Smart growth
One Century of Global IQ Gains: A Formal Meta-Analysis of the Flynn Effect (1909–2013)
Jakob Pietschnig & Martin Voracek
Perspectives on Psychological Science, May 2015, Pages 282-306
Abstract:
The Flynn effect (rising intelligence test performance in the general population over time and generations) varies enigmatically across countries and intelligence domains; its substantive meaning and causes remain elusive. This first formal meta-analysis on the topic revealed worldwide IQ gains across more than one century (1909–2013), based on 271 independent samples, totaling almost 4 million participants, from 31 countries. Key findings include that IQ gains vary according to domain (estimated 0.41, 0.30, 0.28, and 0.21 IQ points annually for fluid, spatial, full-scale, and crystallized IQ test performance, respectively), are stronger for adults than children, and have decreased in more recent decades. Altogether, these findings narrow down proposed theories and candidate factors presumably accounting for the Flynn effect. Factors associated with life history speed seem mainly responsible for the Flynn effect's general trajectory, whereas favorable social multiplier effects and effects related to economic prosperity appear to be responsible for observed differences of the Flynn effect across intelligence domains.
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The Origins of Counting Algorithms
Jessica Cantlon et al.
Psychological Science, forthcoming
Abstract:
Humans' ability to count by verbally labeling discrete quantities is unique in animal cognition. The evolutionary origins of counting algorithms are not understood. We report that nonhuman primates exhibit a cognitive ability that is algorithmically and logically similar to human counting. Monkeys were given the task of choosing between two food caches. First, they saw one cache baited with some number of food items, one item at a time. Then, a second cache was baited with food items, one at a time. At the point when the second set was approximately equal to the first set, the monkeys spontaneously moved to choose the second set even before that cache was completely baited. Using a novel Bayesian analysis, we show that the monkeys used an approximate counting algorithm for comparing quantities in sequence that is incremental, iterative, and condition controlled. This proto-counting algorithm is structurally similar to formal counting in humans and thus may have been an important evolutionary precursor to human counting.
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Cognitive Aging in Older Black and White Persons
Robert Wilson et al.
Psychology and Aging, forthcoming
Abstract:
During a mean of 5.2 years of annual follow-up, older Black (n = 647) and White (n = 647) persons of equivalent age and education completed a battery of 17 cognitive tests from which composite measures of 5 abilities were derived. Baseline level of each ability was lower in the Black subgroup. Decline in episodic and working memory was not related to race. Decline in semantic memory, perceptual speed, and visuospatial ability was slower in Black persons than White persons, and in semantic memory and perceptual speed this effect was stronger in older than younger participants. Racial differences persisted after adjustment for retest effects. The results suggest subtle cognitive aging differences between Black persons and White persons.
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What would Batman do? Self-distancing improves executive function in young children
Rachel White & Stephanie Carlson
Developmental Science, forthcoming
Abstract:
This experimental research assessed the influence of graded levels of self-distancing – psychological distancing from one's egocentric perspective – on executive function (EF) in young children. Three- (n = 48) and 5-year-old (n = 48) children were randomly assigned to one of four manipulations of distance from the self (from proximal to distal: self-immersed, control, third person, and exemplar) on a comprehensive measure of EF. Performance increased as a function of self-distancing across age groups. Follow-up analyses indicated that 5-year-olds were driving this effect. They showed significant improvements in EF with increased distance from the self, outperforming controls both when taking a third person perspective on the self and when taking the perspective of an exemplar other (e.g., Batman) through role play. Three-year-olds, however, did not show increased EF performance as a function of greater distance from the self. Preliminary results suggest that developments in theory of mind might contribute to these age-related differences in efficacy. These findings speak to the importance of psychological distancing in the expression of conscious control over thought and action from a young age and suggest a promising new avenue for early EF intervention.
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Is Playing Video Games Related to Cognitive Abilities?
Nash Unsworth et al.
Psychological Science, forthcoming
Abstract:
The relations between video-game experience and cognitive abilities were examined in the current study. In two experiments, subjects performed a number of working memory, fluid intelligence, and attention-control measures and filled out a questionnaire about their video-game experience. In Experiment 1, an extreme-groups analysis indicated that experienced video-game players outperformed nonplayers on several cognitive-ability measures. However, in Experiments 1 and 2, when analyses examined the full range of subjects at both the task level and the latent-construct level, nearly all of the relations between video-game experience and cognitive abilities were near zero. These results cast doubt on recent claims that playing video games leads to enhanced cognitive abilities. Statistical and methodological issues with prior studies of video-game experience are discussed along with recommendations for future studies.
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Functional role of frontal alpha oscillations in creativity
Caroline Lustenberger et al.
Cortex, June 2015, Pages 74–82
Abstract:
Creativity, the ability to produce innovative ideas, is a key higher-order cognitive function that is poorly understood. At the level of macroscopic cortical network dynamics, recent electroencephalography (EEG) data suggests that cortical oscillations in the alpha frequency band (8–12 Hz) are correlated with creative thinking. However, whether alpha oscillations play a fundamental role in creativity has remained unknown. Here we show that creativity is increased by enhancing alpha power using 10 Hz transcranial alternating current stimulation (10 Hz-tACS) of the frontal cortex. In a study of 20 healthy participants with a randomized, balanced cross-over design, we found a significant improvement of 7.4% in the Creativity Index measured by the Torrance Test of Creative Thinking (TTCT), a comprehensive and most frequently used assay of creative potential and strengths. In a second similar study with 20 subjects, 40 Hz-tACS was used in instead of 10 Hz-tACS to rule out a general "electrical stimulation" effect. No significant change in the Creativity Index was found for such frontal gamma stimulation. Our results suggest that alpha activity in frontal brain areas is selectively involved in creativity; this enhancement represents the first demonstration of specific neuronal dynamics that drive creativity and can be modulated by non-invasive brain stimulation. Our findings agree with the model that alpha recruitment increases with internal processing demands and is involved in inhibitory top-down control, which is an important requirement for creative ideation.
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Karen Lillycrop et al.
International Journal of Epidemiology, forthcoming
Background: Early life environments induce long-term changes in neurocognitive development and behaviour. In animal models, early environmental cues affect neuropsychological phenotypes via epigenetic processes but, as yet, there is little direct evidence for such mechanisms in humans.
Method: We examined the relation between DNA methylation at birth and child neuropsychological outcomes in two culturally diverse populations using a genome-wide methylation analysis and validation by pyrosequencing.
Results: Within the UK Southampton Women's Survey (SWS) we first identified 41 differentially methylated regions of interest (DMROI) at birth associated with child's full-scale IQ at age 4 years. Associations between HES1 DMROI methylation and later cognitive function were confirmed by pyrosequencing in 175 SWS children. Consistent with these findings, higher HES1 methylation was associated with higher executive memory function in a second independent group of 200 SWS 7-year-olds. Finally, we examined a pathway for this relationship within a Singaporean cohort (n = 108). Here, HES1 DMROI methylation predicted differences in early infant behaviour, known to be associated with academic success. In vitro, methylation of HES1 inhibited ETS transcription factor binding, suggesting a functional role of this site.
Conclusions: Thus, our findings suggest that perinatal epigenetic processes mark later neurocognitive function and behaviour, providing support for a role of epigenetic processes in mediating the long-term consequences of early life environment on cognitive development.
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Remembering to Prepare: The Benefits (and Costs) of High Working Memory Capacity
Lauren Richmond, Thomas Redick & Todd Braver
Journal of Experimental Psychology: Learning, Memory, and Cognition, forthcoming
Abstract:
The dual mechanisms of control framework postulates that cognitive control can operate in 2 distinct modes: a "proactive" preparatory mode and a "reactive" wait-and-see mode. Importantly, the 2 modes are associated with both costs and benefits in cognitive performance. Here we explore this framework, in terms of its relationship with working memory capacity (WMC). We hypothesize that high-WMC individuals are more likely to utilize proactive control yielding not only benefits, but also specific costs to performance. Across 2 separate, large-sample experiments, healthy young adults performed different variants of the AX-Continuous Performance Test context processing task, a well-established probe of proactive and reactive cognitive control. In 2 experiments, WMC predicted both improvements and relative impairments in task performance in a manner that was consistent with usage of proactive control. These findings suggest that individuals differ in the degree to which they utilize proactive control based on WMC.