I am sure I will get thoroughly slammed by some people about this observation.
Going through my dressage books and looking at pictures of dressage riders in magazines and on the web I have noticed something that is interesting to me.
In many of the old pictures I see riders holding their heads UP and their faces vertical. Their horses often tend to have the highest part of their neck at the poll with an open throatlatch even when the horse’s face is mostly vertical.
BUT in the pictures where the rider is looking down at the horse’s neck the horses generally look like they are behind the vertical, with the neck “breaking” at the third cervical vertebrae rather than the poll and the horse’s throatlatch is not as open. Over the years I have seen more pictures of dressage riders looking down and their horse’s faces behind the vertical until this has become the “new normal/new proper position.”
I have always had a huge problem not looking down at the horse’s neck, which in my case was related fully to my back not being straight (partially my own conformation and partially an osteoporosis hump now) &/or my shoulders being in a permanent slouch. I finally “cured” it though I still have to keep my attention on it (the cure–holding my face vertical all the time while I ride) and by finally learning how to “fix” my shoulders (by pushing out with my diaphragm.)
I can really understand why dressage riders feel like they need to keep looking down, it is the only way a rider can SEE how their aids affect the horse. When I started keeping my face vertical all the time I had to start refining my FEEL because I could not look down and SEE how the horse was doing, and I also depend on my riding teacher to get after me if I start looking down again (with my MS my “feel” is not perfect.)
Yes I ride Forward Seat instead of dressage. But I have noticed that the horses I ride do move forward with more impulse when I keep my face vertical and my eyes on the horizon and I have to use my leg aids less to keep the horse moving forward freely. Besides, looking up and forward is a key element to a proper Forward Seat position and looking down was a big part of ruining my position.
Just my extremely humble opinion of course.