By the same token, you can say the opposite is what is actually happening. If you keep the head down, you will have the tendency to bend the chest down and push the hips back and be more hip dominant. That's what happens in a low bar squat - you don't have the vertical back that is in the high bar squat.
In fact, Rippetoe recommends AGAINST a "look-forward" approach, because, according to him, if you look forward or (even worse) up, you will have the tendency to push the knees forward and lose hip drive.
Also, a hip dominant jump is a chest forward, hips back, tibias more vertical jump (head down), whereas a quad dominant jump has a more vertical back and a more positive shin angle, with the head looking up.
So... who knows what the real deal is? Interesting, nonetheless.
