Figure it out
Is Education Associated With Improvements in General Cognitive Ability, or in Specific Skills?
Stuart Ritchie, Timothy Bates & Ian Deary
Developmental Psychology, forthcoming
Abstract:
Previous research has indicated that education influences cognitive development, but it is unclear what, precisely, is being improved. Here, we tested whether education is associated with cognitive test score improvements via domain-general effects on general cognitive ability (g), or via domain-specific effects on particular cognitive skills. We conducted structural equation modeling on data from a large (n = 1,091), longitudinal sample, with a measure of intelligence at age 11 years and 10 tests covering a diverse range of cognitive abilities taken at age 70. Results indicated that the association of education with improved cognitive test scores is not mediated by g, but consists of direct effects on specific cognitive skills. These results suggest a decoupling of educational gains from increases in general intellectual capacity.
---------------------
David Baker et al.
Intelligence, March–April 2015, Pages 144–158
Abstract:
The phenomenon of rising IQ scores in high-income nations over the 20th century, known as the Flynn Effect, indicates historical increase in mental abilities related to planning, organization, working memory, integration of experience, spatial reasoning, unique problem-solving, and skills for goal-directed behaviors. Given prior research on the impact of formal education on IQ, a three-tiered hypothesis positing that schooling, and its expansion and intensification over the education revolution, is one likely cause of the Flynn Effect is tested in three studies. First, a neuroimaging experiment with children finds that neuromaturation is shaped by common activities in school, such as numeracy, and share a common neural substrate with fluid IQ abilities. Second, a field study with adults from insolated agrarian communities finds that variable exposure to schooling is associated with related variation in the mental abilities. Third, a historical–institutional analysis of the cognitive requirements of American mathematics curriculum finds a growing cognitive demand for birth cohorts from later in the 20th century. These findings suggest a consilience of evidence about the impact of mass education on the Flynn Effect and are discussed in light of the g-factor paradigm, cognition, and the Bell Curve debate.
---------------------
Height, Human Capital, and Earnings: The Contributions of Cognitive and Noncognitive Ability
Andreas Schick & Richard Steckel
Journal of Human Capital, Spring 2015, Pages 94-115
Abstract:
Taller workers receive a substantial premium in earnings or wages, which some studies attribute to noncognitive abilities or social skills that are correlated with stature and rewarded in the labor market. Recent research argues that cognitive abilities explain the relationship. This paper reconciles the competing views by recognizing that net nutrition, a major determinant of adult height, fosters both cognitive and noncognitive abilities. Using data from Britain’s National Childhood Development Study, we show that taller children have higher average cognitive and noncognitive test scores and that each aptitude accounts for a substantial and roughly equal portion of the stature-earnings premium. Together, cognitive and noncognitive abilities explain the height premium.
---------------------
Jonathan Daw, Guang Guo & Kathie Mullan Harris
Social Science Research, July 2015, Pages 422–439
Abstract:
Prominent authors in the behavioral genetics tradition have long argued that shared environments do not meaningfully shape intelligence and academic achievement. However, we argue that these conclusions are erroneous due to large violations of the additivity assumption underlying behavioral genetics methods – that sources of genetic and shared and nonshared environmental variance are independent and non-interactive. This is compounded in some cases by the theoretical equation of the effective and objective environments, where the former is defined by whether siblings are made more or less similar, and the latter by whether siblings are equally subject to the environmental characteristic in question. Using monozygotic twin fixed effects models, which compare outcomes among genetically identical pairs, we show that many characteristics of objectively shared environments significantly moderate the effects of nonshared environments on adolescent academic achievement and verbal intelligence, violating the additivity assumption of behavioral genetic methods. Importantly, these effects would be categorized as nonshared environmental influences in standard twin models despite their roots in shared environments. These findings should encourage caution among those who claim that the frequently trivial variance attributed to shared environments in behavioral genetic models means that families, schools, and neighborhoods do not meaningfully influence these outcomes.
---------------------
Robin Clarke
Personality and Individual Differences, August 2015, Pages 46–51
Abstract:
A fundamental principle of the antiinnatia theory of autism and IQ is that the same factors (genetic and environmental) which in extreme high levels cause autism, in more modal levels cause increased IQ. And the factors which generally cause raised IQ, in extreme levels cause autism. The antiinnatia theory further proposed that molecules randomly part-time binding to DNA and thereby reducing gene-expression would cause autism (and in less high levels cause raised IQ). Studies have found that mercury binds dose-dependently to DNA thereby reducing gene-expression, and thus the theory predicts that mercury pollution would cause raised IQ (such as the Flynn effect). This appears contrary to the standard assumption that mercury pollution causes decrements of IQ. In this study, data from the Upper Fremont glacier finds considerable overall correspondence between changes of mercury pollution and changes of IQ. In respect of both mercury and IQ there was roughly-speaking 100 years of increase followed by 15 years of decrease in at least five countries. But mercury pollution is likely to be causing serious harms other than decrements of population averages of IQ.
---------------------
Christian Plewnia et al.
PLoS ONE, April 2015
Abstract:
Cognitive control (CC) of attention is a major prerequisite for effective information processing. Emotional distractors can bias and impair goal-directed deployment of attentional resources. Frustration-induced negative affect and cognition can act as internal distractors with negative impact on task performance. Consolidation of CC may thus support task-oriented behavior under challenging conditions. Recently, transcranial direct current stimulation (tDCS) has been put forward as an effective tool to modulate CC. Particularly, anodal, activity enhancing tDCS to the left dorsolateral prefrontal cortex (dlPFC) can increase insufficient CC in depression as indicated by a reduction of attentional biases induced by emotionally salient stimuli. With this study, we provide first evidence that, compared to sham stimulation, tDCS to the left dlPFC enhances processing speed measured by an adaptive version of the Paced Auditory Serial Addition Task (PASAT) that is typically thwarted by frustration. Notably, despite an even larger amount of error-related negative feedback, the task-induced upset was suppressed in the group receiving anodal tDCS. Moreover, inhibition of task-related negative affect was correlated with performance gains, suggesting a close link between enhanced processing speed and consolidation of CC by tDCS. Together, these data provide first evidence that activity enhancing anodal tDCS to the left dlPFC can support focused cognitive processing particularly when challenged by frustration-induced negative affect.
---------------------
Martin Bellander et al.
Neuropsychology, March 2015, Pages 247-254
Objective: Little is known about genetic contributions to individual differences in cognitive plasticity. Given that the neurotransmitter dopamine is critical for cognition and associated with cognitive plasticity, we investigated the effects of 3 polymorphisms of dopamine-related genes (LMX1A, DRD2, COMT) on baseline performance and plasticity of working memory (WM), perceptual speed, and reasoning.
Method: One hundred one younger and 103 older adults underwent approximately 100 days of cognitive training, and extensive testing before and after training. We analyzed the baseline and posttest data using latent change score models.
Results: For working memory, carriers of the val allele of the COMT polymorphism had lower baseline performance and larger performance gains from training than carriers of the met allele. There was no significant effect of the other genes or on other cognitive domains.
Conclusions: We relate this result to available evidence indicating that met carriers perform better than val carriers in WM tasks taxing maintenance, whereas val carriers perform better at updating tasks. We suggest that val carriers may show larger training gains because updating operations carry greater potential for plasticity than maintenance operations.