Are first-borns really more assertive? How birth order affects personality

unnamed file
Image: Stocksy

In spite of sharing genes and environments, siblings are often not as similar in nature as one might think. But where do the supposed differences come from? Alfred Adler, a late-19th- and early-20th-century Austrian psychotherapist and founder of individual psychology, suspected that birth order leads to differences in siblings.

Such categorizations are popular because they’re rather intuitive, and one can always find an example of the sensible big sister or the rebellious young brother.

[I]n a 2015 study, which included 377,000 high school students, psychologist Rodica Damian and her colleague Brent W. Roberts, both then at the University of Illinois at Urbana-Champaign discovered that firstborns tended to be more conscientious, extraverted and willing to lead. Contrary to expectations, they were also more tolerant and emotionally stable than adolescents with older siblings. Yet the differences were very small, and the researchers concluded that the importance that is generally attached to sibling position in shaping one’s character is exaggerated.

“It is quite possible that the position in the sibling sequence shapes the personality—but not in every family in the same way,” says Frank Spinath, a psychologist at Saarland University in Germany. “In other words, there may be an influence but not a systematic one.”

Read full, original post: Does Birth Order Affect Personality?

Related Articles

Infographic: Global regulatory and health research agencies on whether glyphosate causes cancer

Infographic: Global regulatory and health research agencies on whether glyphosate causes cancer

Does glyphosate—the world's most heavily-used herbicide—pose serious harm to humans? Is it carcinogenic? Those issues are of both legal and ...

Most Popular

ChatGPT-Image-Aug-4-2026-10_15_14-AM
Viewpoint—A hard look at the Fauci diaries: Do they change what we know about COVID’s origins?
ChatGPT-Image-Mar-10-2026-01_39_01-PM
Viewpoint—“Miracle molecule” debunked: Why acemannan supplements don’t work
Picture1
Hiroshima at 81: America’s new nuclear bomb, a buried Iranian target, and a question no one wants to ask
ChatGPT-Image-Aug-4-2026-12_42_58-PM
Viewpoint: Fact-checking CNN interview with RFK, Jr. underscores the depth of his disinformation delusions
ChatGPT-Image-Jul-17-2026-09_50_27-AM
Viewpoint: How disease tracking and prevention has cratered under the Kennedy-Trump administration
ChatGPT-Image-Aug-4-2026-07_52_00-PM
No liability for scientific due diligence: California Supreme Court rejects bizarre lawsuit faulting Gilead for fully evaluating HIV drug before release
png livestock cow cattle a
Consumer skepticism about gene-edited milk is neither fixed nor particularly high—and falls even more if it’s priced lower
ChatGPT-Image-Aug-4-2026-09_31_50-AM-2
Viewpoint: Could the U.S. become dependent on China to develop critical new genetic and drug therapies?
ChatGPT-Image-Aug-4-2026-02_05_46-PM
Does Congress have the guts to successfully challenge Trump’s politicization of science funding?
Screenshot-2026-07-17-at-1.34.59-PM
Poll: Vaccine hesitancy soars when patients distrust health providers and turn to social media
Screenshot-2026-07-31-at-10.52.03-AM
Love sweets and fatty foods? You can blame your genes, but there are ways to quell the obsessions
ChatGPT-Image-Jul-31-2026-07_35_35-AM
Wikipedia has assembled an informative list of fake news websites from across the ideological spectrum
glp menu logo outlined

Get news on human & agricultural genetics and biotechnology delivered to your inbox.