scholarly journals Spurious correlations in research on the effects of specific cognitive abilities

2021 ◽  
Author(s):  
Kimmo Sorjonen ◽  
Bo Melin

Studies on the effect of non-g ability residuals have often employed double adjustment for general cognitive ability (g), as they have calculated the ability residuals adjusting for g and then calculated the effect of the non-g residuals while adjusting for g. The present simulations demonstrate that the double adjustments may result in spurious negative associations between the non-g residual on one cognitive ability, e.g. verbal ability, and variables with a positive association with another ability, e.g. SAT math and math ability. In analyses of the 1997 National Longitudinal Survey of Youth (NLSY97), the negative associations between non-g residuals on verbal and math ability and aptitude test scores on the other ability vanished when not double adjusting for g. This indicates that the observed negative associations may be spurious and not due to differential investment of time and effort in one ability at the expense of the other ability, as suggested in the literature. Researchers of the effects of specific abilities are recommended to validate their findings and interpretations with analyses not double adjusting for g.

1992 ◽  
Vol 3 (6) ◽  
pp. 346-353 ◽  
Author(s):  
N.L. Pedersen ◽  
R. Plomin ◽  
J.R. Nesselroade ◽  
G.E. McClearn

Little is known about the importance of genetic effects on individual differences in cognitive abilities late in life. We present the first report from the Swedish Adoption/Twin Study of Aging (SATSA) for cognitive data, including general cognitive ability and 13 tests of specific cognitive abilities. The adoption/twin design consists of identical twins separated at an early age and reared apart (46 pairs), identical twins reared together (67 pairs), fraternal twins reared apart (100 pairs), and fraternal twins reared together (89 pairs); average age was 65 years. Heritability of general cognitive ability in these twins was much higher (about 80%) than estimates typically found earlier in life (about 50%). Consistent with the literature, heritabilities of specific cognitive abilities were lower than the heritability of general cognitive ability but nonetheless substantial. Average heritabilities for verbal, spatial, perceptual speed, and memory tests were, respectively, 58%, 46%, 58%, and 38%.


1998 ◽  
Vol 9 (3) ◽  
pp. 183-189 ◽  
Author(s):  
Stephen A. Petrill ◽  
Robert Plomin ◽  
Stig Berg ◽  
Boo Johansson ◽  
Nancy L. Pedersen ◽  
...  

In the first twin study of the old-old, individuals 80 years old and older, we examined the relationship between general and specific cognitive abilities from a genetic perspective. That is, we examined the extent to which genetic and environmental factors influence major group factors of cognitive abilities, independent of general cognitive ability. As part of the OctoTwin project in Sweden, general and specific cognitive abilities were assessed in 52 monozygotic and 65 same-sex dizygotic twin pairs 80 years old and older using a battery of seven tests that assess verbal, spatial, speed-of-processing, and memory performance. Results suggest that genetic effects associated with general cognitive ability (g) account for the correlation between g and verbal, spatial, and speed-of-processing abilities. No genetic influences were found for these specific cognitive abilities separate from g. In contrast, memory ability appears to be more distinct genetically from g than are other cognitive abilities. Comparison with younger samples suggests that cognitive abilities relating to speed of processing may be genetically dedifferentiated in the old-old.


1992 ◽  
Vol 41 (1) ◽  
pp. 65-72 ◽  
Author(s):  
E.L. Grigorenko ◽  
M.C. LaBuda ◽  
A.S. Carter

AbstractData on five tests of general and specific cognitive abilities, cognitive styles, and creativity, obtained from members of 60 identical and 63 fraternal Russian adolescent twin pairs, are presented. All tests are adaptations of standardized instruments widely used outside of the Soviet Union. Identical and fraternal twin correlations for general cognitive ability yielded a lower estimate of heritability (0.29) than generally found in other countries worldwide (0.52) although the twin correlations themselves are fairly comparable to figures from other countries and cultures — 0.83 and 0.69 for Russian identical and fraternal twin pairs, respectively, vs 0.86 and 0.60 for non-Russian identical, and fraternal twin pairs. Twin correlations for other cognitive-related abilities assessed were also comparable to correlations obtained outside the Soviet Union with the exception of creativity which yielded higher within-pair resemblance than reported in previous twin studies.


2019 ◽  
Vol 28 (2) ◽  
pp. 189-194 ◽  
Author(s):  
Kristof Kovacs ◽  
Andrew R. A. Conway

For more than a century, the standard view in the field of human intelligence has been that there is a “general intelligence” that permeates all human cognitive activity. This general cognitive ability is supposed to explain the positive manifold, the finding that intelligence tests with different content all correlate. Yet there is a lack of consensus regarding the psychological or neural basis of such an ability. A recent account, process-overlap theory, explains the positive manifold without proposing general intelligence. As a consequence of the theory, IQ is redefined as an emergent formative construct rather than a reflective latent trait. This implies that IQ should be interpreted as an index of specific cognitive abilities rather than the reflection of an underlying general cognitive ability.


1997 ◽  
Vol 8 (6) ◽  
pp. 442-447 ◽  
Author(s):  
Robert Plomin ◽  
David W. Fulker ◽  
Robin Corley ◽  
John C DeFries

Children increasingly resemble their parents in cognitive abilities from infancy through adolescence Results obtained from a 20-year longitudinal adoption study of 245 adopted children and their biological and adoptive parents, as well as 245 matched nonadoptive (control) parents and offspring, show that this increasing resemblance is due to genetic factors Adopted children resemble their adoptive parents slightly in early childhood but not at all in middle childhood or adolescence In contrast, during childhood and adolescence, adopted children become more like their biological parents, and to the same degree as children and parents in control families Although these results were strongest for general cognitive ability and verbal ability similar results were found for other specific cognitive abilities—spatial ability, speed of processing, and recognition memory These findings indicate that within this population, genes that stably affect cognitive abilities in adulthood do not all come into play until adolescence and that environmental factors that contribute to cognitive development are not correlated with parents' cognitive ability


2018 ◽  
Author(s):  
Roxanne Connelly ◽  
Vernon Gayle

The ‘Flynn effect’ describes the substantial and long-standing increase in average cognitive ability test scores, which has been observed in numerous psychological studies. Flynn makes an appeal for researchers to move beyond psychology’s standard disciplinary boundaries and to consider sociological contexts, in order to develop a more comprehensive understanding of cognitive inequalities. In this article we respond to this appeal and investigate social class inequalities in general cognitive ability test scores over time. We analyse data from the National Child Development Study (1958) and the British Cohort Study (1970). These two British birth cohorts are suitable nationally representative large-scale data resources for studying inequalities in general cognitive ability.We observe a large parental social class effect, net of parental education and gender in both cohorts. The overall finding is that large social class divisions in cognitive ability can be observed when children are still at primary school, and similar patterns are observed in each cohort. Notably, pupils with fathers at the lower end of the class structure are at a distinct disadvantage. This is a disturbing finding and it is especially important because cognitive ability is known to influence individuals later in the lifecourse.


2018 ◽  
Vol 6 (3) ◽  
pp. 37 ◽  
Author(s):  
Jonathan Wai ◽  
Matt Brown ◽  
Christopher Chabris

In education research and education policy, much attention is paid to schools, curricula, and teachers, but little attention is paid to the characteristics of students. Differences in general cognitive ability (g) are often overlooked as a source of important variance among schools and in outcomes among students within schools. Standardized test scores such as the SAT and ACT are reasonably good proxies for g and are available for most incoming college students. Though the idea of g being important in education is quite old, we present contemporary evidence that colleges and universities in the United States vary considerably in the average cognitive ability of their students, which correlates strongly with other methods (including international methods) of ranking colleges. We also show that these g differences are reflected in the extent to which graduates of colleges are represented in various high-status and high-income occupations. Finally, we show how including individual-level measures of cognitive ability can substantially increase the statistical power of experiments designed to measure educational treatment effects. We conclude that education policy researchers should give more consideration to the concept of individual differences in cognitive ability as well as other factors.


2019 ◽  
Vol 31 (1) ◽  
pp. 1-57 ◽  
Author(s):  
Jessica Oschwald ◽  
Sabrina Guye ◽  
Franziskus Liem ◽  
Philippe Rast ◽  
Sherry Willis ◽  
...  

Abstract Little is still known about the neuroanatomical substrates related to changes in specific cognitive abilities in the course of healthy aging, and the existing evidence is predominantly based on cross-sectional studies. However, to understand the intricate dynamics between developmental changes in brain structure and changes in cognitive ability, longitudinal studies are needed. In the present article, we review the current longitudinal evidence on correlated changes between magnetic resonance imaging-derived measures of brain structure (e.g. gray matter/white matter volume, cortical thickness), and laboratory-based measures of fluid cognitive ability (e.g. intelligence, memory, processing speed) in healthy older adults. To theoretically embed the discussion, we refer to the revised Scaffolding Theory of Aging and Cognition. We found 31 eligible articles, with sample sizes ranging from n = 25 to n = 731 (median n = 104), and participant age ranging from 19 to 103. Several of these studies report positive correlated changes for specific regions and specific cognitive abilities (e.g. between structures of the medial temporal lobe and episodic memory). However, the number of studies presenting converging evidence is small, and the large methodological variability between studies precludes general conclusions. Methodological and theoretical limitations are discussed. Clearly, more empirical evidence is needed to advance the field. Therefore, we provide guidance for future researchers by presenting ideas to stimulate theory and methods for development.


2019 ◽  
Vol 30 (2) ◽  
pp. 786-800 ◽  
Author(s):  
Jessica B Girault ◽  
Emil Cornea ◽  
Barbara D Goldman ◽  
Shaili C Jha ◽  
Veronica A Murphy ◽  
...  

ABSTRACTCortical structure has been consistently related to cognitive abilities in children and adults, yet we know little about how the cortex develops to support emergent cognition in infancy and toddlerhood when cortical thickness (CT) and surface area (SA) are maturing rapidly. In this report, we assessed how regional and global measures of CT and SA in a sample (N = 487) of healthy neonates, 1-year-olds, and 2-year-olds related to motor, language, visual reception, and general cognitive ability. We report novel findings that thicker cortices at ages 1 and 2 and larger SA at birth, age 1, and age 2 confer a cognitive advantage in infancy and toddlerhood. While several expected brain–cognition relationships were observed, overlapping cortical regions were also implicated across cognitive domains, suggesting that infancy marks a period of plasticity and refinement in cortical structure to support burgeoning motor, language, and cognitive abilities. CT may be a particularly important morphological indicator of ability, but its impact on cognition is relatively weak when compared with gestational age and maternal education. Findings suggest that prenatal and early postnatal cortical developments are important for cognition in infants and toddlers but should be considered in relation to other child and demographic factors.


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