Very good point. Yes, the holes are visible and right across from his pasture. I never thought about the depth perception thing. I may try something new today and take him on a totally different ride/direction....perhaps down the driveway opposite away (but still away from the barn) and down/around the other side of the pasture to see what he does.
I also wonder if "mentally" this is just now a trouble/tantrum spot for him....almost like habit.
I do try to "bend" him to look the other way, but I almost think that makes it worse. My trainer feels I should ride straight, forward and when he takes a step to TURN, address it with one-rein stop opposite direction, then ask confidently for forward....and if he does it again, one-rein stop and yield hindquarters in a circle several times....then ask for forward again. It does work but takes a few tries.
The other issue may be "open spaces". (gosh I feel like a psychologist!!).....If you can picture....you are pointed down the fenceline.....fence is on the right.....then 5 to 10 yards of the grassy path we go down, then the tree line with few areas of holes, and then to the left of the trees, HUGE open sod field....several acres......it is very open, dark green from the sod....wind comes in over it pretty strong. It feels, well, VERY open and perhaps scary to him...all of this put together. He will trot on the sod field side but still attempts turn-arounds...although I try the field side after I am exhausted from the other side! Maybe we try the field side first...? It's quite interesting. But maybe a different ride/change of pace is what he needs. Unfortunately there isn't alot of places to ride the other way...a highway further the other way we would run into but I could turn him up the field and take him down the other side of the sod field......we'll try today. I may tire him out in the ring and take him out there for more of a "treat" today....loose rein, relaxed and see how he does. Oh, the quandries!!!! :)