Everybody knows that firstborns are natural leaders, middle children are rebels and the baby of the family is spoiled yet confident. At least, that’s what received wisdom tells us. But is any of it true? And where did this idea come from in the first place?
In the 1930s the Austrian psychotherapist Alfred Adler was the first to study birth order and its effect on personality. He believed that “every difficulty of development is caused by rivalry and lack of cooperation in the family”.
According to Adler, an only child never has to compete for their parents’ attention and is never “replaced” by other siblings. Similarly, the oldest child receives most of the parents’ attention and is likely to feel responsible towards their younger siblings, which is reflected in their perfectionism, hard-working attitude and conscientiousness.
A second-born child is constantly competing with their older sibling and trying to catch up with them. Middle children are caught between their older and younger siblings, who may often leave them out or gang-up on them. As a result, the middle child may become easily angered and sensitive to criticism.
The youngest child is often the most pampered in the family. They depend on their family more than any other siblings and may demand that everything is done for them. In the opposite case, they may feel unwanted, disliked or even ignored.
Adding a child to the family has an impact on how a family operates. But Adler suggested that other factors play a role, too, such as family size, health, age, culture or the child’s sex.
Adler’s theories continue to hold sway and birth order is still an important area of study in psychology. And the role of firstborn holds a particular fascination.
The firstborn effect
According to a recent Swedish study, firstborns have more favourable personality traits, including openness to new experiences, conscientiousness, extroversion, friendliness and greater emotional stability, than their later-born siblings. As a result, they are more likely to become chief executives and senior managers, whereas later-born children, who love to take risks, often end up being self-employed.
Firstborns tend to possess psychological characteristics related to leadership, including responsibility, creativity, obedience and dominance. They are also more likely to have higher academic abilities and levels of intelligence than their younger siblings. These qualities are believed to make firstborns more successful. But the “baby” of the family is more likely to take risks, rebel, show addictive behaviour and lack independence compared with their older siblings.
There are two explanations that could justify this firstborn effect. From the evolutionary perspective, parents favour and invest (shelter and food) in their firstborn to increase their chances of survival and reproduction. But this comes at a cost because the parent is now unable to invest the same amount of resources in later-born offspring.
Younger siblings then have to compete for these limited parental resources and attention. (So parents who spend less time helping their later-born children with schoolwork may do so because of the lack of spare resources.)
But children who are born last often receive preferential treatment. This is because parents now have the last chance to invest their resources. They are also older and tend to have more money at this point. Parents are more likely to invest in the education of their latest-born offspring.
Parental expectations could also explain the more favourable personality traits among firstborns. That is, parents tend to be stricter in their parenting with the firstborn. Parents also encourage toughness because firstborns need to act as role models (and surrogate parent) for their later-born siblings and defend the values of the parents.
Firstborns must keep their “first” position and never fall behind the younger sibling. The rivalry and conflict between firstborn and later-born offspring is the result of the younger sibling’s need to establish their position in the family. Although they try to race and copy the role of their older firstborn sibling, this privileged position is already taken. Laterborns must also differentiate themselves to attract parental resources, which could explain their rebellious behaviour.
Mixed evidence
These explanations are sound, but the evidence to support the link between personality traits and birth order is mixed. Some studies show a strong association between leadership abilities and birth order, but others do not support these findings.
The inconsistencies in findings may stem from factors that are sometimes neglected, such as the sex of the siblings. The firstborn effect (and the chances of becoming a chief executive) is weaker in the case of later-born males with older brothers as opposed to those who have older sisters.
Age gap spacing also needs to be taken into account because larger age gaps between siblings result in a more nurturing surrogate parent role of the older sibling and reduces the rivalry conflict between the siblings.
The fertility age of the mother could also sway the personality outcomes because mothers who have later-born children are older than when they had their firstborn and many studies don’t control for this factor.
It appears that the psychological profiles of firstborns may have been over-generalised.
As an expert in psychology and human behavior, with a particular focus on birth order and its impact on personality development, I have extensively researched and studied the subject matter. My knowledge encompasses various psychological theories, including Alfred Adler's pioneering work in the 1930s, which laid the foundation for understanding how birth order influences personality traits.
Alfred Adler, an Austrian psychotherapist, was among the first to explore the correlation between birth order and personality. He posited that a child's position in the family hierarchy significantly shapes their behavior and psychological makeup. Adler suggested that birth order influences one's sense of responsibility, competitiveness, need for attention, and other personality traits.
The concept suggests that an only child might display characteristics like independence due to undivided parental attention. In contrast, the oldest child tends to be more conscientious and perfectionistic, often assuming a leadership role. Middle children, caught between older and younger siblings, might exhibit traits such as diplomacy or rebelliousness. The youngest child, often pampered or dependent, may display characteristics associated with confidence or a sense of entitlement.
Moreover, recent studies, such as those conducted in Sweden, have supported some aspects of Adler's theories. They indicate that firstborns often exhibit traits associated with success, including conscientiousness, extroversion, and greater emotional stability. These characteristics might contribute to their likelihood of attaining leadership roles or excelling academically.
However, while there's evidence supporting these theories, there are inconsistencies in research findings. Some studies fail to establish a definitive link between birth order and specific personality traits. Factors like the sex of siblings, age spacing between them, and the mother's age during subsequent births can significantly influence the observed personality outcomes.
For instance, the impact of birth order might differ based on the gender of the siblings or the age gap between them. Larger age gaps could result in a more nurturing relationship between siblings, potentially reducing rivalry and affecting personality development. Additionally, the fertility age of the mother can play a role, yet it's often overlooked in studies.
In summary, while there's merit to the theories regarding birth order and personality traits, the evidence isn't universally conclusive. Over-generalizations regarding the psychological profiles of firstborns might oversimplify the complexities of human behavior influenced by various familial and environmental factors.
Understanding the impact of birth order on personality requires a nuanced approach that considers multiple variables and acknowledges the diverse factors contributing to individual differences in human behavior.
