How intelligence and education contribute to substance use: Hints from the Minnesota Twin family study

In old and even middle age, there are associations between physical health and both intelligence and education. This may occur because intelligence and/or education exert effects on lifestyle choices that, in turn, affect later health. Substance use is one aspect of lifestyle choice in young adulthood that could play such a role. The effects of intelligence and/or education on substance use could be direct and environmental, or indirect due to the presence of confounding genetic and shared family influences. We used the Minnesota Twin Family Study to distinguish these effects in males and females at age 24. In contrast to prevailing expectations, there were moderately negative direct nonshared environmental effects of both IQ and education on both smoking and drinking in both males and females. That is, controlling for family background effects in the form of both genetic and shared environmental influences, both higher IQ and greater education were associated with greater alcohol and nicotine use. These effects were accounted for by alcohol and nicotine use at age 17. Our results suggest that genetic and family-culture variables confound the associations between intelligence and education and substance use in young adults, rendering them indirect. Further research is needed to understand the roles of IQ and education in alcohol and nicotine use and their relative impacts on physical health throughout the lifespan.     

Genetic and environmental transactions underlying educational attainment

This report used a population-representative longitudinal twin study with two birth cohorts to explore the association between intelligence and education by understanding how genetic and environmental influences on intelligence moderate genetic and environmental influences on school grades and educational attainment. Nonshared environmental influences on grades were strong when IQ was low, but decreased across the range of IQ. Shared environmental influences common to age 24 educational attainment and age 17 IQ were strong when IQ was low, but genetic influences common to IQ and education were strong when IQ was high. These results suggest that the causal mechanisms linking educational variables with intelligence differ for people with different levels of intelligence.     

Cognitive competencies and aggressive behavior: A developmental study

A number of studies have demonstrated that increased socially related cognitive skills are associated with decreases in aggressive behavior. However, the link between aggression and intelligence or academic skills is less evident. While some research indicates that poor academic performance is related to aggression, it is unclear which components of intellectual ability and performance are critical to the management of aggressive behaviors. In two independent longitudinal studies of elementary school-age children, the relationship among several aspects of cognitive competence and several aspects of aggressive behavior were examined. The results of the first study showed that aggressive behavior observed in kindergarten children was more closely related to academic performance in the first and second grades than to general cognitive ability (IQ). The results of the second study, a comprehensive three-year investigation of upper elementary school-age children, indicated that teachers' assessments of aggression and parents' ratings of cruelty were consistent over time for boys, but not for girls. The intercorrelations among aggression measures within each of the three years also revealed stable sex differences. Boys identified as aggressive in the classroom were more likely to be perceived as aggressive, cruel, and/or delinquent at home, but for girls, there was little correlation between aggression at school and in the home. The analyses relating measures of cognitive functioning to indices of aggressive behavior made clear the importance of discriminating among various facets of these psychological constructs. IQ had a negligible relationship with aggression and a weak inverse relationship to delinquency. An overall index of cognitive functioning was a somewhat more consistent negative correlate of aggression, cruelty, and delinquency, especially for boys. A similar pattern was found for the correlates of academic performance. Academic disability was strongly related to delinquency in boys, and to a lesser degree to aggression in boys. Of the several cognitively related factors that were explored, Low Need Achievement manifested the strongest and most consistent relationships with the different facets of aggression and antisocial behavior, especially in boys. The implications of these results for psychological interventions in the school are discussed.     

A Prospective Longitudinal Study of High School Dropouts Examining Multiple Predictors Across Development

Prior studies report a variety of demographic, school, individual, and family characteristics that are related to high school drop out. This study utilizes data from a 19-year prospective longitudinal study of “at-risk” children to explore multiple predictors of high school dropouts across development. The proposed model of dropping out emphasizes the importance of the early home environment and the quality of early caregiving influencing subsequent development. The results of this study demonstrate the association of the early home environment, the quality of early caregiving, socioeconomic status, IQ, behavior problems, academic achievement, peer relations, and parent involvement with dropping out of high school at age 19. These results are consistent with the view of dropping out as a dynamic developmental process that begins before children enter elementary school. Psychosocial variables prior to school entry predicted dropping out with power equal to later IQ and school achievement test scores. In our efforts to better understand processes influencing dropping out prior to high school graduation, early developmental features warrant further emphasis.     

Sensory processing, reading, IQ, and attention

Detection thresholds for two visual- and two auditory-processing tasks were obtained for 73 children and young adults who varied broadly in reading ability. A reading-disabled subgroup had significantly higher thresholds than a normal-reading subgroup for the auditory tasks only. When analyzed across the whole group, the auditory tasks and one of the visual tasks, coherent motion detection, were significantly related to word reading. These effects were largely independent of ADHD ratings; however, none of these measures accounted for significant variance in word reading after controlling for full-scale IQ. In contrast, phoneme awareness, rapid naming, and nonword repetition each explained substantial, significant word reading variance after controlling for IQ, suggesting more specific roles for these oral language skills in the development of word reading.     

Developmental changes in inspection time: what a difference a year makes

This paper provides a partial replication and extension of a classic longitudinal study by Nettelbeck and Wilson [J. Exp. Child Psychol. 40 (1985) 1] that compared the relative influence of maturation and task experience on developmental changes in inspection time (IT). In the study reported in this paper 226 children aged between 6 and 9 were tested on an IT task in Year 1 and immediately retested to assess the importance of task familiarity. They were also retested 1 year and 2 years later. Counter to Nettelbeck and Wilson's conclusion, analyses of these data comparing the relative difference made by age maturation and by task experience revealed that task experience has a much bigger effect on children's IT than maturation. The implications of this for wider theoretical interpretations of the relationship between IT and development are discussed.     

The Flynn effect,group differences,and g loadings

Flynn effect gains are predominantly driven by environmental factors. Might these factors also be responsible for group differences in intelligence? Group differences in intelligence have been clearly shown to strongly correlate with g loadings. The empirical studies on whether the pattern of Flynn effect gains is the same as the pattern of group differences yield conflicting findings. We present new evidence on the topic using a number of datasets from the US and the Netherlands. Score gains and g loadings showed a small negative average correlation. The general picture is now that there is a small, negative correlation between g loadings and Flynn effect gains. It appears that the Flynn effect and group differences have different causes.     

Attachment Disruptions,IQ, and PTSD in African American Adolescents: A Traumatology Perspective

Attachment disruptions, other traumas, posttraumatic stress disorder (PTSD), and intelligence quotient (IQ) were measured in a sample of 181 African American adolescents. Path analysis was utilized to test the effects of different types of attachment disruptions on IQ and PTSD. Findings supported that mother and father abandonments and being in foster care are associated with decreased perceptual reasoning, processing speed, and working memory, and increased discrepancy between perceptual and verbal toward decreased perceptual reasoning. Such suppression and discrepancy contribute to poor academic achievement. Results validated the traumatology perspective on attachment disruptions as traumas that are associated with PTSD, suppression of most IQ potentials, and with potential brain hemispheric desynchronization. The ramifications of these results for helping African American adolescents are discussed.     

Cognitive and emotional empathy in typically developing children: The influence of age,gender, and intelligence

In the current study, the influence of age, gender and IQ on cognitive and emotional empathy in school-aged children and adolescents was examined adopting two behavioural paradigms: participants were shown film clips with different scenes of social interaction to which they were asked to respond. Thus, 134 children aged seven to 17 years (mean age = 138.4 months, sd = 31.66 months) were tested for emotion recognition, perspective taking and emotional empathy. Age strongly influenced components of cognitive empathy and explained 33.5% to 39.1% of the variance. Gender and IQ also were significant predictors, yet only explained 3% to 5%, respectively 8% to 9% of the variance. In contrast, neither age, gender nor IQ were related to emotional empathy. Results suggest developmental maturation of cognitive, but not emotional empathy throughout childhood and adolescence. To explain variability in emotional empathy, additional biological and psychosocial factors need to be studied.     

NEUROBEHAVIORAL SEQUELAE OF CHILD SEXUAL ABUSE

This study examined intellectual and memory functioning in a sample of sexually abused children compared to demographically and age-matched controls. The severity of abuse and other pertinent factors were also examined in relation to cognitive performance. Elevated levels of psychopathology were present in the abused children, as well as diminished performance on tasks influenced by attention/concentration. However, after controlling for differences in IQ and socioeconomic status (SES), significant differences in memory function were not found. Results are discussed in the context of stress effects on cognition and the potential resiliency of cognitive function in children undergoing treatment for sexual abuse.