current study includes 135 MZ and 128 DZ twin pairs from the Western Reserve Twin Project.

The genetic and environmental variance underlying elementary cognitive tasks.

Although previous studies have examined the genetic and environmental influences upon general intelligence and specific cognitive abilities in school-age children, few studies have examined elementary cognitive tasks in this population. The current study included 149 MZ and 138 same-sex DZ twin pairs who participated in the Western Reserve Twin Project. Thirty measures from the Cognitive Abilities Test (CAT; Detterman, 1986) were studied.

DNA markers associated with high versus low IQ: the IQ Quantitative Trait Loci (QTL) Project.

General cognitive ability (intelligence, often indexed by IQ scores) is one of the most highly heritable behavioral dimensions. In an attempt to identify some of the many genes (quantitative trait loci; QTL) responsible for the substantial heritability of this quantitative trait, the IQ QTL Project uses an allelic association strategy. Allelic frequencies are compared for the high and low extremes of the IQ dimension using DNA markers in or near genes that are likely to be relevant to neural functioning.

Differences in heritability across groups differing in ability, revisited.

Three recent studies have used twin data to explore the possibility of differential contributions of heritability and environmentality to individual differences in cognitive ability as a function of ability level (Detterman, D. K., et al.

Giftedness and intelligence: one and the same?

Giftedness, like other rare phenomena, is often explained by principles beyond those used to explain the normal variation of mental ability. Before parsimony is abandoned and additional principles are invoked, the following five points should be considered. (1) Gifted samples often have restricted ranges, reducing correlations with intelligence and making standard tests insensitive to relationships that may exist.

Assessment of basic cognitive abilities in relation to cognitive deficits.

A modal model of information-processing was used to select a battery of nine tasks of basic cognitive ability (learning, relearning, reaction time, probe recall, Sternberg search, self-paced probe, stimulus discrimination, tachistoscopic full report, tachistoscopic partial report). Parameters from these tasks operationalized the model. After extensive pilot testing of the tasks to establish reliability, we tested 40 subjects (20 with mental retardation and 20 college students) on all tasks and the WAIS-R.

Differences in heritability across groups differing in ability.

Differences in heritability and environmentality were assessed for 54 DZ and 86 MZ same-sex twin pairs between 6 and 12 years of age from the Western Reserve Twin Project. A principal-component score composed of the subtests of the WISC-R, PPVT, WRAT, and MAT represented each twin's cognitive ability. Using a modification of a regression technique developed by DeFries and Fulker (1985), it was possible to assess differential heritability and environmentality across ability level.

Effect of instructions on elementary cognitive tasks sensitive to individual differences.

The effect of instructions on basic cognitive tasks was investigated. In the first study, 60 college students completed both a choice reaction time and a modified match-to-sample task. Students were given either written, non-verbal, or no instructions.

Is it smart to play the horses? Comment on "A day at the races: a study of IQ, expertise, and cognitive complexity" (Ceci & Liker, 1986).

Ceci and Liker (1986b) presented data that they contended shows two things: (a) Handicapping harness races is a cognitively complex undertaking that can be captured by a multiple regression model, and (b) neither overall skill at handicapping nor the complexity of the mental model used is related to standard measures of intelligence. The first contention is not at issue. But the second contention, that handicapping performance is unrelated to IQ, is not supported by the data presented; in fact, the opposite conclusion seems more likely.

Theoretical notions of intelligence and mental retardation.

A theory of the cause of mental retardation that views human intelligence as a set of independent abilities organized in a complex system was presented. Mental retardation is conceived as a deficit in a few of the independent abilities having high centrality (i.e.

Information-processing correlates of computer-assisted word learning by mentally retarded students.

Information-processing correlates of computer-assisted word learning by moderately and severely mentally retarded students were identified. Nineteen subjects completed 10, 15-minute computer-assisted instruction sessions and seven basic cognitive tasks measuring simple learning, choice reaction time, relearning, probed recall, stimulus discrimination, tachistoscopic threshold, and recognition memory. Stimulus discrimination, probed recall, and simple learning were significantly related to word learning.

Stimulus encoding by mentally retarded and nonretarded adults.

Stimulus encoding was studied with a group of mentally retarded and nonretarded adults. Two sets of 24 nonverbal stimuli were selected; one had a wide range of stimulus structure variables and the other, a representative sample of stimuli. Performance on a match-to-sample task for both stimulus sets was assessed and correlated with the stimulus structure of the standard stimulus.

Performance of mentally retarded and nonretarded persons on a lifted-weight task with strategies reduced or eliminated.

To test the hypothesis that a strategy deficit entirely accounts for retarded persons' inferior short-term memory performance, we attempted to eliminate strategies by selecting a task in which strategies would be difficult to use (memory for the position of a lifted weight) and by having subjects report the use of any strategy. In Experiment 1, discriminability among lifted weights was roughly equated for retarded and nonretarded subjects. Experiment 2 showed that for subjects not reporting use of a strategy, nonretarded subjects performed better than did retarded subjects.

The von Restorff effect and induced amnesia: production by manipulation of sound intensity.

When an outstanding item appears in an otherwise homogeneous list of items, the outstanding item is better remembered (the von Restorff effect), and items before and after it may be more poorly remembered (induced amnesia) than corresponding items in a control list. In the present experiments the outstanding item was a word presented as a loud shout among other words presented at normal conversational levels. In two experiments, large retrograde- and anterograde-induced amnesiae effects were demonstrated using a free-recall and a recognition task.