It's very much like mind reading. Or like a language you have with the dog. My theory on herding dog intelligence is because they are reliant on their vision and their brains need to be better at processing all that vision requires equates to smarter dogs. My BC was so reliant on his sight, I have several memories of him not being able to find a treat or something because he didn't see where it landed or it went under something. He knew he saw me throw it, so he'd get kind of frantic an look all over the place. Eventually, he would realize he had a nose and could smell around for it.