An enduring aim of research in the psychological and brain sciences is to understand the nature of individual differences in human intelligence, examining the stunning breadth and diversity of ...intellectual abilities and the remarkable neurobiological mechanisms from which they arise. This Opinion article surveys recent neuroscience evidence to elucidate how general intelligence, g, emerges from individual differences in the network architecture of the human brain. The reviewed findings motivate new insights about how network topology and dynamics account for individual differences in g, represented by the Network Neuroscience Theory. According to this framework, g emerges from the small-world topology of brain networks and the dynamic reorganization of its community structure in the service of system-wide flexibility and adaptation.
Accumulating evidence from network neuroscience indicates that g depends on the dynamic reorganization of brain networks, modifying their topology and community structure in the service of system-wide flexibility and adaptation.
Whereas crystallized intelligence engages easy-to-reach network states that access prior knowledge and experience, fluid intelligence recruits difficult-to-reach network states that support cognitive flexibility and adaptive problem-solving.
The capacity to flexibly transition between networks states therefore provides the basis for g – enabling rapid information exchange across networks and capturing individual differences in information processing at a global level.
This framework sets the stage for new approaches to understanding the neural foundations of g, examining individual differences in brain network topology and dynamics.
Fluid intelligence (gF) and working memory (WM) span predict success in demanding cognitive situations. Recent studies show that much of the variance in gF and WM span is shared, suggesting common ...neural mechanisms. This study provides a direct investigation of the degree to which shared variance in gF and WM span can be explained by neural mechanisms of interference control. The authors measured performance and functional magnetic resonance imaging activity in 102 participants during the n-back WM task, focusing on the selective activation effects associated with high-interference lure trials. Brain activity on these trials was correlated with gF, WM span, and task performance in core brain regions linked to WM and executive control, including bilateral dorsolateral prefrontal cortex (middle frontal gyrus; BA9) and parietal cortex (inferior parietal cortex; BA 40/7). Interference-related performance and interference-related activity accounted for a significant proportion of the shared variance in gF and WM span. Path analyses indicate that interference control activity may affect gF through a common set of processes that also influence WM span. These results suggest that individual differences in interference-control mechanisms are important for understanding the relationship between gF and WM span.
There are several studies showing that executive functions such as working memory, inhibition, and cognitive flexibility are related to reading abilities. However, most of these studies did not ...simultaneously take different executive functions and intelligence into account. Therefore, the aim of our study was to investigate if working memory, inhibition, cognitive flexibility, and fluid intelligence uniquely contribute to reading. Furthermore, we tested the hypothesis that reading comprehension and reading speed are correlated but separable reading abilities with different relations to other cognitive functions. To test this assumption, we examined if executive functions and fluid intelligence unequally relate to reading comprehension and reading speed. A total of 186 school children (mean age = 9.31 years) participated in our study and performed a complex span task (working memory), task switching (cognitive flexibility), a stroop-like task (inhibition), raven matrices (fluid intelligence), a reading speed task and three reading comprehension tasks. Structural equation modeling (SEM) showed that working memory, inhibition, cognitive flexibility and fluid intelligence differently contributed to reading speed and reading comprehension. Working memory, inhibition and fluid intelligence were related to reading speed, indicating that a higher working memory capacity, better inhibitory abilities and higher fluid intelligence were associated with higher reading speed. Moreover, cognitive flexibility and fluid intelligence were related to reading comprehension, suggesting that higher cognitive flexibility and fluid intelligence were associated with better reading comprehension. Thus, our results point to differential contributions of executive functions to reading comprehension and reading speed.
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BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The study of the relationship between bilingualism and the possible impact it might have on the control aspect of intelligence of adults in general and preschool children, in particular, has always ...been the subject of controversy for researchers. This research, following the related findings and gaps in the literature and inspired by Craik and Bialystok's (2005) framework, tries to divulge whether bilingualism could be related to the control aspect of intelligence. As our secondary goal, we also tried to see whether there are correlations between different tests assessing control.
In this descriptive correlational study, via the convenience sampling method, we selected our participants. Methods: In doing so, 10 age-gender-matched Mazandarani-speaking monolinguals and the same matched bilinguals have been selected. Moreover, the literacy and socioeconomic status of subjects have been controlled. The tests for assessing subjects' executive control included day-night Stroop, the dimensional change card sort (DCCS), test of variables of attention (TOVA), and the computerized attention network test (ANT). Our participants' performance in language proficiency task as well as control tasks was demonstrated. Furthermore, via the conduction of the Pearson correlation statistics, the relationships between the participants' performance in diverse control tasks and language task were investigated.
The results showed that bilinguals outperform monolinguals in all control tests except DCCS.
Bilingualism could provide children with an executive control advantage promoting them in tasks demanding thought and action control.
Language proficiency is not necessarily related to an advanced attentional control.Mazandarani-speaking monolinguals and bilinguals perform equally in the "knowledge" domain of intelligence.Bilinguals' performance in the control task of intelligence was better than their monolingual counterparts.It was corroborated that intelligence is not a homogeneous psychological construct.Generally, in tasks requiring suppression, bilinguals outperform monolinguals.
The investigation of the relationship between control aspect of intelligence and the statue of monolingualism or bilingualism has always been the subject of controversy. "Control" aspect signifies the ability of an individual to suppress the provoking stimuli, that is, to ignore the external stimuli in favor of an intended linguistic or non-linguistic element. Our major objective in this research was to compare the performance of Mazandarani-speaking bilinguals and monolinguals in diverse control as well as vocabulary assessment tasks. Specifically, we wanted to see whether bilingual children could perform better than monolingual children in tasks requiring the inhibition capability. Furthermore, we attempted to investigate whether there were correlations between different control assessment tasks. Extending previous researches, we administered two additional cognitive tasks, namely, test of variables of attention (TOVA) and day and night task to evaluate our participants' control capability. In linguistic (vocabulary) proficiency assessment task, Peabody picture vocabulary task (PPVT), we did not find bilinguals' advantage over monolinguals. In contrast, bilinguals outperformed their monolingual counterparts in all other control tasks except dimensional change card sort (DCCS). Meanwhile, strong correlations between most control tasks were observed. The results corroborated that bilingual children outperformed their monolingual counterparts in tasks demanding strong thought and action control. Also, the conduction of most control tasks might be more challenging for monolinguals, and bilingual children, thanks to their linguistic statutes, could ignore irrelevant response or stimuli more easily, and perform better in the majority of cognitive control demanding tasks.
Global signal regression (GSR) is one of the most debated preprocessing strategies for resting-state functional MRI. GSR effectively removes global artifacts driven by motion and respiration, but ...also discards globally distributed neural information and introduces negative correlations between certain brain regions. The vast majority of previous studies have focused on the effectiveness of GSR in removing imaging artifacts, as well as its potential biases. Given the growing interest in functional connectivity fingerprinting, here we considered the utilitarian question of whether GSR strengthens or weakens associations between resting-state functional connectivity (RSFC) and multiple behavioral measures across cognition, personality and emotion.
By applying the variance component model to the Brain Genomics Superstruct Project (GSP), we found that behavioral variance explained by whole-brain RSFC increased by an average of 47% across 23 behavioral measures after GSR. In the Human Connectome Project (HCP), we found that behavioral variance explained by whole-brain RSFC increased by an average of 40% across 58 behavioral measures, when GSR was applied after ICA-FIX de-noising. To ensure generalizability, we repeated our analyses using kernel regression. GSR improved behavioral prediction accuracies by an average of 64% and 12% in the GSP and HCP datasets respectively. Importantly, the results were consistent across methods. A behavioral measure with greater RSFC-explained variance (using the variance component model) also exhibited greater prediction accuracy (using kernel regression). A behavioral measure with greater improvement in behavioral variance explained after GSR (using the variance component model) also enjoyed greater improvement in prediction accuracy after GSR (using kernel regression). Furthermore, GSR appeared to benefit task performance measures more than self-reported measures.
Since GSR was more effective at removing motion-related and respiratory-related artifacts, GSR-related increases in variance explained and prediction accuracies were unlikely the result of motion-related or respiratory-related artifacts. However, it is worth emphasizing that the current study focused on whole-brain RSFC, so it remains unclear whether GSR improves RSFC-behavioral associations for specific connections or networks. Overall, our results suggest that at least in the case for young healthy adults, GSR strengthens the associations between RSFC and most (although not all) behavioral measures. Code for the variance component model and ridge regression can be found here: https://github.com/ThomasYeoLab/CBIG/tree/master/stable_projects/preprocessing/Li2019_GSR.
•Global signal regression improves RSFC-behavior associations.•Global signal regression improves RSFC-based behavioral prediction accuracies.•Improvements replicated across two large-scale datasets and methods.•Task-performance measures enjoyed greater improvements than self-reported ones.•GSR beneficial even after ICA-FIX.
•Fluid and crystalized intelligence both predict metaphor comprehension.•Crystalized intelligence impacts a broad range of metaphor types.•Fluid intelligence only impacts more complex metaphors.•The ...Semantic Similarities Test (SST) is a new measure of crystalized intelligence.
The nature of the mental processes involved in metaphor comprehension has been the focus of debate, with controversy focusing on the relative role of general analogical reasoning versus language-specific conceptual combination. In the present set of studies, we take an individual-differences approach to examine the comprehension of a variety of metaphors, some taken from literary sources, using several types of comprehension tests. In a series of metaphor-comprehension studies with college students, we measured both fluid intelligence (using the nonverbal Raven’s Progressive Matrices test) and crystalized verbal intelligence (using a new Semantic Similarities Test as well as the Vocabulary subscale of the Wechsler Adult Intelligence Scale). Previous work has shown that measures of fluid intelligence are closely linked to individual differences in analogical reasoning, whereas measures of crystalized verbal intelligence are linked to language-specific abilities. We found that each measure had a dissociable predictive relationship to metaphor comprehension. The pattern of individual differences indicated that crystalized intelligence influences metaphor comprehension across a broad range of metaphor types, whereas individual differences in fluid intelligence mainly impact comprehension of more cognitively complex metaphors, such as those that arise in literary sources.
Meta-analyses have found that working memory (WM) can be improved with cognitive training; however, some authors have suggested that these improvements are mostly driven by biases in the measurement ...of WM, especially the use of similar tasks for assessment and training. In the present meta-analysis, we investigated whether WM, fluid intelligence, executive functions, and short-term memory can be improved by cognitive training and evaluated the impact of possible sources of bias. We performed a risk of bias assessment of the included studies and took special care in controlling for practice effects. Data from 52 independent comparisons were analyzed, including cognitive training aimed at different cognitive functions. Our results show small improvements in WM after training (SMD = 0.18). Much larger effects were observed when the analysis was restricted to assessment tasks similar to those used for training (SMD = 1.15). Fluid intelligence was not found to improve as a result of training, and improvements in WM were not related to changes in fluid intelligence. Our analyses did however indicate that cognitive training can improve specific executive functions. Contrary to expectations, a set of meta-regressions indicated that characteristics of the training programme, such as dosage and type of training, do not have an impact on the effectiveness of training. The risk of bias assessment revealed some concerns in the randomization process and possible selective reporting among studies. Overall, our results identified various potential sources of bias, with the most significant being the choice of assessment tasks.
•Bayesian regression analyses found various combinations of executive predictors of mathematical achievement for each school grade.•Executive models had a similar ability to classify students with ...mathematical difficulties and their peers to that of broader cognitive models that include fluid intelligence and processing speed.•Executive functions, fluid intelligence, and processing speed played specific roles in predicting mathematical difficulties in each school grade.
Schoolchildren with better executive functioning skills achieve better mathematics results. It is less clear how inhibition, cognitive flexibility, and working memory combine to predict mathematics achievement and difficulty throughout primary and secondary school. This study aimed to find the best combination of executive function measures for predicting mathematical achievement in Grades 2, 6, and 10 and to test whether this combination predicts the probability of having mathematical difficulties across school grades even when fluid intelligence and processing speed were included in the models. A total of 426 students—141 2nd graders (72 girls), 143 6th graders (72 girls), and 142 10th graders (79 girls)—were cross-sectionally assessed with 12 executive tasks, one standardized mathematical task, and a standardized test of intelligence. Bayesian regression analyses found various combinations of executive predictors of mathematical achievement for each school grade spanning Grade 2 to measures of cognitive inhibition (negative priming) and cognitive flexibility (verbal fluency); Grade 6 to measures of inhibition: resistance to distractor interference (receptive attention), cognitive flexibility (local–global), and working memory (counting span); and Grade 10 to measures of inhibition: resistance to distractor interference (receptive attention) and prepotent response inhibition (stop signal) and working memory (reading span). Logistic regression showed that the executive models derived from the Bayesian analyses had a similar ability to classify students with mathematical difficulty and their peers with typical achievement to broader cognitive models that included fluid intelligence and processing speed. Measures of processing speed, cognitive flexibility (local–global), and prepotent response inhibition (stop signal) were the main risk factors in Grades 2, 6, and 10, respectively. Cognitive flexibility (verbal fluency) in Grade 2 and fluid intelligence, which was more stable in all three grades, acted as protective factors against mathematical difficulty. These findings inform practical considerations for establishing preventive and intervention proposals.
Mental rotation in adults can be supported by spatial activities and shows sex differences in favor of males. Yet, whether these results apply to young children and whether possible early sex ...differences in mental rotation might be alleviated through spatial play remains unclear. Thus, we investigated whether play with different levels of guidance (high guidance vs. medium guidance vs. low guidance) would affect girls' and boys' mental rotation in a sample of 183 German 5- and 6-year-olds. Any play form fostered children's mental rotation. However, girls profited less from high guidance than boys. Play can foster mental rotation, but different levels of guidance seem to have differential effects on girls and boys.
•Guided as well as free lay fosters mental rotation in 5- to 6-year-old children.•Boys seem to profit more from higher amounts of guidance than girls.•Fluid intelligence is related to mental rotation skills in young children.
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