Mokinho, from multiple first hand experiences, I must insist that horses can sense a riders fear and anxiety. When a rider is afraid, their hands are rigid, their seat is tense, and their legs are also very firm. Humans tend to "freeze up" when they are fearful, and I myself do all of that when I am afraid while on my horse. In return, the horse feels my rigidity and my tenseness, they can feel I am not walking WITH them in the saddle (since when you are stiff, you don't flow as well with the horse's stride, its almost choppy). And in return, the horse, a prey animal, reacts in such a way:
The Alpha is fearful of something.. I wonder what it is? I better be on guard to make sure nothing attacks me!
Horses are followers, and most horses follow their leader (aka you, the handler). In the wild, when the leader is frightened, they react accordingly. So, when they feel their alpha is tense and fearful, they also get very fearful hoping whatever is scaring you will not attack them.. if that makes sense.
Even just as recently as today, I accidentally spooked my horse when I jolted suddenly in the saddle because a ladybug attacked me. He felt me tense up suddenly and jumped as if to say "Oh my god!! What is it?!! Ohmygodohmygod!!" The only thing that spooked him, was MY insecurity when I freaked out about the lady bug and suddenly tightened up in my seat and gripped my legs around his barrel tighter.
I hope all this makes sense. I just have to reiterate that I 100% believe (through multiple, multiple personal experiences) that horses DO feel when their rider/handler is fearful/angry/happy through our body language and posture. Any horse person will tell you can speak to your horse by the way you are standing and approach your horse. Its just basic horsemanship =)
I hope it doesnt seem like im attacking ya =) I am not! But this is a huge thing I teach people when they are fearful of leading and riding their horses, they cannot show their fear or they will no longer be the alpha in the relationship ;)