'H, I, J, K, L, M, N, O, PEE! Get it? Pee!': Siblings' shared humour in childhood.

Humour is a central feature of social interactions in childhood that has received little attention. In a sample of 86 7-year-old children (M age = 7.82 years, SD = 0.80), we investigated patterns and individual differences in spontaneous humour observed during free play with their older (M age = 9.55 years, SD = 0.88) or their younger sibling (M age = 5.87 years, SD = 0.96). We coded children's instances, categories, and responses to humour. We investigated the nature of children's humour on the dyadic and individual level. Humour was common, and siblings' production of humour was highly interdependent between play partners. Dyadic humour differed according to structural features of the sibling relationship (age, gender composition), and 7-year-old focal children's humour varied according to gender. This study contributes to knowledge regarding the dyadic nature of children's humour and individual patterns of humour beyond the preschool years. Statement of contribution What is already known on this subject? Humour is an integral part of children's close and intimate interactions. Children produce humour from an early age and increasingly produce more complex humour as they develop. Few studies examine children's humour with siblings and beyond the fourth year of life. What does this study add? Children's humour during free play with siblings was common and highly dyadic. Sibling dyads' humour differed according to age and gender composition. Seven-year-old boys produced more humour than girls.

Longitudinal development of secondary sexual characteristics in girls and boys between ages 91/2 and 151/2 years.

OBJECTIVES: To identify ages when adolescents were in sexual maturity stages 2 through 5; to explain the relations between breast (girls), genital (boys), and pubic hair (girls and boys) development between ages 9(1/2) and 15(1/2) years; and to evaluate synchrony of pubertal development across characteristics. DESIGN: Annual pubertal assessments. SETTING: Ten locations in the United States. PARTICIPANTS: A total of 859 adolescents (427 boys [49.7%] and 432 girls [50.3%]; 737 white [85.8%] and 122 black [14.2%]). MAIN OUTCOME MEASURES: Changes in the 5 stages of breast, genital, and pubic hair development. RESULTS: Girls were in breast maturity stages 2 and 3 earlier than comparable pubic hair stages. Although breast development in girls started earlier than pubic hair development, girls completed breast and pubic hair development at approximately the same age. Black girls were in all stages of breast and pubic hair development earlier than white girls. Boys were in stages 2, 3, 4, and 5 of genital development before the comparable pubic hair stage. In boys, genital development started earlier than pubic hair development, but pubic hair development was completed in less time. Black boys were in genital and pubic hair development about 7 months earlier than white boys. Black and white boys completed genital development in approximately 4(1/2) years, but black boys took approximately 6 months longer than white boys to complete pubic hair development. At stage 2, for 66.2% of girls, breast development preceded their pubic hair development; for 91.1% of boys, genital development preceded their pubic hair development. CONCLUSIONS: The results of this study are useful in understanding normative variation in the timing and change in the development of secondary sexual characteristics at puberty. They will help identify adolescents with atypical changes in sexual maturation and unusual progression of sexual maturation and growth disorders.

Family rearing antecedents of pubertal timing.

Two general evolutionary hypotheses were tested on 756 White children (397 girls) studied longitudinally: (1) rearing experiences would predict pubertal timing; and (2) children would prove differentially susceptible to rearing. Analysis of pubertal measurements, including some based on repeated physical assessments, showed that mothering and fathering, earlier and later in childhood, predicted pubertal development, but only for girls, with negative parenting appearing most influential; maternal harsh control predicted earlier menarche. Rearing effects varied by infant negative emotionality, proving stronger (and opposite) for girls who in infancy were lower rather than higher in negativity. Maternal menarche, controlled in all analyses, was a stronger predictor than rearing. Findings are discussed in terms of theory development, genetic and nutritional influences, and sample restrictions.