By Emily Reynolds

Wherever you fall in a group of siblings, there are plenty of stereotypes about the sort of person you are or will turn out to be. Oldest of the bunch? You’ll be bossy, then. Youngest? Spoilt. Only child? Selfish and narcissistic, of course.

But this last stereotype, at least, can now be put to bed. That’s thanks to new research published in Social Psychological and Personality Science in which Michael Dufner from the University of Leipzig and colleagues found that the cliché, though widespread, is fundamentally inaccurate.

In the first part of the study, the researchers looked at the prevalence of the stereotype. They gave 556 online participants items from the Narcissistic Admiration and Rivalry Questionnaire — “I secretly take pleasure in the failure of my rivals”, for example — and asked them to indicate how much the statements applied to typical only children and, separately, how much they applied to a typical person with at least one sibling. Two different aspects of narcissism were measured: narcissistic admiration, which refers to the narcissistic desire to seek out admiration, attention or flattery, and narcissistic rivalry, which involves demeaning or devaluing others to avoid criticism.

The second part of the study looked at data from the Innovation Sample of the Socio-Economic Panel — a large-scale, nationally representative longitudinal study of private households in Germany. This includes measures of narcissism for 1,810 participants, including 233 without siblings.

The first set of results did indeed indicate that we tend to ascribe higher levels of narcissistic admiration and narcissistic rivalry to only children. But results from the second part of the study seemed to suggest that our stereotyping has no grounding: only children did not actually differ in narcissism levels compared to those with siblings.

The findings may have wider implications, too. Only children, perceived as high in narcissism, may be shunned or experience discrimination from others — even though this perception is based on completely unjustified grounds. “Given this downside, researchers and journalists should refrain from portraying only children as narcissistic,” write the authors.

There are two caveats: firstly, the research was conducted only in Germany, so additional social factors may have impacted the results (the team specifically point out that cultures with higher levels of collectivism — which have a greater focus on the community, rather than the individual — may end up with a different set of results). And the research looked only at grandiose narcissism, characterised by a sense of superiority and domineering behaviour, but not vulnerable narcissism, characterised by introversion and insecurity. Measuring only one form means the research may not be conclusive across the board.

As the results of this research show, stereotypes about birth order are rarely useful in predicting someone’s personality. Though you’d certainly be forgiven for forgetting that the next time you need an excuse to call your older sibling bossy.

– The End of a Stereotype: Only Children Are Not More Narcissistic Than People With Siblings

Emily Reynolds (@rey_z) is a staff writer at BPS Research Digest