Birth Order Theory: Insights Into Your Personality

Updated March 16, 2023by BetterHelp Editorial Team

Personality can develop from a variety of sources and influences in a child's life, including birth order. The study of personality and its formation has interested researchers, psychologists, and scientists for centuries. According to the American Psychiatric Association, “personality refers to the enduring characteristics and behavior that comprise a person’s unique adjustment to life, including major traits, interests, drives, values, self-concept, abilities, and emotional patterns.” People's personalities can affect many aspects of their human experience. Studying variables in personalities usually entails looking at two categories:

  • Understanding differences in people's personality characteristics, such as temperament, sociability, and motivation

  • Discovering how various parts of a person come together as a whole

There are many theories of how personality forms, adapts, and is affected by one's external environment that vary across cultures and associations. One personality study focuses on a person's birth order and their subsequent relationships with their siblings. Birth order theory was developed by Alfred Adler in the 20th century. It stated that the order in which a child is born impacts their personality. 

Birth Order Theory: Adler's Research

Alfred Adler was born just outside Vienna in 1870. He started his medical career as an ophthalmologist and then switched to general practice in a less affluent part of Vienna. In 1907, he met Sigmund Freud and developed a working relationship with him and other prominent psychoanalysts of the time. As Adler progressed in his career, he sought to create a psychological movement based on a holistic view of the individual. Unlike Freud, Adler believed the social and community aspects of a person's life were just as important as internal thoughts and emotions. Adler's desire to understand how social factors influence personality extended to child development. His birth order theory described how the effect of birth order shapes children’s thoughts and behaviors, from firstborn children to the youngest children, as well as all in between.

What Birth Order Theory Is Not

Birth order personality traits are not necessarily present when a child is born into a family. For example, firstborn children are not necessarily born with niche or particular personality traits ingrained in their psyche. Instead, in birth order theory, Adler illustrates how family environments and dynamics can shape individual psychology during a child's formative years. Although every family is different, there are similarities in the interactions between parents and children and siblings.

The Family's Role In Birth Order Personality Traits

Birth order research and studies show that there are several influences shaping personality in addition to birth order. Common factors include:

  • Biological: Children tend to inherit many traits and features from their parents. These can include intelligence, courage, and physical features.

  • Social: By interacting with others in an individual's social circle, children learn behaviors and thought patterns from their experiences, like those in the education system and beyond.

  • Cultural: A child growing up within a culture consciously or unconsciously tends to adopt traits consistent with the culture's beliefs, ideas, and norms.

  • Physical Environment: An individual's surroundings often impact the development of personality. For example, the personalities of those growing up in a rural area may be different from the personalities of those living in an urban environment.

  • Situational: As a child grows up, they face different situations, which may help them adapt and change aspects of their personality. These situations could include meeting new friends, experiencing a trauma, or welcoming a new sibling.

When looking at these factors, we see family life can incorporate all of these. Since most children's lives are, at first, shaped by everything going on in the family, it makes sense that some psychologists have remained interested in birth order theory throughout the years since Adler studied personality and birth order.

The following traits are general examples of how birth order differences and personality may be related. Of course, many other factors could impact the development of a child's personality; some of these reasons will be discussed further below.

Only Children

These children tend to get much more attention from adults than a child with siblings does. This means many of their early interactions involve individuals significantly older than them. These interactions can make them feel like "tiny adults," and they can seem more mature than peers with siblings. Traits may include:

  • Confidence

  • Maturity for their age

  • Sensitivity

  • Use of adult language

  • Self-centeredness

  • A tendency to enjoy being the center of attention

  • Refusal to cooperate with others

  • A tendency to feel unfairly treated when not getting their own way

  • A desire to be more like adults, so may not relate well with peers

First Child

Since the firstborn child is used to being an only child until siblings come along, they may exhibit some of the characteristics of an only child. Also, the firstborn may have these birth order personality traits:

  • Achiever and leader

  • Feelings of superiority over other children

  • Difficulty when the second child is born, such as feeling unloved or neglected

  • A tendency to be controlling and focused on being correct about results

  • Use of good (or bad) behavior to regain parents' attention

  • A tendency to be bossy or authoritarian about rules

  • A desire to please others

  • Reliability

Second Child

Second-born and middle children begin their lives with their parents' attention on the firstborn. Having an older sibling as a role model makes second-born and middle children try to catch up with older children. Adler believes the second child will most likely be better adjusted. A second child may:

  • Be more competitive

  • Lack the undivided attention of parents

  • Be a people pleaser

  • Be a peacemaker

  • Develop abilities the first child doesn't exhibit to gain attention

  • Be rebellious

  • Be independent and not need the support of others

Middle Child

Many have heard of the "middle child syndrome" and the difficulties these children can present. With the significant changes they experience early in life, they may become frustrated or resentful. Not only do they lose their "youngest child" status, but they also have to compete for attention with older and later-born children. Middle-born children of bigger families often aren't as competitive as single middle children since their parents' attention is often spread thinner among larger family dynamics. Middle children in bigger families may be more prone to use cooperation to get what they want. Middle children may demonstrate the following tendencies:

  • Can feel life is unfair

  • Can be even-tempered

  • May feel unloved or left out

  • May not have the rights and responsibilities of the oldest sibling or the privileges of the youngest

  • May be adaptable

  • Can be impatient

  • May be outgoing and rambunctious

  • May treat younger siblings more roughly

  • Can feel "squeezed" in the family environment

Youngest Child

The "baby" of the family tends to get more attention from parents since the older siblings are developing and becoming more independent. Traits of the youngest child may include the following:

  • May be charming and outgoing

  • Can be an attention seeker

  • Behaves like the only child

  • Feels inferior, like everyone is bigger or more capable

  • Expects others to make decisions and take responsibility

  • May not be taken seriously

  • Can become "speedier" in development to catch up to other siblings

Other Factors Influencing Birth Order Personality

Each family is different and has unique dynamics. The subject of birth order positions alone will not determine the complexities of a person’s personality. As child and family develop and evolve, certain circumstances or measures may impact a child's personality. Across different families, children of the same birth order can show diverse personality differences, especially across a large representative sample.

Blended Or Step-Families

When two parents remarry, especially when children are in their formative years, the family of origin often goes through a period of disorientation and competition. For example, two firstborns in the new family may search for their "place" and may compete to keep their "firstborn status."

Differences In Ages

When there is an age gap of three or more years between siblings, it is common for the birth orders to restart. In a family with many children, this could create birth order subgroups with varying birth order effects.

Health And Mental Issues

A child born with significant physical or neurodevelopmental disabilities can seem to remain in the "youngest" position regardless of birth order. This may impact the psychological birth order position of the other children.

Gender Of Siblings

The most psychological competition tends to occur between children of the same gender and similar in ages. The competition, in part for parental attention, can start in childhood and move into young adulthood and beyond.

Death Of A Sibling

The impacts of a child's death can be devastating for families. Some children may adapt by developing overindulgent tendencies. Also, a glorification of the deceased child can occur, whereby other siblings may never live up to the image of the deceased sibling. This can deeply alter the birth order effect.


An adopted child often has special circumstances in the family dynamic. For parents with difficulties conceiving, having an adopted child may be seen as a special gift. These parents may have a greater tendency to spoil or overindulge the child. When an adopted child comes into an established family, they may find difficulties fitting into the dynamic. Sometimes these feelings of inadequacy warrant therapy.

Does A Correlation Of Birth Order And Personality Exist?

Previous research has linked higher intelligence to a family's older children. This could be due to the fact that parents have more emotional and intellectual resources to give when fewer children are present in the body of the family.

In a study of more than 20,000 participants, however, details revealed no significant effects of birth order of the Big Five personality traits: extraversion, emotional stability, agreeableness, conscientiousness, and openness to experience.

Does this mean birth order theory should be discarded? Probably not. This only proves that the formation of personality is not simply explained by a child's birth position in the family. Multiple factors, including socioeconomic status, parental attitudes, gender roles, and social influences, can also contribute to shaping an individual's personality. Birth order may explain some parts of personality, from people's tendencies to career and relationship outcomes, but all factors must be considered in the development of personality, including psychology, sociology, and economic research.

If you have questions about personality and birth order, a licensed psychotherapist may be able to help. Psychotherapy may help find the root cause of some challenges while allowing you to discover ways to live a happy, fulfilling life. If you are not interested in traditional in-person therapy, you might consider using affordable online counseling through BetterHelp. Online therapy has been shown to be just as effective as in-person therapy and tends to be just as affordable without insurance. 


Your personality may or may not have much to do with your birth order. You can do many things to become attuned to yourself and your personality, especially with the guidance of a licensed online therapist. If you have questions about personality or mental health in general, you can talk to an online therapist with experience helping others with similar concerns. Take the first step today.

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