The influence of rearing order on personality development within two adoption cohorts

There is an extensive literature on the relationship between birth order and psychological traits, but no previous study has investigated the influence of ordinal position on personality development within adoptive siblings. Such a design is important because it effectively separates the effects of biological birth order and rearing order. Here we report data from two adoption cohorts in which subjects were biological first-borns reared in various ordinal positions. Data were analyzed with reference to Sulloway's (1996) evolutionarily based sibling rivalry theory of birth order effects. Between- and within-family analyses indicated that rearing order's influence on personality was very weak. The only clear difference was for conscientiousness, on which first-reared siblings scored higher. We draw possible implications for Sulloway's theory and speculate upon an alternative, prenatal biological process that may produce birth order differences.     

Birth Order Effects on Personalityand Achievement Within Families

We investigated birth order effects on personality and achievement in four studies (N = 1,022 families) including both student and adult samples. Control over a wide range of variables was effected by collecting within-family data: Participants compared their siblings (and themselves) on a variety of personality and achievement dimensions. Across four diverse data sets, first-borns were nominated as most achieving and most conscientious. Later-borns were nominated as most rebellious, liberal, and agreeable. The same results obtained whether or not birth order was made salient (to activate stereotypes) during the personality ratings. Overall, the results support predictions from Sulloway's niche model of personality development, as well as Zajonc's confluence model of intellectual achievement.     

The associations of birth order with personality and intelligence in a representative sample of U.S. high school students

We tested birth order associations with personality traits and intelligence using Project Talent, a representative sample (N = 377,000) of U.S. high school students. Using a between-family design and several background factors (i.e., age, sex, sibship size, parental socio-economic status, and family structure), we were able to control for potential confounds, and estimate the links between birth order and outcomes across several different social categories. In addition to differences between firstborns and laterborns across the entire sample, we also tested birth rank trends in a sub-sample of targets from sibships of three, raised by two parents. Overall, the average absolute association between birth order and personality traits was .02, whereas the one between birth order and intelligence was .04.     

Associations between Birth Order and Personality Traits: Evidence from Self-Reports and Observer Ratings

Sulloway (1996) proposed that personality traits developed in childhood mediate the association of birth order with scientific radicalism. Birth-order effects on traits within the five-factor model of personality were examined in three studies. Self-reports on brief measures of Neuroticism, Extraversion, and Openness in a national sample (N= 9664) were unrelated to birth order. Self-reports on the 30 facet scales of the Revised NEO Personality Inventory (NEO-PI-R) in an adult sample (N= 612) showed only small effects for Altruism and Tender-Mindedness. Peer ratings (N= 166) supported the hypotheses that laterborn children would be higher in facets of Openness and Agreeableness, but spouse ratings (N= 88) did not replicate those findings. Birth order may have subtle effects on perceived personality, but it is unlikely that this effect mediates associations with scientific radicalism.     

Personality and life satisfaction in China: The birth order effect under the influence of national policy

Individuals’ development is a multilayered affair. The influence of family relationship on personality, such as  and  focusing on birth order, is subject to influence from other social systems in which the families are situated. The current research examined the relation of birth order to personality and life satisfaction in China, where only children have become the majority because of national policy. Across two studies with both between-family data (N = 1468) and within-family data (N = 171), onlyborns and laterborns surpassed firstborns on openness to experience. In addition, only-child participants were more satisfied with their own lives than were sibling participants, especially laterborns. The results offer new insights into the dynamic relations between ecology and personality.     

Birth order differences in normal personality traits: Perspectives from within and outside the family

The hypotheses of Sulloway (1996) regarding birth order differences in five-factor model personality traits were tested in a sample of 231 college students with the NEO Five-Factor Inventory (NEO-FFI; Costa & McCrae, 1992). Data were collected from three sources (self, peer, and parent) to systematically evaluate previous observations that birth order differences are more commonly found when ratings are obtained from family members than from observers outside the family (Ernst & Angst, 1983). Using a between-family design, students were selected only from families with two or three full biological siblings and no half-siblings, step-siblings, or adopted siblings. Firstborn (n = 103) and laterborn (n = 128) students were compared using NEO-FFI ratings by the self, by a same-sex college peer, and by a biological parent. No birth order differences were found for any of the five NEO-FFI scores using any of the three rating sources. Effect sizes (Cohen’s d) were less than .20 for all comparisons. Suggestions for new approaches to the study of birth order differences are considered, including the use of within-family designs and more contextualized personality variables.     

Birth order and selected work-related personality variables

A possible link between birth order and various individual characteristics (e. g., intelligence, potential eminence, need for achievement, sociability) has been suggested by personality theorists such as Adler for over a century. The present study examines whether birth order is associated with selected personality variables that may be related to various work outcomes. 3 of 7 hypotheses were supported and the effect sizes for these were small. Firstborns scored significantly higher than later borns on measures of dominance, good impression, and achievement via conformity. No differences between firstborns and later borns were found in managerial potential, work orientation, achievement via independence, and sociability. The study's sample consisted of 835 public, government, and industrial accountants responding to a national US survey of accounting professionals. The nature of the sample may have been partially responsible for the results obtained. Its homogeneity may have caused any birth order effects to wash out. It can be argued that successful membership in the accountancy profession requires internalization of a set of prescribed rules and standards. It may be that accountants as a group are locked in to a behavioral framework. Any differentiation would result from spurious interpersonal differences, not from predictable birth-order related characteristics. A final interpretation is that birth order effects are nonexistent or statistical artifacts. Given the present data and particularistic sample, however, the authors have insufficient information from which to draw such a conclusion.     

Sibship size, birth order, and personality

In a sample of 273 American college students who were administered seven personality tests, only death obsession scores were consistently associated with sibship size and birth order (not optimism, pessimism, anxiety, a Taoist orientation, suicidal ideation, or obsessive-compulsive tendencies).     

Context-Specific Learning, Personality, and Birth Order

Most people believe that learning to get along (or not get along) with their siblings played an important role in shaping their personality, and that their position in the family—oldest, youngest, or in the middle—had lasting effects. Yet studies of birth order generally fail to support these beliefs. The apparent contradiction can be resolved by taking into account the context-specific nature of learned behavior. There is abundant evidence that people do not automatically transfer behavior from one context to another: They wait until they have evidence that what they learned in Context 1 will also be useful in Context 2. Because patterns of behavior acquired in the family of origin tend to be useless or inappropriate in other settings, birth order effects show up only in that context. Outside the family they grew up in, firstborns and later-borns are indistinguishable in personality.     

质疑星座决定人格特质的实证研究

星象学的基本假设是一个人出生时的星运位置可以决定其人格特质和重大际遇。本研究以16PF为工具,测查了165名大一学生,并按被试的出生日期和时辰确定了其星座。总的来说,结果不支持星座决定人格倾向的理论。     

Personality change in adolescence: Results from a Japanese sample

We examined developmental trends in personality traits during adolescence by using data from the secondary school affiliated with the University of Tokyo (N = 3656; range 12–18; 1832 female), collected from 1981 to 2010. Hierarchical linear modeling analyses revealed cumulative mean-level changes in personality averaging approximately 1 SD across adolescence. Scales related to Neuroticism showed linear increases, and those related to Extraversion showed distinct developmental patterns: General Activity and Rhathymia did not change, while Ascendance and Social Extroversion declined. Additionally, we found significant gender and birth cohort effects on personality. Although the intercepts differed according to both factors, the trajectories were different only for the birth cohort. These findings suggest that personality development trajectories differ according to the sociocultural context.     

Birth order and personality: Some empirical findings and a biobehavioral theory

The birth-order variables assessed included sex and number of siblings, assignment to 2- or 3-child family for separate sample analysis, family position as appropriate to given sample, spacing effect—was the birth of the second child spaced 4 years or more after the first child—dominance relationships in the family, sex of nearest siblings, sex of other siblings as appropriate, whether raised by both original parents, whether raised by foster parent(s). The personality variables assessed included sociability, anxiety, dominance, superego, phlegmatic temperament, involvement, self-regard and other scales measured by the new Howarth Personality Questionnaire. Samples of 50 for the 2-child families and 58 for the 3-child families were analyzed and it was found that: (a) in the 2-child families eldest children were less cooperative than younger, that those reporting dominance by another sibling were higher in state anxiety and this also applied to the younger of the pair, that those spaced in birth order were less afraid of being socially unacceptable, that those raised by both parents were higher in involvement; (b) in the 3-child families those dominated by a sibling, regardless of position, had more hypochondriac symptoms (a sign of anxiety), and that those spaced in birth order showed less cooperativeness. A biobehavioral theory to encompass biological-hormonal spacing effects and dominance as well as other intrafamilial behaviors was proposed.     

Beliefs about birth rank and their reflection in reality

Beliefs about birth rank reflect what the society regards as social reality, and they may also influence that reality. Three studies found that people believe those with different birth ranks differ in their personalities, that higher birth ranks are likely to attain higher occupational prestige, and that the personality characteristics attributed to the various birth ranks favor the actual attainment of higher occupational prestige. In one example of such beliefs, firstborns were rated as most intelligent but least creative whereas the opposite was true of last-borns. The 4th study found that those with higher birth ranks in fact attain more prestigious occupations and actually do complete more years of schooling.     

Predictors of scientific majors for black and white college students

The differences in the personality and social backgrounds of science and non-science majors were assessed for 91 black and 109 white natural, social, and nonscience college majors. Subjects were administered the 16PF, Bem Sex-Role Inventory, and the Attitude Toward Women Scale, and data were collected on birth order, number of siblings, and social class level. Natural science majors were of a higher social class, had higher intelligence test scores, were more reserved, sober, practical, and male sex-role oriented than the social and non-science majors. Blacks and females resembled their white or male counterparts when categorized by college major.     

The kids are alright: growth and stability in personality development from adolescence to adulthood

This longitudinal study provides a comprehensive analysis of continuity and change in personality functioning from age 18 to age 26 in a birth cohort (N = 921) using the Multidimensional Personality Questionnaire (A. Tellegen, 1982). Data were analyzed using 4 different methods: differential continuity, mean-level change, individual differences in change, and ipsative change. Convergent evidence pointing toward personality continuity, as opposed to change, was found. The personality changes that did take place from adolescence to adulthood reflected growth in the direction of greater maturity; many adolescents became more controlled and socially more confident and less angry and alienated. Consistent with this, greater initial levels of maturity were associated with less personality change over time. The results indicate that the transition from adolescence to young adulthood is marked by continuity of personality and growth toward greater maturity.     

Brought Up to Rebel in the Sixties: Birth Order Irrelevant,Parental Worldview Decisive

In Born to Rebel 1997 [1996] and subsequent works Frank Sulloway asserts that laterborns are more supportive of radical rebellions than are firstborns. Failure to replicate his historical cases and lack of significant sibling differences in contemporary studies of personality have produced fierce debate and grave doubts about the theory. It has yet to find robust support from studies of contemporary rebellions. Using retrospective survey data on the 1960s radicalization from 1,246 former students at the University of Oslo, we find no effect of birth order on who became student radicals. What we find are strong effects on political orientation of conventional radicalizing factors: upbringing in an urban environment and in particular in a home with radical parents. Within the group of radicals, birth order did not increase the propensity for political protest activity such as demonstrations and civil disobedience. Laterborns moreover had no higher proclivity than firstborns to apolitical protest behavior such as using cannabis or letting males' hair grow. Coming on top of concerns about the empirical support for other parts of the theory, our findings indicate that Sulloway's contested claim about the extrafamilial effects of birth order is not viable.     

Birth order, family structure and personality variables

The birth order and family structure variables assessed included first or only child, position in multi-child family, position in dyadic family, age of parents at birth of given child, whether reared by one or both parents, whether reared under permissive or authoritarian family atmosphere. The personality variables assessed included Sociability, Anxiety, Dominance, Superego, Phlegmatic Temperament, Involvement, Self-Regard and other scales measured by the Howarth Personality Questionnaire. One hundred seventy female and 142 male undergraduates were tested. Significant relationships found included: anxiety lower in firstborns; superego higher in firstborns; persistence higher in those not dominated by elder sibling; phlegmatic temperament higher in permissive families; involvement and phlegmatic temperament lower in single parent families; self-pride higher in the elder of a sibling pair; individual tolerance higher in children reared by both rather than single parent.     

Personality, birth order and attachment styles as related to various types of jealousy

The relationships between jealousy, personality, attachment styles and birth order were examined in a sample of 100 Dutch men and 100 Dutch women. Three types of jealousy were examined: reactive jealousy (a negative response to the emotional or sexual involvement of the partner with someone else), preventive jealousy (efforts to prevent intimate contact of the partner with a third person), and anxious jealousy (obsessive anxiety, upset, and worrying about the possibility of infidelity of the partner). The three types of jealousy were not at all related to egoism and dominance, but significantly correlated with neuroticism, social anxiety, rigidity and hostility. Only among women was a low self-esteem correlated with jealousy. On all three jealousy measures, those with an anxious-ambivalent attachment style were more jealous than those with an avoidant style, with those with a secure attachment style being the least jealous. Attachment style was strongly related to most personality dimensions, but the effects of attachment style upon jealousy stayed virtually the same when controlling for personality factors. The most important finding in the present study was that laterborns were more jealous according to all three measures than firstborns, a finding that was not due to personality differences between first- and laterborns, nor to differences in attachment style, gender or occupational level of the father. Because some evidence was found that only borns were slightly less jealous than firstborns, it is suggested that the experience of exclusive love and attention in one's childhood, leads to a lower level of jealousy among firstborns.     

Born lucky? The relationship between feeling lucky and month of birth

Research suggests that season of birth is associated with several psychiatric and neurological disorders, and also with adult monoamine neurotransmitter turnover. Personality traits are modulated in part by neurotransmitters; and population studies show season of birth variations in adult personality traits such as novelty seeking. Also, neurotransmitters are involved in suicidal behavior; and studies have found season of birth associations with suicide methods. The present general population survey was conducted via the Internet, and involved 29,584 self-selected participants (51.6% women) from 67 countries. For those born in the UK (75.6%), we investigated the relationship between season of birth, the participant’s belief in being a lucky person, and personality attributes related to this belief. In both genders and in all age groups, birth during the summer half-year was associated with significantly higher belief in being lucky, as compared to birth during the winter half-year, with a maximum around birth in May and a minimum around birth in November. Women scored significantly higher on listening to intuition and employing techniques to improve intuition, in perseverence, believing in positive long-term outcomes, and chatting to strangers. Men scored significantly higher on feeling lucky, not worrying or dwelling on failures, and expecting good things in life.     

A Psychological Biography for Jesus: Responding to Donald Capps'

Don Capps employed a Freudian Model and current biblical criticism models of Crossan, Borg, and others to evaluate the biblical data regarding the person and self-concept of Jesus of Nazareth. This article points to some vulnerabilities for serious criticism inherent in Capps's model and suggests the necessity of a wider range of psychological models for screening the data available on Jesus' development as a person in order to draw conclusions about his nature and motivations. Capps concludes that Jesus was a melancholic personality who was at odds with his society because he and his family were defamed regarding his problematic birth story, resulting in the violent symbolic action of cleansing the temple, thus expressing his arrival at self-confidence and self-affirmation.