Perspectives: Ruled by Birth Order?; January / February 2010; Scientific American Mind; by Joshua K. Hartshorne; 2 Page(s)

When I tell people I study whether birth order affects personality, I usually get blank looks. It sounds like studying whether the sky is blue. Isn’t it common sense? Popular books invoke birth order for self-discovery, relationship tips, business advice and parenting guidance in titles such as The Birth Order Book: Why You Are the Way You Are (Revell, 2009). Newspapers and morning news shows debate the importance of the latest findings (“Latter-born children engage in more risky behavior; what should parents do?”) while tossing in savory anecdotes (“Did you know that 21 of the first 23 astronauts into space were firstborns?”).

But when scientists scrutinized the data, they found that the evidence just did not hold up. In fact, until very recently there were no convincing findings that linked birth order to personality or behavior. Our common perception that birth order matters was written off as an example of our well-established tendency to remember and accept evidence that supports our pet theories while readily forgetting or overlooking that which does not. But two studies from the past three years finally found measurable effects: our position in the family does indeed affect both our IQ and our personality. It may be time to reconsider birth order as a real influence over whom we grow up to be.