Many people believe that firstborn children, because of their privileged position in the family, behave differently than later-born children. Although parents, siblings, and nonparents probably overemphasize the influence of birth order, evidence suggests that the experiences of individuals are related to their ordinal position in the family.
Psychologists have studied the distinctive personality of firstborn children for more than a century. Alfred Adler, the father of individual psychology, postulated that the child's position in the family has a monumental effect on the child's personality. He believed that the firstborn child is dethroned by the birth of a sibling and the firstborn must now share parental attention with a rival. In order to cope with this traumatic betrayal, firstborns become problem children or they strongly emulate their parents. Because of their identification with their parents and their perceived loss of status, power and authority become extremely important to firstborn children. Although Adler's theory was not based on empirical research, it spurred thousands of studies that related birth order to everything from extrasensory perception to juvenile delinquency.
Many of the commonly held ideas about first-borns originate from inferences about their interactions with parents and siblings. The extant literature suggests that parents harbor expectations of how firstborns should behave and parents act in accordance with those beliefs. During infancy, mothers attend to firstborns by responding to and stimulating them more than latterborns. Mothers also tend to rate their firstborn infants as more difficult than later-born children. This finding may reflect that mothers feel more comfortable in their parenting role by the time a subsequent child enters the family. The relative amount of attention that firstborn preschoolers receive tends to decline with the birth of siblings. Nevertheless, firstborn children continue to experience distinctive relationships with their parents. Investigators have found that parents expect higher achievement, are more controlling, and make added demands on their firstborn young children. Moreover, throughout childhood, fathers tend to be more involved with their firstborns relative to later-born children.
Firstborns also seem to initiate more interactions, both positive and negative, with their younger siblings than vice versa. They are more likely to engage their younger siblings in conversation, but they are also more likely to be verbally disapproving. As compared to older peers, firstborn children tend to instruct younger siblings by providing appropriate feedback and guidance. The opportunity to be a "teacher" may help explain why firstborn children, on average, have higher IQs than only or youngest children.
Speech and Intelligence
Firstborn children are temporarily only children and thus are exposed to one-to-one speech with their parents. When a new child is born, firstborns and their siblings receive less child-directed speech and are privy to multiparty speech. Specifically, mothers appear to provide more linguistic support and more complex grammatical statements to their firstborns even when their firstborns and latterborns are observed at the same age. Concordantly, firstborn toddlers have larger vocabularies, reach language milestones earlier, and demonstrate more sophisticated grammar than their siblings. The early language competence of firstborns may partially explain the proclivity of firstborns to achieve in school. In contrast, later-born children's skill in conversational speech and their expertise in understanding the mental states of others potentially contribute to their renowned social acumen.
On average, firstborn children have been cited as having higher intelligence levels than later-born children. For example, one study examined scores on the 1965 National Merit Scholarship Qualifying Test and, regardless of family size, the scores tended to be higher for firstborns. The confluence model has been proposed to explain the superior intellectual rankings of firstborns. In this paradigm, a child's intellectual level depends on the average intellectual level of all the family members. When a new child is born into the family, the intellectual environment declines. This model states that, in general, large families have impoverished intellectual climates, as there are many immature minds for several years. Also, age spacing between siblings is an important variable in this theory. Small age differences are beneficial to the first-born in that the firstborn is not exposed to very young siblings for too long. In addition, the firstborn has the opportunity to teach siblings, which facilitates the crystallization of knowledge of the firstborn. Applying the confluence model, if one could choose an ordinal position, one would prefer to be a firstborn with a younger sibling close in age. With its emphasis on average intellectual atmosphere, the confluence model has created much debate.
Some of the implications of the theory have not received support in the literature. For example, additional adults in the household, such as grandparents, do not seem to increase children's IQ as would seem to be predicted by the confluence model. Furthermore, differences found in IQ among firstborns, latterborns, and only children are typically small and unstable.
Birth Order and Personality
The results of research regarding the associations between birth order and personality are varied. In general, meta-analyses of systematic studies indicate that firstborn children are achievement-oriented, ambitious, conforming, anxious, assertive, and less empathetic than latterborns. Frank J. Sulloway, using a Darwinian perspective, argued that children assume different personalities or niches within the family to gain favor with parents. Firstborns do this by identifying with their parents and by conforming to parental standards. Because firstborn children are older, wiser, and more powerful, latterborns become diverse in their interests and they become more open to experience. Sulloway's treatise stemmed from his study of 3,890 career histories of scientists. Even though many firstborns were scientists (e.g., Isaac Newton, Albert Einstein, Sigmund Freud), supporters of the scientists were predominantly latterborns. Sulloway interpreted this finding as indicative of the personality differences between firstborn and later-born children.
Firstborns tend to reject new theories, especially when the innovation upsets the status quo, while latterborns are more receptive to revolutionary thinking. As an example, Sulloway found that for every 12.8 first-borns who supported evolution, there were 124 latter-borns who welcomed the theory. This personality trait, openness to experience, and the concomitant defensiveness and conservatism of firstborns holds true even when size of the family, socioeconomic status, and culture are taken into account.
Some researchers have concluded that the effect of birth order on children's behavior is overrated. Many studies have not systematically controlled for intercorrelated family variables such as age spacing between siblings, size of family, and ages of siblings. Thus, certain child behaviors associated with birth order may actually be due to family size. Beyond birth order, other predictors such as gender, temperament, parenting styles, and socioeconomic status influence children's development and must be considered. For example, the literature has indicated that in families with two sisters, second-born daughters are more conforming than firstborn daughters.
Are all firstborn children power-hungry conservatives as suggested by Adler, or "goody-goodies" as proclaimed by Sulloway? Intuitively, the experiences of firstborns are affected by their ordinal position in the family. The literature has shown that parents have disparate expectations for firstborn children, although these expectations vary within and among cultures. Studies have also demonstrated that parents are more involved with their firstborn children. Moreover, evidence exists that there are behavioral, intellectual, and personality differences between first-borns and latterborns. Although it is important to acknowledge that birth-order investigators face methodological challenges, the status of being the first child in a family clearly plays some role in a child's development.
Adler, Alfred. The Individual Psychology of Alfred Adler: A Systematic Presentation in Selections from His Writings, edited and annotated by Heinz L. Ansbacher and Rowena R. Ansbacher. New York: Basic, 1956.
Hoff-Ginsberg, Erika. "The Relation of Birth Order and Socioeconomic Status to Children's Language Experience and Language Development." Applied Psycholinguistics 19 (1998):603-629.
Sulloway, Frank J. Born to Rebel: Birth Order, Family Dynamics, and Creative Lives. New York: Pantheon, 1996.
Zajonc, R. B., and Gregory B. Markus. "Birth Order and Intellectual Development." Psychological Review 82, no. 1 (1975):74-88.