Continuity and change in children's social maladjustment: A developmental behavior genetic study.

Two developmental models were used to study genetic and environmental mechanisms underlying continuity and change in children's maladjustment. The transmission model assumed that successive levels of functioning were causally linked and that earlier experiences or prior genetic influences affected later maladjustment. The liability model related continuity in problem behavior to stable underlying environmental or genetic factors. The analyses pertained on average to 436 pairs of full siblings, 119 pairs of half siblings, and 122 pairs of cousins for whom maternal ratings of problem behaviors were available at ages 4–6, 6–8, and 8–10. Nonshared environmental influences appeared to be most important for changes in children's problem behaviors and did not have significant effects on age-to-age continuity. To represent the genetic and shared environmental mechanisms underlying stability in problem behavior, the authors preffered liability models without time specific effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimuli controlling maladaptive consummatory behavior in infant dogs.

Studied stimulus condition, age and sex of Ss, and day of testing to determine their effect on the oral components of an abnormal behavioral state first observed in an operant conditioning situation and assumed to be a form of adjunctive behavior. A total of 60 beagle puppies, 4-8 and 15-17 days old, were intermittently stimulated to suck by a finger placed above or below the tongue or a milk-containing nipple placed above the tongue. Finger-below stimulation generally produced a response of the tongue sustained against the roof of the mouth, and finger above was correlated with a tongue position on the floor of the mouth. Findings are discussed in relation to pathological behavior on 3 levels of generality: response class, adjunctive behavior class, and etiology of pathological behavior. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

School performance and genetic and environmental variance in antisocial behavior at the transition from adolescence to adulthood.

Antisocial behavior increases in adolescence, particularly among those who perform poorly in school. As adolescents move into adulthood, both educational attainment and the extent to which antisocial behavior continues have implications for adolescents’ abilities to take on constructive social roles. The authors used a population-representative longitudinal twin study to explore how links among genetic and environmental influences at ages 17 and 24 may be implicated in the developmental processes involved. At age 17, expression of both genetic and nonshared environmental vulnerabilities unique to antisocial behavior was greater among those with low GPA than among those with higher GPA. This suggested that maintenance of high GPA buffered the impact of both genetic and environmental influences encouraging antisocial behavior. When GPA was high, both genetic and environmental influences involved in both traits encouraged good school performance and restrained antisocial behavior. At age 24, however, correlated family environmental influences drove the association between educational attainment and antisocial behavior. Antisocial characteristics involving school performance and educational attainment that transcend generations may slot individuals into social categories that restrict opportunities and reinforce antisocial characteristics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Epistasis and its contribution to genetic variance components

We present a new parameterization of physiological epistasis that allows the measurement of epistasis separate from its effects on the interaction (epistatic) genetic variance component. Epistasis is the deviation of two-locus genotypic values from the sum of the contributing single-locus genotypic values. This parameterization leads to statistical tests for epistasis given estimates of two-locus genotypic values such as can be obtained from quantitative trait locus studies. The contributions of epistasis to the additive, dominance and interaction genetic variances are specified. Epistasis can make substantial contributions to each of these variance components. This parameterization of epistasis allows general consideration of the role of epistasis in evolution by defining its contribution to the additive genetic variance.     

Relationship between reported and observed dominance and conflict among parents of schizophrenics.

The results of well-controlled studies indicate no significant differences among the mothers of schizophrenics and those of controls in the amount of reported dominance. However, several equally well-controlled studies demonstrate that the parents of schizophrenics behave in a more conflictual manner toward each other than is true of the parents of controls. The subjects for this study were 35 sets of Caucasian parents: 11 were parents of hospitalized poor premorbid schizophrenics, 12 were parents of hospitalized good premorbid schizophrenics, and 12 were parents of hospitalized tubercular patients (controls). The parents were asked individually whether they agreed or disagreed with the dominance and conflict items from the Parental Attitude Research Instrument. They were then asked to resolve, individually then jointly, 12 hypothetical child-rearing problems. The parental dialogues were all tape-recorded and later scored for dominance and conflict. The results suggest that parents in general are not reliable judges of dominant behavior, but appear to be better estimators of conflictual behavior. The latter finding is especially marked for the parents of controls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sources of variance in responses to questionnaires and in behavior.

16 psychiatric patients were observed in and were asked to describe their reactions to 6 psychiatric ward subsettings. Findings indicate: (1) that persons, settings, and Person * Setting interactions accounted for statistically significant and important proportions of the total variance, both in responses to questionnaires and in actual behavior; and (2) that these proportions remained remarkably stable over a 3-mo interval, except for a consistent tendency for the proportions attributable to settings to increase. Implications discussed include that different psychiatric ward subsettings may be differentially therapeutic to different Ss, and that the findings bear on the upper limit of validity indexes obtainable with standard interview or rating predictions of S behavior. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the sampling variance of intraclass correlations and genetic correlations

Widely used standard expressions for the sampling variance of intraclass correlations and genetic correlation coefficients were reviewed for small and large sample sizes. For the sampling variance of the intraclass correlation, it was shown by simulation that the commonly used expression, derived using a first-order Taylor series performs better than alternative expressions found in the literature, when the between-sire degrees of freedom were small. The expressions for the sampling variance of the genetic correlation are significantly biased for small sample sizes, in particular when the population values, or their estimates, are close to zero. It was shown, both analytically and by simulation, that this is because the estimate of the sampling variance becomes very large in these cases due to very small values of the denominator of the expressions. It was concluded, therefore, that for small samples, estimates of the heritabilities and genetic correlations should not be used in the expressions for the sampling variance of the genetic correlation. It was shown analytically that in cases where the population values of the heritabilities are known, using the estimated heritabilities rather than their true values to estimate the genetic correlation results in a lower sampling variance for the genetic correlation. Therefore, for large samples, estimates of heritabilities, and not their true values, should be used.     

Does genetic variance for cognitive abilities account for genetic variance in educational achievement and occupational status? A study of twins reared apart and twins reared together

Studies of brothers and twins have shown that about 50 per cent of the variance in educational achievement and 40 per cent of the variance in occupational status reflects between-family variance. About half of the between-family variance for educational achievement and even more for occupational status is due to genetic effects and the remainder is due to sharing the same environment. With data on 35 pairs of male twins reared apart and 56 pairs reared together we investigated the extent to which genetic variance in SES can be attributed to genetic variance for cognitive abilities. For both educational achievement and occupational status there was significant genetic variance both in common with and independent of genetic variance for cognitive abilities. Thus, there are genetic effects contributing to familial similarity for SES that are not the same as those of importance for cognitive abilities. Candidate traits that may account for this remaining genetic variance in SES are personality, interests, or talents not represented in standard cognitive tests.     

Familiarity and children's behavior in same-age and mixed-age peer groups.

Investigated the hypothesis that differences in children's behavior in same- and mixed-age peer groups found in previous research (e.g., J. Goldman, 1981) were an artifact of different degrees of familiarity or acquaintanceship between group members. 144 previously unacquainted 1st- and 3rd-grade children were assigned to same- and mixed-age triads, and their performance at a tower building task was assessed. Following this baseline measurement, triads were randomly assigned to conditions where familiarization with teammates was manipulated, and then task performance was reassessed. The mixed-age effects found in previous research were replicated, and some of the differences found between same- and mixed-age interaction decreased when older Ss became familiar with their younger teammates. Possible mechanisms underlying mixed-age interaction are discussed. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prosocial self-schemas, self-awareness, and children's prosocial behavior

Three studies examined the hypothesis that a child's prosocial self-schema predicts prosocial behavior. In Study 1, only self-aware boys showed a self-schema-behavior relation. Study 2 altered both salience of donating opportunity and relationship of recipient to donor. The hypothesized Self-Awareness x Self-Schema interaction was significant, and there were no gender differences. Study 3 systematically manipulated the salience of the donating opportunity. All participants were self-aware. For boys in high and low salience conditions, prosocial self-schema predicted donating behavior. For girls, prosocial self-schema predicted behavior only in the high salience condition. The findings demonstrate that self-schemas can regulate behavior when participants are self-aware. Girls, however, may require higher salience of the donating opportunity for the self-schema to affect their behavior.     

Mother's emotional expressivity and children's behavior problems and social competence: Mediation through children's regulation.

The relations between mothers' expressed positive and negative emotion and 55–79-month-olds' (76% European American) regulation, social competence, and adjustment were examined. Structural equation modeling was used to test the plausibility of the hypothesis that the effects of maternal expression of emotion on children's adjustment and social competence are mediated through children's dispositional regulation. Mothers' expressed emotions were assessed during interactions with their children and with maternal reports of emotions expressed in the family. Children's regulation, externalizing and internalizing problems, and social competence were rated by parents and teachers, and children's persistence was surreptitiously observed. There were unique effects of positive and negative maternal expressed emotion on children's regulation, and the relations of maternal expressed emotion to children's externalizing problem behaviors and social competence were mediated through children's regulation. Alternative models of causation were tested; a child-directed model in which maternal expressivity mediated the effects of child regulation on child outcomes did not fit the data as well. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Origins of generalized control expectancies: reported child stress and observed maternal control and warmth

The relations among reported stressful events, maternal control and warmth, and children's locus of control of reinforcement were investigated. Fifty-five 2nd-grade. U.S. children completed the Children's Nowicki-Strickland Internal-External Locus of Control Scale, and their mothers completed a modified form of Coddington's Life Events Scale for their child. Mother and child also were videotaped while they worked together on three puzzles. The results indicated that, compared with children with external control expectancies, children with internal control expectancies had experienced less stress in their lives. Furthermore, when observed interacting with their children, mothers of children with internal control expectancies were rated as displaying less control and more warmth than mothers of children with external control expectancies. The findings generally are consistent with predictions based on Rotter's social learning theory for the development of individual differences in generalized control expectancies.     

Cultural differences in the relationship between parenting and children's behavior.

Parent and teacher data for 14,990 children from the National Longitudinal Survey of Children and Youth were used in multilevel analyses to examine the relationship between ethnicity, children's aggression and emotional problems, and parenting. Using parent and teacher report, relationships between ethnicity and child behavior were present but modest. The association between parental harshness and child aggression differed between ethnic groups and across informants. Using teacher report of outcomes, parental harshness was positively related to child aggression in European Canadian families but negatively related in South Asian Canadian families. For all ethnic groups, parental harshness was positively related to children's aggression when parent report of outcomes was used, but relationships varied in strength across ethnic groups. The relationship of parental harshness with child emotional problems did not differ across groups, irrespective of informant. The results are discussed within the context of an ecological model of parenting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Family process variables and children's disruptive behavior problems.

Marital, parent–child, and family-level processes were examined for 4 groups of 7 to 11-year-old boys and their families: boys with no behavioral problems (control), boys with behavioral problems consistent with attention deficit hyperactivity disorder (ADHD), boys with behavioral problems consistent with oppositional defiant disorder (ODD), and boys with behavioral problems consistent with ADHD and ODD. A discriminant analysis that used marital and family factors alone was able to correctly classify families into one of the 4 behavior problem groups with nearly 90% accuracy. The combination of parental commands and parental coercion separated the control group from the 3 clinical groups, but it was the combination of family cohesiveness and responsive and consistent parenting that best distinguished the 3 clinical groups from one another. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in children's altruistic behavior and reputations for helpfulness.

Examined sex differences in altruism by administering reputation and behavioral measures to 279 5th and 6th graders. Ss' reputations for altruism were assessed with teacher ratings and a classroom sociometric task. Altruistic behavior was measured with 6 classroom tasks that provided Ss with opportunities to help other Ss. Girls scored significantly higher than did boys on both reputation tasks and on a composite reputation score. Girls also scored significantly higher than did boys on 2 of the behavioral tasks and on the composite behavioral measure. Thus, although girls were perceived as much more helpful than boys, the behavioral differences were of a lesser magnitude. Results replicate closely those reported by H. Hartshorne et al (1929). (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental trends in children's perceptions of parental child-rearing behavior.

Administered the Child's Report of Parental Behavior Inventory to 342 children in Grades 1 through 4. Results concerning 2 control factors confirm a previously noted trend that with advancing age, children perceive a decrease in psychologically controlling behaviors and a concomitant increase in parental rule making and limit setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-specific patterns of genetic variance in Drosophila melanogaster. II. Fecundity and its genetic covariance with age-specific mortality

Under the mutation accumulation model of senescence, it was predicted that the additive genetic variance (VA) for fitness traits will increase with age. We measured age-specific mortality and fecundity from 65,134 Drosophila melanogaster and estimated genetic variance components, based on reciprocal crosses of extracted second chromosome lines. Elsewhere we report the results for mortality. Here, for fecundity, we report a bimodal pattern for VA with peaks at 3 days and at 17-31 days. Under the antagonistic pleiotropy model of senescence, it was predicted that negative correlations will exist between early and late life history traits. For fecundity itself we find positive genetic correlations among age classes > 3 days but negative nonsignificant correlations between fecundity at 3 days and at older age classes. For fecundity vs. age-specific mortality, we find positive fitness correlations (negative genetic correlations) among the traits at all ages > 3 days but a negative fitness correlation between fecundity at 3 days and mortality at the oldest ages (positive genetic correlations). For age-specific mortality itself we find overwhelmingly positive genetic correlations among all age classes. The data suggest that mutation accumulation may be a major source of standing genetic variance for senescence.     

Effects of sociometric testing on children's behavior and loneliness in school.

Examined the effects of a positive and negative peer nomination sociometric measure on children's (a) interactions with peers in general, (b) interactions with preferred and nonpreferred playmates, and (c) ratings of mood and of loneliness in school. Twenty-three 5th graders completed either a peer nomination sociometric or a control task (nominating preferred and nonpreferred school subjects). Before and after the nomination task, observers assessed the affective quality (positive, neutral, or negative) of subjects' peer interactions, and children completed mood and loneliness questionnaires. The procedures were subsequently replicated by administering the sociometric task to the control subjects. Analyses revealed no differences between the peer and control nomination task groups on any of the dependent variables measured. Analyses of pre–post differences provided no evidence of negative effects, suggesting that the risk to elementary-school-age children of completing such a sociometric measure, provided certain procedural guidelines are followed, may be minimal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How should we explain variation in the genetic variance of traits?

Recent work has called attention to large differences among traits in the amount of standardized genetic variance they possess. There are four general factors which could play a role in causing this variation: mutation, elimination of deleterious variation, selection of favorable alleles, and balancing selection. Three factors could directly influence the mutational variability of traits: canalization, the mutational target size, and the timing of trait expression. Here I carry out simple tests of the importance of some of these factors using data from Drosophila melanogaster. I compiled information from the literature on the mutational and standing genetic variances in outbred populations, inferred the relative mutational target size of each trait, its a timing of expression, and used models of life history to calculate fitness sensitivities for each trait. Mutational variation seems to play an important role, as it is highly correlated with standing variance. The target size hypothesis was supported by a significant correlation between mutational variance and inferred target size. There was also a significant relationship between the timing of trait expression and mutational variance. These hypotheses are confounded by a correlation between timing and target size. The elimination and canalization hypotheses were not supported by these data, suggesting that they play a quantitatively less important role in determining overall variances. Additional information concerning the pleiotropic consequences of mutations would help to validate the fitness sensitivities used to test the elimination and canalization hypotheses.