Birth order is something that hardly comes to mind when considering intelligence or personality, but with more studies being done on the subject, is there really a possibility that birth order influences such integral parts of our psychology? Many scientists pose the questions of, is there an impact on a person's IQ or personality by the number of siblings that precede them? In the past, data from such research had been inconclusive, but recent studies have found measurable effects of our position in the family on our IQ and personality. An article which delves deeper into these studies can be found here:
It's natural to first respond to these studies with skepticism. There are so many variables, such as family size, social status, and environment, which could play a part in skewing such data. It's important to keep in mind though, that these results aren't concrete, they simply display what the data suggests based on its interpretation.
The data only implies that there is only a small negative correlation between the birth order and IQ/Personality. This by no means destines a person to have low or high IQ or a particular sort of personality. A few questions that were inspired by these studies for me are: What are the rival hypotheses? Does the correlation carry throughout cultures? How much should birth order be weighed when evaluating an individual's IQ or personality? My personal conclusion is that the link between birth order and IQ/Personality isn't quite near worth weighing too heavily.