What's on your mind?

This has been a regular point of discussion between me and my wife.  What the heck to babies think about all day?  How do their minds interpret everything they see, when they don't know colors, shapes or even words?  Is she laughing at me because I'm trying to be goofy, or because she thinks my face is weird?  What is going on behind that cute face?

I was especially thinking that today as we went shopping.  I could tell she was a little tired, because she was staring off into space the entire time.  But I'd still like to know what was on her mind.  Was she just a little bored because there was nothing exciting on the ceiling (the car seat was tilted backward a little bit in the shopping cart, so she was looking straight up the entire time)?  Or was she just thinking about the next time she'll get to hang out with Mom's boobs?  That would make two of us.

Regardless of what she was thinking, I scored some awesome, pre-cooked ribs.  So I'll call the trip a win.