Robcat has it in one. The courts are concerned with whether the child can appreciate the significance of their testimony, know the difference between truth and lies, and between reality and imagination.

That said, I have found that a child's memory of things is less colored by their past experience, 'cause they have had less past experience. But you have to be able to understand that things are seen from a child's perspective.

I spent 26 years as a cop, and I always found that a child's description was hands down better than an adults. One particular incident is a perfect example, occurring when I was a rookie. We were looking for a suspicious person hanging around a path used by kids. Only kids has seen this person, and I was taking statements from those kids who had seen this guy. The older the kid, the more compartmentalized the description. The youngest witness (about 5 years) described the suspect clothes well, then as a "monster with a horn coming out of his head".

Right.

When I located the suspect, he was a young man who was prohibited from drinking, and would go off and drink to insensibility. His face got cold so he wore a Halloween mask - of a monster with a short horn coming out of his forehead.

Oooops.