Higher General Cognitive Ability Research Articles

Gardening and cognitive ageing: Longitudinal findings from the Lothian Birth Cohort of 1921

Identifying modifiable lifestyle behaviours that facilitate healthy cognitive ageing is of major public interest for the prevention of cognitive decline and dementia. Gardening is associated with numerous health benefits, yet few studies have explored the significance of gardening activity in relation to cognitive ageing. Here, longitudinal cognitive data from 467 older adults (aged 79 ± 0.6) of the LBC1921 study were used to examine associations of self-reported gardening at age 79 with lifetime cognitive change (age 11 to 79), and cognitive level (age 79) and slope across later life (age 79 to 90). Cognitive function was assessed at age 11 and 79 using the Moray House Test (MHT), and a battery of psychometric tests assessed cognitive function at ages 79, 83, 87 and 90 (MHT, Raven's Matrices, Verbal Fluency, Logical Memory). Models controlled for individual-level socio-demographic, lifestyle and health covariates including overall physical activity. Higher frequency of gardening was significantly associated with greater lifetime cognitive gain from age 11 to 79 on the MHT (std β = 0.112 P = 0.024), higher general cognitive ability (g) level at age 79 (std β = 0.145, P = 0.001), and higher test-specific scores on the MHT (std β = 0.153, P = 0.001) and Raven's Matrices (std β = 0.102, P = 0.040). Gardening was not associated with subsequent cognitive slopes from age 79 to 90. Overall, these findings suggest that engaging in gardening activities may contribute modestly to healthy cognitive functioning up to the eighth decade of life. Although physical activity was higher in gardeners, it did not explain the gardening and cognitive function relationship.

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.

Brain aging differs with cognitive ability regardless of education

Higher general cognitive ability (GCA) is associated with lower risk of neurodegenerative disorders, but neural mechanisms are unknown. GCA could be associated with more cortical tissue, from young age, i.e. brain reserve, or less cortical atrophy in adulthood, i.e. brain maintenance. Controlling for education, we investigated the relative association of GCA with reserve and maintenance of cortical volume, -area and -thickness through the adult lifespan, using multiple longitudinal cognitively healthy brain imaging cohorts (n = 3327, 7002 MRI scans, baseline age 20–88 years, followed-up for up to 11 years). There were widespread positive relationships between GCA and cortical characteristics (level-level associations). In select regions, higher baseline GCA was associated with less atrophy over time (level-change associations). Relationships remained when controlling for polygenic scores for both GCA and education. Our findings suggest that higher GCA is associated with cortical volumes by both brain reserve and -maintenance mechanisms through the adult lifespan.

Paradoxical cognitive trajectories in men from earlier to later adulthood

Because longitudinal studies of aging typically lack cognitive data from earlier ages, it is unclear how general cognitive ability (GCA) changes throughout the life course. In 1173 Vietnam Era Twin Study of Aging (VETSA) participants, we assessed young adult GCA at average age 20 and current GCA at 3 VETSA assessments beginning at average age 56. The same GCA index was used throughout. Higher young adult GCA and better GCA maintenance were associated with stronger specific cognitive abilities from age 51 to 73. Given equivalent GCA at age 56, individuals who had higher age 20 GCA outperformed those whose GCA remained stable in terms of memory, executive function, and working memory abilities from age 51 to 73. Thus, paradoxically, despite poorer maintenance of GCA, high young adult GCA still conferred benefits. Advanced predicted brain age and the combination of elevated vascular burden and APOE-ε4 status were associated with poorer maintenance of GCA. These findings highlight the importance of distinguishing between peak and current GCA for greater understanding of cognitive aging.

Impact of COVID-19 lockdown on psychosocial factors, health, and lifestyle in Scottish octogenarians: The Lothian Birth Cohort 1936 study.

Little is known about effects of COVID-19 lockdown on psychosocial factors, health and lifestyle in older adults, particularly those aged over 80 years, despite the risks posed by COVID-19 to this age group. Lothian Birth Cohort 1936 members, residing mostly in Edinburgh and the surrounding Lothians regions in Scotland, mean age 84 years (SD = 0.3), responded to an online questionnaire in May 2020 (n = 190). We examined responses (experience and knowledge of COVID-19; adherence to guidance; impact on day-to-day living; social contact; self-reported physical and mental health; loneliness; and lifestyle) and relationships between previously-measured characteristics and questionnaire outcomes. Four respondents experienced COVID-19; most had good COVID-19 knowledge (94.7%) and found guidance easy to understand (86.3%). There were modest declines in self-reported physical and mental health, and 48.2% did less physical activity. In multivariable regression models, adherence to guidance by leaving the house less often associated with less professional occupational class (OR = 0.71, 95%CI 0.51-0.98) and poorer self-rated general health (OR = 0.62, 95%CI 0.42-0.92). Increased internet use associated with female sex (OR = 2.32, 95%CI 1.12-4.86) and higher general cognitive ability (OR = 1.53, 95%CI 1.03-2.33). Loneliness associated with living alone (OR = 0.15, 95%CI 0.07-0.31) and greater anxiety symptoms (OR = 1.76, 95%CI 0.45-1.24). COVID-19 related stress associated with lower emotional stability scores (OR = 0.40, 95%CI 0.24-0.62). Decreased physical activity associated with less professional occupational class (OR = 1.43, 95%CI 1.04-1.96), and lower general cognitive ability (OR = 0.679, 95%CI 0.491-0.931). Characteristics including cognitive function, occupational class, self-rated health, anxiety, and emotional stability, may be related to risk of poorer lockdown-related psychosocial and physical outcomes.

Change in Physical Activity, Sleep Quality, and Psychosocial Variables during COVID-19 Lockdown: Evidence from the Lothian Birth Cohort 1936.

(1) Objectives: The COVID-19 pandemic has disproportionately affected the lives of older people. In this study, we examine changes in physical activity, sleep quality, and psychosocial variables among older people during COVID-19 lockdown. We build on cross-sectional studies on this topic by assessing change longitudinally. We also examined whether participant characteristics including demographic, cognitive, personality, and health variables were related to more positive or negative changes during lockdown. (2) Methods: 137 older participants (mean age 84 years) from the Lothian Birth Cohort 1936 study were included in the analysis. They completed the same questionnaires assessing physical activity, sleep quality, mental wellbeing, social support, loneliness, neighbourhood cohesion, and memory problems before (mostly 2 years earlier) and again during national lockdown. (3) Results: On average, levels of physical activity were reduced (those doing minimal physical activity increased from 10% to 19%) and perceived social support increased during lockdown (effect size drm = 0.178). More positive change in the psychosocial and behavioural outcome variables during lockdown was associated with personality traits (greater intellect, emotional stability, and extraversion) and having a higher general cognitive ability. Participants with a history of cardiovascular disease, more symptoms of anxiety, or who lived alone were more likely to experience negative changes in the outcome variables during lockdown. (4) Discussion: These results provide further insight into the experiences of older people during the COVID-19 pandemic and could help to identify those at greatest risk of negative psychosocial or behavioural changes during this time.

Age 20 Cognitive Ability Moderates the Long-Term Influence of Lifestyle Behaviors on Brain Aging in Late Midlife

We examined whether the longitudinal association between lifestyle behaviors and brain age is moderated by early general cognitive ability (GCA). The sample comprises 356 participants from the Vietnam Era Twin Study of Aging (VETSA). At mean age 40 (SD 2.7; range 34-44) a positive lifestyle index was created comprising three self-reported behaviors: not smoking, zero to moderate alcohol consumption, and high social engagement. GCA at mean age 20 was assessed with the Armed Forces Qualification Test. At mean age 68 (SD 2.6; range 61-72), participants underwent structural magnetic resonance imaging which was used to create predicted brain age difference (PBAD) scores. Multivariate models included GCA, lifestyle and their interaction as IVs, adjusted for age, ethnicity, APOE genotype, height, and family membership. Age 20 GCA and age 40 lifestyle significantly predicted age 68 PBAD [F=5.83; p=.02 and F=15.14; p<.001, respectively]. Both positive behaviors and higher age 20 GCA were associated with less brain aging. The GCA-lifestyle interaction was also significant. Those with both lower age 20 GCA and fewer positive behaviors had older brains relative to chronological age [F=5.00; p=. 03]. When GCA was high, however, participants had younger brains, regardless of lifestyle behaviors, suggesting a protective effect of early high GCA or cognitive reserve on later brain health. However, for those with lower cognitive reserve, positive lifestyle behaviors appeared to be protective against brain aging nearly three decades later. Results highlight the important role of cognitive reserve and lifestyle factors for later life brain health.

Hemodynamic latency is associated with reduced intelligence across the lifespan: an fMRI DCM study of aging, cerebrovascular integrity, and cognitive ability.

Changes in neurovascular coupling are associated with both Alzheimer's disease and vascular dementia in later life, but this may be confounded by cerebrovascular risk. We hypothesized that hemodynamic latency would be associated with reduced cognitive functioning across the lifespan, holding constant demographic and cerebrovascular risk. In 387 adults aged 18-85 (mean = 48.82), dynamic causal modeling was used to estimate the hemodynamic response function in the left and right V1 and V3-ventral regions of the visual cortex in response to a simple checkerboard block design stimulus with minimal cognitive demands. The hemodynamic latency (transit time) in the visual cortex was used to predict general cognitive ability (Full-Scale IQ), controlling for demographic variables (age, race, education, socioeconomic status) and cerebrovascular risk factors (hypertension, alcohol use, smoking, high cholesterol, BMI, type 2 diabetes, cardiac disorders). Increased hemodynamic latency in the visual cortex predicted reduced cognitive function (p < 0.05), holding constant demographic and cerebrovascular risk. Increased alcohol use was associated with reduced overall cognitive function (Full Scale IQ 2.8 pts, p < 0.05), while cardiac disorders (Full Scale IQ 3.3 IQ pts; p < 0.05), high cholesterol (Full Scale IQ 3.9 pts; p < 0.05), and years of education (2 IQ pts/year; p < 0.001) were associated with higher general cognitive ability. Increased hemodynamic latency was associated with reduced executive functioning (p < 0.05) as well as reductions in verbal concept formation (p < 0.05) and the ability to synthesize and analyze abstract visual information (p < 0.01). Hemodynamic latency is associated with reduced cognitive ability across the lifespan, independently of other demographic and cerebrovascular risk factors. Vascular health may predict cognitive ability long before the onset of dementias.

Continental Genetic Ancestry Source Correlates with Global Cognitive Ability Score

The origins of between-group variation in cognitive ability have been a source of controversy for decades. In this pre-registered study, I tested the hypothesis that such differences are entirely environmental by examining the correlation between the proportion of individuals’ genetic heritage that originates on different continents with their total cognitive test score. In a sample of 193 Hispanic Americans and African Americans, it was found that the proportion of European genetic heritage was positively correlated (r = .277 to .300, p<.001) with the total cognitive test score. This makes any assertion of a purely environmental cause of mean group differences in cognitive ability less probable. One possible explanation is that the ancestors of Europeans experienced stronger selection pressures for high cognitive ability than the ancestral groups for Africans and Native Americans. However, this study may or may not generalize to other groups or a worldwide sample. Molecular genetics data suggest that most genetic causes are not specific for European (or any other continental) heritage. Such genetic variations are polymorphic in most human populations. Any person — from any demographic group — with a high proportion of such alleles is more likely than others to have high general cognitive ability.

FINANCIAL EXPLOITATION OF OLDER ADULTS: PRELIMINARY RESULTS FROM A PROSPECTIVE LONGITUDINAL STUDY

This paper presents study design and preliminary results from a new study funded by the National Institute on Aging that is examining financial exploitation (FE) among 720 White, African-American and Hispanic adults age 60+ (240 per group; 120 age 60-79; 120 age 80+). A conceptual model linking socio-demographics, physical health, social support / integration, cognitive function, financial skills / supports, and psychosocial factors to FE is being evaluated. Three assessments (baseline, 12; 24 mos.) include: a detailed cognitive battery, web-based banking simulation tasks, scam scenarios, and a standardized battery of self-report measures assessing socio-demographic and psychosocial variables. Preliminary baseline results from ~200 participants show support for the proposed model. Exposure to sales, remote purchasing behavior, and telemarketer receptivity (scam exposure); and scam vulnerability as measured by credibility ratings of “legitimate” and “fake” scam scenarios are positively associated with reports of both stranger-initiated and trusted other FE. Older adults with smaller social networks and less social support were more likely to report both exposure and vulnerability to scams. Higher general cognitive abilities, financial skills, and numeracy; and better performance on online banking tasks correlate with less scam exposure and vulnerability. Preliminary analyses of psychosocial factors also show that more depressed, impulsive, and trusting older adults report more exposure and scam vulnerability. The paper will present updated analyses of ~500 baseline participants. Understanding multiple pathways to FE is important to advance theory and for the development of interventions to minimize risk.

Genetic and environmental architecture of executive functions in midlife.

Research on executive functions (EFs) has revealed evidence for general abilities that underlie performance across multiple EF tasks and domains. This Common EF factor is highly stable in adolescence through young adulthood, correlates with other important cognitive abilities, and is explained largely by genetic influences. However, little is known about Common EF beyond young adulthood. This study examines 3 hypotheses regarding the latent structure, genetic/environmental etiology, and cognitive correlates of Common EF in middle age. We examined data from 1,284 middle-aged twins (51-60 years) in the Vietnam Era Twin Study of Aging who completed 7 neuropsychological measures of EFs, as well as measures of general cognitive ability and processing speed. Our confirmatory factor analysis indicated that Common EF explained variation across all 7 EF tasks. Inhibition and shifting were subsumed entirely under the Common EF factor, and there was an additional working memory span-specific factor. Common EF was heritable in midlife (a2 = .46), with additional evidence for both shared environmental influences (c2 = .41) and nonshared environmental influences (e2 = .13). Higher Common EF was moderately associated with higher general cognitive ability, measured both in early adulthood and midlife, and faster processing speed in midlife. These correlations were primarily driven by shared genetic influences. These results support the hypothesis that Common EF captures similar EF abilities in midlife as in adolescence and young adulthood. However, environmental influences may explain a larger portion of variance in this construct as individuals age. (PsycINFO Database Record

Highly reflective reasoners show no signs of belief inhibition

The processes underlying individual differences in reasoning performance are not entirely understood. What do people who do well on reasoning tasks where beliefs and logic conflict do differently from other people? Because abundant evidence shows that even poorer reasoners detect these conflicts, it has been suggested that individual differences in reasoning performance arise from inhibition failures later in the reasoning process. The present paper argues that a minority of highly skilled reasoners may deviate from this general reasoning process from an early stage. Two studies investigated signs of belief inhibition using a lexical access paradigm (Study 1) and a negative priming paradigm (Study 2). Study 1 showed that while other people exhibited signs of belief inhibition following a belief–logic conflict, people with the highest disposition for cognitive reflection did not. In Study 2, this finding was replicated and similar results were also obtained when comparing groups with higher and lower general cognitive ability. Two possible explanations are discussed.The reasoners with a highly reflective cognitive style or high general cognitive ability may have engaged and inhibited belief processing but if so, they may have been exceptionally efficient at recovering from it, wherefore no belief inhibition effects were found. An alternative account is that these reasoners started Type 2 processing directly, without first engaging in and then inhibiting belief-based processing. Under either explanation, the results indicate that individual differences in reasoning may partly arise from differences that occur early in the reasoning process.

Dopamine D1 sensitivity in the prefrontal cortex predicts general cognitive abilities and is modulated by working memory training

A common source of variance (i.e., “general intelligence”) underlies an individual's performance across diverse tests of cognitive ability, and evidence indicates that the processing efficacy of working memory may serve as one such source of common variance. One component of working memory, selective attention, has been reported to co-vary with general intelligence, and dopamine D1 signaling in prefrontal cortex can modulate attentional abilities. Based on their aggregate performance across five diverse tests of learning, here we characterized the general cognitive ability (GCA) of CD-1 outbred mice. In response to a D1 agonist (SKF82958, 1 mg/kg), we then assessed the relationship between GCA and activation of D1 receptor (D1R)-containing neurons in the prelimbic region of the medial prefrontal cortex, the agranular insular cortex, and the dorsomedial striatum. Increased activation of D1R-containing neurons in the prelimbic cortex (but not the agranular insular cortex or dorsomedial striatum) was observed in animals of high GCA relative to those of low GCA (quantified by c-Fos activation in response to the D1 agonist). However, a Western blot analysis revealed no differences in the density of D1Rs in the prelimbic cortex between animals of high and low GCA. Last, it was observed that working memory training promoted an increase in animals’ GCA and enhanced D1R-mediated neuronal activation in the prelimbic cortex. These results suggest that the sensitivity (but not density) of D1Rs in the prelimbic cortex may both regulate GCA and be a target for working memory training.

Shared genetic aetiology between cognitive ability and cardiovascular disease risk factors: Generation Scotland's Scottish family health study

People with higher general cognitive ability in early life have more favourable levels of cardiovascular disease (CVD) risk factors in adulthood and CVD itself. The mechanism of these associations is not known. Here we examine whether general cognitive ability and CVD risk factors share genetic and/or environmental aetiology. In this large, pedigree-based cross-sectional study of Scottish families ( N = 1983 families; 6086 individuals) we estimate the heritability (ranging from 0.08 to 0.91) of a diverse battery of CVD risk factors, and also examine the extent and causes of their relationship with general cognitive ability. General cognitive ability was associated significantly with almost all the risk factors investigated, explaining between 0.2% and 11% of variance. For those measures with an effect size greater than around 1%, the relationship was primarily influenced by genes (30 to 94%) rather than the environment. These findings have relevance to the growing field of cognitive epidemiology, in which intelligence is used to predict morbidity and mortality. We provide evidence that risk factors such as education and income – which are typically treated as environmental indicators by epidemiologists and controlled for in their studies of morbidity – are genetically confounded with IQ.

A Cognitive (Attributions)-Emotion Model of Observer Reactions to Free-Riding Poor Performers

Whereas most free-riding research has focused on limiting free-riding and on understanding free-riding motives, we were concerned with capturing the psychological processes used by observers to interpret the poor performance behavior of a team member. Using a sample of 268 observers of a simulated team interaction, we found that peer reactions to a poor performance could be explained through attribution theory (AT). Poor performers perceived as possessing high general cognitive ability (g) and low conscientiousness traits were more likely to be rated high on free-riding when compared to those perceived as possessing low g/low conscientiousness traits. In addition, AT helped explain observer anger and intent to punish free-riders.

Apolipoprotein E genotype and memory in the sixth decade of life

Virtually all adult studies of APOE genotypes and cognition have included individuals over 60. In older adults, epsilon 4 carriers may manifest greater cognitive asymmetries than non-epsilon 4 carriers even in the absence of overall mean differences. General cognitive ability may also be affected by aging and APOE genotype, but most studies have inadequately addressed this potential confound. The goals of this study were to examine, in middle age, the relationship of APOE genotype with episodic memory and verbal-visuospatial episodic memory asymmetries, after accounting for prior general cognitive ability. We compared epsilon 4+ and epsilon 4- individuals in 626 male twins in their 50s. We examined verbal and visuospatial episodic memory and verbal-visual asymmetry scores after adjusting for cognitive ability at age 20. Analyses corrected for correlations between twin pair members. Compared with epsilon 4- individuals, epsilon 4 carriers performed significantly more poorly on verbal, but not visuospatial memory, manifested significantly greater cognitive asymmetry, and also had significantly more concerns about memory. At age 20, epsilon 4 carriers had higher general cognitive ability than epsilon 4- individuals, and current memory differences were enhanced after adjusting for age 20 cognitive ability. Small, but significant, APOE-epsilon 4-related memory deficits appear in the sixth decade of life in individuals who show no signs of preclinical dementia. The results partially support studies of older adults that suggest that increased cognitive asymmetries reflect risk for dementia and are associated with the APOE-epsilon 4 genotype. The results also highlight the potential problems of not having accurate data on prior cognitive ability.

DNA pooling and dense marker maps: a systematic search for genes for cognitive ability.

Pooling DNA from subjects within a group and comparing the pooled DNA across groups for a dense map of DNA markers offers a solution to the conundrum that linkage is systematic but not powerful whereas allelic association is powerful but not systematic. We used DNA pooling to screen 66 markers on chromosome 22 in original and replication samples of children of high general cognitive ability (g) and controls of average g. Although none of these markers survived our three-stage screening design (original pooling, replication pooling, individual genotyping), the results of DNA pooling were largely confirmed by individual genotyping. We can therefore exclude associations of major effect size on chromosome 22 for g, a key variable for cognitive neuroscience research on learning and memory.

Exploring the Genetic and Environmental Etiology of High General Cognitive Ability in Fourteen‐ to Thirty‐Six‐Month‐Old Twins

Although numerous theories have attempted to explain the origins of high general cognitive ability (g), the genetic and environmental etiology of high g during infancy and early childhood has not previously been investigated. We report results of a twin study of high cognitive ability at 14, 20, 24, and 36 months using twins from the more than 600 children participating in the MacArthur Longitudinal Twin Study. High g groups were formed from the ninetieth percentile and above at each age, with IQ equivalent means at or above 126 across the ages. Results suggest increasing genetic influence and increasing genetic stability from 14 to 36 months using DeFries-Fulker multiple regression analyses. However, genetic influences are substantial when examining individuals who possess high g scores averaged across all 4 ages. These results suggest that, although high cognitive ability may be genetically influenced in early childhood, these influences differ in magnitude from 14 to 36 months.

Exploring the Genetic and Environmental Etiology of High General Cognitive Ability in Fourteen- to Thirty-Six-Month-Old Twins

Exploring the Genetic and Environmental Etiology of High General Cognitive Ability in Fourteen- to Thirty-Six-Month-Old Twins

Working Smarter and Harder: A Longitudinal Study of Managerial Success

We thank Glenn Carroll, Jeffrey Pfeffer, Bob Sutton, and James Wade for comments on earlier drafts of this paper. We measure the effects of motivation and ability on the early career success of a sample of Master's of Business Administration (MBA) graduates in the early years of their careers. We argue that performance is a joint effect of two important individual characteristics: general cognitive ability and motivation. General cognitive ability, which is representative of the general population, refers to individual differences in tasks or pursuits that demand mental effort, such as abstraction, rule inference, generalization, and manipulating or transforming problems. Motivation is conceptualized as a stable mental state that energizes human behavior. Results show that the combination of high general cognitive ability and motivation is significantly associated with more early career success. MBAs who were both smarter and worked harder were more successful in their job search upon graduation, were earning higher salaries, had more rapid pay increases, and received more promotions in their early careers. These findings add to the mounting evidence that studying enduring individual characteristics is critical to predicting behavior.'