Thank you for your responses.
Yes, I had a similar thing with a horse last weekend, maybe you have read about it in my diary of the other horses. What I do in these situations, though, is that I just become slower and more careful and smooth in my movements, while keeping up the same style of offering an interaction and then (again, slowly!) walking away if they don't react.
So I tried this just yesterday. I would offer him to do an exercise, and when he didn't respond quickly enough, I slowly walked away, turned and faced him. Most often, he would then look at me for about 10 seconds, frozen, then do a leg lift or paw the ground - saying "here, i'm doing an exercise. Except I want to do this one, and over here, not over there." Usually at this point I'd walk up to him to treat him, and then ask for the leg lift again. Speed of execution did not increase, as expected.
And when I didn't respond to his pawing except verbally, he'd stand still for another 20 seconds, looking at me, look back at the herd, look at me, yawn a few times, then sigh and slowly amble over to me. Like he was saying "fine, i'll come over there. except i see no reason as to why we should be doing things there and not here where I am already".
Mohican, on the other hand, binds to my moves almost perfectly. He'll respond immediately to any gesture, change in posture, balance, speed. And since he knows what clicker training is now, it took 3 (!!!) clicks to get this food hound to turn his head away from a closed hand offering treats. Exercises for him are much harder - he will respond to body language, but with an exercise he has to think for a second and then respond. Almost as if he has to stop reacting to my body language, switch gears, and execute a remembered movement based on a smaller cue than just my body language.
After all, each behaviour, even starting to walk, is always a chain of multiple, little behaviours... If you reward only the last piece of that chain, it requires a lot of brainpower to do it for complex things. Outlaw is thinking a lot, so I don't think it's a question of compliance...
I would agree with you here, of course. But for some reason I don't do it out in the field. :\ I think its because one time I tried - I'd step forward, and reward any movement in the direction of following me, be it a step forward, a neck stretch, anything *forward* - and he grew bored of the task before understanding what I was trying to get him to do. Maybe I need to break it down even more...