So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

because observed behavior is the result of interactions between environmental factors and genes during the extended period of development. Therefore, to better understand expert and exceptional performance, we must require that the account specify the different environmental factors that could selectively promote and facilitate the achievement of such performance. In addition, recent research on expert performance and expertise (Chi, Glaser, & Farr, 1988; Ericsson & Smith, 1991a) has shown that important characteristics of experts' superior performance are acquired through experience and that the effect of practice on performance is larger than earlier believed possible. For this reason, an account of exceptional performance must specify the environmental circumstances, such as the duration and structure of activities, and necessary minimal biological attributes that lead to the acquisition of such characteristics and a corresponding level of performance. An account that explains how a majority of individuals can attain a given level of expert performance might seem inherently unable to explain the exceptional performance of only a small number of individuals. However, if such an empirical account could be empirically supported, then the extreme characteristics of experts could be viewed as having been acquired through learning and adaptation, and studies of expert performance could provide unique insights into the possibilities and limits of change in cognitive capacities and bodily functions. In this article we propose a theoretical framework that explains expert performance in terms of acquired characteristics resulting from extended deliberate practice and that limits the role of innate (inherited) characteristics to general levels of activity and emotionality. We provide empirical support from two new studies and from already published evidence on expert performance in many different domains.

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The role of deliberate practice in the acquisition of expert performance.

Despite the widespread use of exploratory factor analysis in psychological research, researchers often make questionable decisions when conducting these analyses. This article reviews the major design and analytical decisions that must be made when conducting a factor analysis and notes that each of these decisions has important consequences for the obtained results. Recommendations that have been made in the methodological literature are discussed. Analyses of 3 existing empirical data sets are used to illustrate how questionable decisions in conducting factor analyses can yield problematic results. The article presents a survey of 2 prominent journals that suggests that researchers routinely conduct analyses using such questionable methods. The implications of these practices for psychological research are discussed, and the reasons for current practices are reviewed.

/pdf/evaluating-the-use-of-exploratory-factor-analysis-in-4fpz0boat8.pdf

Evaluating the use of exploratory factor analysis in psychological research.

This review collates and examines critically a theoretically convergent but widely dispersed body of research on the influence of external environments on the functioning of families as contexts of human development. Investigations falling within this expanding domain include studies of the interaction of genetics and environment in family processes; transitions and linkages between the family and other major settings influencing development, such as hospitals, day care, peer groups, school, social networks, the world of work (both for parents and children), and neighborhoods and communities; and public policies affecting families and children. A second major focus is on the patterning of environmental events and transitions over the life course as these affect and are affected by intrafamilial processes. Special emphasis is given to critical research gaps in knowledge and priorities for future investigation. The purpose of this article is to document and delineate promising lines of research on external influences that affect the capacity of families to foster the healthy development of their children. The focus differs from that of most studies of the family as a context of human development, because the majority have concentrated on intrafamilial processes of parent-child interaction, a fact that is reflected in Maccoby and Martin's (1983) recent authoritative review of research on family influences on development. By contrast, the focus of the present analysis can be described as "once removed." The research question becomes: How are intrafamilial processes affected by extrafamilial conditions? Paradigm Parameters In tracing the evolution of research models in developmental science, Bronfenbrenner and Crouter (1983) distinguished a series of progressively more sophisticated scientific paradigms for investigating the impact of environment on development. These paradigms provide a useful framework for ordering and analyzing studies bearing on the topic of this review. At the most general level, the research models vary simultaneously along two dimensions. As applied to the subject at hand, the first pertains

http://rinaldipsych.synthasite.com/resources/Bronfenbrenner.pdf

Ecology of the family as a context for human development: research perspectives

1 Front Matter 2 Executive Summary 3 Part I: Introduction to Reading 4 1. Introduction 5 2. The Process of Learning to Read 6 Part II: Who Are We Talking About? 7 3. Who Has Reading Difficulties? 8 4. Predictors of Success and Failure in Reading 9 Part III: Prevention and Intervention 10 5. Preventing Reading Difficulties Before Kindergarten 11 6. Instructional Strategies for Kindergarten and the Primary Grades 12 7. Organizational Strategies for Kindergarten and the Primary Grades 13 8. Helping Children with Reading Difficulties in Grades 1 to 3 14 Part IV: Knowledge into Action 15 9. The Agents of Change 16 10. Recommendations for Practice and Research 17 References 18 Biographical Sketches 19 Index

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Preventing reading difficulties in young children

Understanding both typical human development and indivdual differences within the same theoretical framework has been difficult because the 2 orientations arise from different philosophical traditions. It is argued that an evolutionary perspective can unite the study of both species-typical development and individual variation. Research on determininants of development from many perspectives can be understood within an evolutionary framework in which organism and environment combine to produce development. Species-normal genes and environments and indidividual variations in genes and environments both affect personality, social, and intellectual development. These domains are used as examples to integrate theories of normal development and individual differences. Within the usual samples of European, North American, and developed Asian countries, the results of family and twin studies show that environments within the normal species range are crucial to normal development. Given a wide range of environmental opportunities and emotional supports, however, most children in these societies grow up to be individually different based on their individual genotypes. Understanding the ways in which genes and environments work together helps developmentalists to identify children in need of intervention and to tailor interventions to their particular needs.

/pdf/developmental-theories-for-the-1990s-development-and-2inmomk7du.pdf

Developmental theories for the 1990s: development and individual differences.

Stress in the parenting role has been found to be related to family functioning and parenting behavior. However, most research in this area has been conducted with clinical samples and has not compared parenting stress of mothers and fathers. In this study, 589 married couples with young children (1

Parenting stress among dual-earner mothers and fathers: Are there gender differences?

Within and Beyond the Classroom Door: Assessing Quality in Child Care Centers.

This study examined the influence on children's social development of variation in the quality of their child-care environments. The sample consisted of 166 children attending representative childcare centers that varied widely in quality. Possible relations associated with age, child-care experience, and family background were controlled using hierarchical multiple regression. Both global estimates of child-care quality and specific program features, such as director experience, ratios, and verbal interactions, were obtained from observational measures and staff questionnaires. Measures of social development were derived from parent and caregiver ratings of the children. Of greatest importance is the finding that overall quality, caregiver-child verbal interactions, and director experience were each highly predictive of the children's social development in child care. Family background measures were also significantly predictive of several of the social outcomes, whereas childcare experience showed few significant effects. The implications for social policies and future research in child care are discussed. The developmental effects of child care have long held interest for psychologists, first because child care represented an intriguing exception to parental care, and now because some form of child care is the norm for over half of all American children. Parallel with these demographic trends, the research literature has shifted from questions that entail comparisons of home-reared children and those enrolled in child care to more sophisticated questions about how children in child care are affected by differences in program quality (Belsky, 1984; Clarke-Stewart & Fein, 1983). A related issue concerns the identification of specific quality indicators that affect child development. A third, relatively new, empirical focus is on the joint effects of child care and family variables (Everson, Sarnat, &

Child-care quality and children's social development.

The poor performance of black children on IQ tests and in school has been hypothesized to arise from (a) genetic racial differences or (6) cultural/ environmental disadvantages. To separate genetic fac- tors from rearing conditions, 130 black/interracial chil- dren adopted by advantaged white families were studied. The socially classified black adoptees, whose natural parents were educationally average, scored above the IQ and the school achievement mean of the white popu- lation. Biological children of the adoptive parents scored even higher. Genetic and environmental de- terminants of differences among the black/interracial adoptees were largely confounded. The high IQ scores of the socially classified black adoptees indicate malle- ability for IQ under rearing conditions that are relevant to the tests and the schools. It is well known that black children reared by their own families achieve IQ scores that average about a standard deviation (IS points) below whites (Jensen, 1973; Loehlin, Lindzey, & Spuhler, 197S). This finding is at the heart of a continuing contro- versy in the educational arena. Recent studies (Cleary, Humphreys, Kendrick, & Wesman, 1975) confirm the hypothesis that low IQ scores predict poor school performance, regardless of race. Thus, more black children than white children fail to achieve academically and to earn the credentials required by higher occupational status, with its

/pdf/iq-test-performance-of-black-children-adopted-by-white-580k5ri2e5.pdf

Sandra Scarr

Papers

Developmental theories for the 1990s: development and individual differences.

Parenting stress among dual-earner mothers and fathers: Are there gender differences?

Within and Beyond the Classroom Door: Assessing Quality in Child Care Centers.

Child-care quality and children's social development.

IQ test performance of Black children adopted by White families.