In larger analyses, the link between birth order and personality traits appears much weaker. A 2015 study looking at more than 20,000 people in Germany, the United Kingdom and the United States found no link between birth order and personality characteristics — though the researchers did find evidence that older children have a slight advantage in I.Q. (View Highlight)
Dr. Damian worked on a different large-scale study, also published in 2015, that included more than 370,000 high schoolers in the United States. It found slight differences in personality and intelligence, but the differences were so small, she said, that they were essentially meaningless (View Highlight)
I think people are just looking for meaning and self-understanding,” Ms. Stanizai said. “Horoscopes, birth order, attachment styles” are just a few examples, she said. “People are just looking for a set of code words and ways of describing their experiences.” (View Highlight)