Correction to Rushton and Jensen (2005).

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 published here. (The following abstract of this article originally appeared in record 2005-03637-001.) 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 ability, transracial adoption, racial admixture, regression, related life-history traits, human origins research, and hypothesized environmental variables. The new evidence reviewed here points to some genetic component in Black-White differences in mean IQ. The implication for public policy is that the discrimination model (i.e., Black-White differences in socially valued outcomes will be equal barring discrimination) must be tempered by a distributional model (i.e., Black-White outcomes reflect underlying group characteristics). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

There are no public-policy implicatons: A reply to Rushton and Jensen (2005).

J. P. Rushton and A. R. Jensen (see record 2005-03637-001) purport to show public-policy implications arising from their analysis of alleged genetic bases for group mean differences in IQ. This article argues that none of these implications in fact follow from any of the data they present. The risk in work such as this is that public-policy implications may come to be ideologically driven rather than data driven, and to drive the research rather than be driven by the data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thirty years of research on race differences in cognitive ability.

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 ability, transracial adoption, racial admixture, regression, related life-history traits, human origins research, and hypothesized environmental variables. The new evidence reviewed here points to some genetic component in Black-White differences in mean IQ. The implication for public policy is that the discrimination model (i.e., Black-White differences in socially valued outcomes will be equal barring discrimination) must be tempered by a distributional model (i.e., Black-White outcomes reflect underlying group characteristics). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What if the hereditarian hypothesis is true?

J. P. Rushton and A. R. Jensen (see record 2005-03637-001) review 10 bodies of evidence to support their argument that the long-standing, worldwide Black-White average differences in cognitive ability are more plausibly explained by their hereditarian (50% genetic causation) theory than by culture-only (0% genetic causation) theory. This commentary evaluates the relevance of their evidence, the overall strength of their case, the implications they draw for public policy, and the suggestion by some scholars that the nation is best served by telling benevolent lies about race and intelligence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The cultural malleability of intelligence and its impact on the racial/ethnic hierarchy.

This commentary highlights previous literature (see record 2005-03637-001) focusing on cultural and environmental explanations for the racial/ethnic group hierarchy of intelligence. Assumptions underlying definitions of intelligence, heritability/genetics, culture, and race are noted. Historical, contextual, and testing issues are clarified. Specific attention is given to studies supporting stereotype threat, effects of mediated learning experiences, and relative functionalism. Current test development practices are critiqued with respect to methods of validation and item development. Implications of the genetic vs. culture-only arguments are discussed with respect to the malleability of IQ. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review of The IQ game: A methodological inquiry into the heredity-environment controversy and Intelligence, Heredity and Environment.

Reviews the books, The IQ Game. A Methodological Inquiry into the Heredity-Environment Controversy by Howard F. Taylor (1980); and Intelligence, Heredity and Environment by Philip E. Vernon (1979). A fundamental issue in psychology is the relation between differences in heredity and differences in human behaviour and mental characteristics. The history of vigorous debate on this question is ancient, and two recent books show that it is far from being resolved. The approaches and conclusions by the two authors are so different that they are best presented as a study of contrasts. In doing so, I have chosen three specific topics for discussion which are addressed explicitly by both authors. Taylor reviews Burt's publications as well as critiques by Kamin (1974), Dorfman (1978), Hearnshaw (1979) and others, concluding that the data 'obviously cannot be used in this analysis.' Vernon, on the other hand, reprints many of Burt's correlations for IQ scores of relatives in several tables and relies heavily on Sir Cyril's analyses. He notes there are reasons to doubt the accuracy of some of the figures, but he vigorously defends Burt against charges of fraud and accuses Leon Kamin, who first exposed Sir Cyril, of being 'a good deal more one-sided than Burt.' Both authors make extensive use of the concept of 'heritability,' but only Taylor explains it clearly and correctly. Of these two books, only the one by Taylor adds anything positive to the extensive discussions of heredity and intelligence during the last decade. The IQ Game is a major contribution, being thorough, critical and thought-provoking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A reexamination of black-white mean differences in work performance: More data, more moderators.

This study is the largest meta-analysis to date of Black-White mean differences in work performance. The authors examined several moderators not addressed in previous research. Findings indicate that mean racial differences in performance favor Whites (d = 0.27). Effect sizes were most strongly moderated by criterion type and the cognitive loading of criteria, whereas data source and measurement level were influential moderators to a lesser extent. Greater mean differences were found for highly cognitively loaded criteria, data reported in unpublished sources, and for performance measures consisting of multiple item scales. On the basis of these findings, the authors hypothesize several potential determinants of mean racial differences in job performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bias and error rates for premorbid IQ estimators: Comment on Veiel and Koopman (2001).

H. O. F. Veiel and R. F. Koopman (2001) advance statistical and legal theses. They correctly point out that the usual regression formula for estimating a pre-event IQ underestimates high IQs and overestimates low IQs (due to regression to the mean). They call this a conditional bias and show it can be sizeable. The author takes issue with their claim that a new estimator they propose should be used in place of the usual formulas, because it negates this statistical bias. Their argument against the usual estimator conflates statistical bias and legal bias. Their discussion in favor of their new estimator mentions, but does not derive a general formula for, a gross loss of precision entailed by use of the new estimator. The author quantifies this loss of precision and, using Veiel and Koopman's numerical example, shows that their estimator quadruples error. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychological and physical health at age 70 in the Lothian Birth Cohort 1936: Links with early life IQ, SES, and current cognitive function and neighborhood environment.

Objective: Researchers in many fields are interested in the robust observation that higher socioeconomic status (SES) is associated with better mental and physical health. Prominent explanations for the association involve effects of stress due to relative material and social adversity in lower socioeconomic environments, but early-life intelligence may also contribute directly to both later-life socioeconomic status and health. Here, we evaluated the effects of early-life IQ on mental and physical health outcomes at age 70, in the context of effects of SES. Design: The Lothian Birth Cohort of 1936 took part in the Scottish Mental Survey of 1947, providing a measure of IQ at age 11. They have been extensively surveyed at age 70. Main Outcome Measures: Body mass index, constraints on daily life activities, hospital anxiety and depression, number of diseases, level of physical activity, weekly units of alcohol consumption, and pack-years of smoking. Results and Conclusion: SES had apparently direct effects on most outcomes, but age 11 IQ was also involved in several, either directly or because it contributed to SES. Several interactions helped to integrate these associations. High age-11 IQ tended to buffer effects of adverse environments on physical and mental problems in old age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gender differences in planning, attention, simultaneous, and successive (PASS) cognitive processes and achievement.

Gender differences in ability and achievement have been studied for some time and have been conceptualized along verbal, quantitative, and visual–spatial dimensions. Researchers recently have called for a theory-based approach to studying these differences. This study examined 1,100 boys and 1,100 girls who matched the U.S. population using the Planning, Attention, Simultaneous, Successive (PASS) cognitive-processing theory, built on the neuropsychological work of A. R. Luria (1973). Girls outperformed boys on the Planning and Attention scales of the Cognitive Assessment System by about 5 points (d?=?.30 and .35, respectively). Gender differences were also found for a subsample of 1,266 children on the Woodcock-Johnson Revised Tests of Achievement Proofing (d?=?.33), Letter-Word Identification (d?=?.22), and Dictation (d?=?.22). The results illustrate that the PASS theory offers a useful way to examine gender differences in cognitive performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intellectual functioning in adults with ADHD: A meta-analytic examination of full scale IQ differences between adults with and without ADHD.

Although attention has been given to the intellectual functioning of children with attention-deficit/hyperactivity disorder (ADHD) relative to their non-ADHD peers, few studies have examined intellectual functioning in adults with ADHD. The purpose of the current investigation was to examine differences in intellectual ability between adults with and without ADHD via a meta-analytic review. Of the 33 studies meeting inclusion criteria, primary analyses focused on 18 studies representing 1,031 adults with ADHD and 928 non-ADHD, nonclinical comparison adults and containing Wechsler Adult Intelligence Scale (WAIS; D. Wechsler, 1955, 1981, 1994) Full Scale IQ scores or estimates. A significant effect was found such that adults with ADHD scored lower than non-ADHD adults on WAIS intelligence tests. However, this difference was small and not clinically meaningful. The presence of several moderators reflecting characteristics of the ADHD samples and study methodology suggested that only a subset of adults with ADHD (e.g., those with comorbid disorders) may experience lower general intellectual ability relative to non-ADHD comparison adults. Implications of the findings for clinical and research settings are presented as well as suggestions for improving methodology and reporting in future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relation between source memory and episodic memory: Comment on Siedlecki et al. (2005).

On the basis of an interesting structural equation analysis, K. L. Siedlecki, T. A. Salthouse, and D. E. Berish (see record 2005-02476-002) argued that "it may not be meaningful to refer to source memory as a construct distinct from episodic memory" (p. 31). This commentary highlights that this same point could also be made on conceptual grounds. To suggest that source and episodic memory are distinct concepts would confound tasks with theoretical constructs. All episodic tasks involve making attributions about the origin of mental experiences (source monitoring). Conversely, source memory tasks are designed to investigate episodic memory. No task is special, but each may be useful, depending on the focus of interest. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Expanding variance and the case of historical changes in IQ means: A critique of Dickens and Flynn (2001).

The Flynn effect is the rise in mean IQ scores during the 20th century, amounting to about 0.33 IQ points per year. Many theoretical explanations have been proposed, though none are universally accepted. W. Dickens and J. R. Flynn's (2001) new approach explains the large IQ changes by means of recursive models of IQ growth. A salient feature of their models is that IQ phenotypes and their supportive environments are correlated; in addition, environmental effects can rebound on phenotypic IQ to increase or lower IQ. In this critique, the authors examine an empirical challenge to their models, which typically imply large changes in IQ variance. However, the historical rise in IQ mean level has not been accompanied by substantial variance changes, a finding inconsistent with the properties of the proposed model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biased estimators, biased experts, and the ivory tower: A reply to Grove (2001).

This reply responds to W. M. Grove's (2001) critique of H. O. F. Veiel and R. F. Koopman's (2001) article on bias in widely used methods of estimating premorbid IQ. In this reply, the authors show that Grove is misrepresenting part of Veiel and Koopman's arguments, extending them to show that the proposed adjustment to regression estimates of IQ not only is unbiased but also is the maximum-likelihood estimate of the true IQ, and argue that Grove's notion of the acceptability of biased methods in judicial proceedings reflects a fundamental misapprehension of their nature and purpose. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A test of the adaptive specialization hypothesis: Population differences in caching, memory, and the hippocampus in black-capped chickadees (Poecile atricapilla).

To test the hypothesis that accurate cache recovery is more critical for birds that live in harsh conditions where the food supply is limited and unpredictable, the authors compared food caching, memory, and the hippocampus of black-capped chickadees (Poecile atricapilla) from Alaska and Colorado. Under identical laboratory conditions, Alaska chickadees (a) cached significantly more food; (b) were more efficient at cache recovery; (c) performed more accurately on one-trial associative learning tasks in which birds had to rely on spatial memory, but did not differ when tested on a nonspatial version of this task; and (d) had significantly larger hippocampal volumes containing more neurons compared with Colorado chickadees. The results support the hypothesis that these population differences may reflect adaptations to a harsh environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Introduction to the Special Section on Cognitive Abilities: 100 Years After Spearman's (1904) "'General Intelligence,' Objectively Determined and Measured".

The study of individual differences in cognitive abilities is one of the few branches of psychological science to amass a coherent body of empirical knowledge withstanding the test of time. There is wide consensus that cognitive abilities are organized hierarchically, and C. Spearman's (1904) general intelligence occupies the vertex of this hierarchy. In addition, specific abilities beyond general intelligence refine longitudinal forecasts of important social phenomena and paint a rich portrait of this important domain of psychological diversity. This opening article identifies and then reviews 5 major areas concerning the personological significance of cognitive abilities and the methods used to study them. In models of human behavior and important life outcomes, cognitive abilities are critical in more ways than social scientists realize. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The essential role of behavioral genetics in developmental psychology: Reply to Partridge (2005) and Greenberg (2005).

The authors address the methodological, theoretical, and ideological criticisms of their article on adolescent perceptions of parenting behavior (see record 2005-14938-011) made by G. Greenberg (see record 2005-14938-013) and T. Partridge (see record 2005-14938-012). Behavioral genetic methods have provided unique insights on the origins of individual differences in behavior and, when applied to parenting and other putative psychosocial influences, challenge conventional developmental theory. McGue et al.'s goal was not, as Greenberg and Partridge appeared to believe, to establish the heritability of parenting--that was already known; rather, McGue et al. showed how the relationship between inherited factors and an individual's environment changes during a critical developmental transition. There is a great need for developmental researchers to explore the combined influence of genetic and environmental factors using a range of approaches, including that of McGue et al. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Race and genetics: Controversies in biomedical, behavioral, and forensic sciences": Correction to Ossorio and Duster (2005).

Reports an error in "Race and Genetics: Controversies in Biomedical, Behavioral, and Forensic Sciences" by Pilar Ossorio and Troy Duster (American Psychologist, 2005[Jan], Vol 60[1], 115-128). In this article, Table 1 contains several errors due to an editorial mistake. In the Population and Incarceration columns, the data for Blacks and Whites were transposed. In addition, decimal points were omitted from the data in the Rate (%) of Incarceration per Population columns. The correct version of Table 1 appears in the erratum. (The following abstract of the original article appeared in record 2005-00117-011.) Among biomedical scientists, there is a great deal of controversy over the nature of race, the relevance of racial categories for research, and the proper methods of using racial variables. This article argues that researchers and scholars should avoid a binary-type argument, in which the question is whether to use race always or never. Researchers should instead focus on developing standards for when and how to use racial variables. The article then discusses 1 context, criminology, in which the use of racial variables in behavioral genetics research could be particularly problematic. If genetic studies of criminalized behavior use forensic DNA databanks or forensic genetic profiles, they will be confounded by the many racial biases of the law enforcement and penal system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trajectories emerging from discrete versus continuous processing models in phonological competitor tasks: A commentary on Spivey, Grosjean, and Knoblich (2005).

M. J. Spivey, M. Grosjean, and G. Knoblich (see record 2005-11966-005) showed that in a phonological competitor task, participants' mouse cursor movements showed more curvature toward the competitor item when the competitor and target were phonologically similar than when the competitor and target were phonologically dissimilar. Spivey et al. interpreted this result as evidence for continuous cascading of information during the processing of spoken words. Here we show that the results of Spivey et al.need not be ascribed to continuous speech processing. Instead, their results can be ascribed to discrete processing of speech, provided one appeals to an already supported model of motor control that asserts that switching movements from 1 target to another relies on superposition of the 2nd movement onto the 1st. The latter process is a continuous cascade, a fact that indirectly strengthens the plausibility of continuous cascade models. However, the fact that we can simulate the results of Spivey et al.with a continuous motor output model and a discrete perceptual model shows that the implications of Spivey et al.'s experiment are less clear than these authors supposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The many facets of the locomotor response to a novel environment test: Theoretical comment on Mitchell, Cunningham, and Mark (2005).

Several animal studies have shown that there is a positive correlation between locomotor activity in response to a novel environment and acquisition of drug self-administration behavior. This finding led to the assumption that animals with heightened reactivity to novel environments are more sensitive to the rewarding effects of drugs compared with animals with reduced reactivity. But are these individuals really more responsive to drugs, or could they have enhanced sensitivity to rewards in general or even simply be better learners? In the previous issue of this journal, J. M. Mitchell, C. L. Cunningham, and G. P. Mark (2005) (see record 2005-03585-010), investigated these important matters. They reported that the locomotor response to a novel environment does not predict responding for cocaine but reflects overall differences in the ability to learn operant tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)