The impact of childhood intelligence on later life: following up the Scottish mental surveys of 1932 and 1947

The Scottish Mental Surveys of 1932 and 1947 collected valid IQ-type test scores for almost everyone born in 1921 and 1936 and attending school on June 1, 1932 (N=89,498) and June 4, 1947 (N=70,805). These surveys are described. This research, using the surveys' data, examined (a) the stability of intelligence differences across the life span, (b) the determinants of cognitive change from childhood to old age, and (c) the impact of childhood intelligence on survival and health in old age. Surviving participants of the Scottish Mental Surveys were tested, and the surveys' data were linked with public and health records. Novel findings on the stability of IQ scores from age 11 to age 80; sex differences in cognitive aging; the dedifferentiation hypothesis of cognitive aging; and the effect of childhood IQ on all-cause and specific mortality, morbidity, and frailty in old age are presented.     

The effect of month of birth on the attainments of primary and secondary school pupils

Background Previous research has produced conflicting results regarding the effects of season of birth and age‐position on cognitive attainments. In Northern Ireland the school year divides the summer season into two providing an opportunity to evaluate the relative contribution of season of birth and age‐position effects. Aims To investigate the relationship between attainment in literacy skills and month of birth for primary and secondary school pupils and to determine the relationship between motor skills and month of birth in primary school pupils. Sample One thousand one hundred and twenty four primary school pupils participated, and results for key stage 3 (KS3) English and GCSE English Language, for 3,493 Year 10 and 3,697 Year 12 secondary school pupils, respectively, were obtained. Method Primary school pupils were individually assessed using standardised reading and spelling tests, as well as tests of motor skill. They were also assessed using a standardised group reading test in their class groups. For the secondary school pupils, the results for two year cohorts, in KS3 English and GCSE English language, respectively, were analysed. Results For the primary school pupils there was evidence of both a season of birth and an age‐position effect on all of the cognitive measures, particularly in the early years of schooling. There was, also, evidence of a significant age‐position effect at both KS3 and GCSE in favour of the older pupils. For the younger primary school pupils there was evidence of significant age‐position effects on both motor measures. Conclusions The findings from the present study suggest that month of birth may be related to both season of birth and age‐position effects. These effects may be compounded, particularly in the early years of primary school, when summer born children are youngest in their year, as in England. In Northern Ireland, age‐position effects are also evident in secondary school public examination results, which may have implications for long‐term life choices.     

Intelligence and school readiness in preschool children with prenatal drug exposure.

This prospective, longitudinal study examined factors affecting intelligence and school readiness in children 4-5 years of age with prenatal cocaine/opiate exposure. Intelligence and school readiness scores were not significantly different for the drug-exposed group (N = 104) than for unexposed, demographically matched controls (N = 35), although both groups scored slightly below average. Caregivers of drug-exposed children scored significantly lower in intelligence and reading achievement than caregivers of controls; both were below average. Caregiver reading scores accounted for the largest variance in both child intelligence and school readiness; for school readiness, birth weight also contributed but was less important in the model. Neither prenatal drug exposure nor continuing caregiver drug use was significant in the regression analyses. The relationship between child scores and caregiver reading achievement is consistent with studies showing the importance of a stimulating, supportive home environment, and suggests interventions to foster caregiver literacy skills and facilitate caregiver-child cognitive interactions such as reading to the child.     

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.     

Intelligence and executive functioning in adult age: Effects of sibship size and birth order

Several studies have demonstrated that social influences from having been brought up in a family with few siblings and early in birth order result in higher scores on intelligence tests in childhood and adolescence as compared to having been brought up in large sibships. The present study examined whether influences of such social factors would have long-lasting effects on intelligence (block design and word comprehension) and executive functions (working memory and verbal fluency) in adulthood and old age, i.e., long after the individuals had moved out of the family structure they were born in. After having controlled for socioeconomic status and a variety of health conditions affecting cognition in adult life, a sibship size effect was demonstrated for executive functions but not for intelligence. The social influences of birth order affected only executive functions and working memory in particular; earlier born individuals performed better than later born individuals in tests assessing executive function but not in tests assessing intelligence. Implications for the relationship between executive functioning and intelligence, and implications for the Confluence and Resource Dilution Models (Blake, 1981; Downey, 1995, 2001; Zajonc, 1976) are discussed.     

Intelligence in childhood and risk of psychological distress in adulthood: The 1958 National Child Development Survey and the 1970 British Cohort Study

Lower cognitive ability is a risk factor for some forms of severe psychiatric disorder, but it is unclear whether it influences risk of psychological distress due to anxiety or the milder forms of depression. The participants in the present study were members of two British birth national birth cohorts, the 1958 National Child Development Survey (n = 6369) and the 1970 British Cohort Study (n = 6074). We examined the association between general cognitive ability (intelligence) measured at age 10 (1970 cohort) and 11 years (1958 cohort) and high levels of psychological distress at age 30 (1970 cohort) or 33 years (1958 cohort), defined as a score of 7 or more on the Malaise Inventory. In both cohorts, participants with higher intelligence in childhood had a reduced risk of psychological distress. In sex-adjusted analyses, a standard deviation (15 points) increase in IQ score was associated with a 39% reduction in psychological distress in the 1958 cohort and a 23% reduction in the 1970 cohort [odds ratios (95% confidence intervals) were 0.61 (0.56, 0.68) and 0.77 (0.72, 0.83), respectively]. These associations were only slightly attenuated by further adjustment for potential confounding factors in childhood, including birth weight, parental social class, material circumstances, parental death, separation or divorce, and behaviour problems, and for potential mediating factors in adulthood, educational attainment and current social class. Intelligence in childhood is a risk factor for psychological distress due to anxiety and the milder forms of depression in young adults. Understanding the mechanisms underlying this association may help inform methods of prevention.     

School performance and IQ-test scores at age 13 as related to birth weight and gestational age

The cohort in the present longitudinal research program consisted of 873 children in an entire school grade, in a Swedish community. The present results showed a main effect of birth weight; low birth weight (LBW) children had lower school performance and intelligence-test (IQ) scores at age 13 than did normal birth weight (NBW) children irrespective of parental SES. Second, there was no significant main effect of gestational age (GA) on scholastic performance and IQ-test scores. Third, there was a significant main effect of the combination of birth weight and GA on scholastic performance and IQ-test scores. The LBW children born at term (38-40 pregnancy weeks; pw) had significantly lower scores and school grades as compared to the control group while the LBW children born with short gestational age (34-37 pw) and with very short gestational age (less than 34 pw) had significantly lower scores and marks in fewer areas of academic attainment.     

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.     

Performance of disabled and normal readers on the continuous performance test

Twelve-year-old reading-disabled children of normal intelligence were compared on the Continuous Performance Test with two control groups of normal intelligence and reading ability either of the same age or of the same reading age as the reading-disabled group. Signal-detection analysis showed that the reading-disabled were more conservative than chronological-age controls in their willingness to identify the target letter sequence. Although this conservative performance was shared by the reading-age controls, the readingdisabled suffered an additional handicap of relatively frequent anticipatory errors. Groups also differed on a sensitivity measure, suggesting a deficit in working memory in the reading-disabled children.This research was supported by the New Zealand Neurological Foundation. We thank the children and school staff for their willing cooperation. We are indebted to the research students who found the subjects and helped collect the data.     

Time Reading in Middle and Secondary School Students: The Influence of Basic-Numerical Abilities

Abstract

Time reading skills are central for the management of personal and professional life. However, little is known about the differential influence of basic numerical abilities on analog and digital time reading in general and in middle and secondary school students in particular. The present study investigated the influence of basic numerical skills separately for analog and digital time reading in N?=?709 students from 5th to 8th grade. The present findings suggest that the development of time reading skills is not completed by the end of primary school. Results indicated that aspects of magnitude manipulation and arithmetic fact knowledge predicted analog time reading significantly over and above the influence of age. Furthermore, results showed that spatial representations of number magnitude, magnitude manipulation, arithmetic fact knowledge, and conceptual knowledge were significant predictors of digital time reading beyond general cognitive ability and sex. To the best of our knowledge, the present study is the first to show differential effects of basic numerical abilities on analog and digital time reading skills in middle and secondary school students. As time readings skills are crucial for everyday life, these results are highly relevant to better understand basic numerical processes underlying time reading.     

Fourth Editor of the Journal of Genetic Psychology

The aim of the present study was to examine whether school performance is influenced by absence because of illness and if there are any differences in the relationship due to grade, sex, and season of birth. Data were taken for 598 pupils born in 1947 whose complete records for the 1st through 6th grades were stored at the city archive of Uppsala. Simple correlational analyses were conducted between spring absence due to illness in the 2nd through 6th grades and teacher-assigned grades during the same spring for verbal and arithmetic performance. Significant negative correlations were found between absence and both arithmetic and verbal performance in Grades 5 and 6. Subgroup analysis revealed significant correlations for the girls in the 5th grade and for boys in the 6th grade. However, only girls and boys born during the first half of the year showed these significant correlations between absence due to illness and performance.     

RELATIVE CHANGES IN INTELLIGENCE FROM 13 TO 18: I. Background and methodology

H ärnqvist , K. Relative changes in intelligence from 13 to 18. I. Background and methodology. Scand. J. Psychol ., 1968, 9, 50–64.—A ten-percent sample of the Swedish school population born in 1948 took an intelligence test at the age of 13. The male part was tested again at 18 in connection with enrolment for military service in 1966. Complete test scores are available for 4616 men. The data were used to investigate relative changes in intelligence connected with differences in education and home background. In this report the theoretical and statistical bases for such comparisons are analyzed. In part II the results are reported.     

Neurocognitive profiles of preterm infants randomly assigned to lower or higher hematocrit thresholds for transfusion

Objective: Preterm infants are frequently transfused with red blood cells based on standardized guidelines or clinical concerns that anemia taxes infants' physiological compensatory mechanisms and thereby threatens their health and well-being. The impact of various transfusion guidelines on long-term neurocognitive outcome is not known. The purpose of this study is to evaluate long-term neurocognitive outcome on children born prematurely and treated at birth with different transfusion guidelines.

Methods: Neurocognitive outcomes were examined at school age for 56 preterm infants randomly assigned to a liberal (n?=?33) or restrictive (n?=?23) transfusion strategy. Tests of intelligence, achievement, language, visual-spatial/motor, and memory skills were administered. Between-group differences were assessed.

Results: Those in the liberal transfusion group performed more poorly than those in the restrictive group on measures of associative verbal fluency, visual memory, and reading.

Conclusions: Findings highlight possible long-term neurodevelopmental consequences of maintaining higher hematocrit levels.     

The impact of periventricular brain injury on reading and spelling abilities in the late elementary and adolescent years.

The present study was designed: (1) to investigate the long-term consequences of both the presence and the severity of periventricular brain injury (PVBI) on intellectual, academic, and cognitive outcome in extremely-low-birthweight (ELBW: < 1,000 grams) children at a mean age of 11 years; and (2) to determine the nature of the underlying difficulties associated with academic problems in these children. The results indicated that ELBW children without PVBI performed as well as full-term children on intelligence, academic, and cognitive ability tests. In contrast, ELBW children with mild and severe PVBI achieved significantly lower scores than either ELBW children without PVBI or children who were born at term. A second analysis indicated that, after accounting for Full Scale IQ, working memory and phonological processing were significant predictors of reading and spelling performance in ELBW children. These findings suggest that the presence and severity of PVBI, and not ELBW status alone, is associated with performance on tests of intelligence, and academic and cognitive functioning, and that some of the same factors known to be associated with learning disabilities in full-term children contribute to learning disabilities in ELBW children.     

The Impact of Periventricular Brain Injury on Reading and Spelling Abilities in the Late Elementary and Adolescent Years

The present study was designed: (1) to investigate the long-term consequences of both the presence and the severity of periventricular brain injury (PVBI) on intellectual, academic, and cognitive outcome in extremely-low-birthweight (ELBW: < 1,000 grams) children at a mean age of 11 years; and (2) to determine the nature of the underlying difficulties associated with academic problems in these children. The results indicated that ELBW children without PVBI performed as well as full-term children on intelligence, academic, and cognitive ability tests. In contrast, ELBW children with mild and severe PVBI achieved significantly lower scores than either ELBW children without PVBI or children who were born at term. A second analysis indicated that, after accounting for Full Scale IQ, working memory and phonological processing were significant predictors of reading and spelling performance in ELBW children. These findings suggest that the presence and severity of PVBI, and not ELBW status alone, is associated with performance on tests of intelligence, and academic and cognitive functioning, and that some of the same factors known to be associated with learning disabilities in full-term children contribute to learning disabilities in ELBW children.     

The influence of geographic region on the seasonality of early motor development

This investigation was conducted to determine whether the strong seasonality effect on infant motor development that has been noted in moderate climates would be replicated with infants born in a geographic region with more extreme conditions. One hundred and forty-five full-term infants (72 males, 73 females) born in Edmonton, alberta were assessed using the Alberta Infant Motor Scale (AIMS) at 7 months of age. No seasonality effects on the AIMS total scores or the prone, supine, sitting, or standing subsection scores were detected. A weak and statistically non-significant correlation was obtained between the average monthly AIMS scores and the average monthly temperatures 7 months after birth. These results suggest that extreme climatic conditions in urban geographic regions may dampen effects of season of birth on infant motor development.     

School adjustment in adolescence for previously rejected,average and popular children

Background: Earlier research shows that peer‐rejected children are at risk of a wide range of subsequent adjustment difficulties in different social contexts, as, for example, in school. Aims: This study investigated the academic performance and school adjustment in adolescence of children with different peer status in middle childhood. Sample: Age 15 boys and girls (N=90), who at age 10 and 11 were sociometrically rejected, popular, or of average popularity in their school class. Methods: School marks, intelligence scales, and self‐reports were used as adjustment measures. School dropout rate for boys was also included. Results: The academic performance and intelligence level of rejected boys and girls were short of the standards of children from the other status groups, while the scores of popular boys and girls were of superior standard. There were some slight indications that rejected girls (but not rejected boys) had negative attitudes towards school and schoolwork, and that popular girls had positive school attitudes. The school dropout rate of rejected boys was much higher than that of other boys. Conclusions: The results show that the rejected children are a risk group for school problems also over a long period of time. Considering the important developmental aspects of the adolescence years, there appear to be good reasons, therefore, to worry about the future adulthood adjustment of peer‐rejected children.     

The Role of Paternal Age in the Prediction of Offspring Intelligence

Recent evidence suggests that paternal age at birth influences myriad developmental outcomes among children, but few studies have examined the possibility for father's age to influence children's intellectual development among a sample of high-risk families. The authors use data from the Fragile Families and Child Wellbeing Study to examine the association between paternal age at birth among 480 male and 449 female children's verbal IQ scores, as assessed with a version of the Peabody Picture Vocabulary Test at 9 years old. The nonlinear association between paternal age and children's verbal intelligence was also examined. Paternal age at birth appears to have a marginally significant nonlinear relationship with male children's verbal IQ scores, despite controlling for a number of possible confounders associated with both young and advanced paternal age.     

The race that precedes coactivation: development of multisensory facilitation in children

Rationale: The facilitating effect of multisensory integration on motor responses in adults is much larger than predicted by race‐models and is in accordance with the idea of coactivation. However, the development of multisensory facilitation of endogenously driven motor processes and its relationship to the development of complex cognitive skills in school‐age children is largely unexplored. Method: Twenty adults and 95 children where allocated into six age groups: 6, 7, 8, 9, 10–11 and adults. Participants’ motor reaction times (MRTs) and accuracy in response to the detection of auditory, visual and audiovisual stimuli were recorded. Children's reading accuracy and nonverbal IQ were also assessed. Results: In general, MRTs of children were significantly slower with greater variability than those of adults. Although the average level of multisensory facilitation was similar for all age groups, mean cumulative density functions (CDFs) showed that multisensory facilitation in 6 and 10–11‐year‐olds is within the predictive limits of race‐models. Where coactivation was seen in the CDF of individual children it was not as strong or as consistent as that in adults. The degree of multisensory facilitation did not correlate with age, reading accuracy or IQ. Conclusion: The average level of multisensory facilitation to endogenously driven motor responses does not change gradually with age nor is it related to intelligence or reading accuracy. In general, multisensory integration remains immature until 10–11 years of age and lies within the predicted confines of race‐models.     

Executive Functions in Preschool Children Born Preterm: Application of Cognitive Neuroscience Paradigms

Although children born preterm are at risk for neuropsychological impairments at school age and adolescence, including difficulties with visual motor integration, spatial/constructional skills, attention, arithmetic, and nonverbal executive functions, specific neuropsychological outcome has not been investigated adequately in preschoolers. Application of cognitive neuroscience tasks offers the opportunity to characterize early executive functions in young children born preterm. In a preliminary sample of 29 preschool children born preterm (M birth gestational age = 32.4 weeks), executive function outcome was compared to that of fullterm controls by contrasting performance on two prototypic delayed-response-type paradigms, Delayed Alternation and Spatial Reversal. Preschoolers born preterm correctly retrieved the reward on fewer trials on Delayed Alternation than did matched controls. Furthermore, preschool children born preterm used problem-solving strategies that included more perseverative errors than controls. These preliminary findings highlight the utility of cognitive neuroscience paradigms to understand neuropsychological outcome in preschool children born preterm and suggest areas of developmental vulnerability that may include dorsolateral prefrontal circuits.