Arthur R. Jensen's research while affiliated with University of California, Berkeley and other places

Publications (160)

Article
This essay describes Rushton’s contribution to examining the nexus of intelligence, race, and genetics, specifically what I termed “Spearman’s hypothesis”. It states that Black–White differences are “most marked in just those [tests] which are known to be saturated with g”. I (Jensen) had confirmed this hypothesis using large data sets in the 1970s...
Article
This article is a critique on M. W. Smith’s “Alfred Binet’s remarkable questions: A cross-national and cross-temporal analysis of the cultural biases built into the Stanford-Binet Intelligence Scale and other Binet tests,” published in Genetic Psychology Monographs, 1974, 89, 307-334.
Article
Recent theory and research has focused on the relationship between speed of performing elementary cognitive operations and general intelligence. The developers of the British Ability Scales (BAS) included the Speed of Information Processing (SOIP) subtest as a measure of mental processing speed. To test the validity of the SOIP subtest, a group of...
Article
In this Editorial we correct the false claim that g loadings and inbreeding depression scores correlate with the secular gains in IQ. This claim has been used to render the logic of heritable g a “red herring” and an “absurdity” as an explanation of Black–White differences because secular gains are environmental in origin. In point of fact, while g...
Article
We provide a detailed review of data from psychology, genetics, and neuroscience in a point-counterpoint for-mat to enable readers to identify the merits and demerits of each side of the debate over whether the culture-only (0% ge-netic-100% environmental) or nature + nurture model (50% genetic-50% environmental) best explains mean ethnic group dif...
Article
Recent editorials in this journal have defended the right of eminent biologist James Watson to raise the unpopular hypothesis that people of sub-Saharan African descent score lower, on average, than people of European or East Asian descent on tests of general intelligence. As those editorials imply, the scientific evidence is substantial in showing...
Chapter
General ability, defined as psychometric g, arises from the empirical fact that scores on various cognitive tests are positively correlated in the population. The g factor is highly stable across different factor analytic algorithms, across different test batteries and across different populations. Because all cognitive tests, from the simplest to...
Article
Résumé De récents éditoriaux dans ce journal ont défendu le droit de l'éminent biologiste James Watson à soutenir l'hypothèse mal vue selon laquelle les populations d'origine subsaharienne obtiennent en moyenne aux tests d'intelligence générale des résultats inférieurs à ceux des populations d'origine européenne ou est-asiatique. Comme indiqué par...
Article
A large number of national and geographic population samples were used to test the hypothesis that the variation in mean values of skin color in the diverse populations are consistently correlated with the mean measured or estimated IQs of the various groups, as are some other physical variables, known as an ecological correlation. Straightforward...
Article
An entire elementary school system with 60% white and 40% black pupils was given several abiity tests group-administered by 12 white and eight black examiners (Es). The tests measured verbal and nonverbal IQ, perceptual-motor cognitive development, “speed and persistence” under neutral and motivating instructions, listening-attention, and short-ter...
Article
Reports an error in the original article by J. Philippe Rushton and Arthur R. Jensen (Psychology, Public Policy, and Law, 2005[Jun], Vol 11[2], pp. 235-294). An equation on p. 271 was incorrect. In the note to Table 5 on p. 273, a similar equation was incorrect. Finally, on p. 274, the last line of the first paragraph was incorrect. Corrections are...
Article
Despite repeated claims to the contrary, there has been no narrowing of the 15- to 18-point average IQ difference between Blacks and Whites (1.1 standard deviations); the differences are as large today as they were when first measured nearly 100 years ago. They, and the concomitant difference in standard of living, level of education, and related p...
Article
The culture-only (0% genetic-100% environmental) and the hereditarian (50% genetic-50% environmental) models of the causes of mean Black-White differences in cognitive ability are compared and contrasted across 10 categories of evidence: the worldwide distribution of test scores, g factor of mental ability, heritability, brain size and cognitive ab...
Article
Previous studies have shown that the pattern of mean differences on various mental tests (and other psychometric features) between black (B) and white (W) children all of the same age is imitated by comparing racially homogeneous groups composed of all W or all B children that differ in chronological age (CA). When the younger/older CA ratio is bet...
Article
The lower average correlations among mental tests in groups of individuals of above-average IQ than is found in groups of individuals of below-average IQ implies a smaller general factor, or g, in the higher-IQ group, a phenomenon Spearman called the ‘Law of Diminishing Returns’. This phenomenon was confirmed in six independent data sets based on t...
Article
African–White differences on the sub-tests of the Wechsler Intelligence Scale for Children-Revised (WISC-R) in Zimbabwe are like the Black–White differences in the US in being positively associated with the sub-tests' g loadings (g being the general factor of intelligence). Published means and S.D.s for 204 12-to 14-year-old Zimbabweans on 10 WISC-...
Article
In the 1999 Galton Lecture for the annual conference of The Galton Institute, the author summarizes the main elements of Galton's ideas about human mental ability and the research paradigm they generated, including the concept of 'general' mental ability, its hereditary component, its physical basis, racial differences, and methods for measuring in...
Article
Acquisition of word meanings, or vocabulary, reflects general mental ability (psychometric g) more than than do most abilities measured in test batteries. Among diverse subtests, vocabulary is especially high on indices of genetic influences. Bloom's exposition of the psychological complexities of understanding words, involving the primacy of conce...
Article
Full-text available
The regressions of occupational status and income on psychometric g factor scores were examined in large samples of White (W) and Black (B) American armed forces veterans in their late 30s and who are fairly representative of the population of employed W and B males. These results indicate that when Bs and Ws are matched on g scores, there is no ev...
Article
Psychometric data (19 variables) on the cognitive abilities of large samples of American white (W) and black (B) male armed services veterans were factor analyzed to test Spearman's hypothesis that variation in the size of the mean W–B difference on various cognitive tests is directly related to variation in the size of the tests' loadings on the g...
Article
A revival of test bashing has followed the growing public disillusionment with racial preferences as a means for abrogating the adverse impact of tests on certain groups in educational and occupational selection. This, added to the racial differences in g and the slight and ephemeral effects of Head Start and other more intensive interventions aim...
Article
In large samples of American armed forces veterans, those below the first percentile and above the 99th percentile in serum testosterone level show significantly and considerably lower g factor scores derived from a battery of 19 diverse psychometric variables. Between these extremes of testosterone level, however, there is little relationship betw...
Article
A pesar de la relativamente corta historia de la Psicología como ciencia, existen pocos constructos psicológicos que perduren 90 años después de su formulación y que, aún más, continúen plenamente vigentes en la actualidad. El factor «g» es sin duda alguna uno de esos escasos ejemplos y para contrastar su vigencia actual tan sólo hace falta comprob...
Article
The two parameters of the Hick paradigm, the intercept (a) and the slope (b), of reaction time (RT) as a function of the information load scaled in bits (i.e., the binary logarithm of the number of stimulus-response alternatives) differ in their (negative) correlation with IQ, a generally having a larger correlation than b. The typically low and of...
Article
Though “Jensenism” is a term listed in several dictionaries. Arthur Jensen has produced a more extensive body of work than suggested by the dictionary entry. To the public, he is mainly known for his work on the genetics of intelligence. This article discusses the work that is publicly less well known. Work discussed includes studies in learning, m...
Article
Data on the Wechsler Intelligence Scale for Children-Revised (WISC-R) from a now classic adoption study (Capron & Duyme, 1989, 1996) were used to examine the hypothesized relationship between diverse cognitive tests' g loadings and the degree to which the scores on each of the tests is influenced by the socioeconomic status (SES) of the biological...
Article
Responds to the discussion by A. H. Yee et al (see record 1994-09250-001) of A. R. Jensen's (e.g., see record 1986-18910-001) research on racial differences in abilities and states that the references to Jensen's work are dated. Jensen notes more recent research (Jensen and P. A. Whang; see PA, Vol 81:1181 and 20927) and provides an explanation f...
Article
Responds to the discussion by A. H. Yee et al (see record 1994-09250-001 ) of A. R. Jensen's (e.g., see record 1986-18910-001 ) research on racial differences in abilities and states that the references to Jensen's work are dated. Jensen notes more recent research (Jensen and P. A. Whang; see PA, Vol 81:1181 and 20927) and provides an explanation f...
Article
Scores on 17 diverse tests of cognitive abilities obtained from 82 pairs of monozygotic (MZ) and 61 pairs of dizygotic (DZ) twins were correlated with head size. A general factor, or psychometric g, was extracted from the tests, and g factor scores were found to be correlated with head size variables not only within individuals, but within twin pai...
Article
Full-text available
55 intellectually gifted children were compared with 53 academically average children (all Ss aged 11–14 yrs) on elementary cognitive tasks (ECGTs) with no symbolic content and different levels of requisite processing complexity. Ss were administered the Advanced Progressive Matrices and 3 ECGTs: simple reaction time (RT), choice RT, and the odd-ma...
Article
We have examined the stability of psychometric g, the general factor in all mental ability tests or other manifestations of mental ability, when g is extracted from a given correlation matrix by different models or methods of factor analysis. This was investigated in simulated correlation matrices, in which the true g was known exactly, and in typi...
Article
An analysis of IQ in relation to head size (and by inference, brain size) was performed on some 14,000 children and their full siblings, almost evenly divided by race (white and black) and sex, on whom data were obtained at ages 4 and 7 years in the National Collaborative Perinatal Project. Within each race × sex group, IQ is significantly correlat...
Article
Chinese-American (CA) and Anglo-American (AA) children in grades 4 to 6 were compared on a nonverbal test of intelligence (Raven′s Standard Progressive Matrices) and 12 chronometric variables, which measure the speed and consistency of retrieval of well-learned simple arithmetic facts (i.e., addition, subtraction, and multiplication of single digit...
Chapter
Understanding the nature of cognition and the developmental role of environmental factors in those who are born deaf is an important subject for research. Professor Braden, however, also suggests that a wider range of implications for psychology, particularly differential psychology, is to be found in this specialized field of research. Besides pro...
Article
Individual differences with respect to diverse tests of mental abilities that range in complexity from simple reaction time to abstract reasoning are all positively correlated in the population. The total covariance among all such tests can be analyzed into a number of uncorrelated components of variance, or factors, that, in terms of their general...
Article
As part of a study on speed of information processing and intelligence, 205 young adult postsecondary students were tested for somatosensory evoked potential (SEP) latencies and intelligence. Following stimulation at the wrist, latencies of three SEPs were determined: N13, generated in the cervical spinal cord/medulla region; N19, generated in the...
Article
Chinese-American and Anglo-American school children were compared on a nonverbal test of intelligence (Raven's Progressive Matrices) and on twelve chronometric variables which measure the speed with which basic information processes (e.g. stimulus apprehension, decision, and discrimination) can be carried out. All of these tasks are correlated with...
Article
There appears to be little published information for modern humans on the relation between body weight (WT) and brain weight or size (cranial capacity, CC). We present data on WT, stature, head measurements, and calculated CC from 211 young adult Caucasian male students. In this sample the correlation between WT and CC is +.202 (p < .01) and the va...
Article
Reed and Jensen (1992) studied 147 normal young adults and reported a significant positive correlation between nerve conduction velocity (NCV) in a brain nerve pathway (V:P100) and a measure of nonverbal IQ, in agreement with clinical studies. It was argued that V:P100 is a useful approximation to cortical NCV, should affect the speed of informatio...
Article
To account for the highly variable size of the mean difference between representative samples of the white and black populations on various psychometric tests of cognitive performance, Spearman (1927) suggested the hypothesis that the relative size of the mean white-black difference (in standardized scores) on various mental tests is a direct funct...
Article
Comments on R. J. Sternberg and R. K. Wagner's (see record 1993-32168-001) article on the flaws of the " g-ocentric" view of intelligence and job performance. It is argued that Sternberg and Wagner are wrong to identify g merely as academic intelligence. More should be known empirically about the nature of tacit knowledge for it to become a theor...
Article
Reaction time (RT) and movement time (MT), and intraindividual variability in RT and MT, measured in elementary cognitive tasks at three levels of complexity of information processing, administered to 213 college males, show nonsignificant correlations with body build, specifically the ponderal index, hence not replicating the results of a study by...
Chapter
Education’s traditional value of enhancing the quality of life for the individual need not be eclipsed by the growing recognition of its importance to the national welfare. A well-educated population is now deemed crucial in this technological era. The cultivation of excellence in the kinds of achievement that depend on an educated work force is an...
Article
Psychometric g, the general factor in individual differences in all types of tests and performances involving any mental ability, has much wider importance and implications than are encompassed by the field of psychometrics. It is argued that the nature of g must be understood in terms of information processes rather than in terms of the specific k...
Article
Individual differences in the trial-to-trial variability of reaction time (RT), indexed by the standard deviation of the individual's RTs over n trials (RTSD), generally has a larger negative correlation with psychometric g than does the median RT (RTmd) over n trials. Large data sets are brought to bear on the question of whether RTmd and RTSD, wh...
Article
This is a detailed report of the first demonstration in normal individuals of a correlation between intelligence level (“IQ”) and nerve conduction velocity (NCV) in a brain nerve pathway. A total of 147 postsecondary students were tested for nonverbal IQ and latency of the P100 (a visually evoked potential recorded over the primary visual cortex);...
Article
Full-text available
This study investigates whether a unitary elemental process or a number of independent elemental processes, as measured by elementary cognitive tasks (ECTs), underlie psychometric g. A sample of 101 university students was administered two intelligence tests (Raven's Advanced Progressive Matrices and the Multidimensional Aptitude Battery) and a lar...
Article
Full-text available
Carroll (1991) has argued that our empirical test of the hypothesis that psychometric g is a unitary factor fails methodologically to prove that g is not unitary, and that our finding could have resulted from some impurity in the g extracted from 11 psychometric tests. The gist of this argument is that our multiple regression method for testing the...
Article
Individual differences on diverse tests of mental abilities that range in complexity from simple reaction time to abstract reasoning are all positively correlated in the population. The total covariance among all such tests can be analyzed into a number of uncorrelated components of variance, or factors, that, in terms of their generality, are hier...
Article
Individual differences in reaction time (RT) to various elementary cognitive tasks (ECTs) reflect variance in both peripheral (sensorimotor) and central components of information processing. Minimizing the variance associated with peripheral processes by controlling simple RT in chronometric studies of more complex ECTs involving choice, discrimina...
Article
Shakuntala Devi, one of the world's most prodigious mental calculators on record, past or present, is especially remarkable for the incredible speed with which she performs mental calculations on very large numbers. This rare phenomenon prompted the question of whether such exceptional performance dependes on the speed of elementary information pro...
Article
The historical separation of the study of learning and of intelligence is seen as an anomaly in the development of scientific psychology. Although learning and intelligence can be conceptually distinguished in terms of formal definitions and measurements, a review of evidence on the relationship between individual differences in measures of learnin...
Article
Academically gifted children and their full siblings were compared on the Raven Matrices, and reaction time (RT) on an elementary cognitive task—the Semantic Verification Test (SVT). Significant differences between the gifted and their intellectually less gifted siblings and the significant correlation between RT and Raven scores within as well as...
Article
Full-text available
A meta-analysis of research on the relationship between inspection time (IT) and intelligence (IQ) was performed to: (1) determine whether a nonzero relationship between IT and IQ exists, (2) estimate the size of this relationship if it exists, and (3) test whether IT is ontogenetically related to g. Separate meta-analyses were initially conducted...
Article
The Semantic Verification Test (SVT) consists of brief, simple statements, which are either true or false, about various arrangements of the letters ABC (e.g. B after A). Mean reaction time (RT) for confirming or disconfirming the various statements varies according to their complexity. In independent studies of university students and Navy recruit...
Article
White and black prison inmates differ psychometrically from the general population mainly on the g factor of the Wechsler Adult Intelligence Scale-Revised. The average white-black difference is also predominantly a difference in g, although the groups also differ in spatial ability independently of g. The higher Performance than Verbal subtest scor...
Article
Raw scores on the Standard and Advanced forms of the Raven Progressive Matrices were rescaled in a college sample by means of equipercentile equating to yield a common scale that accommodates a wider range of talent than do the raw scores of either form. The common scale is expressed as IQ with mean and standard deviation equated to the national no...
Article
The well-established association between myopia and superior intelligence in the general population was investigated in a group of intellectually gifted children and their less gifted full siblings to determine whether the relationship of myopia to psychometric intelligence is consistent with the hypothesis of pleiotropy, i.e., both characteristics...
Article
Full-text available
Longstreth (1984, 1986) and Carroll (1987) have recently raised questions concerning the effects of practice and order and retinal displacement in Jensen's use of the Hick paradigm. The results of this study indicate that the effect of practice and order is nonsignificant. The effect of retinal displacement, although significant, accounts for such...
Article
The original data of McGurk's classic study of black-white differences on cultural and noncultural tests is re-analyzed at the item level to investigate the role of possible item biases that would cause the noncultural items to be relatively more difficult than the cultural items for blacks than for whites. The evidence indicates that McGurk's resu...
Article
This study is based on three distinct elementary cognitive tasks (ECTs) using chronometric techniques: (a) the S. Sternberg memory scan task, (b) a visual scan task which is perfectly analogous to the memory scan, except that the target digit is presented first and the subject must then scan a set of digits and indicate the presence or absence of t...
Article
The Kaufman Assessment Battery for Children (K-ABC) and the Wechsler Intelligence Scale for Children-Revise (WISC-R) are compared with respect to the magnitudes of the average white-black differences in standardized scaled scores and in raw scores. The two test batteries were administered to a sample of 172 fourth- and fifth-grade children comprisi...
Article
One of the most obvious “facts of life” to all teachers, at every level of education, is the phenomenon of individual differences—in mental abilities, special talents, and traits of personality. Especially salient are those characteristics of pupils that are the most clearly related to the success of teachers’ efforts to impart knowledge and intell...
Article
The highest common factor in any large and diverse collection of mental tests is measured by means of factor analysis, and is conventionally labeled psychometric g (for general ability). The g factor, which is highly correlated across even quite different batteries of tests, provided the tests are fairly numerous and varied, reflects the empirical...
Article
Longstreth's (1984) critique of Jensen's research on the relationship of IQ to individual differences in visual reaction time (RT), measured in the Hick paradigm, is found to have numerous errors of fact and interpretation, some trivial and some of theoretical importance. Longstreth's narrowly focused and conjectural style of criticism, which pecul...
Article
A group of bright-average 7th grade junior-high-school students was contrasted with a group of manifestly academically gifted students of comparable age who were taking college-level courses in mathematics and science. The groups differed significantly and markedly (showing an overall mean difference of 1.34 SD) on every one of the nine different r...
Article
Humphreys's test of Spearman's hypothesis (viz., that the size of the standardized black-white differences on various psychometric tests is positively related to the tests' loadings on g, the general intelligence factor) is methodologically weak. It is based on comparison of a fairly representative sample of the black population of U.S. school chil...
Article
Although the black and white populations in the United States differ, on average, by about one standard deviation (equivalent to 15 IQ points) on current IQ tests, they differ by various amounts on different tests. The present study examines the nature of the highly variable black–white difference across diverse tests and indicates the major system...
Article
Magnitude comparisons of black-white differences on a variety of cognitive tests give a somewhat different picture of the results of a small-sample study by Borkowski and Krause (1983), who based their conclusions mainly on significance tests. Some of the critical variables in the study consisted of differences scores with unacceptably low reliabil...
Article
The study of individual differences in reaction time (RT) had its origin not in psychology, but in astronomy. The Prussian astronomer F. W. Bessel, in 1823, coined the term personal equation for the consistent differences among telescopic observers in recording the exact moment that the transit of a star crosses a hairline in the visual field of th...
Article
A battery of eight different reaction time (RT) tests, measuring the speed with which individuals perform various elementary cognitive processes, and a group test of scholastic aptitude (the Armed Services Vocational Aptitude Battery, ASVAB) were given to 50 black and 56 white male vocational college students. The regression of the general factor s...
Article
Indian Muslim school boys, ages 13 to 15 years, whose parents are first cousins, were compared with classmates whose parents are genitically unrelated on the Raven Standard Progressive Matrices, a nonverbal test of intelligence. The inbred group (N=86) scored significantly lower and had significantly greater variance than the noninbred group (N=100...
Article
Claims that the Kaufman Assessment Battery for Children (K-ABC) is less culturally biased than other standard tests of intelligence and therefore shows a much smaller average difference between black and white children are critically examined in terms of the psychometric properties of the K-ABC. It is concluded that the apparently reduced differenc...
Article
The specificity doctrine, a legacy of the positivism and radical behavorism that have dominated the history of American psychology, holds that psychometric tests measure nothing other than the specific bits of knowledge and learned skills reflected in the item content of the tests. This prevailing doctrine has influenced the interpretation of test...
Chapter
As one who has been reading about test bias now for over 30 years, I have noticed a quite dramatic change in this literature within just the last decade. This development was auspicious, perhaps even essential, for the production of my most recent book, Bias in Mental Testing (1980a). Developments in the last decade made it possible to present a fa...
Chapter
Rushton has performed a most necessary service to the advancement of behavioral science. He has indicated, succinctly yet quite comprehensively, how differential psychology can fruitfully be brought under the purview of the newly developing science of sociobiology. We may rather safely predict that his effort will meet at least temporary resistance...
Article
Sex differences on 13 subtests of the Wechsler Intelligence Scale for Children Revised (WISC-R), and in the factor structure of the 13 subtests, are examined in the white subsample (N = 944 males, 924 females) of the total national standardization sample of the WISC-R (Kaufman and Doppelt, 1976; Wechsler, 1974). This sample of children, whose ages...
Article
The differential effects of inbreeding on 11 subtests of the WISC, in a Japanese (Hiroshima) population, are related to the factor structure of the tests. The degree of inbreeding depression on mental abilities is most strongly correlated with the subtests' loadings on the General factor, g, which is common to all of the subtests. Loadings on the V...

Citations

... Additionally, ASVAB subtests predicted effort and leadership (e.g., number of awards and certificates, ratings of overall effectiveness and leadership). Ree et al.'s (1994) and Oppler et al.'s (2001) work are just two of many studies (e.g., Jensen, 1985;Murphy, 1985) demonstrating the utility of the ASVAB in predicting military job performance. ...
... Jensen's most noted early work, the 1969 monograph published in the Harvard Educational Review (Jensen, 1969) sparked a heated debate on the role of genes in intelligence and on genetic racial differences in behavior. While Jensen (1995) notes that racial categorization in his studies is based on self-identification, he states that the between group differences are highly correlated with other "biologically based" variables. Jensen (1995) goes on to briefly discuss his work on racial differences in head size, reaction time, and the correlations between these variables and I.Q. ...
... pre-employment testing). The saturation of g in measures of cognitive ability has been considered as a reason for race-group differences on these measures (Jensen, 1980(Jensen, , 1984(Jensen, , 1998Hunter & Hunter, 1984). Test developers and researchers interested in tests of general mental ability should minimize adverse impact by developing and administering tasks that are less dependent on previous knowledge, such as measures of working memory capacity. ...
Citing chapter
... Tests of music aptitude-an individual's potential to achieve in music (Gordon, 1999)-are one means of assessing individual musical differences for the purposes of improving instruction. Interest in human aptitudes appears in the writings of Plato and Aristotle (Jensen, 1987), and formal measurement was realized in post-Darwinian society through the work of scholars such as Galton (1822Galton ( -1911 and Binet (1857Binet ( -1911. Early efforts to test musical perception by Delezenne (1776Delezenne ( -1866, Galton, andCattell (1860-1944) led to the groundbreaking work of Seashore (1866Seashore ( -1949, whose Measures of Musical Talent (1919) became the first published music aptitude test (Humphreys, 1993). ...
... A powerful reconciliatory view between domain-general and domain-specific development has been suggested by Karmiloff-Smith (1992). According to her, Piaget's theory of development needs to be complemented with domain-specific epigenetic processes and in doing so (Jensen, 1985;Eysenck, 1986;Nettelbeck, 1987;Anderson, 1992) have attributed individual differences in performance to the speed of processing within the cognitive system, unlike others who place their focus on either the control and coordination of processing (Sternberg, 1983), or the ability for inhibition of irrelevant information (Dempster, 1991). On the other hand, there are authors who point to either the speed of processing as a factor in cognitive development (Nettelbeck and Wilson, 1985;Hale, 1990;Kail, 1986Kail, , 1991Case 1985), or to processing capacity as a cognitive task resource allocator measure limiting the representations of greater complexity underlying cognitive development (Halford, 1999). ...
... 139) or as a test of a person's "innate educative ability" (Raven, 1941, p . 144) and not general intelligence ("g"), they are now regarded as a typical form of intelligence testing and seen by some authors as almost purely measurements of "g" (Jensen 1980(Jensen , 1993Spearman, 1946) . Very high g loadings have been found (e .g ...
... Children learn and develop arithmetic skills during early childhood. Because of the hierarchical nature of mathematics skills, arithmetic serves as a foundation for developing increasingly advanced mathematical abilities (Ashcraft, 1992;Jensen & Whang, 1994;National Council of Teachers of Mathematics, 2006). Given the importance of arithmetic, it is critical to understand factors that contribute to early arithmetic development. ...
... Please note however, that many other performance indicators are also popular. For example, median response times are used or movement and decision time are distinguished in an attempt to purify cognitive speed from motor speed (Jensen and Vernon, 1986), or dispersion of response times is taken as an indicator of the robustness of information processing (Papenberg et al., 2011). More recently the diffusion model for decision reaction times and their relations with individual differences in other abilities became popular (Schmiedek, Oberauer, Wilhelm, Süß, and Wittmann, 2007), and will be discussed in the section on "cognitive measurement models". ...
... Cooper 2005; Rowe and Rodgers 2005). As part of this issue is consideration of whether perceived differences in IQ are genetic as well as whether differences in IQ scores among populations indicate differential adaptive functioning (Jensen 2013). Individuals with a score of 65-75, or two standard deviations below the population mean, are classed as having Intellectual Disability Disorder. ...
... Most of these attempts involved children of preschool or grammar school age, while a few involved high school age children (Feuerstein, 1979;Feuerstein, Rand, Hoffman & Miller, 1979) and elderly subjects (Baltes, Dittmann-Kohli & Kliegl, 1986;Baltes & Willis, 1982;Willis, 1987;Willis & Schaie, 1986;Willis, Blieszner & Baltes, 1981). The effects of these interventions have been summarized in several reviews (Brody, 1985;Caruso et al., 1982;Jensen, 1969Jensen, , 1989Royce, Darlington & Murray, 1983;Spitz, 1986). Nearly all the interventions attempted to improve performance by training subjects in methods of learning or problem solving. ...