Considerations Relating to the Study of Group Differences in Intelligence

Gender Differences in the Wechsler Intelligence Scale for Children in a Large Group of Italian Children with Attention Deficit Hyperactivity Disorder

Despite being repeatedly investigated in children with typical development, research on gender differences in intellectual abilities in specific groups of children, including children with attention deficit hyperactivity disorder (ADHD), has been scarce. In this paper, we evaluated the performance of a large group of Italian children with ADHD using the WISC-IV. We aimed at investigating the presence of gender differences using a multi-group confirmatory factor analysis approach. Results showed that the WISC is largely gender-invariant. However, some tasks present non-invariant patterns (block design and coding). Differences at the latent level also showed some differences (favoring boys) in the verbal comprehension index. Conversely, differences at the latent level were not found in the full-scale IQ or in the other main indices. These results have theoretical and practical implications.

The Cyclical Return of the IQ Controversy: Revisiting the Lessons of the Resolution on Genetics, Race and Intelligence

In 1976, the Genetics Society of America (GSA) published a document entitled "Resolution of Genetics, Race, and Intelligence." This document laid out the Society's position in the IQ controversy, particularly that on scientific and ethical questions involving the genetics of intellectual differences between human populations. Since the GSA was the largest scientific society of geneticists in the world, many expected the document to be of central importance in settling the controversy. Unfortunately, the Resolution had surprisingly little influence on the discussion. In 1979, William Provine analyzed the possible factors that decreased the impact of the Resolution, among them scientists' limited understanding of the relationship between science and ethics. Through the analysis of unpublished versions of the Resolution and exchanges between GSA members, I will suggest that the limited impact of the statement likely depended on a shift in the aims of the GSA due to the controversies that surrounded the preparation of the document. Indeed, the demands of the membership made it progressively more impartial in both scientific and political terms, decreasing its potential significance for a wider audience. Notably, the troubled history of the Resolution raises the question of what can make effective or ineffective the communication between scientists and the public-a question with resonance in past and present discussions on topics of social importance.

Cognitive Ability in Everyday Life: The Utility of Open-Source Measures

The measurement of individual differences in cognitive ability has a long and important history in psychology, but it has been impeded by the proprietary nature of most assessment measures. With the development of validated open-source measures of ability (collected in the International Cognitive Ability Resource, or ICAR, available at ICAR-project.com ), it is now possible for many researchers to assess ability in large surveys or small, lab-based studies without the expenses associated with proprietary measures. We review the history of ability measurement and discuss how the growing set of items included in ICAR allows ability assessments to be more generally available to all researchers.

Assessing the intellectual ability of asylum seekers

The European Union has seen an increased number of asylum seekers and economic migrants over the past few years. There will be request to assess some of these individuals to see if they have an intellectual disability (ID). If this is to be done using the current internationally recognized definitions of ID, we will need to be confident that the IQ tests we have available are able to accurately measure the IQs of people from developing countries. The literature showing substantial differences in the mean measured IQs of different countries is considered. It is found that, although there are numerous problems with these studies, the overall conclusion that there are substantial differences in mean measured IQ is sound. However, what is not clear is whether there are large differences in true intellectual ability between different countries, how predictive IQ scores are of an individual from a developing country ability to cope, and whether or not an individual's IQ would increase if they go from a developing country to a developed one. Because of these uncertainties, it is suggested that a diagnosis of ID should not be dependent on an IQ cut-off point when assessing people from developing countries.

What Makes Nations Intelligent?

Modern society is driven by the use of cognitive artifacts: physical instruments or styles of reasoning that amplify our ability to think. The artifacts range from writing systems to computers. In everyday life, a person demonstrates intelligence by showing skill in using these artifacts. Intelligence tests and their surrogates force examinees to exhibit some of these skills but not others. This is why test scores correlate substantially but not perfectly with a variety of measures of socioeconomic success. The same thing is true at the international level. Nations can be evaluated by the extent to which their citizens score well on cognitive tests, including both avowed intelligence tests and a variety of tests of academic achievement. The resulting scores are substantially correlated with various indices of national wealth, health, environmental quality, and schooling and with a vaguer variable, social commitment to innovation. These environmental variables are suggested as causes of the differences in general cognitive skills between national populations. It is conceivable that differences in gene pools also contribute to international and, within nations, group differences in cognitive skills, but at present it is impossible to evaluate the extent of genetic influences.

Barriers to Understanding Racial Differences in Intelligence: Commentary on Hunt and Carlson (2007)

Hunt and Carlson (2007), (this issue) present sensible guidelines for the conduct of research on group differences in intelligence. In this response, I want to indicate why I believe that their call for more research is not likely, in the near term, to lead to a clarification of the reasons for racial differences in performance on tests of intelligence. There are three barriers to progress in this field that I will consider. First, there are gaps in knowledge that render the interpretation of research problematic (see Brody, 2003, for a discussion of the indeterminate nature of research alleged to support a genetic basis for racial differences in intelligence). Second, structural inequalities in social arrangements may lead to problematic outcomes for many studies of racial differences in intelligence. Third, conceptual confusions derived from the consideration of race as a category and not as a continuum render group comparisons suspect.

Letting the daylight in: Reviewing the reviewers and other ways to maximize transparency in science

With the emergence of online publishing, opportunities to maximize transparency of scientific research have grown considerably. However, these possibilities are still only marginally used. We argue for the implementation of (1) peer-reviewed peer review, (2) transparent editorial hierarchies, and (3) online data publication. First, peer-reviewed peer review entails a community-wide review system in which reviews are published online and rated by peers. This ensures accountability of reviewers, thereby increasing academic quality of reviews. Second, reviewers who write many highly regarded reviews may move to higher editorial positions. Third, online publication of data ensures the possibility of independent verification of inferential claims in published papers. This counters statistical errors and overly positive reporting of statistical results. We illustrate the benefits of these strategies by discussing an example in which the classical publication system has gone awry, namely controversial IQ research. We argue that this case would have likely been avoided using more transparent publication practices. We argue that the proposed system leads to better reviews, meritocratic editorial hierarchies, and a higher degree of replicability of statistical analyses.

External measures of cognition

The human brain is undoubtedly the most impressive, complex, and intricate organ that has evolved over time. It is also probably the least understood, and for that reason, the one that is currently attracting the most attention. In fact, the number of comparative analyses that focus on the evolution of brain size in Homo sapiens and other species has increased dramatically in recent years. In neuroscience, no other issue has generated so much interest and been the topic of so many heated debates as the difference in brain size between socially defined population groups, both its connotations and implications. For over a century, external measures of cognition have been related to intelligence. However, it is still unclear whether these measures actually correspond to cognitive abilities. In summary, this paper must be reviewed with this premise in mind.

Impact of Experiences With Racism on African-Descent Persons’ Susceptibility to Stereotype Threat Within the United Kingdom

The present study examines the impact of experiences with individual, institutional, cultural, and collective racism on susceptibility to stereotype among African-descent persons within the United Kingdom ( n = 103). Results of hierarchical multiple regression analysis indicated that (contrary to hypotheses) experiences with individual, institutional, and cultural racism were not significantly or marginally related to susceptibility to stereotype threat when entered together in Model 1. However (consistent with hypotheses), experience with collective racism was a significant positive predictor of susceptibility to stereotype threat after controlling for the effects of experiences with individual, institutional, and cultural racism in Model 2. Moreover (and unexpectedly), once experience with collective racism was added, experience with cultural racism emerged as a marginal negative predictor of susceptibility to stereotype threat. Implications for the continuing relevance of Erving Goffman’s symbolic interactionist theory and construct of stigma, along with Claude Steele’s construct of stereotype threat, to the field of Black psychology is discussed.

Real-time craving differences between black and white smokers

Black and White smokers may experience aspects of nicotine dependence, including craving, differently. This study used a naturalistic technique, ecological momentary assessment (EMA), to explore differences in craving, mood, expectancy, and smoking enjoyment between Black and White smokers. Participants carried personal digital assistants (PDAs) programmed to obtain multiple daily assessments. Black smokers reported higher craving after smoking and at random assessment times and higher cigarette enjoyment. No differences were found in mood or expectancy. Racial differences in psychological factors related to smoking are explored in the contexts of genetic, sociological, and psychophysiological distinctions. Implications for practice and research are discussed. (Am J Addict 2010;00:1-5).

Educational Policy and Country Outcomes in International Cognitive Competence Studies

Prior studies of studentsqqaposxx and adultsqqaposxx cognitive competence have shown large differences between nations, equivalent to a difference of 5 to 10 years of schooling. These differences seem to be relevant because studies using different research paradigms have demonstrated that population-level cognitive abilities are related to a number of important societal outcomes, including productivity, democratization, and health. In this overview of transnational differences, we document a number of positive predictors of international differences in student competence, including the amount of preschool education, student discipline, quantity of education, attendance at additional schools, early tracking, the use of centralized exams and high-stakes tests, and adult educational attainment. We found rather negative relationships for grade retention rates, age of school onset, and class size. Altogether, these results, when combined with the outcomes of earlier studies, demonstrate that international differences in cognitive competence can be explained in part by aspects of the respective countriesqqaposxx educational systems and that these differences consequently can be reduced by reform of their educational policy. This has important implications not just for closing gaps in educational achievement, but for narrowing international gaps in wealth, health, and democracy.

The Rainbow and Kaleidoscope Projects

It is possible, in admissions to higher education, to increase academic excellence and diversity simultaneously. This article reviews how a theory of successful intelligence can be used to accomplish both of these goals. The theory postulates that intelligence comprises creative skills in generating novel ideas, analytical skills in discerning whether they are good ideas, and practical skills in implementing the ideas and persuading others of their worth. The article summarizes several projects designed to simultaneously boost academic excellence and increase diversity in entering classes. In the Rainbow Project, we found that it was possible substantially to increase prediction of first-year university academic performance and simultaneously reduce ethnic-group differences on the predictive test, relative to a standardized test used for admissions in the United States. In the Kaleidoscope Project, we found that students admitted for expanded skills performed as well as did other students, without the ethnic-group differences typically obtained in such measures and excelled in active citizenship and leadership activities.

Applying the Theory of Successful Intelligence to Education—The Good, the Bad, and the Ogre: Commentary on Sternberg et al. (2008)

Sternberg, Grigorenko, and Zhang (2008) have presented a creative model for the application of research on intelligence and personality to education. There are many positive aspects of their effort. These include the coordination of individual differences in cognition and personality and their extension of the concept of intelligence beyond skills that can be tested in the normal testing paradigm. Although various parts of their approach have appeared elsewhere, the development of a single package containing all these ideas is a worthwhile improvement in thinking about education. They cite numerous studies in support of their efforts. However, a close examination of some of the major studies shows that this evidence, though not inconsistent with their claims, is not as strong as their review indicates. If one applies conventional psychometric criteria, simpler explanations than those they propose could be found. Their model of thinking styles is probably too complex for many practical applications. However, a good case can be made that the appropriate criterion is “How useful will this approach be in education?” By this criterion, the total package is impressive and should be seriously considered by educators.

Twin-singleton differences in intelligence: a meta-analysis

Since the emergence of twin studies in the 1920s, time and again the question of possible twin-singleton differences in intelligence has been posed. This study addressed the issue through a meta-analysis of published studies on this theme. Twins on the average seem to have lower IQs than singletons. The best estimate for this group difference is 4.2 IQ points (less than one-third of a standard deviation), with a great divide between study outcomes of less vs more recent birth cohorts (5.1 vs 0.5 IQ points, respectively). The evidence is based on studies from six countries (including population-based ones of entire birth cohorts), a massive database (comparisons of more than 30,000 twins with nearly 1.6 million singletons), a variety of intelligence tests, and birth cohorts spanning most of the 20th century, but, for the most part, on an age range limited to children and adolescents. The effect shows considerable between-study heterogeneity but appears robust (fail-safe N calculations), not due to influential individual studies (sensitivity analysis) or publication bias, was present since the very first published studies (cumulative meta-analysis), and appears generalizable across sex, zygosity, and other intelligence domains beyond the verbal. There are insufficient data as to whether the effect persists over the lifespan, exists as well within families, or has ceased in recent birth cohorts of highly developed countries (Denmark and The Netherlands). Likely causes of the effect appear to be prenatal and perinatal factors (reduced fetal growth and shorter gestation for twins).