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Biomedical subjects

R Plomin

Publications and source records attributed to R Plomin.

At least 163 records · Page 9Linked to original sources
PubMed1987

Roundtable: what is temperament? Four approaches.

4 current approaches to understanding temperament are discussed in the roundtable. In an introductory overview, Goldsmith outlines some of the major convergences and divergences in the understanding of this concept. Theorists representing 4 positions--Goldsmith, Buss and Plomin, Rothbart, and Thomas and Chess--outline their views by responding to each of 6 questions: How do you define temperament and explain the boundaries of the concept? What are the elements of temperatment? How does the construct of temperament permit you to approach issues or organize data in ways that are possible only if this construct is invoked? How does temperament develop? To what extent do you consider temperament to be a personological versus a relational or an interactional construct? and How does your approach deal with issues of temperamental "difficulty"? In 2 commentaries on the theorists' answers, Hinde highlights differences among their positions and indicates issues that current theories of temperament must take into consideration, and McCall draws on common aspects to propose a synthesizing definition that draws on all 4 approaches.

Arousal↗
PubMed1986

Behavioral genetic methods.

Traditional behavioral genetic methods involve the use primarily of family, twin, and adoption correlations to estimate the relative contributions of genetic and environmental influences in the etiology of individual differences. These methods and representative results for personality are described. However, newer methods are emphasized: structural models and model-fitting, multivariate analysis, genetic change and continuity in development, shared and non-shared components of environmental variance, and genetic components of "environmental" variation. Because most applications of these behavioral genetic methods to the study of personality involve self-report omnibus questionnaires, an important direction for future research in this area is to use these methods to explore new issues and new measures that have emerged from personality theory and research during the past decade.

Adoption↗
PubMed1986

Consistency and change in mothers' behavior toward young siblings.

Siblings differ markedly in behavioral development, and it has been suggested that differential maternal treatment may contribute significantly to these differences. The question of how consistently mothers treat their different children was examined in a study of 45 sibling pairs from the Colorado Adoption Project, in which each child at 24 months of age was videotaped at home with the mother. The results showed mothers to be consistent in affection and verbal responsiveness but to differ in their controlling behavior toward the 2 siblings. Comparison of the same mother's behavior to the 2 siblings at 12 months and at 24 months showed little stability in maternal behavior to the same child over this age period.

Adoption↗
PubMed1986

Longitudinal stability of cognitive ability from infancy to early childhood: genetic and environmental etiologies.

A path model of genetic and shared family environmental transmission was fitted to general cognitive ability data from 1-, 2-, 3-, and 4-year-old adopted and nonadopted children and their parents in order to assess the etiology of longitudinal stability from infancy to early childhood. Stability across years is moderate and is due mainly to influences not predicted by parental IQ. Results of the present study, in conjunction with those of previous twin studies, suggest substantial genetic stability from infancy and early childhood to adulthood.

Adoption↗
PubMed1986

Use of regression residuals to quantify individual differences in acute sensitivity and tolerance to alcohol.

Due to the problem of correlation of errors inherent in the difference or ratio scores typically used to quantify individual differences in acute sensitivity and tolerance to alcohol, it is recommended that residual scores from regression analyses be used instead for such quantification. Conceptualizations of acute sensitivity and tolerance and problems with the reliability of change scores are also discussed.

Adoption↗
PubMed1985

Individual differences in anticipation of alcohol sensitivity.

Anticipations of the effect produced by a given amount of alcohol may be as important as actual responses to that amount of alcohol in determining patterns of alcohol use, yet previous research has focused only on physiological response and subjective reports of sensitivity upon administration of alcohol. In this study, the etiology of individual differences in reports of anticipated sensitivity was examined using a sample of 54 pairs of twins and adoptees for whom both members of each pair had consumed two drinks per hour for 2 hours at some time during the year before the study. Genetic influence was suggested for anticipated sensitivity to physical symptoms and coordination but not for other symptoms such as thinking problems, mood, or driving ability. The environmental influences responsible for individual differences in anticipated sensitivity are largely shared by family members, as indicated by the substantial resemblance for pairs of adoptees reared in the same family. Also explored was the correlation between anticipated sensitivity to alcohol and reported recent drinking behavior. In this sample (N = 204) it was found that an anticipation of less sensitivity related to a higher reported average number of drinks consumed per drinking session, independent of weight, sex, or age differences.

Adoption↗
PubMed1985

Drinking behavior in the Colorado adoptee and twin sample.

Using a sample of adult Colorado twins, nontwin sibling pairs and pairs of unrelated adoptees reared together (N = 346), the extent of the similarity in drinking behavior within pairs was estimated. The analyses, which go beyond those possible with a study confined just to twins, suggest that some alcohol-drinking behaviors may be genetically influenced. However, the genetic variance appears to be primarily nonadditive so that it contributes more to differences than to similarities between first-degree relatives. Alternatively, although less likely, these results might suggest a special common environment for identical twins that is not present for fraternal twins, nontwin siblings or unrelated adoptees reared together. Environmental analyses indicate that both types of twins share a special family environmental similarity that is not shared by nontwin siblings. Environmental influences that affect individual differences in drinking behavior appear to contribute more to dissimilarity than to similarity. The results do not support the contention that being raised in the same family contributes substantially to similarity in characteristics of drinking behavior.

Adoption↗
PubMed1985

Environmental differences within the family and adjustment differences within pairs of adolescent siblings.

To what extent do siblings in the same family experience different parental treatment, sibling interaction, and peer relationships? Are such within-family experiential differences related to differences in the siblings' emotional adjustment? The present study explored these questions concerning within-family environment using data from 348 families that each included 2 siblings 11-17 years of age. The results indicate that siblings in the same family experience different environments, as reported by parents and to a larger extent by the siblings themselves. The results also demonstrate that within-family environmental differences are related to differences in development between siblings. Both the parent and sibling reports of the environment converge on the finding that the sibling who is more psychologically well adjusted (as reported by parents, siblings, and teachers) also experiences more maternal closeness, more sibling friendliness, more peer friendliness, more say in family decision making, and more parental chore expectations as compared to the other sibling.

Adolescent↗
PubMed1984

Swedish early separated twins: identification and characterization.

A sample of twins separated early in life has been identified in the Swedish Twin Registry. When the registry was compiled in 1961 (old cohort) and 1973 (young cohort), one or both members of 961 pairs indicated that they were separated by the age of 10. In May 1979, both members of 698 pairs were alive and were sent a questionnaire concerning the circumstances of separation. Items included reasons and timing of separation, biological relatedness of rearing parents, degree of contact after separation (including whether they lived in the same area, attended the same school, or lived together again), rough measures of selective placement, and current frequency of contact. An attempt was then made to categorize the pairs based on degree of separation. A total of 257 pairs met the criteria: rearing parents of one twin biologically unrelated to rearing parents of the cotwin, twins not living together again after separation, and contact after separation a few times a year or less. As much as 50% were separated by their first birthday, and 80% by the age of five. Various data from the twin registry are presented describing the entire sample of early separated twins as compared to a matched sample of twins reared together.

Adolescent↗
PubMed1984

Development of hand preference in the Colorado Adoption Project.

A longitudinal study of the development of hand preference in 152 adopted and 120 nonadopted (control) infants measured in natural behavioral situations at both 12 and 24 mo. of age is reported. Significant developmental trends were observed for both increasing strength and direction of handedness. Less than 10% of the infants exhibited a clear preference at 12 mo. of age, whereas about 30% were lateralized at 24 mo., with more boys than girls being left-handed. In contrast, over 90% of the parents of these children (both biological and adoptive parents of the adopted children and parents of the nonadopted children) were lateralized. Perhaps because so few infants were lateralized at either age, parent-offspring resemblances were inconsistent and the number of significant parent/child correlations was about that expected on the basis of chance alone.

Adoption↗
PubMed1984

Correlates of difficult temperament in infancy.

Despite interest in the construct of "difficult temperament" in infancy, little is known about its correlates within the first 2 years of life. In a study of 272 families consisting of 152 adopted and 120 nonadopted infants tested in their homes at 12 and 24 months of age, a parental report of difficult temperament was related to 3 major areas of correlates: (1) infant functioning (parental ratings of temperament, tester ratings using Bayley's Infant Behavior Record, and Bayley Mental Index scores); (2) parental personality (Cattell's 16PF test and a self-report temperament inventory); and (3) measures of the home environment (Home Observation for Measurement of the Environment and the Family Environment Scales). No systematic significant relationships were found between difficult temperament and other aspects of infant development, parental characteristics, or the home environment for the entire sample or for a subsample consisting of the 10% most difficult infants. In addition, we found no evidence for significant interactions between parental personality and home environment as they affect difficult temperament nor did interactions of any type emerge as significant. Taken together with other evidence indicating that difficult temperament in infancy fails to predict concurrent or later behavioral problems, these data add to growing doubts about the utility of the construct of difficult temperament and suggest the need to consider specific infant temperaments that parents find difficult.

Adoption↗
PubMed1983

Developmental behavioral genetics.

Developmental behavioral genetics is the study of genetic and environmental influences on individual differences in behavioral development. The interdiscipline offers exciting possibilities for research in both child development and behavioral genetics. In this prelude to a special section on developmental behavioral genetics, the potentialities of the interdiscipline are discussed and an overview of the articles that follow is presented.

Adoption↗
PubMed1983

The Colorado Adoption Project.

This report provides an overview of the Colorado Adoption Project (CAP), a longitudinal, prospective, multivariate adoption study of behavioral development. Examples of the types of analyses that can be conducted using this design are presented. The examples are based on general cognitive-ability data for adoptive, biological, and control parents; assessments of their home environment; and Bayley Mental Development Index scores for 152 adopted children and 120 matched control children tested at both 1 and 2 years of age. The illustrative analyses include matched control children tested at both 1 and 2 years of age. The illustrative analyses include examination of genetic and environmental sources of variance, identification of environmental influence devoid of genetic bias, assessment of genotype-environment interaction and correlation, and analyses of the etiology of change and continuity in development.

Adoption↗
PubMed1982

Behavioural genetics and temperament.

Three recent developments in behavioural genetics are relevant to temperament research. First, the search for genetic influences on temperament has been frustrated by the finding that twin studies using self-report and parental rating instruments detect a genetic influence for all personality traits whereas twin studies using objective assessments rarely find a genetic influence. Secondly, environmental influences salient to temperament appear to operate in such a way as to make members of a family (siblings, for example) as different from one another as are individuals in different families. The importance of such 'E1', or non-shared, environmental influences suggests the need for studies of more than one child per family. Thirdly, adoption studies are needed to complement the extensive research on temperament in twins. In addition to its usefulness in isolating genetic influences, the adoption design can study environmental influence devoid of the confounding effects of hereditary influences; it can also isolate interactions between genotypes and environments. Preliminary results from the Colorado Adoption Project show little relationship between the temperaments of adopted and non-adopted one-year-olds and the personality characteristics of thier parents. Measures of the home and family environment did not relate to infant temperament, and no genotype-environment interaction was detected.

Adoption↗
PubMed1982

Neuropharmacogenetics and behavioral genetics.

Genetic studies of neurotransmitter processes to date differ from most behavioral genetic studies in that the former have rarely considered individual variability, have tended to look only for single-gene effects, and generally have overlooked or ignored environmental influences. After examining these differences, we suggest that a rapprochement between the two fields will yield synergistic benefits in studies of the genetics of neuropharmacological processes as they affect behavior.

Animals↗