Some researchers have stressed the negative effects of the peculiar interactive situation of twins on the development of communicative competence; other researchers have shown early positive effects. Referential communication--one of the most evolved, intellectualized, and decentered functions of language that consists of transmitting information…

The paper reports on a study of communication skills in twin infants, a deaf male and a hearing female, who have hearing impaired parents and an older deaf sibling. Videotapes of interaction in the home were transcribed and analyzed according to communication mode and pragmatic function. Findings suggested that both twins were somewhat delayed in…

A study of Kagan's peer play situation for measuring heritable influences on children's behavioral inhibition (that is, shyness) drew its data from the large, multimethod, multivariate MacArthur Longitudinal Twin Study. The MacArthur study examined behavioral inhibition across four ages and two situations, looking for possible sex differences and…

Since the time of Galton, high correlations have been noted in the IQ levels of identical twins, with relationships for twins reared in different families being only slightly lower than for twins reared together. This evidence has been held to demonstrate that intellectual differences among individuals and among groups are largely determined by…

The appropriate-for-gestational-age (AGA) and small-for-gestational-age (SGA) infants from 30 pairs of full-term and 15 pairs of preterm same-sex twins were compared for neonatal temperament. The evaluation of neonatal temperament included ratings of irritability, resistance to soothing, activity level, reactivity, and reinforcement value. Results…

In this case study, the language and cognitive development of a 4-year 5-month old profoundly deaf girl and her normally hearing identical twin sister were investigated by videotaping the twins in their home interacting with each other, the investigator, and family members. Materials used with the children were designed to elicit spontaneous,…

Stability of child and mother characteristics and the predictability of children's cognitive competence and affective characteristics were investigated as part of a longitudinal study. At 2 years of age, 46 sets of male twins and their parents were observed in the home and were rated for attachment, independence, compliance and conscience on the…

The first study presented here looks at the effects of years of schooling on earnings and assesses how much earnings and years of schooling are attributable to inequality of opportunity. The second study examines the effects of schooling on health. The first study examined a sample of approximately 1,000 pairs of identical twins and 900 pairs of…

This data compared language complexity measures, birth information, and family data for twins and singletons of the same sex, age, and socio-economic status. The subjects were four pairs of male twins, four pairs of female twins, four pairs of opposite sex twins, and 24 singletons, 32-33 months of age. Samples of each child's spontaneous…

To investigate the influence of handedness in the referral of elementary school students to a school psychologist, 120 left-handed referrals were matched with 120 right-handed referrals by sex, full-scale intelligence quotient, and chronological age. Comparison of the groups revealed that twins were more numerous among the left-handed students.…

Determinants of Schaefer's (1965) three dimensions of perceived parenting (Acceptance vs. Rejection, Psychological Control vs. Psychological Autonomy, and Firm vs. Lax Control) were investigated by administering a shortened Children's Reports of Parental Behavior Inventory to adolescent twins. The sample consisted of 46 pairs of identical twins…

This paper describes a study which examined the performance of 48 pairs of 18-month-old twins on the Mental Development Scale of the Bayley Scales of Infant Development to determine whether score differences would be found for the three subgroups of identical, fraternal same-sexed, and fraternal opposite-sexed twins. Of the 96 subjects, 46 (23…

To investigate differences in mothers' interaction patterns with their neonate twins based on birth order, relative size at birth, or gender, 37 neonate twins and their mothers were observed during the first 10 minutes of a feeding in a hospital nursery. Time-sampling recordings were made of maternal behaviors related to proximal stimulation,…

Four null hypotheses were formulated to test for relationships between pairs of identical and fraternal twins and their parents on measures of locus of control. Two additional hypotheses were formulated to test for differences between mean scores of identical and fraternal twins and scores of their parents on these same constructs. Twenty pairs of…

This study was designed to assess genetic influence on behavioral inhibition and its varying expression in 92 monozygotic and 86 dizygotic twin pairs. Infant behavior and mother-child interaction were observed and videotaped during structured play sessions at age 14, 20, 24, and 36 months. Analysis of the results suggests that most of the overlap…