Maternal IQ and home environment as determinants of early childhood intellectual competence: A developmental analysis.

Children at risk for sociocultural mental retardation were studied longitudinally from birth to 4 yrs of age. Maternal IQs were assessed before the children's births, and children's IQs and home environments were assessed at regular intervals during the 1st 4 yrs of life. Multiple regression analyses were conducted to separate the contributions of maternal IQ and home environment to child IQ at 24, 36, and 48 mo. When the effect of maternal IQ was controlled, home environment's association with child IQ was significant only at 48 mo. When the effect of home environment was controlled, maternal IQ's association with child IQ was significant only at 24 mo. Taken together, the 2 predictors explained 11, 17, and 29% of the variance in child IQ at the 3 respective times. The overall pattern suggested a monotonic increase in the predictability of child IQ within the context of a shift in the relative importance of maternal IQ and home environment as predictors. The integration of the study of behavioral genetics with the study of the process of intellectual development requires an ontogenetic perspective. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Race, IQ, and the middle class.

Studied whether socioeconomic status indicators sufficiently represent those aspects of the home environment relevant to IQ. Intellectual home environment ratings of the families of 50 Black and 50 White middle-class 9th-grade girls were compared to the girls' Otis-Lennon Mental Ability Test scores, Metropolitan Achievement Test scores, and GPAs. Despite similar standings on Warner's Index of Status Characteristics, there was a difference in the intellectual home environments of Blacks and Whites. There was also a relationship between the intellectual home environment and the S's IQ. Furthermore, the family's environment predicted academic achievement as well as did IQ. To determine the relationship of the environment to intellectual performance, researchers must measure the underlying process variables known to be related to IQ. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The heritability of IQ

IQ heritability, the portion of a population's IQ variability attributable to the effects of genes, has been investigated for nearly a century, yet it remains controversial. Covariance between relatives may be due not only to genes, but also to shared environments, and most previous models have assumed different degrees of similarity induced by environments specific to twins, to non-twin siblings (henceforth siblings), and to parents and offspring. We now evaluate an alternative model that replaces these three environments by two maternal womb environments, one for twins and another for siblings, along with a common home environment. Meta-analysis of 212 previous studies shows that our 'maternal-effects' model fits the data better than the 'family-environments' model. Maternal effects, often assumed to be negligible, account for 20% of covariance between twins and 5% between siblings, and the effects of genes are correspondingly reduced, with two measures of heritability being less than 50%. The shared maternal environment may explain the striking correlation between the IQs of twins, especially those of adult twins that were reared apart. IQ heritability increases during early childhood, but whether it stabilizes thereafter remains unclear. A recent study of octogenarians, for instance, suggests that IQ heritability either remains constant through adolescence and adulthood, or continues to increase with age. Although the latter hypothesis has recently been endorsed, it gathers only modest statistical support in our analysis when compared to the maternal-effects hypothesis. Our analysis suggests that it will be important to understand the basis for these maternal effects if ways in which IQ might be increased are to be identified.     

Mothers' and fathers' perceptions of child deviance: Roles of child behavior, parental depression, and marital satisfaction.

Investigated relationships among parental adjustment, parental perception of child behavior, and an independent measure of child behavior, using 61 consecutive referrals to a university psychology clinic of 5–14 yr olds with home or school problems. 61 mothers (41 of whom were married) and 41 fathers completed the Beck Depression Inventory, the Marital Adjustment Test, and the Conners Parent Rating Scale. Children's teachers completed the Conners Teacher Rating Scale. Mothers' ratings of their children's behavior were significantly correlated with teachers' ratings, but fathers' ratings were not. A stepwise multiple regression analysis showed that teachers' ratings accounted for the greatest amount of variance in the prediction of mothers' ratings of child externalizing problems, followed by maternal depression. Results confirm earlier findings of a relation of maternal depression to maternal perception of child externalizing behavior problems but indicate a stronger correlation between maternal ratings and independent measures of child behavior. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The adopted child's IQ: A critical review.

Summarizes all reliable published data about the nature and nurture of adopted children's IQs, and draws conclusions about the relative importance of heredity and environment on children's mental development. Any study that compares the central tendency of adopted children's IQs with a group mean of 100 IQ points for a normal population cannot be taken seriously until several methodological criteria have been met: (a) representative sampling, (b) no differential loss of Ss over time, (c) accurate, age-corrected information on biological and adoptive parents, (d) careful attention to early separation and placement of children, and (e) elimination of practice effects and regression to the mean artifacts. Analysis of the resemblance between individual adopted children's IQ scores and their adoptive and biological parents' mental abilities shows that the adoptive parents' home environment has only a modest effect on their adopted children's intellectual growth, while heredity and environment of the biological parents have a strong effect on their own children's intellectual growth. At present there is disagreement about the precise values of genetic and environmental effects on IQ, and several assumptions must be made before accurate statistics can be derived. But, the available data strongly suggest that under existing circumstances, heredity is much more important than environment in producing individual differences in IQ. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

IQ at age 4 in relation to maternal alcohol use and smoking during pregnancy.

Examined the relationship of prenatal alcohol exposure to the IQ of children at age 4 in a longitudinal prospective, population-based study. Multiple-regression analyses on data from 421 children indicated that use of more than 1.5 oz (44 ml, or approximately 3 drinks) of alcohol per day during pregnancy was significantly related to an average IQ decrement of almost 5 IQ points (? of a standard deviation; p?=?.008), even after adjustment for maternal and paternal education, race, prenatal nutrition, aspirin and antibiotics, child's sex and birth order, mother–child interaction, and preschool attendance. We caution against using these data to describe "safe" drinking levels, because other outcomes, more sensitive than IQ tests, show significant alcohol effects at lower drinking levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Race, IQ, and rampant misrepresentations: A reply.

In L. E. Longstreth's (see record 1979-23197-001) critique of F. K. Trotman's study (see record 1978-06591-001), he attributes conclusions and interpretations to Trotman that indicate either a misunderstanding or misinterpretation on Longstreth's part or a failure in effective communication on Trotman's part. In any case, Trotman's response represents an attempt to clarify Longstreth's apparently cloudy view of the earlier Trotman work. J. L. Wolff (see record 1979-23222-001) suggested that experimenter bias operated to produce anomalies in Trotman's findings that despite similarity in socioeconomic standing, there was a difference in the intellectual home environments of Blacks and Whites, that IQ was related to home environment, and that home environment did as well as academic achievement in predicting IQ. On examination of Wolff's statements and reference citations, however, Trotman finds evidence of bias and irregularities in his critique. For example, Wolff misconstrues data, selectively either omits or includes reference citations, or statements out of context, and misrepresents previous investigations, suggesting a possibility of commentator bias. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Children's cognitive ability from 4 to 9 years old as a function of prenatal cocaine exposure, environmental risk, and maternal verbal intelligence.

This study examined the effects of prenatal cocaine exposure, environmental risk, and maternal verbal intelligence on children's cognitive ability. Gender and age were examined as moderators of potential cocaine exposure effects. The Stanford-Binet IV intelligence test was administered to 231 children (91 cocaine exposed, 140 unexposed) at ages 4, 6, and 9 years. Neonatal medical risk and other prenatal exposures (alcohol, cigarettes, and marijuana) were also examined for their unique effects on child IQ. Mixed models analysis indicated that prenatal cocaine exposure interacted with gender, as cocaine-exposed boys had lower composite IQ scores. Age at assessment did not moderate this relation, indicating that cocaine-exposed boys had lower IQs across this age period. A stimulating home environment and high maternal verbal IQ also predicted higher composite IQ scores. Cocaine-exposed boys had lower scores on the Abstract/Visual Reasoning subscale, with trends for lower scores on the Short-Term Memory and Verbal Reasoning subscales, as exposure effects were observed across domains. The findings indicate that cocaine exposure continues to place children at risk for mild cognitive deficits into preadolescence. Possible mechanisms for the Exposure × Gender interaction are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social class, experimental setting, and task characteristics as determinants of mother–child interaction.

Used an observational method to investigate the effects of social class (SC; middle vs lower), experimental setting (home vs laboratory), and interaction task (free-play vs command) on mother–child interactions. Ss were 32 pairs of mothers and 4-yr-old sons from intact families. In support of recent research that has emphasized the control of certain sampling and procedural factors, results do not demonstrate substantial SC effects. Those SC effects that did emerge (maternal questions and direct commands) were more strongly predicted by a covariate of SC (mother–child verbal IQ) than by SC. Setting did not influence mother–child behaviors nor did it interact with SC to influence such behaviors. As expected, several significant task effects emerged. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Correlates and consequences of harsh discipline for young children

OBJECTIVE: To examine the incidence, predictors, and consequences of harsh discipline in a sample of low-birth-weight children at 1 and 3 years of age. DESIGN: Analysis of data from the Infant Health and Development Program, an 8-site randomized clinical trial of low-birth-weight infants. The sample for analysis consisted of 715 children who were 3 years of age. The independent measurements of primary interest were the mother's hitting and scolding of her child as disciplinary practice. Analyses were run separately for boys and girls. Bivariate and logistic analyses were used to examine the predictors of the mother's hitting and scolding behavior. Multivariate analysis of variance was used to examine the consequences of the mother's harsh discipline on a child's IQ measured at age 3 years. MAIN OUTCOME MEASURES: The mother's self-report of whether she used more than 1 physical punishment in the past week, as well as an observer's report from 2 home visits of whether the mother hit or scolded the child during the 2-hour home visit. In addition, the Stanford-Binet Intelligence Scale was used to examine the consequences of persistent harsh discipline on child well-being. RESULTS: Findings demonstrate child, maternal, and environmental factors that might aggravate a parent's use of corporal punishment. Boys received higher amounts of harsh discipline on all outcome measures. For boys, growing up in an impoverished home was predictive of the greater likelihood of receiving harsh punishment. Using IQ at age 3 years as the outcome measure, girls were found to be vulnerable to persistent harsh discipline and lack of maternal warmth. Maternal harsh discipline in a context of low maternal warmth was associated with IQ scores for girls that are 12 points lower than the IQ scores of girls who received low punishment and high warmth.     

Socioeconomic status, IQ, and delinquency.

A number of studies have found a negative relationship between IQ and delinquent involvement. Some researchers maintain that IQ is a spurious variable in the relationship between socioeconomic status (SES) and delinquency, whereas others assert that IQ bears a causal relationship to delinquency that is independent of the effects of SES. Results from 2 Danish prospective longitudinal studies are presented that support the latter view. Ss in the 1st study were 129 males born between September, 1959 and December, 1961; all male offspring born between 1944 and 1947 served as Ss in Study 2 (N?=?31,436). In each study, a significant negative correlation between IQ and level of delinquent involvement remained after SES effects were partialled out. It is posited that low IQ children may be likely to engage in delinquent behavior because their poor verbal abilities limit their opportunities to obtain rewards in the school environment. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mother–child problem solving: Continuity through the early childhood years.

Maternal ratings of child temperament and observed maternal behaviors in the home were collected when children were 18 months old. Both variables were examined as predictors of mothers' problem solving behaviors with their toddlers at 30 months and the children's independent problem solving at 5 years. Maternal instructional behavior in the home at 18 months and maternal ratings of temperament at 18 months predicted maternal behaviors when the children were 30 months old and child performance in a cognitive problem-solving task. maternal cognitive assistance during the 18- and 30-month tasks also predicted child cognitive task performance in the laboratory at 5 years of age. These same maternal behaviors were related to the child's performance on the Preschool and Primary Scale of Intelligence (D. Wechsler, 1967) at age 5, and lack of maternal assistance was related to teacher ratings of learning problems at age 5. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Child care and mother–child interaction in the first three years of life.

Relations between nonmaternal child care and ratings of maternal sensitivity and child positive engagement during mother–child interaction at 6, 15, 24, and 36 months were examined for 1,274 mothers and their children participating in the National Institute of Child Health and Human Development(NICHD) Study of Early Child Care. In longitudinal analyses that controlled for selection, child, and family predictors, child care was a small but significant predictor of maternal sensitivity and child engagement. For the whole sample, including families who did and did not use child care, more hours of child care predicted less maternal sensitivity and less positive child engagement. For children who were observed in child care, higher quality child care predicted greater maternal sensitivity, and more child-care hours predicted less child engagement. The effects of child care on mother–child interaction were much smaller in the analytical models than the effects of maternal education but were similar in size to the effects of maternal depression and child difficult temperament. Patterns of association with child care did not differ significantly across ages of assessment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parents' acceptance of control needs and preschoolers' social behaviour: A longitudinal study.

Examined concurrent and longitudinal associations between parents' acceptance of their preschoolers' control needs and the preschoolers' social behavior (SB) vis-à-vis their parents. 30 videotapes of mother–child and father–child interaction in the child's home at age 2 yrs were scored, using the Rothbaum and Schneider-Rosen Parental Acceptance Measure (F. Rothbaum; see record 1988-26069-001). Child SB was assessed at ages 2 and 5 yrs using global ratings of Social Adaptation (SA; F. K. Grossman et al, 1980). There were no significant correlations between Parental Acceptance scores and concurrent SA. There was a significant correlation between maternal acceptance (MA) of control needs assessed when children were age 2 yrs and SA at age 5 yrs. The correlation of MA and children's SA was of greater longitudinal than concurrent significance. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stress, maternal distress, and children's adjustment following immigration: The buffering role of social support.

This study examined, in the context of a stress-buffering model, the relationship of certain family level variables to children's adjustment after immigration. Immigrant Chinese mothers from Hong Kong completed questionnaires regarding postmigration stress, personal distress, perceived social support, and their child's adjustment. Another adult also provided child behavior ratings. Analyses revealed that, for boys, family stress and maternal distress were significant predictors of child problems and that maternal support buffered the association between family stress and child problems. Contrary to expectation, the relationship between maternal distress and boys' problems was stronger at higher levels of maternal support. For families of girls, although there were significant relationships between the predictors and child behavior, no stress buffering was evident. Cultural explanations are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An examination of predictors of maternal perceptions of maladjustment in clinic-referred children.

Investigated whether parental depression or child behavior was the best predictor of maternal perceptions of maladjustment in clinic-referred children. 22 mothers and their children served as Ss. The sample children (mean age 64 mo) were referred for treatment of noncompliant behavior problems; none of the Ss were severely retarded, brain-damaged, or autistic. Maternal perceptions of child maladjustment were measured by 3 scales of the Parent Attitude Test. Maternal depression was determined by the Beck Depression Inventory, while child compliance and child deviant behavior (other than noncompliance) were obtained in home observations collected by independent observers. Results indicate that maternal depression was the best predictor of maternal perception of children. Child behavior did not contribute significantly to the multiple regression analyses. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The IQ paradox is still resolved: Reply to Loehlin (2002) and Rowe and Rodgers (2002).

In their original article (W. T. Dickens & J. R. Flynn, 2001), the authors formalized the consensus model of reciprocal effects between IQ and environment and showed that it can resolve the apparent paradox between high heritability and large environmental effects. Commentators suggested that the model has undesirable properties that call its usefulness into question. J. L. Loehlin (2002) argued that incorporating persistence of IQ into the model causes problematic behavior. D. C. Rowe and J. L. Rodgers (2002) argued that an increasing correlation of IQ and environment should have caused growing variance of IQ. Empirical evidence suggests that IQ is not sufficiently persistent to cause the problems Loehlin found and that the correlation of IQ and environment has not grown much over time so that the reciprocal effects model need not imply increasing variance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does contiguity breed similarity? A within-family analysis of nonshared sources of IQ differences between siblings.

Hypothesized that highly contiguous siblings experience a family environment that is more alike than that experienced by siblings who are separated within the family structure (i.e., siblings with consecutive birth orders should be more alike in IQ than siblings separated by 1 or more birth orders). A dataset from the Fels Research Institute that included 538 children in 173 families (72 2-child families, 44 3-child families, 39 4-child families, and 18 families with 5 or more children). Analytic models based on a simplex birth order correlation structure and on a multiple regression model of IQ differences were developed to test the family structure relationships. Results indicate no family structure effects. It is suggested that genetic sources and 1-time events appear to be more plausible causes of the differences between siblings. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)