Well folks, it's seems pretty conclusive.
According to a survey by the University of Leipzig in Germany, first born children tend to be more intelligent than their siblings due to the higher level of attention they receive in the first years of their lives.
The research indicated that there's an average of 1.5 IQ points in difference between each sibling in a family.
Lead researcher of the study, Dr Julia Rohrer, said,
A first-born will enjoy full parental resources, including attention, the second-born will have to share with the firstborn from the start, and it gets even worse for the third-born.
The study, which was conducted on 5,240 Americans, 4,489 Britons, and 10,456 Germans, seems to indicate that the long held notion that the 'baby' of the family gets all the parental attention is merely a myth.
Dr Rohrer further explained why the eldest tends to be more intelligent,
A first-born can 'tutor' their younger siblings, explaining how the world works and so on. Teaching other people has high cognitive demands -- the children need to recall their own knowledge, structure it and think of a good way to explain it -- which could be a boost to intelligence for some first-borns.
So there you have it.
Has this come as a surprise to anyone?