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Biomedical subjects

E E Maccoby

Publications and source records attributed to E E Maccoby.

At least 19 recordsLinked to original sources

Different reproductive strategies in males and females.

The claim for a connection between stressful, unstable childhood environments and early pubertal maturation has only modest empirical support. However, granting the claim for purposes of discussion, and taking an evolutionary perspective, it is argued here that early puberty need not imply a shift from a "quality" toward a "quantity" reproductive strategy. Indeed, for females to make such a shift when they cannot count on secure pair bonding or paternal investment from a male would not serve their inclusive fitness interests; indeed, probably the reverse. Delayed puberty among juveniles with secure, long-continued bonds with the parental generation may serve a different evolutionary function: to minimize inbreeding. Nonevolutionary factors are more than adequate to account for precocious sexuality in individuals with stressful childhood histories.

Animals

Caught between parents: adolescents' experience in divorced homes.

This study examined adolescents' feelings of being caught between parents to see whether this construct helps to explain (1) variability in their postdivorce adjustment and (2) associations between family/child characteristics and adolescent adjustment. Adolescents 10 to 18 years old (N = 522) were interviewed by telephone 4 1/2 years after their parents' separation. Feeling caught between parents was related to high parental conflict and hostility and low parental cooperation. Being close to both parents was associated with low feelings of being caught. The relation between time spent with each parent and feeling caught depended on the coparenting relationship. Adolescents in dual residence were especially likely to feel caught when parents were in high conflict, and especially unlikely to feel caught when parents cooperated. Feeling caught was related to poor adjustment outcomes. Parental conflict was only related to adjustment outcomes indirectly, through adolescents' feelings of being caught.

Adaptation, Psychological

Gender and relationships. A developmental account.

This article argues that behavioral differentiation of the sexes is minimal when children are observed or tested individually. Sex differences emerge primarily in social situations, and their nature varies with the gender composition of dyads and groups. Children find same-sex play partners more compatible, and they segregate themselves into same-sex groups, in which distinctive interaction styles emerge. These styles are described. As children move into adolescence, the patterns they developed in their childhood same-sex groups are carried over into cross-sex encounters in which girls' styles put them at a disadvantage. Patterns of mutual influence can become more symmetrical in intimate male-female dyads, but the distinctive styles of the two sexes can still be seen in such dyads and are subsequently manifested in the roles and relationships of parenthood. The implications of these continuities are considered.

Child

Neonatal sex-steroid hormones and cognitive abilities at six years.

Five sex-steroid hormones (testosterone, androstenedione, estradiol, estrone, and progesterone) were assayed in umbilical cord blood. Cognitive abilities were assessed as a part of a 6-year follow-up laboratory visit. Four subtests were given: reading, numbers, listening, and spatial ability. There were no significant differences between boys and girls in cognitive ability scores. Higher levels of perinatal androgens (testosterone and androstenedione) were significantly associated with low age-6 spatial ability in girls. Multiple regression analyses revealed a significant proportion of the variance in cognitive abilities in girls could be accounted for by testosterone and androstenedione. No significant predictions were found for boys. The finding of a stable inverse association between sex and effect of hormones on abilities is discussed.

Achievement

Individual differences in mood in early childhood: their relation to gender and neonatal sex steroids.

Predominant mood states were assessed for 104 children via 24-hr mother diaries during the first 2 years of life. Consistent sex differences were found across ages and across cohorts: boys were more often reported to be in a happy/excited mood, girls in a quiet/calm mood. The sexes did not differ in the frequency of negative moods (including crying), however. Scores for happy/excited and quiet/calm mood states were quite stable across the ages sampled: 6, 9, 12, 18, and 26 months. These stabilities were generally greater for boys. Negative moods showed only borderline stability. Relationships between the mood scores and five sex-steroid hormones (progesterone, androstenedione, testosterone, estrone, and estradiol), assayed from umbilical cord blood at the time of the children's birth, were assessed. For boys small, but significant, positive relationships were found between happy/excited moods and androstenedione, estrone, and progesterone. Correlations of opposite sign were found between these hormones and boys' scores for quiet/calm mood. For girls, the correlations were low and insignificant, but generally of opposite sign from those found for boys, and a number of hormones showed significant sex-by-hormone interactions in their relation to children's mood scores. The implication of these findings for the understanding of sex differences is discussed. Also discussed are the problems of interpretation posed by the intercorrelations among hormones when hormone scores are used for prediction of aspects of later development.

Affect

Neonatal sex-steroid hormones and muscular strength of boys and girls in the first three years.

Five sex-steroid hormones were assayed in umbilical cord blood. Strength was assessed in children in three samples at several ages from birth to 33 months. At different ages, different strength measures were taken, viz., at birth, prone head responses; at 3 months, leg strength; from 6 to 33 months, grip strength. Boys had higher average strength scores than girls but the sex differences were small and did not increase or decrease over the age period studied. Across-age strength scores showed a significant relation to androstenedione and a significant interaction of sex and progesterone. Both boys and girls with higher strength scores had lower androstenedione. Girls with high cord blood progesterone showed low strength while boys with high progesterone showed high strength. There were no sex differences in androstenedione or progesterone level. The androstenedione finding did not replicate across samples but the Progesterone X Sex interaction was replicated in all three samples. No relationship was found between strength and other hormones assayed: testosterone, estradiol, and estrone.

Androstenedione

Sex-typing behavior and sex-typing pressure in child/parent interaction.

The sex-typing of children and the sex-typing pressure of parents was investigated during free play in a home visit. There were 30 male and 24 female 45-month-olds observed with their mothers and fathers in separate free-play sessions during which an array of both sex-stereotyped and neutral toys were available. Behavioral observations were recorded for a variety of parent, child, and dyadic behaviors, including initiations of sex-typed play, total sex-typed play, and rough-and-tumble play. Children initiated sex-typed play and played with sex-appropriate toys. Father-child and mother-daughter dyads were more likely to engage in thematic play appropriate to the child's sex, while in mother-son dyads equal amounts of masculine and feminine play occurred. In addition father-son dyads displayed the highest levels of rough-and tumble play and arousal of child by parent. The results suggest that fathers are the discriminating influence on sex-appropriate play.

Child, Preschool

Neonatal sex-steroid hormones and timidity in 6-18-month-old boys and girls.

Five sex-steroid hormones (testosterone, androstenedione, estradiol, estrone, and progesterone) are assayed in umbilical cord blood. Timidity is assessed in home and laboratory observations by reactions to a range of novel toys in children from 6 to 18 months of age. Significant short- (1 week) and long- (several months) term stability in timidity is demonstrated. Girls have higher mean scores on observed timidity than do boys in 2 of the 3 samples tested. An across-age timidity score is computed which shows significant correlations with neonatal progesterone, testosterone, and estradiol for boys, but is not significantly predicted by hormone concentrations in girls.

Androstenedione

Sex differences in aggression: a rejoinder and reprise.

A meta analysis of observational studies of peer-directed aggression by children aged 6 and younger yields a highly significant sex difference. Out of 32 studies, z values reflected higher male aggression in 24, no difference in 8, higher female aggression in none. Furthermore, boys' aggression is most often displayed in the presence of male partners. Evidence is presented that the sex difference is probably not merely an artifact of higher rates of male activity or social interaction. Existing cross-cultural evidence also shows higher rates of male aggression, as does most of the work on free-living primates. Specifically, the 3 observational studies of chimpanzees show considerably more aggression in males. Evidence for a hormonal contribution to male aggression is clear in animals and inconclusive in human beings, although the existing human findings are consistent with such a contribution. Recent evidence on the differential socialization of boys and girls supports our earlier view: that boys do not receive more reinforcement for aggression than girls, and that rates of punishment are also similar once the differential base rates in aggression are taken into account. The role of self-socialization (including choice of same-sex models) is discussed, and the view is expressed that this probably depends upon the development of certain cognitions about sex identity which normally do not develop until a later age than the age at which a consistent sex difference in aggression first appears.

Adolescent

Concentrations of sex hormones in umbilical-cord blood: their relation to sex and birth order of infants.

In 3 groups of human newborns, 5 sex hormones were assayed from samples of umbilical-cord blood, and concentrations were analyzed by the sex and birth order of the infants. The 5 hormones assayed were testosterone, androstenedione, estrone, estradiol, and progesterone. Concentrations of testosterone were significantly greater in males than females. The other 4 hormones did not differ significantly by sex. In both sexes, firstborns had significantly more progesterone and estrogens, with progesterone showing the largest birth-order effects. Among male infants, firstborns had higher concentrations of testosterone. The higher concentrations of progesterone in firstborns of both sexes, and of testosterone in firstborn boys, were found not to be due to length of labor, birth weight, or maternal age. However, they were a function of temporal spacing of childbirths. Later borns who were closely spaced in relation to their next-older siblings had lower concentrations of hormones. The effect of temporal separation was greater on male than female infants for each of the 5 hormones studied. The results are discussed in terms of the possible effects of hormone "depletion" on the psychological development of closely spaced later borns.

Androstenedione