There have been several studies, most recently a Johns Hopkins series of articles, linking the order of birth with personality.
The oldest child is responsable, conservative, and dogmatic..the youngest is the free-thinking, early-adapting and creative member, and so on (I can post some Links in relation to this if you wish)
When teaching Improvisation, I have found that not only is it the usual mechanical and math adept pro-sport poor reader who finds it hardest to think outside the square, but that the first born child is far harder to teach to improvise, indeed almost impossible in many cases, whilst the youngest has natural improvisation skills which just need direction.
Has anyone else encountered this?

Fucarta Non Perfecta: Carpe Cerevisi