A Quick Thought on Children

So, I was thinking one day. We always associate children with innocence. But for what reason? What makes them innocent? Well, when I was at the McWane Center in Birmingham. There was this game there where you put this headband on and there was a little ball on the table under a slab of glass. The less you thought, the further it moved. There were screens that showed brain activity. Anyway, one of my friends was challenged by a girl who was approximately three to play. She won hands down, and the screen showed very minimal brain activity. My point is, do we associate children with innocence because they don't have the ability to think deeply, or have and deep thoughts at all? Does the inability to think make you innocent? Does a dark side naturally come with comprehension? Just a thought.