A recent study is showing that the eldest child in a family will have a slightly higher I.Q. than his or her younger siblings.
When I saw this article the very first thing I did was e-mail the link to my little brother. Then I read it. For some reason the Norwegian study only tested pairs of brothers. Dr. Petter Kristensen, who was the lead author of the study, said that it should apply to females too. The gist is that the oldest sibling usually scores about three points higher on an I.Q. test than their younger sibling does. It doesn't look like this is due to any biological factors.
My personal guess is simply that the first born gets more one on one attention from the parents. I don't think it is because the parents love the first kid anymore, it is just that they are alone with him/her for a while. Your first born is a novelty.
Not that I would know anything about that. My kids were born two minutes apart. I wonder if the applies to twins too? Probably not. One of the leading theories is that when the younger sibling is born the older child takes on the role of teacher, which gives them more skills at critical thinking.
