Differences In General Cognitive Ability Research Articles

Sex/gender differences in general cognitive abilities: an investigation using the Leiter-3.

Research has shown that differences between males and females are not in general intelligence, but only in some specific factors and tasks. We used the Italian standardization of the Leiter-3, which is a completely nonverbal cognitive battery, to investigate the nature of sex/gender (we used sex/gender to reflect the awareness that the effects of biological 'sex' and socially constructed 'gender' cannot be easily separated and that most individuals' identities are informed by both sex and gender) differences. In doing so we used a multigroup confirmatory factor analysis approach. Results confirmed that males and females perform similarly in general intelligence, but present with some specificities. Males perform better on some, but not all, tasks requiring the spatial manipulation of the stimuli, but females consistently outperform males in tasks such as the nonverbal Stroop, requiring inhibition and attention control to a larger extent. The clinical and practical implications of our findings are considerable. The identification of specific cognitive strengths and weaknesses in males and females underscores the importance of tailored approaches in clinical assessments and interventions.

Structural-functional brain network coupling predicts human cognitive ability

Individual differences in general cognitive ability (GCA) have a biological basis within the structure and function of the human brain. Network neuroscience investigations revealed neural correlates of GCA in structural as well as in functional brain networks. However, whether the relationship between structural and functional networks, the structural-functional brain network coupling (SC-FC coupling), is related to individual differences in GCA remains an open question. We used data from 1030 adults of the Human Connectome Project, derived structural connectivity from diffusion weighted imaging, functional connectivity from resting-state fMRI, and assessed GCA as a latent g-factor from 12 cognitive tasks. Two similarity measures and six communication measures were used to model possible functional interactions arising from structural brain networks. SC-FC coupling was estimated as the degree to which these measures align with the actual functional connectivity, providing insights into different neural communication strategies. At the whole-brain level, higher GCA was associated with higher SC-FC coupling, but only when considering path transitivity as neural communication strategy. Taking region-specific variations in the SC-FC coupling strategy into account and differentiating between positive and negative associations with GCA, allows for prediction of individual cognitive ability scores in a cross-validated prediction framework (correlation between predicted and observed scores: r = 0.25, p < .001). The same model also predicts GCA scores in a completely independent sample (N = 567, r = 0.19, p < .001). Our results propose structural-functional brain network coupling as a neurobiological correlate of GCA and suggest brain region-specific coupling strategies as neural basis of efficient information processing predictive of cognitive ability.

Parental socioeconomic status weakly predicts specific cognitive and academic skills beyond general cognitive ability.

Parental socioeconomic status (SES) is a well-established predictor of children's neurocognitive development. Several theories propose that specific cognitive skills are particularly vulnerable. However, this can be challenging to test, because cognitive assessments are not pure measures of distinct neurocognitive processes, and scores across different tests are often highly correlated. Aside from one previous study by Tucker-Drob, little research has tested if associations between SES and cognition are explained by differences in general cognitive ability rather than specific cognitive skills. Using structural equation modelling (SEM), we tested if parental SES is associated with individual cognitive test scores after controlling for latent general cognitive ability. Data from three large-scale cohorts totalling over 16,360 participants from the UK and USA (ages 6-19) were used. Associations between SES and cognitive test scores are mainly (but not entirely) explained through general cognitive ability. Socioeconomic advantage was associated with particularly strong vocabulary performance, unexplained by general ability. When controlling for general cognitive ability, socioeconomic disadvantage was associated with better executive functions. Better characterizing relationships between cognition and adversity is a crucial first step toward designing interventions to narrow socioeconomic gaps. RESEARCH HIGHLIGHTS: Understanding environmental influences on cognitive development is a crucial goal for developmental science-parental socioeconomic status (SES) is one of the strongest predictors. Several theories have proposed that specific cognitive skills, such as language or certain executive functions, are particularly susceptible to socioeconomic adversity. Using structural equation modelling, we tested whether SES predicts specific cognitive and academic tests after controlling for latent general cognitive ability across three large-scale cohorts. SES moderately predicted latent general cognitive ability, but associations with specific cognitive skills were mainly small, with a few exceptions.

A Twin Study of Altered White Matter Heritability in Youth With Autism Spectrum Disorder

White matter alterations are frequently reported in autism spectrum disorder (ASD), yet the etiology is currently unknown. The objective of this investigation was to examine, for the first time, the impact of genetic and environmental factors on white matter microstructure in twins with ASD compared to control twins without ASD. Diffusion-weighted MRIs were obtained from same-sex twin pairs (6-15 years of age) in which at least 1 twin was diagnosed with ASD or neither twin exhibited a history of neurological or psychiatric disorders. Fractional anisotropy (FA) and mean diffusivity (MD) were examined across different white matter tracts in the brain, and statistical and twin modeling were completed to assess the proportion of variation associated with additive genetic (A) and common/shared (C) or unique (E) environmental factors. We also developed a novel Twin-Pair Difference Score analysis method that produces quantitative estimates of the genetic and environmental contributions to shared covariance between different brain and behavioral traits. Good-quality data were available from 84 twin pairs, 50 ASD pairs (32 concordant for ASD [16 monozygotic; 16 dizygotic], 16 discordant for ASD [3 monozygotic; 13 dizygotic], and 2 pairs in which 1 twin had ASD and the other exhibited some subthreshold symptoms [1 monozygotic; 1 dizygotic]) and 34 control pairs (20 monozygotic; 14 dizygotic). Average FA and MD across the brain, respectively, were primarily genetically mediated in both control twins (A= 0.80, 95% CI [0.57, 1.02]; A= 0.80 [0.55, 1.04]) and twins concordant for having ASD (A= 0.71 [0.33, 1.09]; A= 0.84 [0.32,1.36]). However, there were also significant tract-specific differences between groups. For instance, genetic effects on commissural fibers were primarily associated with differences in general cognitive abilities and perhaps some diagnostic differences for ASD because Twin-Pair Difference-Score analysis indicated that genetic factors may have contributed to ∼40% to 50% of the covariation between IQ scores and FA of the corpus callosum. Conversely, the increased impact of environmental factors on some projection and association fibers were primarily associated with differences in symptom severity in twins with ASD; for example, our analyses suggested that unique environmental factors may have contributed to ∼10% to 20% of the covariation between autism-related symptom severity and FA of the cerebellar peduncles and external capsule. White matter alterations in youth with ASD are associated with both genetic contributions and potentially increased vulnerability or responsivity to environmental influences. We worked to ensure sex and gender balance in the recruitment of human participants. We worked to ensure race, ethnic, and/or other types of diversity in the recruitment of human participants. We worked to ensure that the study questionnaires were prepared in an inclusive way. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented racial and/or ethnic groups in science. One or more of the authors of this paper self-identifies as a member of one or more historically underrepresented sexual and/or gender groups in science. One or more of the authors of this paper self-identifies as living with a disability. The author list of this paper includes contributors from the location and/or community where the research was conducted and they participated in the data collection, design, analysis, and/or interpretation of the work.

General cognitive ability, as assessed by self-reported ACT scores, is associated with reduced emotional responding: Evidence from a Dynamic Affect Reactivity Task

Dual process theories often contrast a hot, reactive affective system with a cool, reflective cognitive system. The cognitive system permits rationality and reasoning, but may inhibit spontaneous affect. Such frameworks would seem to suggest that individual differences in general cognitive ability, which is linked to abstract forms of reasoning, may impact dynamic components of emotional reactivity. In two studies involving five samples (total N = 631), participants were asked to continuously rate their emotional experiences in response to presented affective images. General cognitive ability, assessed, by proxy, with self-reported ACT scores, was linked to less intense peak reactions, peak reactions that were delayed, and/or to velocities of affect change that were less pronounced. Such relationships tended to be observed regardless of whether images were positive or negative. The findings provide support for dual process theorizing and suggest that general cognitive ability modulates dynamic components of emotional responding.

Multimodal Brain Signal Complexity Predicts Human Intelligence.

Spontaneous brain activity builds the foundation for human cognitive processing during external demands. Neuroimaging studies based on functional magnetic resonance imaging (fMRI) identified specific characteristics of spontaneous (intrinsic) brain dynamics to be associated with individual differences in general cognitive ability, i.e., intelligence. However, fMRI research is inherently limited by low temporal resolution, thus, preventing conclusions about neural fluctuations within the range of milliseconds. Here, we used resting-state electroencephalographical (EEG) recordings from 144 healthy adults to test whether individual differences in intelligence (Raven's Advanced Progressive Matrices scores) can be predicted from the complexity of temporally highly resolved intrinsic brain signals. We compared different operationalizations of brain signal complexity (multiscale entropy, Shannon entropy, Fuzzy entropy, and specific characteristics of microstates) regarding their relation to intelligence. The results indicate that associations between brain signal complexity measures and intelligence are of small effect sizes (r ∼ 0.20) and vary across different spatial and temporal scales. Specifically, higher intelligence scores were associated with lower complexity in local aspects of neural processing, and less activity in task-negative brain regions belonging to the default-mode network. Finally, we combined multiple measures of brain signal complexity to show that individual intelligence scores can be significantly predicted with a multimodal model within the sample (10-fold cross-validation) as well as in an independent sample (external replication, N = 57). In sum, our results highlight the temporal and spatial dependency of associations between intelligence and intrinsic brain dynamics, proposing multimodal approaches as promising means for future neuroscientific research on complex human traits.

363 School-age Morphological And Neurodevelopmental Outcomes In Patients With Sagittal Craniosynos

OBJECTIVES/GOALS: Several studies compare perioperative parameters and postoperative morphology of open cranial vault remodeling (CVR) and endoscopic-assisted craniectomy (EAC) in the treatment of sagittal craniosynostosis. However, data on neurodevelopmental outcomes comparing these techniques is lacking. METHODS/STUDY POPULATION: Patients with repaired sagittal synostosis were enrolled from a single tertiary care center between five and fifteen years of age. Patients with any craniofacial syndrome (e.g., 22q11.2 deletion) or other medical conditions that could affect neurodevelopment were excluded. Neurodevelopment was measured using the Differential Ability Scale-II (DAS-II). The General Cognitive Ability (GCA) score was the primary outcome measure, describing overall intellectual ability. Secondary outcome measures were measurements of cephalic index (CI) from pre- and postoperative imaging studies. Family socioeconomic status (SES) was estimated using the Hollingshead index (total score, continuous). RESULTS/ANTICIPATED RESULTS: 26 patients [10 CVR (2 Female:8 Male), 16 EAC (6 F:10 M)] were studied. Mean age at repair was greater with CVR than EAC (15.5 ± 8.5 months vs 3.5 ± 1.3 months, respectively, p &lt; 0.001). Mean age at DAS-II testing was 9.0 ± 2.2 years. Patients GCA scores were within the average range relative to test norms (CVR 95.7 ± 15.4 vs EAC 102.6 ± 17.4). After adjusting for SES and preoperative CI, group differences in GCA were modest and statistically nonsignificant (p = 0.646). GCA scores were associated with SES (p = 0.054) but not preop CI (p = 0.479). Differences between CVR and EAC were not statistically significant for any of the imaging parameters (pre and postop CI, pre to postop change in CI, or age at postop imaging; 0.131 &lt;= p &lt;= 0.867). None of the independent variables were significantly associated with postop CI (0.140 &lt;= p &lt;= 0.689). DISCUSSION/SIGNIFICANCE: Interim analysis of the preliminary data suggests no association between surgical procedure and cognitive and morphological outcomes at school-age in patients with sagittal craniosynostosis who underwent CVR versus EAC. Collection of data continues, with the goal to enroll 50 participants in each group by 2022.

General cognitive ability and pericortical contrast

Individual differences in general cognitive ability have been associated with various brain structure metrics. A relatively novel metric referred to as pericortical Gray-White Contrast (GWC) describes the sharpness of the pericortical gray-white boundary. GWC, which is hypothesized to be at least partly influenced by the degree to which myelinated axons invade the lower layers of cortex, is believed to be significantly associated with the dynamics of signal transmission across the brain and hence, with cognitive ability. The current work explores the association between GWC and IQ across the surface of the cortex. Subject data were retrieved from the NIH MRI Study of Normal Brain Development (Evans & Brain Development Cooperative, 2006). 376 subjects with a total of 742 scans were included in the longitudinal analyses. Mixed-effects regression analyses were used to map the relation between cortical contrast and each of full-scale, performance, and verbal IQ derived from the Wechsler Abbreviated Scale of Intelligence, while covarying for scanner, sex, and age effects. Significant associations were shown with FSIQ, PIQ, but not VIQ. We discuss the interpretation of these results and how they may relate to previously published results on structural cortical associations.

Acculturation moderates cognitive performance in adults at risk of autosomal dominant Alzheimer's Disease

Loneliness is significantly associated with health and well-being among oldest-old adults. Due to the outbreak of the COVID-19, physical and social distancing policies might elevate loneliness among the oldest-old population. This study examined the trends and changes in the prevalence of feeling lonely using the 2020 HRS COVID-19 module merged to the 15 waves of the HRS RAND longitudinal datasets from 1992 to 2018. A total of 14,371 respondents, including 614 respondents aged 80 years and older were included. Generalized linear models compared age group differences within the 2020 module. Generalized estimating equations assessed the longitudinal change at the individual level and the trend of feeling loneliness among oldest-old adults from 1992 to 2020. Loneliness was assessed with one item of the CES-D scale (i.e., during the past week, felt lonely). After adjusting for demographic characteristics and health, the results showed that oldest-old adults were more likely to feel lonely compared to younger age groups (18% for 80’s vs. 14% for 50’s) during the early months of the pandemic. A longitudinal trajectory also showed that they feel lonelier than in prior years (19% in 2020 vs. 14% in 2018). However, compared to same-age groups from earlier years, a significantly lower prevalence of feeling lonely was observed (18% in 2020 vs. 27% in 1994). The results show that the outbreak of the COVID-19 may elevate feeling lonely, but the recent cohorts be less lonely than earlier cohorts. Future research should continue to explore protective factors for loneliness among oldest-old adults.

Acculturation moderates cognitive performance in adults at risk of autosomal dominant Alzheimer's Disease.

Acculturative processes via persistent exposure to a set of cultural practices and behaviors can influence cognitive functioning (Park & Huang, 2010). The impact of acculturation on populations at risk for Alzheimer’s disease (AD), however, remains understudied. Persons with or at-risk for early-onset autosomal dominant AD (ADAD) offer a known AD pathogenesis and the opportunity to study whether acculturation moderates their cognitive performance. The present study used a latent variable model to test whether effects of latent cognitive ability on observable cognitive performance depend on acculturation. Participants included 119 adults with or at-risk for ADAD, the majority of whom were of Mexican origin with various levels of U.S. acculturation. Participants completed the Cognitive Abilities Screening Instrument (CASI) and the Acculturation Rating Scale for Mexican Americans-II (ARSMA-II). Confirmatory factor analysis was used to estimate a latent general cognitive ability factor from nine domains (e.g., attention, abstraction and judgment). The ARSMA-II was used to test whether factor loadings depended on level of acculturation, covarying for mutation status. Results revealed ARSMA-II scores nearly significantly moderated the effects of general cognitive ability on abstraction and judgment (λ = 0.20, SE = 0.11, p = .070). Individual differences in general cognitive ability at lower levels of acculturation likely predict lower abstraction and judgment performance. Cognitive assessments may not equally represent true cognitive ability in Mexican-Americans. Although the CASI was developed as a cross-cultural measure of cognitive functioning, caution should be exercised in inferring true cognitive functioning in Mexican-Americans who may not be acculturated to the U.S.

Pathfinder: a gamified measure to integrate general cognitive ability into the biological, medical, and behavioural sciences

Genome-wide association (GWA) studies have uncovered DNA variants associated with individual differences in general cognitive ability (g), but these are far from capturing heritability estimates obtained from twin studies. A major barrier to finding more of this ‘missing heritability’ is assessment––the use of diverse measures across GWA studies as well as time and the cost of assessment. In a series of four studies, we created a 15-min (40-item), online, gamified measure of g that is highly reliable (alpha = 0.78; two-week test-retest reliability = 0.88), psychometrically valid and scalable; we called this new measure Pathfinder. In a fifth study, we administered this measure to 4,751 young adults from the Twins Early Development Study. This novel g measure, which also yields reliable verbal and nonverbal scores, correlated substantially with standard measures of g collected at previous ages (r ranging from 0.42 at age 7 to 0.57 at age 16). Pathfinder showed substantial twin heritability (0.57, 95% CIs = 0.43, 0.68) and SNP heritability (0.37, 95% CIs = 0.04, 0.70). A polygenic score computed from GWA studies of five cognitive and educational traits accounted for 12% of the variation in g, the strongest DNA-based prediction of g to date. Widespread use of this engaging new measure will advance research not only in genomics but throughout the biological, medical, and behavioural sciences.

Spectral clustering based on structural magnetic resonance imaging and its relationship with major depressive disorder and cognitive ability.

There is increasing interest in using data-driven unsupervised methods to identify structural underpinnings of common mental illnesses, including major depressive disorder (MDD) and associated traits such as cognition. However, studies are often limited to severe clinical cases with small sample sizes and most do not include replication. Here, we examine two relatively large samples with structural magnetic resonance imaging (MRI), measures of lifetime MDD and cognitive variables: Generation Scotland (GS subsample, N = 980) and UK Biobank (UKB, N = 8,900), for discovery and replication, using an exploratory approach. Regional measures of FreeSurfer derived cortical thickness (CT), cortical surface area (CSA), cortical volume (CV) and subcortical volume (subCV) were input into a clustering process, controlling for common covariates. The main analysis steps involved constructing participant K-nearest neighbour graphs and graph partitioning with Markov stability to determine optimal clustering of participants. Resultant clusters were (1) checked whether they were replicated in an independent cohort and (2) tested for associations with depression status and cognitive measures. Participants separated into two clusters based on structural brain measurements in GS subsample, with large Cohen's d effect sizes between clusters in higher order cortical regions, commonly associated with executive function and decision making. Clustering was replicated in the UKB sample, with high correlations of cluster effect sizes for CT, CSA, CV and subCV between cohorts across regions. The identified clusters were not significantly different with respect to MDD case-control status in either cohort (GS subsample: pFDR = .2239-.6585; UKB: pFDR = .2003-.7690). Significant differences in general cognitive ability were, however, found between the clusters for both datasets, for CSA, CV and subCV (GS subsample: d = 0.2529-.3490, pFDR < .005; UKB: d = 0.0868-0.1070, pFDR < .005). Our results suggest that there are replicable natural groupings of participants based on cortical and subcortical brain measures, which may be related to differences in cognitive performance, but not to the MDD case-control status.

General Cognitive Ability Predicts Survival-Readiness in Genetically Heterogeneous Laboratory Mice

Although genetically heterogeneous laboratory mice express individual differences in general cognitive ability (c.f., “intelligence”), it is unknown whether these differences are translated into behaviors that would promote survival. Here, genetically heterogeneous laboratory CD-1 mice were administered a series of cognitive tests from which their aggregate general cognitive ability was estimated. Subsequently, all animals were tested on nine (unlearned) tasks designed to assess behaviors that could contribute to survival in the wild. These tests included nest building (in the home and a novel environment), exploration, several indices of food finding, retrieval, and preference, and predator avoidance. Like general cognitive ability, a principal component analysis of these measures of survival-related behaviors (survival-readiness) yielded a general factor that accounted for ~25% of the variance of mice across all of the tasks. An aggregate metric of general cognitive ability predicted an aggregate metric of general survival-readiness (r = .64), suggesting that more intelligent animals would be more suited for survival in natural environments. The nature of the pattern of correlations between general cognitive ability and performance on individual tests of fitness (where tests conducted in previously unexplored contexts were more closely related to general cognitive ability) suggests the possibility that heightened attention (which is taxed in a novel environment) may be the common mediator of both of these classes of abilities, although other potential mediators are discussed. In total, these results suggest that performance on tasks that are explicitly intended to assess the likelihood of survival can be impacted by cognitive abilities.

Intelligence demands flexibility: Individual differences in attentional disengagement strongly predict the general cognitive ability of mice

General cognitive ability (or general intelligence; g) is a latent variable that describes performance across a broad array of cognitive skills. This general influence on cognitive ability varies between individuals and shares a similar structure in both humans and mice. Evidence suggests that much of the variation in general intelligence is related to the efficacy of the working memory system. We have previously observed that one component of the working memory system, selective attention, disproportionately accounts for the relationship between working memory and general intelligence in genetically heterogeneous mice. In the three studies reported here, we test a hypothesis that emerges from human behavioral studies which suggests that attentional disengagement, a sub-component of selective attention, critically mediates its relationship with g. Studies 1 and 2 both assess the factor loadings (on a principal component analysis) of the performance of mice on an array of learning tasks as well as tasks designed to make explicit demands on attentional disengagement. We find that attentional disengagement tasks load more highly than measures of cognitive performance that place less explicit demands on disengagement and that performance in these disengagement tasks is strongly predictive of the general cognitive performance of individual animals. In Study 3 we observed that groups of mice (young and old) with known differences in general cognitive abilities differ more on a discrimination task that requires attentional disengagement than on a simple discrimination task with fewer demands on disengagement. In total, these results provide support for the hypothesis that attentional disengagement is strongly related to general intelligence, and that variations in this ability may contribute to both individual differences in intelligence as well as age-related cognitive declines.

Pupillary and behavioral markers of alerting and orienting: An individual difference approach

Measuring task-evoked pupillary (TEP) responses as an index of phasic activity in the locus coeruleus (LC), we examined two competing hypotheses regarding the alerting and orienting mechanisms of attention. According to a dual mechanism account (Fernandez-Duque & Posner, 1997), two separate noradrenergic and cholinergic mechanisms modulate, respectively, the alerting and orienting effects. However, Corbetta and colleagues (2008) proposed that LC phasic activity may also be involved in orienting effect through its functional relationship with the ventral attentional network. We recruited seventy-five healthy Norwegian participants to perform a Posner cueing task. Both behavioral and pupillary responses revealed the alerting effect. Also, both behavioral and pupillary responses indicated that cued attention is affected by age. Behavioral responses also revealed orienting effect However, we found no TEP differences between valid, invalid, and neutral conditions, suggesting that TEP effects were driven by the alerting effect of cue presentation. Moreover, both behavioral and pupillary estimates of alertness and orienting were uncorrelated. Finally, individual differences in general cognitive abilities did not appear to affect the orienting and alerting mechanisms. This pattern of results is consistent with the dual mechanism account of attention. However, the LC involvement in the (re)orienting attention may be driven by state-specific factors.

Genetic risk for Alzheimer disease in children: Evidence from early-life IQ and brain white-matter microstructure.

It remains unclear whether the genetic risk for late‐onset Alzheimer disease (AD) is linked to premorbid individual differences in general cognitive ability and brain structure. The objective of the present study was to determine whether the genetic risk of late‐onset AD is related to premorbid individual differences in intelligence quotient (IQ) and characteristics of the cerebral white‐matter in children. The study sample included children of the Generation R Study from Rotterdam, The Netherlands. IQ was measured using a well‐validated Dutch nonverbal IQ test (n = 1908) at ages 5 to 9 years. White‐matter microstructure was assessed by measuring fractional anisotropy (FA) of white‐matter tracts using diffusion tensor imaging (DTI) (n = 919) at ages 9 to 12 years. Genetic risk was quantified using three biologically defined genetic risk scores (GRSs) hypothesized to be related to the pathophysiology of late‐onset AD: immune response, cholesterol/lipid metabolism and endocytosis. Higher genetic risk for late‐onset AD that included genes associated with immune responsivity had a negative influence on cognition and cerebral white‐matter microstructure. For each unit increase in the immune response GRS, IQ decreased by 0.259 SD (95% CI [−0.500, −0.017]). For each unit increase in the immune response GRS, global FA decreased by 0.373 SD (95% CI [−0.721, −0.026]). Neither cholesterol/lipid metabolism nor endocytosis GRSs were associated with IQ or cerebral white‐matter microstructure. Our findings suggest that elevated genetic risk for late‐onset AD may in part be manifest during childhood neurodevelopment through alterations in immune responsivity.

Distributed Patterns of Functional Connectivity Predict Working Memory Performance in Novel Healthy and Memory-impaired Individuals.

Individual differences in working memory relate to performance differences in general cognitive ability. The neural bases of such individual differences, however, remain poorly understood. Here, using a data-driven technique known as connectome-based predictive modeling, we built models to predict individual working memory performance from whole-brain functional connectivity patterns. Using n-back or rest data from the Human Connectome Project, connectome-based predictive models significantly predicted novel individuals' 2-back accuracy. Model predictions also correlated with measures of fluid intelligence and, with less strength, sustained attention. Separate fluid intelligence models predicted working memory score, as did sustained attention models, again with less strength. Anatomical feature analysis revealed significant overlap between working memory and fluid intelligence models, particularly in utilization of prefrontal and parietal regions, and less overlap in predictive features between working memory and sustained attention models. Furthermore, showing the generality of these models, the working memory model developed from Human Connectome Project data generalized to predict memory in an independent data set of 157 older adults (mean age = 69 years; 48 healthy, 54 amnestic mild cognitive impairment, 55 Alzheimer disease). The present results demonstrate that distributed functional connectivity patterns predict individual variation in working memory capability across the adult life span, correlating with constructs including fluid intelligence and sustained attention.

Temporal stability of functional brain modules associated with human intelligence.

Individual differences in general cognitive ability (i.e., intelligence) have been linked to individual variations in the modular organization of functional brain networks. However, these analyses have been limited to static (time‐averaged) connectivity, and have not yet addressed whether dynamic changes in the configuration of brain networks relate to general intelligence. Here, we used multiband functional MRI resting‐state data (N = 281) and estimated subject‐specific time‐varying functional connectivity networks. Modularity optimization was applied to determine individual time‐variant module partitions and to assess fluctuations in modularity across time. We show that higher intelligence, indexed by an established composite measure, the Wechsler Abbreviated Scale of Intelligence (WASI), is associated with higher temporal stability (lower temporal variability) of brain network modularity. Post‐hoc analyses reveal that subjects with higher intelligence scores engage in fewer periods of extremely high modularity — which are characterized by greater disconnection of task‐positive from task‐negative networks. Further, we show that brain regions of the dorsal attention network contribute most to the observed effect. In sum, our study suggests that investigating the temporal dynamics of functional brain network topology contributes to our understanding of the neural bases of general cognitive abilities.

Visual habituation in deaf and hearing infants.

Early cognitive development relies on the sensory experiences that infants acquire as they explore their environment. Atypical experience in one sensory modality from birth may result in fundamental differences in general cognitive abilities. The primary aim of the current study was to compare visual habituation in infants with profound hearing loss, prior to receiving cochlear implants (CIs), and age-matched peers with typical hearing. Two complementary measures of cognitive function and attention maintenance were assessed: the length of time to habituate to a visual stimulus, and look-away rate during habituation. Findings revealed that deaf infants were slower to habituate to a visual stimulus and demonstrated a lower look-away rate than hearing infants. For deaf infants, habituation measures correlated with language outcomes on standardized assessments before cochlear implantation. These findings are consistent with prior evidence suggesting that habituation and look-away rates reflect efficiency of information processing and may suggest that deaf infants take longer to process visual stimuli relative to the hearing infants. Taken together, these findings are consistent with the hypothesis that hearing loss early in infancy influences aspects of general cognitive functioning.

Using Standardized Test Scores to Include General Cognitive Ability in Education Research and Policy.

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.