From firstborns labeled as the “responsible one” to the youngest siblings known for their “free spirit,” does birth order actually affect personality, or is it simply a stereotype that shapes their character?
The theory of birth order affecting personality was first introduced in the 1920s by Austrian psychologist Alfred Adler through his books “Understanding Human Nature” and “The Science of Living.” Adler believed that a child’s standing in the family affects their experiences, from how they are treated to their expectations, which then shapes their personality.
“The firstborn […] has a period of being the center of attention,” Adler said. “Then he is suddenly dethroned. This experience may be the cause of his later feeling that he must fight to maintain his position.”
On the other hand, younger siblings are the “baby” of the family. Said Adler, “The position of the youngest child is always a very precarious one […] he has too many people to help him.” The youngest are typically characterized as outgoing and carefree. Adler also discovered distinct outliers to these stereotype patterns — if there is a five-year or more age gap between siblings, they may grow up with “only child” characteristics, which include much more independence and drive. There were also gender-specific exceptions — first-born daughters may have different expectations growing up than first-born sons. Adler came to these conclusions through thousands of one-on-one sessions with patients, where he noticed recurring patterns — while the oldest children complained about a loss of control, the youngest often struggled with finding independence.
While theories such as Adler’s arise, it is ultimately acknowledged that several factors explain why differences in character traits actually occur. According to the Providence Children’s Health Team, one example is that parenting styles shift over time. First-time parents are generally more cautious with their oldest child and enforce stricter rules and set higher expectations. However, as parents gain experience over the years, they tend to become more relaxed with their younger children. This results in children receiving different responsibilities and disciplinary actions, contributing to contrasting environments that shape their characters differently. In addition, younger siblings may also receive more freedom that allows them to take greater risks and be more creative. With looser expectations and fewer rules to follow, the youngest may develop a relaxed and healthy relationship with the parents. In contrast, the oldest has to bear strict parental expectations, developing a strained relationship. Today, psychologists call this change in treatment “differential parenting” or “parental investment.” This parenting style demonstrates how siblings do not have contrasting personalities due to birth order itself, but rather because they are raised by a different version of their parents compared to their siblings.
Although birth order itself may not directly affect personality, it plays a significant role in how parents delegate responsibility among their children, which influences their development. According to Newport Healthcare, parents often turn towards their older child to take care of their younger siblings and pave the way for growth, forcing them to act as role models. These early experiences promote behavior that revolves around responsibility, leadership and accomplishments, resulting in characteristics of self-reliance and maturity.
Furthermore, older children often reach a point where they begin to feel neglected — they are seemingly expected to grow more independent, while watching their parents still offer the care and attention to their younger siblings that they once had. As Adler observes, this difference in treatment hints towards favoritism, which can cause the older child to continuously question their worth.
Gender norms may also shape a child’s expectations and responsibilities, ultimately influencing how they are treated and how they should act. The oldest child’s experiences also differ according to gender. For example, the eldest daughter may possess more sensitive and caring traits when looking after siblings, while the eldest son takes a more hands-on approach to protect them.
In addition, parents may be at different stages of life, whether it may be financially, professionally or emotionally, when raising a child. Changes in social life, school environment and cultural norms can differ between siblings, even if they grow up in the same household.
Aside from environmental factors, another important factor to consider is the role of stereotypes. When children are labeled as “the responsible one” or “the spoiled one,” they may internalize these expectations. This is known as a self-fulfilling prophecy, a term coined by American sociologist Robert Merton in 1948. Over time, these labels can influence personality and shape individuals more than their birth order itself.
These stereotypes are often influenced by the media emphasizing certain traits, such as the “Eldest Daughter Syndrome,” which refers to the responsibilities and burdens that the firstborn daughter has to take on, often negatively consuming most of their childhood. Similarly, the “Thought Daughter” is perceived to be empathetic and to constantly overanalyze situations. According to Nicolle Pacifico, a clinical psychologist, they often feel misunderstood or isolated when others fail to connect with them as deeply as they need. As these terms circulate on social media, it is natural for children to recognize aspects of themselves in these traits, thus playing a role in shaping their personality.
Ultimately, birth order is not the only factor that influences character development. Instead, an individual’s personality is developed through a complicated combination of factors, such as genetics, upbringing, environment and unique individual experiences.
