Social Network Size and Cognitive Functioning in Middle-Aged Adults: Cross-Sectional and Longitudinal Associations

The objective of the present study was to examine relations between social network size and three cognitive abilities (episodic memory, semantic memory, visuospatial ability) in middle-aged adults. We analyzed cross-sectional data on social network size and cognitive functioning that were available for 804 participants aged 40–60 years. In addition, we examined 5- and 10-year follow-up measurements of cognitive functioning that were available for 604 and 255 participants, respectively. Cross-sectional analyses revealed a positive association between social network size and each of the three cognitive abilities. Baseline network size was positively related to 5-year changes in semantic memory, and to 10-year changes in semantic as well as episodic memory, but was unrelated to changes in visuospatial performance. A minor portion of the sample (n = 131) had 10-year follow-up data on network size. Cross-lagged panel correlations revealed that baseline network size was associated with follow-up measurement in cognitive functioning (episodic memory, semantic memory), whereas baseline cognitive performance was unrelated to future network size. Together, the results demonstrate a small but positive relation between network size and declarative memory abilities, in line with models proposing a cognitive reserve built up by factors such as the increased cognitive stimulation associated with a more extensive social network.     

Activity engagement is related to level, but not change in cognitive ability across adulthood

It is unclear whether the longitudinal relation between activity participation and cognitive ability is due to preserved differentiation (active individuals have higher initial levels of cognitive ability), or differential preservation (active individuals show less negative change across time). This distinction has never been evaluated after dividing time-varying activity into its two sources of variation: between-person and within-person variability. Further, few studies have investigated how the association between activity participation and cognitive ability may differ from early to older adulthood. Using the PATH Through Life Project, we evaluated whether between- and within-person variation in activity participation was associated with cognitive ability and change within cohorts aged 20-24 years, 40-44 years, and 60-64 years at baseline (n = 7,152) assessed on three occasions over an 8-year interval. Multilevel models indicated that between-person differences in activity significantly predicted baseline cognitive ability for all age cohorts and for each assessed cognitive domain (perceptual speed, short-term memory, working memory, episodic memory, and vocabulary), even after accounting for sex, education, occupational status, and physical and mental health. In each case, greater average participation was associated with higher baseline cognitive ability. However, the size of the relationship involving average activity participation and baseline cognitive ability did not differ across adulthood. Between-person activity and within-person variation in activity level were both not significantly associated with change in cognitive test performance. Results suggest that activity participation is indeed related to cognitive ability across adulthood, but only in relation to the starting value of cognitive ability, and not change over time.     

Childhood cognitive ability,education, and personality traits predict attainment in adult occupational prestige over 17 years

This study explored a longitudinal data set of nearly 5000 adults examining the effects of childhood cognitive ability (measured at age 11), parental social class (measured at birth), and personality on current occupational prestige (all measured at age 50), taking account the effects of education and the previous occupational levels (both measured at age 33). Participants' levels of occupational attainment significantly went up from age 33 to age 50. Correlational analysis showed childhood cognitive ability, parental social class, education and occupation, and personality traits (openness, conscientiousness, extraversion, emotional stability) were all significantly associated with current occupational prestige. The strongest correlates of current occupational levels were educational qualifications, followed by childhood cognitive ability, parental social class, and personality traits. Structural equation modelling showed that for the change of occupation over 17 years, the strongest predictor was education, followed by childhood intelligence. Personality traits (extraversion, conscientiousness, and openness) had modest but significant influence in the upgrading of occupational attainment over the period of time, and parental social status predicted occupational change mediated through education and initial occupational levels. Education and childhood intelligence are more powerful predictors of current occupational prestige than personality factors or family social background. The implications for policy making and equal opportunities for education are discussed.     

Cross-Category Friendships and Postformal Thought among College Students

Theories of postformal thought (PFT) suggest that cognitive development is enhanced by social interactions where differences must be negotiated. Friendships provide the potential for complex social interactions and are an ideal context in which to explore the relation between cognitive development and the negotiation of social differences. The present research is the first to directly explore the relation between close cross-category friendships and level of postformal cognitive reasoning among college students. Participants from two universities completed questionnaires assessing PFT and friendship characteristics. Results indicate that individuals reported more same-category versus cross-category friendships. This was true for sex, ethnicity, social class, sexual orientation, and age. In addition, individuals high in PFT had more social category differences in their existing close friendships than individuals low in PFT.     

Evaluating associations between maternal social support and cognitive development for infants in poverty

Infant cognitive development may be associated with maternal social support, although these relations have not been well-examined for infants living in poverty. We explore whether maternal social support is associated with cognitive development for 113 infants living in poverty. Infant cognition was measured at age 9–12 months using the Bayley Scales of Infant and Toddler Development 3rd edition. Mothers provided information regarding perceived social support received from fathers, family, friends, and community members. Controls included maternal race and infant sex. Linear regression revealed no significant relationships between maternal social support and infant cognition in this sample.     

Recycling,evolution and the structure of human personality

Lower childhood cognitive ability may be a risk factor for greater cognitive decline in late life and progression to dementia. To assess variation in age-related cognitive change, it is helpful to have valid measures of cognitive ability from early life. Here, we examine the relation between childhood intelligence and cognitive change in later life in two samples, one born in 1921 and the other in 1936. All participants completed the same test of mental ability (one of the Moray House Test series) at age about 11 years, and were re-examined on Raven’s Progressive Matrices at age 77 (1921-born) or age 64 (1936-born). Where possible, the 1921 sample was re-tested at the age of about 80 years old and the 1936 sample re-tested at about 66 years. After taking into account various covariates, including sex, education and occupation, childhood intelligence was a significant predictor of cognitive change in later life. Results were in the direction that participants with lower childhood mental ability experienced relatively greater cognitive decline, whereas those of higher childhood mental ability showed improved performance. This result suggests that higher premorbid cognitive ability is protective of decline in later life.     

Race, brain size, and intelligence: a reply to Cernovsky

Cernovsky's 1990 critique of my work on the relation between brain size and IQ inadequately presents my position. I did not address the issue of sex differences in brain size nor did I conclude that "women are less intelligent than men" (p. 337). In the autopsy study cited by Cernovsky, it was concluded that, when body size is controlled, the male-female difference in brain size is removed but the black-white difference in brain size remains. Cernovsky also ignores much additional data, including that Mongoloid populations have larger and heavier brains than Caucasoids. Here, I review evidence on the relation between (a) brain size and race and (b) brain size and intelligence. Data are also tabulated for personality, speed of maturation, and sexuality, on all of which the Caucasoid average consistently falls between those of Mongoloids and Negroids. This ordering may be explained by a gene-based evolutionary theory of r/K reproductive strategies in which Mongoloids are more K-selected than Caucasoids and Caucasoids more than Negroids.     

Dichotic listening,executive functions and grey matter cortical volume in patients with schizophrenia and healthy controls

Schizophrenia is characterized by cognitive impairment, especially in relation to executive functions. Brain structural abnormalities are also often seen in schizophrenia although little is known of the relationship between cognitive impairment and structural brain changes. Our aim was therefore to investigate this relationship further using MRI and a dichotic listening (DL) task with simple speech sounds and with instructions to focus attention and report only from the left or right ear stimulus. When instructed to focus attention on the left ear syllable a cognitive conflict is induced requiring the allocation of executive resources to be resolved. Grey matter (GM) volume was measured with MRI from four volumes of interests (VOIs), left and right frontal and temporal cortex, respectively, and correlated with DL performance. The results showed significant differences between the groups in their ability to focus attention on and report the left ear stimulus, which was accompanied by reduced GM volume in the left frontal and right temporal lobe VOIs. There was also a significant positive correlation between left frontal GM volume and performance on the DL task, for the groups combined. The results did not support a conclusion that an impairment in cognitive function in schizophrenia was driven by an corresponding impairment in brain structure, since there were no significant correlations when the groups were analyzed separately. It is however concluded that patients with schizophrenia are impaired in executive functions and that they also show reduced GM volumes in left frontal and right temporal lobe areas, compared to healthy controls.     

White matter development during adolescence as shown by diffusion MRI

Previous volumetric developmental MRI studies of the brain have shown white matter development continuing through adolescence and into adulthood. This review presents current findings regarding white matter development and organization from diffusion MRI studies. The general trend during adolescence (age 12–18 years) is towards increasing fractional anisotropy (FA) with age and decreasing mean diffusivity (MD) with age, findings primarily due to decreasing radial diffusivity with age. However, results of studies vary as to the regional specificity of such age-related changes, likely due in part to methodological issues. Another general trend is for FA to positively correlate and MD to negatively correlate with cognitive function. This trend is however region-specific, task-specific, and population-specific; some studies have in fact found negative correlations of FA and positive correlations of MD in specific regions with specific measures of cognitive performance. There are also published reports of sexual dimorphism in white matter development, indicating differing developmental trajectories between males and females as well as differing relationships developmentally between white matter architecture and cognitive function. There is a need for more research to further elucidate the development of white matter and its relation to cognitive function during this critical developmental period.     

How predictive are sex and empathizing–systemizing cognitive style for entry into the academic areas of social or physical sciences?

Based on the Empathizing–Systemizing (E–S) theory, it was hypothesized that the underrepresentation of female students in the physical sciences and the underrepresentation of males in the social sciences relates to differences in E–S cognitive style between the sexes. This hypothesis was tested in 115 physical science students and 155 social science students from a university in the Netherlands. The students completed visuospatial tests and the systemizing quotient-revised (SQ-R) as measures for systemizing, and a Cartoon Prediction test and the empathy quotient (EQ) as measures for empathizing. Independent of sex, the physical science students scored significantly lower than social science students on EQ (with large effect size) and ‘brain type’ that represents the standardized difference score between EQ and SQ-R (with large effect size). Physical science students, furthermore, scored significantly higher on the Cartoon Prediction task and one of the visuospatial tasks; however, these effects were only small of size. Unlike the scores on the SQ-R and the performance tests, the ‘brain type’ score of the EQ and SQ-R questionnaires was a good predictor of entry into social or physical sciences. Interestingly, the typical sex differences in more empathizing and less systemizing in females compared to males were only small for EQ and ‘brain type’, and absent for the SQ-R and the performance tests. This study only partially confirms the E–S theory, because typical sex differences were only minor in this selective sample and only the self-report measures predicted academic area in the absence of a role for sex.     

Age,sex, and verbal abilities affect location of linguistic connectivity in ventral visual pathway

Previous studies have shown that the strength of connectivity between regions can vary depending upon the cognitive demands of a task. In this study, the location of task-dependent connectivity from the primary visual cortex (V1) was examined in 43 children (ages 9–15) performing visual tasks; connectivity maxima were identified for a visual task requiring a linguistic (orthographic) judgment. Age, sex, and verbal IQ interacted to affect maxima location. Increases in age and verbal IQ produced similar shifts in maxima location; in girls, connectivity maxima shifted primarily laterally within the left temporal lobe, whereas the shift was primarily posterior within occipital cortex among boys. A composite map across all subjects shows an expansion in the area of connectivity with age. Results show that the location of visual/linguistic connectivity varies systematically during development, suggesting that both sex differences and developmental changes in V1 connectivity are related to linguistic function.     

Glycosylated Hemoglobin Level,Race/Ethnicity,and Cognition in Midlife and Early Old Age

Empirical evidence linking racial/ethnic differences in glycosylated hemoglobin levels (HbA1c) to cognitive function in midlife and early old age is limited. We use biomarker data from the Health and Retirement Study (HRS, 2006–2014), on adults 50–64 years at baseline (57–73 years by 2014), and fit multinomial logistic regression models to assess the association between baseline HbA1c, cognitive function (using Langa–Weir classifications) and mortality across 8 years. Additionally, we test for modification effects by race/ethnicity. In age- and sex-adjusted models high HbA1c level was associated with lower baseline cognition and higher relative risk ratios (RRR; vs. normal cognition) for cognitive impairment no dementia (CIND; RRR = 2.3; 95%CI = [1.38;3.84]; p < .01), and dementia (RRR = 4.00; 95%CI = [1.76;9.10]; p < .01). Adjusting for sociodemographic, behavioral risk factors, and other health conditions explained the higher RRR for CIND and attenuated the RRR for dementia by approximately 30%. HbA1c levels were not linked to the slope of cognitive decline, and we found no evidence of modification effects for HbA1c by race/ethnicity. Targeting interventions for glycemic control in the critical midlife period can protect baseline cognition and buffer against downstream development of cognitive impairment. This can yield important public health benefits and reductions in burdens associated with cognitive impairment, particularly among race/ethnic minorities who are at higher risk for metabolic diseases.     

Cognitive Functioning,Behavior, and Quality of Life After Stroke in Childhood

Rationale: To provide a better understanding of cognitive functioning, motor outcome, behavior and quality of life after childhood stroke and to study the relationship between variables expected to influence rehabilitation and outcome (age at stroke, time elapsed since stroke, lateralization, location and size of lesion).

Methods: Children who suffered from stroke between birth and their eighteenth year of life underwent an assessment consisting of cognitive tests (WISC-III, WAIS-R, K-ABC, TAP, Rey-Figure, German Version of the CVLT) and questionnaires (Conner's Scales, KIDSCREEN).

Results: Twenty-one patients after stroke in childhood (15 males, mean 11;11 years, SD 4;3, range 6;10–21;2) participated in the study. Mean Intelligence Quotients (IQ) were situated within the normal range (mean Full Scale IQ 96.5, range IQ 79–129). However, significantly more patients showed deficits in various cognitive domains than expected from a healthy population (Performance IQ p?=?.000; Digit Span p?=?.000, Arithmetic's p?=?.007, Divided Attention p?=?.028, Alertness p?=?.002). Verbal IQ was significantly better than Performance IQ in 13 of 17 patients, independent of the hemispheric side of lesion. Symptoms of ADHD occurred more often in the patients' sample than in a healthy population (learning difficulties/inattention p?=?.000; impulsivity/hyperactivity p?=?.006; psychosomatics p?=?.006). Certain aspects of quality of life were reduced (autonomy p?=?.003; parents' relation p?=?.003; social acceptance p?=?.037). Three patients had a right-sided hemiparesis, mean values of motor functions of the other patients were slightly impaired (sequential finger movements p?=?.000, hand alternation p?=?.001, foot tapping p?=?.043). In patients without hemiparesis, there was no relation between the lateralization of lesion and motor outcome. Lesion that occurred in the midst of childhood (5–10 years) led to better cognitive outcome than lesion in the very early (0–5 years) or late childhood (10–18 years). Other variables such as presence of seizure, elapsed time since stroke and size of lesion had a small to no impact on prognosis.

Conclusion: Moderate cognitive and motor deficits, behavioral problems, and impairment in some aspects of quality of life frequently remain after stroke in childhood. Visuospatial functions are more often reduced than verbal functions, independent of the hemispheric side of lesion. This indicates a functional superiority of verbal skills compared to visuospatial skills in the process of recovery after brain injury. Compared to the cognitive outcome following stroke in adults, cognitive sequelae after childhood stroke do indicate neither the lateralization nor the location of the lesion focus. Age at stroke seems to be the only determining factor influencing cognitive outcome.     

A developmental investigation of other‐race contact and the own‐race face effect

Research over the past two decades has demonstrated that individuals are better at recognizing and discriminating faces of their own race versus other races. The own‐race effect has typically been investigated in relation to recognition memory; however, some evidence supports an own‐race effect at the level of perceptual encoding in adults. The current study investigated the developmental basis of the own‐race effect in White primary students (aged 7–11), secondary students (aged 12–15) and university students. Face stimuli were generated by morphing South Asian and White parent faces together along a linear continuum. In a same/different perceptual discrimination task, participants judged whether the face stimuli (morphs and parent faces) were physically identical to or different from the original parent faces. Results revealed a significant race of face effect for each age group, whereby participants were better at discriminating White relative to Asian faces. A significantly larger own‐race effect was observed for the secondary and university students than for primary students. A questionnaire was used to assess other‐race social anxiety and contact; however, this self‐report measure was not found to be related to the observed own‐race effect.     

Social construction: big-G grounding,small-g realization

The goal of this paper is to make headway on a metaphysics of social construction. In recent work (forthcoming), I’ve argued that social construction should be understood in terms of metaphysical grounding. However, I agree with grounding skeptics like Wilson (Inquiry 1–45, 2014) that bare claims about what grounds what are insufficient for capturing, with fine enough grain, metaphysical dependence structures. To that end, I develop a view on which the social construction of human social kinds (e.g., race) is a kind of realization relation. Social kinds, I argue, are multiply realizable kinds. I depart from the Wilson by further arguing that an appeal to grounding is not otiose when it comes to social construction. Social construction, I claim, belongs to the “big-G” Grounding genus, but it is the specific “small-g” relation of realization at work in cases of human kind social construction.     

Causes of racial and socioeconomic differences in cognitive tests

Correlations among profiles of means based upon 75 cognitive variables from Project TALENT are presented for groups defined by race, socioeconomic status, sex, area of the country, and grade in high school. Sex makes by far the largest contribution to differences in shape of profiles. Race and socioenconomic status, in turn, make much larger contributions to differences than grade and area. Sex differences in shapes of profiles are a function primarily of race and, to a lesser extent, of social class. Race differences are larger than socioeconomic differences and the former, in particular, are also a function of sex. Black males differ more from white patterns than black females. There is lack of substantial overlap in the causes of race and socioeconomic differences in shape of cognitive profiles.     

The impact of weight, sex, and race/ethnicity on body dissatisfaction among urban children

The purpose of the current study was to examine the relative contributions of weight status, race/ethnicity, sex, and age on body dissatisfaction in a large group of diverse children. Participants were 4th–6th graders (N = 1212) in ten inner-city schools who participated in an obesity prevention study previously published. Children completed the body dissatisfaction subscale of the Eating Disorder Inventory-2 (EDI-2), and weight status was assessed by measured weights and heights. Multiple regression analyses were conducted. Relative weight status was the strongest predictor of body dissatisfaction, followed by race/ethnicity, and sex. Body dissatisfaction was greatest in obese, Asian, and female children. Overall, results indicated that children's body dissatisfaction varies based on relative weight status, as well as race/ethnicity and sex among urban children. Results highlight the strong need for additional research so that more definitive conclusions may be drawn regarding the development of body image among diverse groups of children.     

Social cognition is not associated with cognitive reserve in older adults

Social and general cognitive abilities decline in late life. Those with high cognitive reserve display better general cognitive performance in old age; however, it is unknown whether this is also the case for social cognition. A total of 115 healthy older adults, aged 60–85 years (m = 44, f = 71) were assessed using The Awareness of Social Inference Test (TASIT-R; social cognition), the Lifetime of Experiences Questionnaire (LEQ; cognitive reserve), and the Wechsler Abbreviated Scale of Intelligence (WASI-II; general cognitive ability). The LEQ did not predict performance on any TASIT-R subtest: Emotion Evaluation Test (β = -.097, p = .325), Social Inference – Minimal (β = -.004, p = .972), or Social Inference – Enriched (β = -.016, p = .878). Sensitivity analyses using two alternative cognitive reserve measures, years of education and the National Adult Reading Test, supported these effects. Cognitive reserve was strongly related to WASI-II performance. Unlike general cognitive ability, social cognition appears unaffected by cognitive reserve. Findings contribute to the emerging understanding that cognitive reserve differentially affects individual cognitive domains, which has implications for the theoretical understanding of cognitive reserve and its brain correlates. Cognitive measures unbiased by cognitive reserve may serve as best indicators of brain health, free of compensatory mechanisms.     

Content variations and performance on formal operational tasks by gender,social class and ability1

The role of task content, gender, social class and cognitive ability in performance on two formal operational tasks is explored in this paper. The participants were 110 Icelandic 12-year-olds, early and late developers, males and females from all socio-economic groups. Two tasks of variable isolation (the pendulum and three content versions of the “plant” problem) and two measures of volume conservation (three traditional tasks and three tasks formally identical whose content was pictorial social play) were presented individually in a school setting. The results suggest that content variations have differential consequences for the performance of early and late developers at age 12. Both the nature of logical competence and task content affect solutions, as suggested by Overton and collaborators in 1987. Some social class and gender differences were observed on two Piagetian tasks (pendulum and volume), which was reduced by changing the task content in the case of social class but not in that of gender. As the gender difference in volume conservation was not reflected ins chool achievement nor on other cognitive tasks it was interpreted as a gender bias. The findings are discussed in view of recent literature on the development of cognitive theory with increased emphasis on context and meaning in a post-structural intellectual climate.