Origins Of Individual Differences Research Articles

A Developmental-Genetic Analysis of Continuity and Change in the Bayley Mental Development Index from 14 to 24 Months: The MacArthur Longitudinal Twin Study

A developmental-genetic model was fitted to Bayley Mental Development Index (MDI) data to address questions concerning the origins of individual differences in MDI performance and the origins of change and continuity during infancy More than 350 pairs of identical and same-sex fraternal twins were studied longitudinally at 14, 20, and 24 months of age There was substantial genetic continuity of general cognitive ability from 14 to 24 months, but significant new genetic variation also appeared at 24 months Shared family environmental influences were global across all three ages and not time-specific Finally, nonshared environmental influences did not contribute to the observed continuity of general cognitive ability, only to change

The origins of individual differences in memory among the elderly: a behavior genetic analysis.

The purpose of this investigation was to apply behavior genetic methods to investigate individual differences in memory performance. Memory and various cognitive and lifestyle variables were obtained from 93 monozygotic twin pairs and 67 dizygotic twin pairs aged 60-88 years as part of the Minnesota Twin Study of Adult Development and Aging. Univariate analysis, used to determine the relative influence of genetic and environmental factors on 4 measures of memory (word recall, immediate and delayed text recall, and figure memory), suggested that 55% of the variance in memory performance could be attributed to genetic factors. Bivariate analysis was used to determine the specific variables that mediate the genetic and environmental influences on memory. Results suggested that the relationship between memory and cognitive variables was genetic in nature, whereas the nature of the relationship between memory and lifestyle variables was environmental.

The origins of individual differences in memory among the elderly: A behavior genetic analysis.

The origins of individual differences in memory among the elderly: A behavior genetic analysis.

Evidence for a genetic etiology in hyperactivity in children.

There has been considerable controversy over the nosology of hyperactivity and attention deficit hyperactivity disorder (ADHD). There have been suggestions that genetic influences may play a role in the origins of individual differences on this dimension or dimensions of behavior and that an understanding of the significance of genetic factors might help to clarify the classification of these disorders. Multiple regression is used to analyze data from a sample of 91 pairs of identical twins and 105 pairs of same sex fraternal twins. The heritability of extreme group membership (h2g = 0.75) was significant for activity rated by the mother. The heritability for one of the measures of attention deficit was also significant (h2g = 0.76). The results are consistent with a significant genetic contribution to individual differences in activity levels and attention abilities.

The Origins of Individual Differences in Occupational Status and Educational Level

Sources of influences on educational and occupational achievement were investigated using the powerful combined twin/adoption design. Analyses for education were based on 331 pairs of twins reared apart (TRA) and 375 pairs of twins reared together (TRT) Analyses for occupation were based on fewer pairs Maximum-likelihood model-fitting analyses revealed that environmental effects unique to the individual. environmental effects shared by the two twins in a pair and genetic effects all were important for individual differences For both education and occupation, environmental effects were more important among women and genetic effects were more important among men For education there were differences in the relative importance of the effects when the analyses were performed separately for cohorts under and above age 60 Consistent with a social change hypothesis, environmental influences were more important among older individuals than among younger, and, conversely, genetic influences seem to have a greater impact on education for the younger age group Regression analyses revealed that the circumstances of separation among the reared apart twins probably have not biased the results These results Support accumulated evidence of the importance of genetic effects as a source of familial resemblance for socioeconomic status among men The disparity in conclusions by sociologists and behavior geneticists from similar data is discussed

Psychosocial stressors: Concepts, causes and effects.

Key advances in life events research included recognition of the need to differentiate events that were independent of disorder; to take the social context of events into account; to assess life events in terms of the long term threat rather than degree of life change; to determine the temporal linkage between life events and onset of psychiatric disorder; to appreciate the importance of long term difficulties as well as acute events; and to examine the role of vulnerability and protective mechanisms in determining individual differences in response to life events. Stress effects in childhood are considered in terms of possible mediating mechanisms; of turning points in life trajectory; of individual differences in response; of difficulties in the concept and measurement of onset of psychiatric disorder; of possible additivity of negative life events; and of the origins of individual differences in exposure to negative life experiences.

Masculinity and Femininity in Twin Children: Genetic and Environmental Factors

Genetic and environmental origins of individual differences in masculine and feminine personality attributes were investigated in a sample of 38 monozygotic and 32 dizygotic twin pairs (total N = 140) during pre- and early adolescence. Self-report measures of both masculine and feminine characteristics were obtained for each child using 2 standardized instruments: the Children's Personality Attributes Questionnaire (CPAQ) and the Adolescent Self-Perception Inventory (ASPI). Multivariate biometrical analyses revealed significant genetic influences in all measures, accounting for 20%-48% of the observed variation in each. Environmental influences, which explained the remaining 52%-80% of variance in masculinity and femininity, were apparently specific to each individual and not shared by members of the same twin pair. The results underscore the importance of considering both genetic and environmental factors in gender-role development, particularly in studies of family resemblance.

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.

BOOK REVIEWS

Book reviewed in this article: Residential Special Education. Ted Cole. Advances in Clinical Child Psychology, Vol.8. Edited by B. B. Lahey and A. E. Kazdin. The Dictionary of Development and Educational Psychology. Edited by R. Harre and Roger lamb. The Lead Debate: The Environment, Toxicology and Child Health. Edited by R. lansdown and W. Yule. Language Development in the School Years. Edited by Kevin Durkin. Origins of Individual Differences in Infancy; The Colorado Adoption Project. Robert Plomin and John C. DeFries. Tics and Related Disorders. Clinical Neurology and Neurosurgery Monographs, Vol. 7. A. J. Lees. Development as Action in Context. Edited by R. K. Silbereisen, K. Eyferth and G. Rubinger. Psychopathological Disorders of Childhood (3rd edn.) Edited by Herbert C. Quay and John S. Werry. Child Health Behavioral: A Behavioral Pediatrics Perspective. N. A. Krasnegor, J. D. Arasteh and M. F. Caraldo. Science and Service in Mental Retardation. Edited by Joseph M. Bebg, assisted by Jean M. de Jong. Special Education. Edited by Fred Adams.

A method for rating the individual distinctiveness of domestic cats

Fourteen adult female domestic cats were watched by two observers for 3 months. Ratings of 18 aspects of each cat's behavioural style were obtained independently from each observer. Correlations between observers were statistically significant for 15 of the 18 aspects and seven of the correlation coefficients were greater than 0·7. The ratings were compared with results of direct recording methods, where equivalent measures were available and, in five out of six cases, the results of the ratings and direct methods were significantly correlated. The rating method is, therefore, generally reliable and can be adequately validated. Some assessments of observer ratings which are not obviously and easily related to direct recordings may prove particularly useful in developmental studies of alternative modes of behaviour and the origins of individual differences.

The Colorado Adoption Project: The Origins of Individual Differences in Infancy . The Colorado Adoption Project. Robert Plomin and John C. DeFries. Academic Press, Orlando, Fla., 1985. xvi, 408 pp. $54.50. Developmental Psychology Series.

The Colorado Adoption Project: <i>The Origins of Individual Differences in Infancy</i> . The Colorado Adoption Project. Robert Plomin and John C. DeFries. Academic Press, Orlando, Fla., 1985. xvi, 408 pp. $54.50. Developmental Psychology Series.

Ratings of temperament in families of young twins

We studied a sample of 576 pairs of twins in three age groups (0–2, 2–5, 5+ years), and obtained for each family a set of temperament ratings which provided isomorphic dimensions for parents and children (EASI Temperament Survey). Both parents were asked to rate independently themselves, their spouse and each of the twin children. The results confirm the findings of Lyon &amp; Plomin (1981) that parental projection does not take place in the rating of each other. Only the mothers' rating of Emotionality shows any indications of projection in the rating of children, and parental agreement on children's temperament shows modest levels of reliability (r = 0·53). There is no evidence of assortative mating for temperament characteristics. The intra‐class correlations for monozygotic and dizygotic twins are consistent with Emotionality and Sociability being under some genetic control only in girls, Activity shows increasing genetic influences with age in both boys and girls, and Impulsivity indicates a lower level of genetically determined variance at all ages in both sexes. We concluded that, in common with recent studies on environment associations with temperament, the origin of individual differences needs to be studied separately in boys and girls. A more general case is made for the utility of twin studies that include data on other family members.

Origins of individual differences in infant shyness.

Origins of individual differences in infant shyness.

Attachment Theory: Retrospect and Prospect

This chapter has several major aims. The first is to provide an overview of attachment theory as presented by John Bowlby in the three volumes of Attachment and Loss (1969/1982b, 1973, 1980), giving special emphasis to two major ideas: (1) attachment as grounded in a motivational-behavioral control system that is preferentially responsive to a small number of familiar caregiving figures and (2) the construction of complementary internal working models of attachment figures and of the self through which the history of specific attachment relationships is integrated into the personality structure. These two concepts, but especially the notion of internal working models, will be used in the second section of the chapter to interpret refinements and elaborations of the theory that have been primarily the result of the work and influence of Mary Ainsworth. Topics discussed are maternal and infant contributions to the quality of attachment relationships, stability and change in the quality of attachment relationships, carryover effects from earlier to later relationships, and intergenerational transmission of attachment patterns as an intracultural and cross-cultural phenomenon. An attempt is made to clarify a variety of theoretical points and to discuss others that remain to be clarified. Finally, I consider how recent insights into the development of socioemotional understanding and the development of event representation can be integrated into attachment theory to shed new light on the origins of individual differences in personality development. In doing so, I have also attempted to provide a framework for the studies presented in this volume.

Origins of individual differences in infant shyness.

Origins of individual differences in infant shyness.

No evidence for sex-linked or sex-limited gene expression influencing spatial orientation.

Scores of 83 pairs of twins and their parents on the Cubes Comparison Test have been analyzed to test competing hypotheses about the origin of individual differences in spatial orientation. Models allowing for polygenic sex-linked or sex-limited gene expression show no improvement in fit over the simple autosomal additive polygenic model. However, individual environmental influences (E 1) account for twice as much variance in males as in females.

The Pennsylvania Infant and Family Development Project, III: The Origins of Individual Differences in Infant-Mother Attachment: Maternal and Infant Contributions

In order to test 4 specific hypotheses regarding the interactional histories associated with variation in quality of infant-mother attachment, data gathered during naturalistic home observations at 1, 3, and 9 months on 60 babies seen in the Ainsworth and Wittig strange situation were examined. Planned comparisons revealed, as predicted, that securely attached infants had experienced intermediate levels of reciprocal interaction and maternal stimulation, considered to be reflective of sensitive care, and that resistant babies had experienced less responsive care than securely attached infants. No support was provided for the hypothesis that avoidant babies had experienced less physical contact with mothers than securely attached infants. Insecurely attached infants were observed to cry significantly more than securely attached infants at 3 and 9 months. A cross-lag panel analysis, designed to assess longitudinal processes of influence, revealed that fussiness was caused by mothering and did not serve to influence mothering. These results are discussed in terms of mothers' relatively greater influence in determining individual differences in attachment, with overstimulation leading to avoidance, understimulation leading to resistance, and intermediate levels of stimulation leading to security.

The Pennsylvania Infant and Family Development Project, III: The Origins of Individual Differences in Infant-Mother Attachment: Maternal and Infant Contributions

In order to test 4 specific hypotheses regarding the interactional histories associated with variation in quality of infant-mother attachment, data gathered during naturalistic home observations at 1, 3, and 9 months on 60 babies seen in the Ainsworth and Wittig strange situation were examined. Planned comparisons revealed, as predicted, that securely attached infants had experienced intermediate levels of reciprocal interaction and maternal stimulation, considered to be reflective of sensitive care, and that resistant babies had experienced less responsive care than securely attached infants. No support was provided for the hypothesis that avoidant babies had experienced less physical contact with mothers than securely attached infants. Insecurely attached infants were observed to cry significantly more than securely attached infants at 3 and 9 months. A cross-lag panel analysis, designed to assess longitudinal processes of influence, revealed that fussiness was caused by mothering and did not serve to influence mothering. These results are discussed in terms of mothers' relatively greater influence in determining individual differences in attachment, with overstimulation leading to avoidance, understimulation leading to resistance, and intermediate levels of stimulation leading to security.

The Genetic Basis of Individual Differences in the Human EEG at Rest

Individual differences in the human electroencephalogram (EEG) are an informative parameter for study of the nature of individual psychophysiological and psychological differences. EEG parameters reflect the basic properties of the nervous system, which in many respects determine the dynamic features of various mental processes [13]. Individual EEG properties are linked to distinctive features in a person's emotional makeup [14], the nature of [that person's] intellectual and behavioral activity [9, 12] and mnemonic functions [3], and other individual psychological and psychophysiological characteristics. Hence, it is very important for differential psychophysiology and psychology to study the origins of individual differences in the EEG.

Pédagogie nouvelle en mathématiques et développement intellectuel

New pedagogy in mathemathics and mental development. — Report of an experiment based on comparison of groups of children from 9 to 13, contrasted as to the kind of mathematics teaching they received, in order to determine the existing connexions between mental level, evolution of logical thought and mathematical trainings, in accordance with hypotheses made from the reflexion on the origin of individual differences.