Genetic and environmental influences on maternal and sibling interaction in middle childhood: A sibling adoption study.

Genetic and environmental influences on maternal and sibling interactions were examined in 67 mother–child–child triads from nonadoptive families and 57 mother–child–child triads from adoptive families (in which both children were adopted and genetically unrelated). Triads were videotaped in 6 play settings in their homes. In addition, each sibling pair was observed in an unstructured setting in the home, and mothers completed an interview about the sibling relationship. Genetic influence was found for individual differences in sibling interactions (competition and positive and negative behavior) and maternal interactions with siblings (maternal attention and control); shared environmental factors were also important. No evidence was found for mean differences between the adoptive and nonadoptive families that could be due to genetic influence; family constellation factors also were not important. Results are discussed with respect to genetic influences on family interactions and relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Family environment and adolescent depressive symptoms and antisocial behavior: A multivariate genetic analysis.

Measures of family environment often show substantial differences between children in the same family and are thus nonshared environment candidates. A key question is whether differential environments are related to differential outcomes when genetic differences between children in the same family are controlled. Parent and child reports and observations of family interactions were used to assess familial negativity and adolescents' depressive symptoms and antisocial behavior in a genetically informative sample of 719 same-sex sibling pairs ranging from 10 to 18 years old. Analyses revealed that parental and sibling negativity is significantly related to adolescent adjustment through nonshared environmental processes, although genetic factors account for most of the association between parental negativity and adolescent adjustment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential association of family subsystem negativity on siblings' maladjustment: using behavior genetic methods to test process theory.

This study investigated the family context of adolescent sibling similarity and differentiation in maladjustment (antisocial behavior and depression) by examining negativity in different subsystems. Two hypotheses were proposed: (1) Parental and sibling negativity tends to diffuse through the family system, especially because of the high level of reciprocity in sibling relationships, leading to sibling similarity; and (2) interparental (coparenting) conflict disrupts cohesive functioning and thereby motivates and facilitates sibling differentiation and niche picking. To control for the effects of similar genes between siblings, the authors used behavioral genetic models with a genetically informed sample of 720 two-parent families, each with at least 2 adolescent siblings. Results for the differences in shared environmental influences across groups high and low in each of the domains of family negativity provided partial support for the hypotheses. The results further understanding of influences on individual differences and support a theory of how parent-child and interparental relationships intersect with sibling relationship dynamics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stability and change in temperament during adolescence.

This study assessed genetic and environmental contributions to temperament during adolescence within the Nonshared Environment and Adolescent Development project (NEAD; D. Reiss, J. M. Neiderhiser, E. M. Hetherington, & R. Plomin, 2000). NEAD is a national study that includes twins and other sibling types who vary in regard to genetic relatedness. Seven hundred twenty sibling pairs (aged 12.1-13.5 years) participated at Time 1, and 395 sibling pairs (aged 14.7-16.2 years) participated again at Time 2. At both Times, mothers and fathers rated their children's temperament (emotionality, activity, sociability, and shyness). At Times 1 and 2, genetic and nonshared environmental factors accounted for variance in temperament, whereas shared environmental contributions were negligible. However, at Time 1, genetic contributions were inflated, and shared environmental contributions were masked if sibling contrast effects were not taken into account. At Time 2, sibling interaction effects had little impact on estimates of genetic and environmental contributions to temperament. Last, temperament stability was primarily explained by genetic factors, whereas both genetic and nonshared environmental factors accounted for change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Continuity and change in general cognitive ability from 1 to 7 years of age.

Explored observed and latent sources of individual differences in cognitive development in data from adopted and nonadopted siblings measured from ages 12 mo to 7 yrs and identical and nonidentical twins measured from ages 12–36 mo. Longitudinal path models, designed to examine the structure of observed stability and assess the genetic and environmental sources of age-to-age change and continuity, suggest that observed continuity arises from age-specific effects that persist over time and from developmental influences that are static and unchanging. Genetic influences account for the age-specific yet persistent effects, shared sibling environment effects are constant from 1–7 yrs of age, and nonshared environmental factors are specific to each measurement age. Thus, genetic influences are a major source of both continuity and change in mental development, whereas shared and nonshared environment effects contribute to continuity and change, respectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Child temperaments, maternal differential behavior, and sibling relationships.

The primary purpose of this study was to examine the influence of two nonshared family environmental components—maternal differential behavior and sibling temperaments—on the sibling relationship of school-age children. Forty mothers and their same-sex children (20 pairs of boys and 20 pairs of girls) participated. In order to examine the associations of temperament and maternal differential behavior with the quality of sibling interactions, mothers were observed in triadic interactions with their two children. On a separate occasion the sibling dyad was observed interacting in the same contexts. The mothers also provided temperament ratings of each of their children's levels of activity, emotional intensity, and persistence. The results indicated that high activity, high emotional intensity, and low persistence levels in both older and younger children were associated with increased agonism between sisters, whereas high activity and low persistence levels for younger brothers were associated with more agonistic behavior among brothers. An imbalance of maternal behavior that favored the younger child was generally associated with lower rates of verbalizations and prosocial and agonistic behavior directed by siblings to one another. The observations of the mother–sibling triadic and sibling dyadic interactions also revealed consistency in the within-family environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Co-occurrence of depressive symptoms and antisocial behavior in adolescence: A common genetic liability.

Recent reviews of research on child and adolescent psychopathology have highlighted the consistently high rates of co-occurring dimensions of psychopathology, particularly between internalizing and externalizing disorders, and have suggested that further research examining the causes of co-occurring syndromes is needed. The authors examined this question in a national sample of 720 same-sex adolescent siblings between 10 and 18 years of age consisting of monozygotic and dizygotic twins, full siblings, half siblings, and unrelated siblings. Composite measures of adolescent and parent reports and observational measures of depressive symptoms and antisocial behavior were subjected to behavioral genetic models that examine the genetic and environmental influences on individual differences in each dimension as well as in the co-occurrence between dimensions. Results indicated that approximately half of the variability in depressive symptoms and antisocial behavior is attributed to genetic factors; shared and nonshared environmental influences were also significant. The co-occurrence of depressive and antisocial symptoms was explained by genetic and shared and nonshared environmental influences. Specifically, approximately 45% of the observed covariation between depressive and antisocial symptoms could be explained by a common genetic liability. Results are interpreted in light of contribution of genetic studies to debates on child and adolescent psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parent–child mutuality in early childhood: Two behavioral genetic studies.

Parent–child dyadic mutuality (shared positive affect, responsiveness, and cooperation) is an important component of family socialization processes. This study sought to extend previous research on mutuality by using a quantitative genetic design to examine between- and within-family variations (e.g., sibling differences) and gene-environment processes. The first study included 125 pairs of identical and same-sex fraternal 3-year-old twins. Observations of mutuality and parents' and observers' ratings of family environment and child behavior were gathered. Greater mutuality was associated with higher socioeconomic status. Moderate sibling similarity in parent-child mutuality was accounted for by child genetic similarity, suggesting evocative gene- environment correlation and nonshared environmental processes. These findings were replicated in a 2nd study of 102 pairs of adoptive and biological siblings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of common rearing on adolescent adjustment: Evidence from a U.S. adoption cohort.

The influence of shared environmental factors on adolescent adjustment was investigated in a sample of 667 adoptive families. Correlations between parental ratings of family functioning and adolescent ratings of adjustment were generally higher for birth offspring than for adoptive offspring, suggesting passive genotype-environment processes. For all except one of the indicators of adolescent adjustment, the nonbiological sibling correlation was low, suggesting that approximately 10% or less of the variance in these measures is attributable to shared environmental effects. However, for a quantitative measure of alcohol and tobacco use, the nonbiologically related sibling correlation was moderate (r?=?26 ) but most consistent with sibling rather than parent effects. These findings provide further evidence of the minimal effect of common rearing on sibling psychological similarity, at least within the broadly constituted U.S. middle class. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A seven-year investigation of marital expectations and marriage among urban, low-income, African American adolescent mothers.

Welfare reform has targeted marriage promotion among low-income women. This study explores patterns of marital expectations and marriage among 181 urban, low-income, African American adolescent mothers and their mothers. Using PROC TRAJ to analyze developmental trajectories of adolescent mother–grandmother relationship quality over 24 months, we categorized relationships as either high or low support. We examined the effects of intergenerational marriage models and adolescent mother–grandmother relationship quality on marital expectations and marriage over the first 7 years postpartum. At 24 months, half (52%) of adolescent mothers expected to marry, but marital expectations did not predict marriage. Marital expectations were associated with concurrent involvement in a romantic relationship, not intergenerational marriage models or a supportive adolescent mother–grandmother relationship. After 7 years, 14% of adolescent mothers were married. Married mothers lived in families characterized by the joint effects of intergenerational marriage models and supportive adolescent mother–grandmother relationships. They were older and had more children than did single mothers, suggesting that they were in a family formation phase of life. Policies that promote the education and employment opportunities necessary to support a family are needed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of aggressive personality and family relationships in explaining family conflict.

This study investigated whether genetic and environmental influences on global family conflict are explained by parents' personality, marital quality, and negative parenting. The sample comprised 876 same-sex pairs of twins, their spouses, and one adolescent child per twin from the Twin and Offspring Study in Sweden. Genetic influences on aggressive personality were correlated with genetic influences on global family conflict. Nonshared environmental influences on marital quality and negative parenting were correlated with nonshared environmental influences on global family conflict. Results suggest that parents' personality and unique experiences within their family relationships are important for understanding genetic and environmental influences on global conflict in the home. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A genetic study of maternal and paternal ratings of problem behaviors in 3-year-old twins.

Genetic and environmental influences on problem behaviors were studied in 3-yr-old twins. Fathers' and mothers' ratings of problem behaviors in twins (236 monozygotic [MZ] girls, 210 MZ boys, 238 dizygotic [DZ] girls, 265 DZ boys, and 409 DZ opposite sex pairs) were obtained with the Child Behavior Checklist for Ages 2–3 (T. M. Achenbach, 1992). Twin correlations and results from a model fitting approach showed that genetic, shared environmental, and nonshared environmental influences accounted on average for about 64%, 9%, and 27% of the variance. Although shared environmental influences were small for most scales, they were important for Total Problems and somewhat larger for Externalizing than for Internalizing behaviors. Significant sex differences in genetic and environmental influences and evidence for sibling contrast effects were found for the Overactive scale. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A study of genetic and environmental effects on the co-occurrence of problem behaviors in three-year-old-twins.

The authors examined the genetic and environmental causes of the co-occurrence of problem behaviors in children. The analyses involved mother and father ratings of Oppositional, Withdrawn/Depressed, Aggressive, Anxious, Overactive, and Sleep Problems in 446 monozygotic and 912 dizygotic pairs of 3-year-old twins. Genetic factors contributed on average .150 (37.3%), shared environment .206 (51.2%), and nonshared environment .046 (11.4%) to the phenotypic correlations between the syndromes. Genetic and environmental factors caused different groupings. Internalizing and Externalizing groupings were indicative of nonshared environmental factors; clusters of problem behaviors with either the Aggressive or Anxious symptoms were most suggestive of genetic factors, and high scores on all syndromes indicated shared environmental influences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adolescent mothers' relationships with their own mothers: Impact on parenting outcomes.

This study examined the relationship between mother–grandmother relationship quality and adolescent mothers' parenting behaviors using longitudinal multimethod, multi-informant data. Participants were 181 urban, African American adolescent mothers. Self-report data on mother–grandmother relationship conflict and depressive symptoms were collected after delivery and at 6-, 13-, and 24-month follow-up visits. Videotaped observations were used to measure mother–grandmother relationship quality at baseline. Mother–child interactions were videotaped at 6, 13, and 24 months to operationalize parenting. Mixed-model regression methods were used to investigate the relation between mother–grandmother relationships and mother–child interactions. Mother–grandmother relationship quality predicted both negative control and nurturing parenting. Mothers whose own mothers were more direct (both demanding and clear) and who reported low relationship conflict demonstrated low negative control in their parenting. Mothers who demonstrated high levels of individuation (a balance of autonomy and mutuality) and reported low relationship conflict showed high nurturing parenting. The implications of these findings for adolescent health and emotional development are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Family functioning and adolescent alcohol use disorders.

Adolescents with alcohol dependence or abuse (n?=?126) were compared with 124 adolescents with other (nondrug) mental disorders and with a control group of 94 adolescents with no mental disorders on dimensions of family functioning. General family functioning, mother–adolescent relationships, and parental monitoring and discipline practices were assessed by using both adolescent and mother reports. Although overall the groups differed significantly on all family variables, the relationships among groups differed for adolescent and mother reports. By mother reports, families of adolescents with alcohol use disorders functioned less well than did families of adolescents with other mental disorders, whereas by adolescent reports these groups were not significantly different. Examination of both adolescent and mother perspectives may be important in understanding the relationship between family functioning and adolescent alcohol use disorders. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The developmental origins of a disposition toward empathy: Genetic and environmental contributions.

The authors investigated the development of a disposition toward empathy and its genetic and environmental origins. Young twins' (N = 409 pairs) cognitive (hypothesis testing) and affective (empathic concern) empathy and prosocial behavior in response to simulated pain by mothers and examiners were observed at multiple time points. Children's mean level of empathy and prosociality increased from 14 to 36 months. Positive concurrent and longitudinal correlations indicated that empathy was a relatively stable disposition, generalizing across ages, across its affective and cognitive components, and across mother and examiner. Multivariate genetic analyses showed that genetic effects increased, and that shared environmental effects decreased, with age. Genetic effects contributed to both change and continuity in children's empathy, whereas shared environmental effects contributed to stability and nonshared environmental effects contributed to change. Empathy was associated with prosocial behavior, and this relationship was mainly due to environmental effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prosocial behavior from early to middle childhood: Genetic and environmental influences on stability and change.

Prosocial behavior is important for the functioning of society. This study investigates the extent to which environment shared by family members, nonshared environment, and genetics account for children's prosocial behavior. The prosocial behavior of twins (9,424 pairs) was rated by their parents at the ages of 2, 3, 4, and 7 and by their teachers at age 7. For parent ratings, shared environmental effects decreased from .47 on average at age 2 to .03 at age 7, and genetic effects increased from .32 on average to .61. The finding of weak shared environmental effects and large heritability at age 7 was largely confirmed through the use of teacher ratings. Using longitudinal genetic analyses, the authors conclude that genetic effects account for both change and continuity in prosocial behavior and nonshared environment contributes mainly to change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic and Environmental Contributions to General Cognitive Ability Through the First 16 Years of Life.

The genetic and environmental contributions to the development of general cognitive ability throughout the first 16 years of life were examined using sibling data from the Colorado Adoption Project. Correlations were analyzed along with structural equation models to characterize the genetic and environmental influences on longitudinal stability and instability. Intraclass correlations reflected both considerable genetic influence at each age and modest shared environmental influence within and across ages. Modeling results suggested that genetic factors mediated phenotypic stability throughout this entire period, whereas most age-to-age instability appeared to be due to nonshared environmental influences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic and environmental influences on antisocial behavior: A meta-analysis of twin and adoption studies.

A meta-analysis of 51 twin and adoption studies was conducted to estimate the magnitude of genetic and environmental influences on antisocial behavior. The best fitting model included moderate proportions of variance due to additive genetic influences (.32), nonadditive genetic influences (.09), shared environmental influences (.16), and nonshared environmental influences (.43). The magnitude of familial influences (i.e., both genetic and shared environmental influences) was lower in parent-offspring adoption studies than in both twin studies and sibling adoption studies. Operationalization, assessment method, zygosity determination method, and age were significant moderators of the magnitude of genetic and environmental influences on antisocial behavior, but there were no significant differences in the magnitude of genetic and environmental influences for males and females. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An observational investigation of sibling interactions in married and divorced families.

Examined differences in sibling relations in divorced and married families and the extent to which sibling relationship quality is associated with the quality of spousal/ex-spousal, mother–child, and father–child relations. Observed 96 sibling dyads, 48 from mother-custody divorced families and 48 from biological two-parent families while playing a popular board game. Mothers completed a battery of questionnaires assessing the quality of other dyadic relationships within the family and family functioning. Results revealed that dyads from divorced families containing an older male were more negative, more resistant, and less compliant than older female dyads from divorced families or older male dyads from married families, with the older children more negative than their younger siblings, especially when interacting with their younger sisters. Quality of sibling interactions was found to be related to the quality of other dyadic relations within the family and overall family functioning. Quality of spousal/ex-spousal relationships contributed more than marital status of the parents in predicting whether siblings were negative. (PsycINFO Database Record (c) 2010 APA, all rights reserved)