The phrase birth order is defined as a person's rank by how old he is among his or her siblings. Birth order is commonly believed to have a profound and lasting effect on psychological development. Although this assertion has been repeatedly challenged by researchers, birth order continues to have a strong presence in pop psychology and popular culture. This article is about the domestic group. ... Popular psychology refers to concepts and theories about human mental life and behaviour that come from outside the technical study of psychology, but purport to go beyond everyday knowledge. ...

Theories

Alfred Adler (1870-1937), an Austrian psychiatrist, and a contemporary of Sigmund Freud and Carl Jung, was one of the first theorists to suggest that birth order influences personality. He argued that birth order often can leave an indelible impression on the individual's style of life, which is a habitual way of dealing with the tasks of friendship, love, and work. Other factors that may be equally influential are: parental attitudes; organ inferiority, illness, and disability; gender confusion; or social, economic and religious circumstances. Any overburdening factor may intensify normal inferiority feelings and lead to unconscious compensations or over-compensations (i.e, an extremely talented older or younger sibling). Other birth order factors that should be considered are: the spacing in years between siblings; the total number of children; and the changing circumstances of the parents over time. Adler suggested that birth order does not cause any direction of personality development, but it may be used by the individuals as a building brick for their freely chosen style of life and fictional final goal. Many researchers, in attempting to prove or disprove the sole effects of birth order, cite the complexity of other influences. Alfred Adler (February 7, 1870 – May 28, 1937) was an Austrian medical doctor and psychologist, founder of the school of individual psychology. ... For other uses, see Psychiatrist (disambiguation). ... Sigmund Freud (IPA: ), born Sigismund Schlomo Freud (May 6, 1856 – September 23, 1939), was an Austrian neurologist and psychiatrist who founded the psychoanalytic school of psychology. ... Jung redirects here. ... The term style of life was used by psychiatrist Alfred Adler as one of several constructs describing the dynamics of the personality. ... Classical Adlerian psychology is a values-based, fully-integrated, theory of personality, model of psychopathology, philosophy of living, strategy for preventative education, and technique of psychotherapy. ...

The influence of birth order on the development of personality is a controversial issue in psychology. It is widely believed that personality is strongly influenced by birth order, but many psychologists dispute this. Personality psychologists largely (though by no means without debate) agree that the Big Five personality traits (also known as Five Factor) represent something like a natural taxonomy of human personality variables. Cross-linguistically the vast majority of adjectives used to describe human personality fit into one of the following five areas, easily remembered by the acronym OCEAN: Openness, Conscientiousness, Extroversion, Agreeableness, and Neuroticism. An individuals personality is an aggregate conglomeration of decisions weve made throughout our lives (Bradshaw). ... Psychological science redirects here. ... In psychology, the Big Five personality traits are five broad factors or dimensions of personality discovered through empirical research (Goldberg, 1993). ... Openness to experience is a capacity within oneself to apprehend, absorb, and appreciate the world in its multitude of aspects and dimension. ... Conscientiousness is the trait of being painstaking and careful, or the quality of being in accord with the dictates of ones conscience. ... The terms Introvert and Extrovert (originally spelled Extravert by Carl Jung, who invented the terms) are referred to as attitudes and show how a person orients and receives their energy. ... The personality trait of agreeableness reflects individual differences in the extent to which people are concerned with cooperation and social harmony. ... For the band, see Neurotic (band). ...

In his book Born to Rebel, Frank Sulloway suggests that birth order effects on the Big Five are strong and consistent. He argues that firstborns to be more conscientious, more socially dominant, less agreeable, and less open to new ideas compared to laterborns. However, critics such as Fred Townsend, Toni Falbo, and Judith Rich Harris, claim to have refuted Sulloway's theories. An issue of Politics and the Life Sciences, dated September, 2000 but not published until 2004 ^[1] due to legal threats from Sulloway (who claimed its content to be defamatory, although it was carefully and rigorously researched and sourced), contains criticisms of Sulloway's theories, including studies that show conflicting findings. Fank Sulloway is a Historian of Science and Behavioral Scientist in California. ... Judith Rich Harris (February 10, 1938 - ) is a psychologist and the author of The Nurture Assumption, a book criticizing the belief that parents are the most important factor in child development. ... In English and American law, and systems based on them, libel and slander are two forms of defamation (or defamation of character), which is the tort or delict of publishing (meaning to a third party) a false statement that negatively affects someones reputation. ...

In their book Sibling Relationships: Their Nature and Significance across the Lifespan Michael E. Lamb, Brian Sutton-Smith, Lawrence Erlbaum Associates make the point that sibling relationships often last an entire lifetime. They point out that the lifespan view proposes that development is continuous, with individuals continually adjusting to the competing demands of socialization agents and endogenous tendencies. Thus, even those concerned only with interactions among young siblings implicitly or explicitly acknowledge that all relationships change over time and that any "effects" may be eliminated, reinforced, or altered by later experiences. Brian Sutton-Smith is a play theorist who has spent his lifetime attempting to discover the cultural significance of play in human life, arguing that any useful definition of play must apply to both adults and children. ... Lifespan is the maximum number of years a species can survive, defined by the oldest documented age of an individual member. ... A family posing for a group photo socializes together. ...

Personality research

Most of the claims about birth order have not been supported by scientific research. Indeed, many of the traits believed to be associated with different birth positions appear to contradict each other. Only children are supposedly more extraverted because they need to go outside of the family to meet other children, yet they are also believed to be more introverted so they can tolerate being by themselves. In fact, extraversion and introversion are stable personality traits, and they are related more strongly to genetic factors than to birth order. Firstborns are attributed with a variety of traits that do not even correlate with each other, much less with birth order. In general, birth order effects are weaker than commonly believed. For the software company, see Introversion Software. ... Positive linear correlations between 1000 pairs of numbers. ...

In practice, systematic birth order research is a challenge because it is difficult to control for all of the variables that are statistically related to birth order. Family size, and a number of social and demographic variables are associated with birth order and serve as potential confounds. For example, large families are generally lower in socioeconomic status than small families. This means that third born children are not only third in birth order, but they are also more likely to come from larger, poorer families than firstborn children. If thirdborns have a particular trait, it may be due to birth order, or it may be due to family size, or to any number of other variables. It is often impossible to determine which variable is the actual cause of the observed trait. This methodological issue has plagued research in this area. Spacing of children, parenting style, and gender are additional variables to consider. Consequently, there is a large number of published studies on birth order that vary widely in quality and are inconsistent in their conclusions. In statistics, a spurious relationship (or, sometimes, spurious correlation) is a mathematical relationship in which two occurrences have no logical connection, yet it may be implied that they do, due to a certain third, unseen factor (referred to as a confounding factor or lurking variable). The spurious relationship gives an...

Literature reviews that have examined many studies and attempted to control for confounding variables tend to find minimal effects for birth order. Ernst and Angst (1983) reviewed all of the research published between 1946 and 1980. They also did their own study on a representative sample of 6,315 young men from Switzerland. They found no substantial effects of birth order and concluded that birth order research was a "waste of time." More recently, Jefferson, Herbst, and McCrae (1998) analyzed data from a national sample of 9,664 subjects on the Big Five personality traits of extraversion, neuroticism, agreeableness, conscientiousness, and openness to experience. Contrary to Sulloway's predictions, they found no significant correlation between birth order and self-reported personality. There was, however, some tendency for people to perceive birth order effects when they were aware of the birth order of an individual. A Literature review is a body of text that aims to review the critical points of current knowledge on a particular topic. ... In psychology, the Big Five personality traits are five broad factors or dimensions of personality discovered through empirical research (Goldberg, 1993). ...

In her review of the scientific literature, Judith Rich Harris (1998) suggests that birth order effects may exist within the context of the family of origin, but that they are not enduring aspects of personality. When people are with their parents and siblings, firstborns behave differently than laterborns, even during adulthood. However, most people don't spend their adult lives in their childhood home. Harris provides evidence that the patterns of behavior acquired in the childhood home don't affect the way people behave outside the home, even during childhood. Harris concludes that birth order effects keep turning up because people keep looking for them, and keep analyzing and reanalyzing their data until they find them. Judith Rich Harris (February 10, 1938 - ) is a psychologist and the author of The Nurture Assumption, a book criticizing the belief that parents are the most important factor in child development. ...

Intelligence

Summary of the findings of Belmont and Marolla. Scores on Raven's Progressive Matrices relate to birth order and family size.

Since the 1970s, one of the most influential theories to explain why firstborns frequently score higher on intelligence and achievement tests than other children is the confluence model of Robert Zajonc. This model states that because firstborns mainly have adult influences around them in their early years, they will spend their initial years of life interacting in a highly intellectual family environment. This effect may also be observed in siblings who, although later born, have a sibling at least five years senior with no siblings in between. These children are considered to be "functional firstborns". The theory further suggests that firstborns will be more intelligent than only children, because the latter will not benefit from the "tutor effect" (i.e. teaching younger siblings). Image File history File links Download high resolution version (510x762, 24 KB) Fair use is claimed since this is a single diagram (a small portion) of a scientific journal article, being reproduced here for scholarly, noncommercial purposes. ... Image File history File links Download high resolution version (510x762, 24 KB) Fair use is claimed since this is a single diagram (a small portion) of a scientific journal article, being reproduced here for scholarly, noncommercial purposes. ... The cover of a test booklet for Ravens Standard Progressive Matrices Ravens Progressive Matrices (often referred to simply as Ravens Matrices) are multiple choice tests of abstract reasoning, originally developed by Dr John C. Raven in 1938. ... Robert B. Zajonc (1923-present) is a social psychologist who is best known for his decades of work on the mere exposure effect, the phenomenon that repeated exposure to a stimulus brings about an attitude change in relation to the stimulus. ...

Zajonc's theory has been criticised for confounding birth order with both age and family size, and alternative theories (such as Resource Depletion Theory) have been offered to explain the Belmont and Marolla findings. In a meta-analysis of the research, Polit and Falbo (1988) found that firstborns, only children, and children with one other sibling score higher on tests of verbal ability than laterborns and children with multiple siblings. This effect suggests that smaller families lead to children with higher test scores. Because there was no specific advantage for firstborn children, the results are consistent with Resource Depletion Theory, but not the confluence model.

The basic finding that firstborns have higher IQ scores has been disputed. One group of researchers examined data from the National Longitudinal Survey of Youth (NLSY) (USA), which gave them the opportunity to look at a large randomly selected sample of US families. The sample included children whose academic performance had been reviewed multiple times throughout their academic careers. This study found no relationship between birth order and intelligence (Rodgers, Cleveland, Van den Oord, & Rowe, 2000).

Researchers reporting in the journal Science in June 2007 found that "The eldest children in families tend to develop slightly higher IQs than their younger siblings." [1]

Notes and references

• Adler, A. (1964). Problems of neurosis. New York: Harper and Row.
• Belmont, M., & Marolla, F.A. (1973). "Birth order, family size, and intelligence". Science 182: 1096–1101. 
• Ernst, C. & Angst, J. (1983). Birth order: Its influence on personality. Springer.
• Harris, J. R. (1998). The nurture assumption: Why children turn out the way they do. New York: Free Press.
• Jefferson, T., Herbst, J. H., & McCrae, R. R. (1998). Associations between birth order and personality traits: Evidence from self-reports and observer ratings. Journal of Research in Personality, 32, 498-509.
• Lamb, M. E., Sutton-Smith, B. (1982).Sibling Relationships: Their Nature and Significance of cool monkeys are bule and i like cookies with peanuts they are the cross the Lifespan. Lawrence Erlbaum Associates.
• Leman, K. (1985). The Birth Order Book: Why You Are the Way You Are. New York: Dell Publishing.
• Polit, D. F. & Falbo, T. (1988). The intellectual achievement of only children. Journal of Biosocial Science, 20, 275-285.
• Rodgers, J. L., Cleveland, H. H., van den Oord, E. and Rowe, D. (2000). Resolving the Debate Over Birth Order, Family Size and Intelligence. American Psychologist, Vol. 55.

Further reading

• Michalski, R. L. , & Shackelford, T. K. (2002). Birth order and sexual strategy. Personality and Individual Differences, 33 , 661-667. Full text

• Sulloway, F.J. (2001). Birth Order, Sibling Competition, and Human Behavior. In Paul S. Davies and Harmon R. Holcomb, (Eds.), Conceptual Challenges in Evolutionary Psychology: Innovative Research Strategies. Dordrecht and Boston: Kluwer Academic Publishers. pp. 39-83. [http://www.sulloway.org/Holcomb.pdf Full text

External links

• Birth order chart
• Birth order and intelligence
• Birth Order and Exceptional Longevity by Natalia S. Gavrilova and Leonid A. Gavrilov
• Birth order in the job market
• A Literature Review: A Closer look at Ordinal Positioning within a Family System
• An Adlerian Overview of Birth Order Characteristics
• Research summary in The Independent