I'm a middle child. Second born out of four. I've noticed something interesting. Growing up, I was the most disciplined/strict. While my older and younger siblings were mostly let off the hook. They weren't expected to have the best grades, but for me, anything under an A was unacceptable. I was also the one who took self-teaching to a whole new level. And even now, I find myself being the only one (out of the four) that looks up things and teaches myself. I continue to look into new topics.
On the flip side, I've found that while I had more discipline and strict schedules, as I grew older (started in middle school and progressed since) I've become more lazy and "pleasure" focused. Put off homework and assignments, don't really focus on producing anything. I just sit around and devour information I find on the net. My siblings are similar now, but not as much as I.
My parents are now focusing on disciplining the younger kids (me and my older bro are out at uni and living on our own now). And what used to fly when the younger kids were younger, doesn't any more. They still have the same lazy approach when it comes to self teaching (they don't, and rely on older people to help them). And I've noticed a clear divide. The older, yet self-teaching, kids, and the younger force-fed kids.
As for my older brother, he seems to be getting along just fine. He's gotten work at several places, got an internship, etc. I haven't been as proactive in work, but have been getting better grades (he failed a class and now has to take an extra one to make it up).
I've recently been trying to take matters into my own hands and become more disciplined and strict. Though I've failed many times at this.
So what's that mean? Probably that my parents are more attentive/focused on praising the younger child while disciplining the one that came before. But overall it's interesting since I taught myself most of the stuff I know, yet my younger siblings do not have that same drive to learn (instead opting to chat with friends or play garry's mod).
Edit: I should note that I've outpaced my older brother in education. I was on track to graduate before him, but he's managed to find a way to graduate at the same time (even though he's a bit late). I'm two years younger, yet at the same education level (caught up in highschool/community college).