Birth Order Might Not Be Such An Important Indicator After All

Academic studies can be fascinating … and totally confusing. So we decided to strip away all of the scientific jargon and break them down for you.

The Background

Parents and researchers have long speculated that birth order could determine kids’ personalities. Stereotypes say that first-born children are high-achieving and bossy, while younger siblings are adaptable and mischievous. These anecdotal claims, however, aren’t exactly backed up by consistent studies. Past research consistently suggests that birth order could have an effect on intelligence — children’s performances on intelligence tests tend to decline slightly from firstborns to later-borns — but researchers have yet to find too much compelling evidence to suggest that older and younger children develop key personality traits according to their birth order.

To further investigate, researchers from the University of Leipzig and the University of Mainz in Germany conducted a study using longitudinal data from three prior studies on international children surveyed over the course of several decades.

The Setup

Researchers analyzed survey data collected throughout the participating children’s lives from the National Child Development Study (4,489 participants from Great Britain), the National Longitudinal Survey of Youth 1997 Cohort (5,240 participants from the U.S.) and the Socio-Economic Panel (10,457 participants from Germany). Each of these surveys included self-reported personality inventories, which measured the Big Five personality traits: extraversion, emotional stability, agreeableness, conscientiousness, and openness to experience. All of the surveys also included IQ tests.

Since people’s personalities can change as they get older — one might become more conscientious with age, for example — the researchers made sure to control for the children’s ages in their analysis. They also controlled for number of children in the family to rule out socioeconomic —> Read More