Does birth order affect personality?

BY Laura Dean-Osgood

1st Jan 2015 Life

Does birth order affect personality?
It’s a topic that’s fascinated psychologists for centuries, but could your attention-seeking, high-achieving or peacekeeping ways really be a result of whether you’re an older or younger sibling? Laura Dean-Osgood investigates.

Psychological theory

Image: Alfred Adler via Redicf
In the early 1900s, psychologist Alfred Adler described several characteristics that emerge as a result of your order of birth.
He suggested that a child’s personality will be influenced by the family’s situation. For example, the middle-child is ‘sandwiched’, and may feel squeezed out of a power of position, thus creating even-tempered and peacekeeping characteristics.
Psychologists then went on to suggest that birth order has ‘strong and consistent effects’ on key personality traits, specifically openness, conscientiousness, extraversion, agreeableness and neuroticism.
Much of the research that has followed agrees that the factors present at the time of birth are likely to affect the person you become (including whether you have siblings). But among the factors that are clearly linked to birth order (competing for parental attention) there are several factors that aren’t (school environment, where you live).

The birth order personality types

In broad terms, birth-order characteristics are said to present themselves in the following ways:
  • The oldest child: a high achiever, a perfectionist, and a great leader often found in careers such as law or medicine
  • The middle child: understanding, cooperative and flexible, but with a competitive edge. Middle children often end up in careers that require the use of their diplomacy skills
  • The youngest child: the baby of the family whose been made to feel special and often gravitates towards a career in creative industries.
  • The only child: a mature and resourceful character who can identify with adults, as well as people who are oldest and youngest siblings.
If none of this is ringing true, then perhaps you’ve stepped into another sibling’s role.
Some theories suggest that if one sibling fails to take up their position (i.e. the oldest doesn’t become a natural leader) then the next child will simply step up and take their place.

Just stereotypes?

Siblings adults
A more recent study suggests that these theories are nothing but stereotypes that have stood the test of time. The study published in the journal PNAS, looked at data from over 20,000 people from England, Germany and the US.
It considered factors including IQ, self-reported intelligence, extroversion and conscientiousness, and reported a ‘weak statistical significance’ between birth order and personality. The authors did report, however, that IQ appeared to be highest in the oldest child and declined in subsequent siblings.
The very nature of the topic makes it incredibly hard to research and as such there’s not any hard scientific research to back up these theories. But you only have to Google the terms ‘birth order and personality’ or ‘awkward middle child’ to see it’s a subject that’s very much alive and kicking.