Oh, btw, how do you define smart? Quickness of learning? If so, the explanation would be plain too simple. Or else?
Spurious, aren't you loading this a bit? I mean, you know the deal but you're pretending you don't! Please Register or Log in to view the hidden image! Isn't it that quite literally, the interconnections in a child's brain are forming at a rate that makes an adult's look pathetic? Isn't that due to the presence of some chemical that makes that so? Somewhere I saw a video of actual connections being formed in real time (I'm not sure if it was in a petri dish or whatever). It was pretty cool. Wouldn't there be a directly correlation between that and "smartness"? Meh. Maybe not?