Birth Order: Scientists Answer If The Order Determines Success Or Failure

“I do not fit into the family like my older sibling” is a common notion among children. But researchers have found that there is no significant difference in terms of intelligence and personality between the first child and subsequent children in a famly.

A study by researchers at the University of Houston and the University of Illinois -- supposedly the biggest in history looking at birth order and personality -- analyzed nearly 377,000 high school students and found that the older siblings have an IQ advantage of just one point over their younger siblings.

In addition, the children born first were found to be more agreeable, outgoing and extroverted than the ones born later in life. Even though the difference was statistically significant, the researchers said it was “infinitely small” enough to be observed by people in real life.

“In some cases, if a drug saves 10 out of 10,000 lives, for example, small effects can be profound. But in terms of personality traits and how you rate them, a .02 correlation doesn’t get you anything of note. You are not going to be able to see it with the naked eye. You’re not going to be able to sit two people down next to each other and see the differences between them. It’s not noticeable by anybody,” said lead researcher Brent Roberts in a university statement.

The researchers took into consideration a number of control factors while conducting the analysis, including the number of children, their age and the socioeconomic status of the family. Co-author Rodica Damian says that the research findings have a message for all the parents out there to impact their parenting and relate it to their child's personality or IQ.

The complete analysis of the study has been published in the Journal of Research in Personality.