Birth order, also referred to as position in the family, is the timing of an individual’s birth within the family structure. The effect of birth order on personality development has been the subject of increasing social science research from the late 20th century to the present. While factors such as gender, age span between siblings, cultural practice, parenting styles, and genetic makeup affect personality traits, statistical studies show that birth order also may play an influential role in the shaping of behavioral patterns lasting into adulthood.
One of the first to examine the dynamics of family structure was Austrian psychologist Alfred Adler (1870-1937), founder of the school of individual psychology. Adler believed that the relationship with siblings often foreshadowed later individual outcomes. His general hypothesis purported that oldest borns suffer from a degree of neuroticism stemming from the arrival of the second child, which diverts attention from the first. Later borns, he believed, are overindulged, and the middle borns are most likely to develop successfully. However, he produced no long-term scientific research to support this theory.
Common anecdotal wisdom has often emphasized stereotypical negative traits based on sibling order, describing the oldest as domineering, the middle as neglected, the youngest as spoiled, and only children as selfish. However, research based on long-range data contradicts these widely held but unsupported beliefs and demonstrates a complex cause-and-effect association. Comprehensive research has sought to discover a correlation between birth order and a wide array of social factors, including personality type, career choice, success in marriage, and receptiveness to new ideas.
Of particular interest to mid-20th-century investigators was the discovery of factors leading individuals to succeed in certain career fields, especially those requiring decision making under pressure. Such high-profile positions examined included U.S. presidents and astronauts participating in the early stages of the U.S. space program. Data reveal that 52% of American presidents have been first- or older borns and 21 of NASA’s 23 first astronauts who flew into space were either the oldest or only children; all 7 of the original Mercury astronauts were also firstborns. Other studies show that prominent television newscasters and talk show hosts are often firstborns or only children. These data have led to conclusions linking older borns and only children with a high potential for achievement and leadership as well as possessing a desire for approval. Higher-than-average scores on verbal performance by only children and firstborns have
also been attributed to a greater amount of time spent in the company of adults.
Research led by psychologist Frank Toman studied the impact of birth order on marriage, friendship, and gender roles, with emphasis on the variables of the sex of the siblings and birth spacing. Toman and his colleagues surveyed mid-20th- century European families to determine the success of marriages based on birth order of partners and the sex of their siblings. Their findings concluded that marriages were most likely to succeed between the older brother of a sister and the younger sister of a brother (or the reverse). These he called complementary sibling roles, which prepared the partners for a similar role in the marriage relationship. Persons who married a counterpart—such as the oldest in the family with same-sex siblings— were more likely to divorce, because the partners compete to play the same role rather than complement one another. Toman’s theory is widely recognized in marriage and family counseling and has been used as one of a number of tools to measure compatibility.
Researcher Frank Sulloway’s studies, based on contemporary and historical data, find a correlation between birth order and “openness to experience,” even when factoring in other influences such as sex, social class, family size, race, and age. Later borns, he describes, are historically more likely to support causes that challenge the status quo, from the Protestant Reformation to the American abolitionist movement. He cites examples such as Mahatma Gandhi, Martin Luther King Jr., Fidel Castro, Ho Chi Minh, Susan B. Anthony, and Malcolm X as such later borns. On the other had, firstborns, he contends, are often more likely to defend traditional order.
If older borns and only children are apt to be high achievers, does it hold that those lower in the birth order are less successful? Sociologist Howard M. Bahr found this was not the case in his study of New York City adult men in rehabilitation centers. His study was comprised of adult males who were not taking responsibility for themselves or others and might be described as social “failures.” He found that birth order did not appear to play a statistical role, except in the case of only children, who were overrepresented. Bahr speculated that high parental expectations, which often result in the success of children, may also account, in some cases, for a withdrawal from the unreasonable pressures often placed on an only child.
Birthrate Cycles and Family Structure
The timing of an individual’s birth may shape personality, not only within the family structure but also in the broader historical context. Global social and economic conditions have a significant effect on birthrates and, therefore, family size. From 1800 to 1900, family size in the United States dropped from an average of 7 children to 3.5, reflecting the move from an agrarian to an industrialized society. During the worldwide Depression of the 1930s, the average American family produced 2.5 children, with a low of 2.3 in 1933, resulting in what some sociologists have described as the adult “silent generation” of the 1950s that largely supported traditional values and held conservative political and economic views.
The post-World War II surge in the U.S. birthrate peaked in 1957 with an average of 3.7 children per family. Improved contraception methods, introduced widely in the 1960s, coupled with social and environmental concerns, encouraged a smaller family size; in 1972 average family had 2 children. Current UN statistics show that Europe, Canada, Australia, and China show declining birthrates (less than replacement of 2 children per family). The United States and large parts of South America show a stable birthrate averaging 2 children per family, and the most rapidly growing population is occurring in countries of sub-Saharan Africa.
These birthrate cycles impact the family structure and therefore birth order patterns, with implications for society as a whole. These trends produce, in industrialized nations, smaller families with more only children and fewer middle children, possibly creating what some experts call a society of leaders and followers with fewer middle children as mediators.
Research continues in the study of birth order and its effect on personality development and long- lasting behavioral patterns. Theorists in general have found a consistently high correlation between birth order and certain personality traits, together with gender, and other time-related factors such as spacing between siblings, and historical circumstance. Results generally describe firstborns as responsible, goal oriented, and supporters of the status quo; middle borns as flexible, competitive, and diplomatic; later borns as outgoing, creative, and tending to question authority; and only children as often exhibiting magnified traits of both the older and later borns. It would appear that the timing of an individual’s birth is one of several factors to consider in personality analysis, and birth order may have a significant effect on the way in which individuals see themselves and how they respond to those around them. In turn, family size and the resulting characteristics attributed to birth order may have an impact on society as a whole.
Leman, K. (1984). The new birth order book: Why you are the way you are. Old Tappan, NJ: Revell.
Sulloway, F. (1996). Born to rebel: Birth order, family dynamics, and creative lives. New York: Pantheon.
Toman, W. (1976). Family constellation: Its effects on personality and social behavior. New York: Springer