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Biomedical subjects

David C Geary

Publications and source records attributed to David C Geary.

15 recordsLinked to original sources
PubMed2006

Second to fourth digit ratio and numerical competence in children.

The ratio between the 2nd and 4th fingers (2D:4D)-a potential proxy for prenatal testosterone (T) exposure-shows a sex difference, with males usually having lower mean values; the latter potentially indicates higher prenatal T exposure. We studied relations between 2D:4D and competencies in the domains of counting, number knowledge, and visual-number representation in 73 children aged 6-11 years. Significant negative correlations between numerical performance in all of these areas and right and left hand 2D:4D ratios were found for boys but not girls. To the extent that 2D:4D ratios reflects prenatal exposure to T, the implications are (i) high prenatal T may be associated with better performance on some basic numerical measures for boys, and (ii) prenatal exposure to T may affect boys and girls differently with respect to some numerical competencies.

Achievement↗
PubMed2006

Parenting and community background and variation in women's life-history development.

For a community sample of 623 low-income women (mean age = 26.9 years), the authors use life-history theory to explore relations between parenting and community background and timing of reproductive development and sexual behaviors. Among other patterns, reported levels of paternal involvement during childhood were related to delayed menarche and ages at 1st sexual intercourse and 1st childbirth. The relation between parental investment and women's reproductive delay varied with estimates of wealth in the community in which the participants grew up. The results suggest that parents increased their investment as the level of community wealth increased, and in ways that likely facilitated women's ability to compete for social status in adulthood. Implications for future research on the relation between parenting and child outcomes are discussed.

Adolescent↗
PubMed2006

Fertility cycle patterns in motives for sexual behavior.

Three studies examined the relationship between fertility, as indexed by day in cycle or salivary estradiol levels, and reported motives for sexual intercourse. Data from university and community samples in both cross-sectional and repeated-measures designs showed that sex-for-intimacy motives are endorsed significantly less by women who are relatively more fertile or show higher salivary estrogen levels. Sex for enhancement, self-affirmation, and partner approval also declined, although the data were less consistent. The remaining motives (coping and power) showed no consistent patterns across fertility status. Results suggest that sexual motives are rooted partly in woman's biology and are discussed in terms of plausible evolutionary mechanisms that might promote female "choosiness" at midcycle.

Adult↗
PubMed2005

The motivation to control and the origin of mind: exploring the life-mind joint point in the Tree of Knowledge System.

The evolved function of brain, cognitive, affective, conscious-psychological, and behavioral systems is to enable animals to attempt to gain control of the social (e.g., mates), biological (e.g., prey), and physical (e.g., nesting spots) resources that have tended to covary with survival and reproductive outcomes during the species' evolutionary history. These resources generate information patterns that range from invariant to variant. Invariant information is consistent across generations and within lifetimes (e.g., the prototypical shape of a human face) and is associated with modular brain and cognitive systems that coalesce around the domains of folk psychology, folk biology, and folk physics. The processing of information in these domains is implicit and results in automatic bottom-up behavioral responses. Variant information varies across generations and within lifetimes (e.g., as in social dynamics) and is associated with plastic brain and cognitive systems and explicit, consciously driven top-down behavioral responses. The fundamentals of this motivation-to-control model are outlined and links are made to Henriques' (2004) Tree of Knowledge System and Behavioral Investment Theory.

Animals↗
PubMed2005

A life history assessment of early childhood sexual abuse in women.

Life history theory provided a framework for examining the relations among child sexual abuse (CSA), childhood adversity, and patterns of reproductive development and behavior. A community survey that assessed CSA, life history variables (e.g., age of menarche), and social and family background was administered to 623 women (mean age=26.9 years). Independent of social and family background, CSA was associated with earlier age of (a) menarche, (b) first sexual relationship, (c) desire to have children, (d) first childbirth, and (e) lower self-evaluated physical attractiveness. Cluster analyses revealed different patterns of experiential correlates of reproductive development within the group of abused women, suggesting CSA may operate in combination with other childhood circumstances to modify the timing and pattern of individual maturation.

Adolescent↗
PubMed2005

Evolution of life-history trade-offs in mate attractiveness and health: comment on Weeden and Sabini (2005).

J. Weeden and J. Sabini's finding of small to no relation between traits rated as attractive in a mate and health of that mate might be interpreted as consistent with C. Darwin's (1859) proposal that these traits are arbitrary signs of beauty. However, such a conclusion would be premature. A combination of consistent empirical findings with nonhuman species and theoretical reasons argues for a continued search for honest signals of genetic fitness and reproductive health in human mate choices. Moreover, (a) even quite small relationships can be important when viewed across generations, and (b) traits that make a potential mate attractive at one age can result in poor health or early death at a later age. These life-history trade-offs greatly complicate the empirical study of attractiveness-health relations, and their potential importance has been underestimated by J. Weeden and J. Sabini.

Attitude↗
PubMed2004

Strategy choices in simple and complex addition: Contributions of working memory and counting knowledge for children with mathematical disability.

Groups of first-grade (mean age = 82 months), third-grade (mean age = 107 months), and fifth-grade (mean age = 131 months) children with a learning disability in mathematics (MD, n = 58) and their normally achieving peers (n = 91) were administered tasks that assessed their knowledge of counting principles, working memory, and the strategies used to solve simple (4+3) and complex (16+8) addition problems. In all grades, the children with MD showed a working memory deficit, and in first grade, the children with MD used less sophisticated strategies and committed more errors while solving simple and complex addition problems. The group differences in strategy usage and accuracy were related, in part, to the group difference in working memory and to group and individual differences in counting knowledge. Across grade-level and group, the switch from simple to complex addition problems resulted in a shift in the mix of problem-solving strategies. Individual differences in the strategy mix and in the strategy shift were related, in part, to individual differences in working memory capacity and counting knowledge.

Adolescent↗
PubMed2004

Evolution of human mate choice.

This article provides a review of evolutionary theory and empirical research on mate choices in nonhuman species and uses it as a frame for understanding the how and why of human mate choices. The basic principle is that the preferred mate choices and attendant social cognitions and behaviors of both women and men, and those of other species, have evolved to focus on and exploit the reproductive potential and reproductive investment of members of the opposite sex. Reproductive potential is defined as the genetic, material, and/or social resources an individual can invest in offspring, and reproductive investment is the actual use of these resources to enhance the physical and social well- being of offspring. Similarities and differences in the mate preferences and choices of women and men are reviewed and can be understood in terms of similarities and differences in the form of reproductive potential that women and men have to offer and their tendency to use this potential for the well-being of children.

Animals↗
PubMed2003

Estrogen fluctuations, oral contraceptives and borderline personality.

Results from three studies suggest fluctuation in estrogen level may influence the expression of borderline personality disorder (BPD) symptoms. In the first study, 226 women were administered the Personality Assessment Inventory, borderline scales (PAI-BOR; L.C. Morey, The Personality Assessment Inventory, Professional Manual, 1991) and a questionnaire that assessed time in menstrual cycle and use of oral contraceptives, that is synthetic estrogens. BPD symptoms were most common in women using oral contraceptives and during times in the menstrual cycle when estrogen level is rising. In Study 2, 52 women were measured four times across one menstrual cycle and provided salivary samples at each test session. The samples were assayed and estrogen levels were obtained. The principle finding was that variation in estrogen levels predicted the presence of BPD symptoms (r=0.4, p<0.01). This relationship remained significant when a general increase in negative affect was statistically controlled. Study 3 employed a pre-post Oral Contraceptive (OC) design with a control group. It was found that for women with high pre-existing levels of BPD, symptoms became significantly worse after starting pill use (F (3,42)=4.7; p<0.01). Research findings that link the serotonin system and estrogen are reviewed and theoretical and practical implications are discussed.

Adolescent↗
PubMed2002

Brain and cognitive evolution: forms of modularity and functions of mind.

Genetic and neurobiological research is reviewed as related to controversy over the extent to which neocortical organization and associated cognitive functions are genetically constrained or emerge through patterns of developmental experience. An evolutionary framework that accommodates genetic constraint and experiential modification of brain organization and cognitive function is then proposed. The authors argue that 4 forms of modularity and 3 forms of neural and cognitive plasticity define the relation between genetic constraint and the influence of developmental experience. For humans, the result is the ontogenetic emergence of functional modules in the domains of folk psychology, folk biology, and folk physics. The authors present a taxonomy of these modules and review associated research relating to brain and cognitive plasticity in these domains.

Animals↗
PubMed2002

Sex differences in behavioral and hormonal response to social threat: commentary on Taylor et al. (2000).

Taylor and colleagues proposed that women uniquely respond to stressors by tending to children and befriending other women rather than by fighting or fleeing (S. E. Taylor et al., 2000). In this article, the authors expand Taylor et al.'s evolutionary frame and incorporate several unique aspects of human social dynamics. First, humans are characterized by extensive paternal investment, and thus men's tending is predicted and observed in some stressful contexts. Second, the dynamics of women's befriending suggest an evolutionary elaboration of the mechanisms that support reciprocal altruism. Third, coalitional male-male competition indicates that men's befriending is a predicted component of their fight-or-flight response. Finally, men's tending should result in the evolution of female-female competition over this form of parental investment.

Altruism↗
PubMedDate not supplied

Mathematics and learning disabilities.

Between 5% and 8% of school-age children have some form of memory or cognitive deficit that interferes with their ability to learn concepts or procedures in one or more mathematical domains. A review of the arithmetical competencies of these children is provided, along with discussion of underlying memory and cognitive deficits and potential neural correlates. The deficits are discussed in terms of three subtypes of mathematics learning disability and in terms of a more general framework for linking research in mathematical cognition to research in learning disabilities.

Child↗
PubMedDate not supplied

Role of cognitive theory in the study of learning disability in mathematics.

Gersten, Jordan, and Flojo (in this issue) provide the beginnings of an essential bridge between basic research on mathematical disabilities (MD) in young children and the application of this research for the early identification and remediation of these forms of learning disability. As they acknowledge, the field of MD is in the early stages of development, and thus recommendations regarding identification measures and remedial techniques must be considered preliminary. I discuss the importance of maintaining a tight link between theoretical and empirical research on children's developing numerical, arithmetical, and mathematical competencies and future research on learning disabilities in mathematics. This link will provide the foundation for transforming experimental procedures into assessment measures, understanding the cognitive strengths and weaknesses of children with these forms of learning disability, and developing remedial approaches based on the pattern of cognitive strengths and weaknesses for individual children.

Cognition↗