Family size,birth order,and intelligence in a large South American sample

The confluence theory, which hypothesizes a relationship between intellectual development birth order, and family size, was examined in a colombian study of more than 36,000 college applicants. The results of the study did not support the confluence theory. The confluence theory states that the intellectual development of a child is related to average mental age of the members of his family at the time of his birth. The mental age of the parents is always assigned a value of 30 and siblings are given scores equivalent to their chronological age at the birth of the subject. Therefore, the average mental age of family members for a 1st born child is 30, or 60 divided by 2. If a subject is born into a family consisting of 2 parents and a 6-year old sibling, the average mental age of family members tends, therefore, to decrease with each birth order. The hypothesis derived from the confluence theory states that there is a positive relationship between average mental age of a subject's family and the subject's performance on intelligence tests. In the Colombian study, data on family size, birth order and socioeconomic status was derived from college application forms. Intelligence test scores for each subject was obtained from college entrance exams. The mental age of each applicant's family at the time of the applicant's birth was calculated. Multiple correlation analysis and path analysis were used to assess the relationship. Results were 1) the test scores of subjects from families with 2,3,4, and 5 children were higher than test scores of the 1st born subjects; 2) the rank order of intelligence by family size was 3,4,5,2,6,1 instead of the hypothesized 1,2,3,4,5,6; and 3) only 1% of the variability in test scores was explained by the variables of birth order and family size. Further analysis indicated that socioeconomic status was a far more powerful explanatory variable than family size.     

Sibship composition,birth order and education: Evidence from Vietnam

This paper examines the effects of sibship composition and birth order on the school enrolment and educational attainment of children, using data from the Vietnam Population and Housing Census 2009. Utilizing an instrumental variable estimation method to address the endogeneity of sibship size, we find that it has a significant, negative effect on child education. Examining the impact of sibling sex composition, we find that having an additional boy lowers children’s average educational attainment for both girls and boys. We establish that birth order has a significant, negative effect on child educational attainment, although that effect seems to vanish with the youngest sibling. Our findings have several policy implications. First, the negative effect of sibship size on education implies that Vietnam’s lower fertility rate, the result of family planning policy during the 1990s and 2000s, may contribute to its remarkable educational achievements. Second, we find that birth order and sibling sex composition are more important than sibship size in children’s educational outcomes. As parents disproportionately allocate more resources for boys and earlier born children, government-targeted programs should tackle those issues to provide equal school opportunities for all children.     

Birth order,family size and educational attainment

This paper investigates the effect of family size and birth order on educational attainment. An instrumental variables approach is used to identify the effect of family size. Instruments for the number of children are twins at last birth and the sex mix of the first two children. The effect of birth order is identified, by examining the relation with years of education for different family sizes separately. No significant effect of family size on educational attainment of the oldest child is found. Birth order has a significant negative effect. Potential mechanisms behind the birth order effects are investigated. The results show that birth order effects are not affected by the average age gap between children. Information on financial transfers shows that earlier born children have a higher probability of receiving money from their parents than later born children, also the amount they receive is higher. These results indicate that the allocation of parental resources is a potential mechanism behind the birth order effects.     

Stress levels and attitudes of normal siblings of children with disabilities

This study examines the effects on normal children of the presence in the family of siblings with disabilities, attempting to measure both their level of stress and attitudes towards disability. The stress level and attitudes towards disability of normal siblings of children with disabilities (SCD) and siblings of normal children (SNC) were compared in terms of gender, family size and educational level. The stress level was measured by Holroyd's Questionnaire on Resources and Stress; attitudes towards disability were examined by Attitudes Towards Disabled Person Scale. 60 subjects participated in this study; 30 of them were SCD and 30 of them were SNC. t-test was used for data analysis. Results revealed a significant difference between the stress level of SCD and SNC. However, no significant difference was found between two sibling groups' attitudes towards disability. Also, gender, family size and educational level showed no significant difference either on the stress level of both sibling groups nor on their attitudes towards disability.This study is based on the master thesis of the first author.     

Analysis of Covariance in a Randomly Replicated Arithmetic Methods Experiment

Birth order was used to predict grades and school related attitudes following Bradley’s hypothesis that first-borns are more academically interested and less socially interested than later borns. Income, sex of child, and size of family were studied as interacting variables. Several interaction effects were found in the absence of birth order main effects which indicate a need to study birth order as an interacting variable rather than as a single independent variable.     

The implications of family size and birth order for test scores and behavioral development

This article, using longitudinal data from the National Child Development Study, presents new evidence on the effects of family size and birth order on test scores and behavioral development at age 7, 11 and 16. Sibling size is shown to have an adverse causal effect on test scores and behavioral development. For any given family size, first-borns ultimately obtain higher test scores than middle-born or last-born children. First-borns and last-borns tend to be better behaved at school than middle-borns, though last-borns have no test score advantage.     

Educational consequences of a sibling's disability: Evidence from type 1 diabetes

While there is a growing literature on family health spillovers, questions remain about how sibling disability status impacts educational outcomes. As disability is not randomly assigned this is an empirical challenge. In this paper we use Danish administrative data and variation in the onset of type 1 diabetes to compare education outcomes of focal children with a disabled sibling to outcomes of focal children without a disabled sibling (matched on date of birth of the focal child, sibling spacing and family size). We find that having a disabled sibling significantly decreases 9^th grade exit exam GPAs, while having no impact on on-time completion of 9^th grade. However, educational trajectories are impacted, as we find significant decreases in high school enrollment and significant increases in vocational school enrollment by age 18. Our results indicate that sibling disability status can generate economically meaningful inequality in educational outcomes.     

Birth order and parental and sibling involvement in sex education. A nationally-representative analysis

This analysis set out to identify associations between birth order and sexual health outcomes, focusing on family involvement in sex education and early sexual experiences. The third National Survey of Sexual Attitudes and Lifestyles is a stratified probability sample survey of 15 162 men and women aged 16–74 in Britain. Logistic regression was conducted to identify odds ratios for the association between birth order and sexual health outcomes. Multiple logistic regression was performed adjusting for socio-demographic factors and sibling number. Middle-born and last-born men had lower odds of reporting ease talking to parents about sex around age 14 and learning about sex from their mothers. Last-born women had lower odds of reporting a parental main source of sex education or having learned about sex from their mother. Findings represent an exploratory analysis in an under-researched area, and provide the basis for further research on the association between birth order and parental involvement in sex education, as well as the role and impact of sex education provided by older siblings.     

Intergenerational correlations in educational attainment: Birth order and family size effects using Canadian data

We exploit the 1986, 1994, and 2001 waves of the Canadian general social surveys in order to estimate intergenerational correlations in education. The use of these specific data is important because of available information on the final educational attainment of survey respondents and both parents, as well as family size and birth order. OLS estimates reveal that: (1) relying exclusively on maternal schooling to capture the effects of parental education results in coefficient estimates that are biased upwards; (2) children born to parents with some post-secondary schooling are more likely to attain similar education levels than children born to parents with lower educational accomplishment; (3) in most specifications coefficient estimates of paternal schooling are greater in magnitude than maternal accomplishment; and finally, (4) coefficient estimates of the number of siblings are consistently negative and significant even after the inclusion of birth order effects, implying that a larger family is correlated with a reduced likelihood of post-secondary education.     

Sisters, brothers, and delinquency: evaluating social influence during early and middle adolescence

Although a number of studies have shown that brothers are highly correlated for delinquent behavior, much less research has been conducted on sisters. We propose that sisters, like brothers, show notable similarity for delinquent behavior, and also promote each other's delinquency through direct interaction. We examined these issues in 164 brother and sister pairs studied over a 4-year period (from early to middle adolescence) in a study of intact families in the rural Midwest. Sibling similarity for self-reports of delinquent behavior were highly correlated for both brothers and sisters. Conditional effects of high levels of hostile-coercive sibling relationships and older sibling delinquency predicted younger sibling delinquency in both brother and sister pairs. For brothers, conditional effects were also detected for high levels of warmth-support, in contrast to sisters. The conditional effects of older sibling delinquency and relationship quality were shown to predict change in younger sibling delinquency through adolescence. The results add to a growing literature on sibling effects as well as theoretical models that emphasize the role of social interaction between siblings as a risk factor for the development of delinquent activity in adolescence.     

Korean Adoptees’ Discursive Construction of Birth Family and Adoptive Family Identity Through Names and Labels

Framed by a social constructionist approach to language, this study explored Korean adoptees’ naming and labeling practices for members of their birth family and the motives underlying these choices. In-depth interviews were conducted with 19 Korean adoptees who had reunited with at least one member of their birth family. Participants discussed how they addressed (named) and referred to (labeled) members of their birth family, and explained why these names and labels were used. Most participants used Korean terms of address (e.g., ??: omma for mother, ??: appa for father) to address members of their birth family. Other participants used labels from their own “native” (i.e., their adopted country’s) language, avoided addressing their birth parents, or, occasionally, used their birth parent’s first name. Participants tended to refer to their birth families as their birth/biological family, or Korean family; however, some participants stated that their terms of reference depended on context. Participants’ naming choices reflected three main motives: an appeal to family identity (relative closeness to their birth or adoptive family), an appeal to outsiders (to protect the feelings of their adoptive family), and an appeal to pragmatism (for clarity). Theoretical and practical implications are discussed.     

Human affection exchange: VII. Affectionate communication in the sibling/spouse/sibling‐in‐law triad

This study sought to investigate affectionate communication among members of sibHng/spouse/sibling‐in‐law triads as well as the influence of such communication on relational quality. Under the principles of Affectionate Exchange Theory, affectionate communication among these family members may ultimately serve the evolutionary mandates of viability and procreation. Three hundred twenty‐seven participants, comprising 109 sibling/spouse/sibling‐in‐law triads, completed surveys about their communication of affection, relational satisfaction, and closeness. Consistent with predictions, spouses reported communicating more affection to each other than did siblings, who reported communicating more affection than siblings‐in‐law. The communication of affection by spouses and siblings showed a significant correlation, as did the communication of affection by siblings and siblings‐in‐law, and these correlations were significant even when controlling for the affection communicated in the third relationship in the triad (except for nonverbal support communicated in the sibling and marital relationships). Finally, for all three relational types, affectionate communication was positively correlated with both relational satisfaction and closeness.     

Parent-Child Relationships, Family Problem-Solving Behavior, and Sibling Relationship Quality: The Moderating Role of Sibling Temperaments

In this study we sought to determine whether sibling temperaments moderated the associations of parent-child relationship quality and family problem-solving behavior with sibling relationship quality. Observational assessments of mother-child and father-child relationship quality, family problem-solving behavior, and sibling relationship quality were obtained from the families of 49 pairs of brothers and 46 pairs of sisters. Mean ages were 10-2 for older siblings and 7-6 for younger siblings. Parent-reported child temperament assessments were also obtained. The links among mother–older child relationship quality, father–older child relationship quality, and sibling relationship quality were moderated by the older sibling's temperament. The younger and older siblings' temperaments moderated the associations between the quality of the father–younger sibling and sibling relationships. The association between family problem-solving behavior and sibling relationship quality was not moderated by sibling temperaments.     

The development of interpersonal aggression during adolescence: the importance of parents, siblings, and family economics

Latent growth curve modeling employed data from a longitudinal study of 451 sibling families to examine parents, siblings, and family economics as factors in individual differences in the developmental course of interpersonal aggression during adolescence. Findings suggest that individual change in interpersonal aggression during adolescence can be predicted by the gender and aggression of one's sibling; predictions varied by the gender composition of the sibling dyad. Rates of parental hostility predicted levels of interpersonal aggression for both older (mean age = 12 years) and younger siblings (mean age = 15), and growth in aggression for younger siblings. Family economic pressure predicted interpersonal aggression of both siblings indirectly through parental hostility. Implications for future research and preventive interventions are discussed.     

Intellectual development in family constellations with adopted and natural children: a test of the Zajonc and Markus model

A confluence model was developed by Zajonc and Markus to account for the effects of birth order, child spacing, and family size on intellectual development. the fit of the model was tested on a sample of families with biological and adopted children. Although the model fits population data very well, it fails to account for intellectual patterns within families for whom both parent and child IQ data are available. The discrepancy is discussed in terms of sources of variance within and between families that are undetected in average values for a population.     

Children's perceptions of the qualities of sibling relationships

Although many studies of family constellations exist, only recently have investigators begun to examine the qualities of sibling relationships. The purpose of the present investigation was to develop a systematic framework for describing and assessing such relationship qualities. In the first study, upper elementary school children were interviewed about their perceptions of the qualities of their sibling relationships. These interviews yielded a list of 15 salient qualities. In the second study, a self-report questionnaire that assessed their perceptions of these qualities was administered to a sample of 198 fifth- and sixth-grade children. A principal components analysis yielded 4 underlying factors: (a) Warmth/Closeness, (b) Relative Status/Power, (c) Conflict, and (d) Rivalry. Relative Status/Power was found to be strongly related to the relative ages of the child and sibling. The other 3 factors were also related to various family constellation variables, but these relations were modest in size. Because family constellation variables and the qualities of sibling relationships are not isomorphic with one another, it is important to study relationship qualities directly, rather than simply examining family constellation variables. Some of the determinants of such qualities are discussed.     

Risk of maltreatment for siblings: Factors associated with similar and different childhood experiences in a dyadic sample of adult siblings

Siblings share the same environment and thus potentially a substantial number of risk factors for child maltreatment. Furthermore, the number of siblings and the sibling constellation itself might pose a risk for child maltreatment. Little is known about the likelihood that more than one child in a family is maltreated and which factors increase the risk. This study sought to investigate similarities and differences in maltreatment in siblings and risk factors associated with the maltreatment of more than one child from the same family. Data on maltreatment during childhood and adolescence, family background, and sibling constellation were collected from 870 pairs of siblings. In the dyadic analyses, siblings reported similar maltreatment experiences, especially when any type of maltreatment was considered. Parents’ mental health problems were significant predictors for maltreatment of at least one sibling. Father’s mental health problems were predictive of maltreatment of both or only the younger sibling, mother’s mental health problems of both or only the older sibling. Closeness in age and same gender of siblings did not emerge as a consistent predictor. The increasing number of siblings was a risk factor for any type of maltreatment of both siblings. The results highlight the need for preventive measures for families with a large number of children and with parents with mental health problems as well as a repeated risk assessment of all siblings in a family when one sibling was maltreated.     

Does sibling gender affect personality traits?

This paper studies whether sibling gender affects personality traits. We use the idea that if parents decide to have a second child, it is random whether they will have a boy or a girl. Therefore, the relationship between the second-born sibling's gender and the first sibling's personality traits is causal. We employ longitudinal data from a large British cohort which is followed from birth onwards. The dataset includes personality traits at age 10 and 16. Our main result is that oldest boys in a household are more agreeable if their next-born sibling is a girl. This effect is robust across age (10 and 16), when controlling for among others family size, and when applying corrections for multiple hypothesis tests. Agreeableness is an important trait in life as it has been shown to correlate positively among others with being employed, having a skilled job, savings, and life satisfaction.     

The similarity of siblings' attachments to their mother

Do siblings develop similar attachment relationships with their mother? Attachment theory suggests that brothers and sisters growing up in the same family are likely to relate in similar ways to their parents, at least when parental attachment representations and interactive styles remain stable across time. In the current study, sibling attachment data from three research groups (from Pennsylvania State University, Leiden University, and the University of Western Ontario) have been pooled to assemble a sufficiently large sample of observations (N = 138 sibling pairs) for a detailed comparison of sibling attachment relationships. Spacing between the births, differences in maternal sensitivity, and gender of siblings were examined as possible sources of concordance of nonconcordance. Attachment security (including disorganized attachment) of each sibling was assessed with the Strange Situation procedure between 12 and 14 months after birth. Maternal sensitivity was observed with the same rating scale in a laboratory play session in one of the studies and in home observations in the others. Sibling relationships were found to be significantly concordant when classified as secure/nonsecure (62% concordance, p < .01, 1-tailed, intraclass correlation = .23) but not when further subcategorized. Maternal insensitivity to both siblings (shared environment) was associated with concordance of sibling nonsecurity. Siblings of the same gender were more likely to form concordant relationships with their mother (68%; p < .01, 1-tailed, intraclass correlation = .37) than those of opposite gender. Same-sex sibling concordance was comparable to the concordance found for monozygotic twins in earlier studies. Genetic factors may, therefore, play a relatively small role in the development of attachment.     

The Development of Empathic Concern in Siblings: A Reciprocal Influence Model

This study utilized actor–partner interdependence modeling to examine the bidirectional effects of younger (M_age = 18 months) and older siblings (M_age = 48 months) on later empathy development in a large (n = 452 families), diverse (42% immigrant) Canadian sample. Controlling for parenting, demographic characteristics, sibling relationship quality, and within-child stability in empathic concern, both younger and older siblings’ observed empathic concern uniquely predicted relative increases in the other's empathy over a period of 18 months. The strength of the partner effects did not differ by birth order. Sex composition moderated the younger sibling partner effect, whereas age gap moderated the older sibling partner effect. This study highlights the important role that siblings play in enhancing the development of care and concern for others.