In search of shared and nonshared environmental factors in security of attachment: A behavior-genetic study of the association between sensitivity and attachment security.

The current article presents results from a twin study of genetic and environmental components of maternal sensitivity and infant attachment and their association. The sample consisted of 136 twin pairs from 2 sites: Leiden, the Netherlands, and London, UK. Maternal sensitivity was assessed in the home at 9-10 months, and infant attachment security was observed in the laboratory at 12 months. The study yielded little evidence that genetic factors are involved in variations between twins in maternal sensitivity ratings but did find that shared variance in maternal sensitivity was able to account for some of the similarity between twins in attachment security. Weak nonshared associations between sensitivity and attachment appeared to suppress the magnitude of the correlation between attachment and sensitivity in twin children. The results could indicate that the attachment security of one twin may depend on the relationship the parent has with the other twin. The results are brought to bear on the validity of attachment theory as a theory of primarily shared environmental effects in children's development and the continuing challenge posed to attachment theory by within-family differences in socioemotional processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selection response in finite populations

Formulae were derived to predict genetic response under various selection schemes assuming an infinitesimal model. Account was taken of genetic drift, gametic (linkage) disequilibrium (Bulmer effect), inbreeding depression, common environmental variance, and both initial segregating variance within families (sigma AW02) and mutational (sigma M2) variance. The cumulative response to selection until generation t(CRt) can be approximated as [equation: see text] where Ne is the effective population size, sigma AW infinity 2 = Ne sigma M2 is the genetic variance within families at the steady state (or one-half the genic variance, which is unaffected by selection), and D is the inbreeding depression per unit of inbreeding. R0 is the selection response at generation 0 assuming preselection so that the linkage disequilibrium effect has stabilized. beta is the derivative of the logarithm of the asymptotic response with respect to the logarithm of the within-family genetic variance, i.e., their relative rate of change. R0 is the major determinant of the short term selection response, but sigma Me2 Ne and beta are also important for the long term. A selection method of high accuracy using family information gives a small Ne and will lead to a larger response in the short term and a smaller response in the long term, utilizing mutation less efficiently.     

Differential parenting as a within-family variable.

Nonshared environmental influences have been found to be important for adolescent development. This study of 516 families investigated whether differential parental negativity or warmth is linked to adolescent adjustment apart from the effect of the level of parenting toward each child separately. After accounting for level of parental treatment to the adolescent, the authors found that differential parenting to the siblings contributed unique variance in adjustment. Significant interactions were found between level of parenting and differential parenting. In each case, differential parenting was more strongly linked to adjustment when the level of parenting was low in warmth or high in negativity. These results are indirect evidence that differential parenting can be considered a within-family influence on sibling adjustment and as direct evidence that nonshared environmental factors may systematically vary in strength between families. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Maternal and paternal gentle guidance and young children's compliance from a within-family perspective.

Young children's early internalization was examined from a within-family perspective. Mothers, fathers, 16-month-old toddlers, and their older siblings from 59 families participated in a family cleanup paradigm to assess young children's compliance and parental guidance. Sibling age differences in compliant and noncompliant behavior were found, with older siblings using more committed compliance and refusal than toddler siblings. Mothers used more gentle guidance with children than did fathers, and both parents used more gentle guidance with older siblings than with toddler siblings. Examining within-family processes indicated that maternal and paternal gentle guidance interacted to predict older and toddler siblings' committed compliance and explained unique variance in the older and toddler siblings' compliance. Some support was found for differential maternal guidance as a within-family process responsible for the development of young children's early self-regulation that may also vary between families. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic models for the analysis of data from the families of identical twins

Genetic models are described which exploit the unique relationships that exist within the families of identical twins to obtain weighted least squares estimates of additive, dominance and epistatic components of genetic variance as well as estimates of the contributions of X-linked genes, maternal effects and three sources of environmental variation. Since all of the relationships required to achieve a resolution of these variance components are contained within each family unit, the model would appear to be superior to previous approaches to the analysis of quantitative traits in man.     

Modeling Error Variance in Job Specification Ratings: The Influence of Rater, Job, and Organization-Level Factors.

The authors modeled sources of error variance in job specification ratings collected from 3 levels of raters across 5 organizations (N=381). Variance components models were used to estimate the variance in ratings attributable to true score (variance between knowledge, skills, abilities, and other characteristics [KSAOs]) and error (KSAO-by-rater and residual variance). Subsequent models partitioned error variance into components related to the organization, position level, and demographic characteristics of the raters. Analyses revealed that the differential ordering of KSAOs by raters was not a function of these characteristics but rather was due to unexplained rating differences among the raters. The implications of these results for job specification and validity transportability are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A multilevel analysis of whole family functioning using the McMaster Family Assessment Device.

This study demonstrates the use of multilevel modeling to examine influences on ratings of whole family functioning collected from multiple family members (N=26,614) living in 11,023 families with 1 or more dependent children aged 0 to 24 years. Results indicate that 45.7% of the variance in ratings of whole family functioning was shared among family members, whereas 54.3% was nonshared. Family-level characteristics, such as socioeconomic status (SES), family structure and composition, and family well-being, accounted for 30.6% of between-family variation (i.e., shared perceptions). Individual-level characteristics, such as sex, age, dependent child status, education, and well-being, accounted for 5.6% of within-family variance (i.e., unique perceptions). There was significant between-family variation in the relationship between dependent child status and ratings of family functioning, and increased rating discrepancies among members of the same family were linked with higher levels of family SES. The findings attest to the validity of measuring whole family functioning directly from self-report ratings provided from multiple family members. However, caution is warranted when assessments are available only from single respondents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Genetic and environmental influences on positive and negative affect: Support for a two-factor theory.

Studied genetic and environmental etiologies of positive and negative affect, as measured by the Bradburn Affect Balance Scale, to gain understanding of a 2-factor theory of well-being. It was hypothesized that negative affect would demonstrate significant genetic and environmental variance and positive affect would be explained primarily by environmental influences. Data were combined from 105 pairs of twins (aged 18–72 yrs) and 220 multigenerational families (aged 16–98 yrs). Simultaneous model fitting indicated significant heritable effects for negative affect and a significant effect of common environment for twins. Significant effects for positive affect included common environment (for parents and offspring and for twin pairs) and assortative mating. These results, documenting differential genetic and environmental influences on positive and negative affect, provide further support for their being separate components of well-being. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The value and correlates of left ventricular cavity assessment in dipyridamole 201Tl SPET studies

Recurrent unipolar depression with an early age of onset is a severe form of unipolar depression that has both genetic and environmental components. We genotyped the members of 16 families identified by probands with early onset (< or = 25 years), recurrent unipolar, major depression for 38 simple sequence tandem repeat polymorphisms (SSTRPs) from chromosomal regions containing 12 genes involved in neuroendocrine or serotonergic functioning. Pairwise linkage analysis was performed with the software package FASTLINK. The affected phenotype was defined four ways, and both dominant and recessive models of depression were analyzed. Seven SSTRPs showed lod scores > 1.00 at theta values between 0.10-0.20. The members of an additional 18 families were genotyped for these seven SSTRPs, and the complete sample of 34 families was evaluated using lod score analysis, affected pedigree member linkage analysis, and within-family association analysis. Evidence for linkage between D11S929 and affective illness remained positive, necessitating the analysis of four additional SSTRPs within 3 cM of D11S929. After all confirmatory analyses were completed, no evidence suggestive of linkage remained between any of the 38 SSTRPs and the affected phenotypes.     

Environment and genes: Determinants of behavior.

Recent behavioral genetic research has demonstrated that genetic influence on individual differences in behavioral development is usually significant and often substantial and, paradoxically, also supports the important role of the environment. This article reviews research on the heritability of intellectual factors, personality factors, and psychopathology. It discusses the importance of investigating within-family environmental differences in order to understand the environmental origins of individual differences in development. (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)     

Change in maternal perception of sibling negativity: within- and between-family influences.

Change in maternal report of sibling negativity was investigated in 313 sibling dyads from 171 families taking part in a longitudinal, general population survey in the United Kingdom. The inclusion of multiple dyads per family allowed for the emergence of 3 novel elements for sibling research: an examination of within-family similarity on sibling relationship quality, modeling within-family similarity as a function of the shared environment and the differentiation of family-wide and dyad-specific predictors. Moderate similarity on sibling negativity was found across different sibling dyads and similarity was higher in 2 versus lone-parent families. Maternal negativity, genetic relatedness, age of the oldest child in the dyad, and the interaction between lone-parent status and maternal differential treatment were found to predict change in sibling negativity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-ratings and judges' ratings of heterosexual social anxiety and skill: A generalizability study.

The performance of 79 male undergraduates in 2 heterosexual social situations was rated by questionnaires (including the Social Anxiety and Skill Questionnaire), self-ratings in role plays, self-ratings of videotapes of role plays, ratings by confederates, and ratings of videotaped role plays by judges. These ratings were characterized with respect to mode, method, and situation facets; the consistency of ratings was obtained under different conditions of these facets, which were investigated by use of a generalizability approach in which estimates of variance components and generalizability coefficients were calculated. Self-report and judges' ratings of anxiety and social skill based on a fairly large number of observations were found to be at best moderately generalizable across the various facets investigated; the relationship between anxiety and skill was found to vary considerably among the various methods; substantial proportions of variance, indicative of level differences, were found within judges for anxiety ratings and within judges and methods for skill ratings; and substantial proportions of variance were influenced by mode of measurement. The implications of these findings for obtaining reliable ratings of heterosexual social anxiety and skill are discussed. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrospective reports of parental physical affection and parenting style: A study of Finnish twins.

Individual differences in parenting behaviors are due, in part, to genetic factors. In the present study, the authors sought to determine whether the degree of genetic influence varied according to the type of parental behavior under consideration. A population-based sample of 2,334 pairs of Finnish twins provided ratings on the physical affection, control, abusiveness, and indifference shown by their father and mother during childhood. Genetic influences, shared environmental influences, and nonshared environmental influences accounted for a small-to-medium proportion (17%-30%), a small-to-large proportion (22%-44%), and a medium-to-large proportion (37%-55%) of the variance in each parenting measure, respectively. There were no significant differences in effect sizes for mothers and fathers or across the 4 types of parental behavior. The genetic results may reflect characteristic styles with which parents respond to genetically influenced behaviors of individuals (gene-environment correlations) or individual perceptions of this relationship (gene-person correlation processes). The findings have implications for intervention and prevention work with families and for interpretation of evidence for interactions between genes and parenting behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infant communicative development: Evidence from adoptive and biological families for genetic and environmental influences on rate differences.

Parent/infant relationships were investigated in 50 biological families selected to provide a control group for a previous adoption study by the 1st author and colleagues (1981) of rate differences in communicative development in infancy. Measures of infant communicative competence, adult cognitive abilities, and aspects of the home environment were constructed and evaluated for both control and adoptive groups (including the birth mothers of the infant adoptees). The Bayley Scales of Infant Development was also administered. The addition of the control infants and families to the overall adoption design permitted testing of a number of genetic and environmental relationships previously documented between birth parents and adoptees and between adoptive parents and adoptees. Path analyses incorporating all 100 control and adopted 1-yr-olds confirmed that parental general intelligence is moderately predictive of rate of infant communicative development and that this relationship is due to shared genetic influence. Although few relationships with the home environment were documented within either group, data suggest that parental imitation of infant vocalizations may represent a direct environmental influence unconfounded by shared genetic variance. (27 ref) (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)     

Normal components of personality variation.

Shows that the results and analyses of the components of variation in normal personality reported by R. A. Price et al (see record 1983-05018-001) are inadequate to support their conclusions. For dimensions of personality such as extraversion, the data from these extended-family pedigrees conform to a simple model invoking only additive genetic effects and within-family environmental variation with an estimated heritability of about .48, a result in line with previous twin and family studies. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personality resemblances in adoptive families when the children are late-adolescent or adult.

Members of 220 families who had adopted children at least 14 yrs previously completed the California Psychological Inventory and Thurstone Temperament Schedule to investigate personality resemblances among adoptees and their adoptive families. Adopted children were in late adolescence or adulthood. Results show that, consistent with other recent adoption studies, there was little resemblance between parents and adopted children or between adopted and natural siblings. The presence of a biological relationship raised correlations slightly, suggesting that much of the explanation for personality variation lies in within-family environmental variation or nonadditive genetic effects. It is noted that, in previous research, young adopted children were better adjusted on the average than biological children in the same families; however, this was no longer true for the late adolescents and young adults of the present study. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Understanding frame-of-reference training: The impact of training on the recall of performance information.

Extends research on the cognitive mechanisms underlying frame-of-reference (FOR) rater training by examining the impact of FOR training on the recall of performance information. It was hypothesized that the shared performance schema fostered by FOR training would serve as the basis for information processing, resulting in better recall for behavioral performance information as well as more accurate ratings of individual ratees. 174 FOR-trained Ss produced more accurate performance ratings, as measured by L. Cronbach's (1955) differential accuracy and differential elevation components, than did 142 control-trained Ss. FOR-trained Ss also recalled more behaviors, representing more performance dimensions, and exhibited less evaluative clustering and a larger relationship between memory and judgment. No differences were found between control and FOR Ss on measures of recognition accuracy. Implications for the evaluative judgment process are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Environmental and genetic variance in children's observed and reported maladaptive behavior

The genetic and environmental contributions to children's maladaptive behavior are assessed in a sample of 154 twin pairs (77 MZ twin pairs and 77 DZ twin pairs), who range in age from 6 to 11 years. To bridge the strengths of behavioral genetic methods and environmental assessment techniques, we use a multimethod, multimeasure approach to data collection, and analyze the data using behavioral genetic modeling techniques. Results indicate that genetic variation accounts for a majority of the variance in parent-reported child maladaptive behavior (average = 62%). One parent-report measure also suggests a smaller, significant contribution of shared environmental variance. In contrast to the parental ratings, the observational coding and global impressions of parent-twin interactive behavior suggest that shared environment is the primary source of variance accounting for parent and child maladaptive behavior. This is due, in part, to the direct influence one's interactive partner has on the expression of maladaptive behavior in an interactive setting. When controlling for the co-participant's behavior, genetic variation increases and shared environmental variation decreases.