When I’m teaching dogs to exhibit this behavior, I do it in places that allow them to be safely off-leash, where they can wander and sniff to their hearts’ content. When the dog is in his own world and not attending to me at all, I position myself so that I can see the dog but he can’t see me. When he looks up and seems just a little concerned, I call him to come, reinforcing him for his successful search. (If he becomes stressed, I come out of my hiding spot so he can see me, and still reinforce him for coming to me.)
This is a good way to perfect recalls and teach your dog that it’s wise to keep track of you, but it only works with dogs who are connected enough to care when they think for a moment that their person is lost. It is not helpful with aloof dogs or those who are completely unperturbed by your absence, and it’s just cruel to disappear on a clingy, nervous dog. Reserve this technique for those who are stable enough to handle your absence and connected enough to care—which, fortunately, is the majority of dogs.
Remember, when we talk about our dogs paying attention to us, we are really talking about two things: spontaneous attention and attention given on cue. There are many ways to improve both kinds of attentiveness, but that doesn’t mean you can change a dog’s essential nature. All the training in the world isn’t going to turn an aloof and independent dog or a dog who is wildly distracted by the smells of the great outdoors into one who is compulsive about checking in and never lets you out of sight. It is, however, possible to teach any dog to respond properly to the cue “watch” and to his name, and to come when called.
It’s also possible, and desirable, to strengthen your relationship with your dog to increase his attentiveness to you. The more fun and satisfying your interactions are, the more likely your dog is to give you his attention spontaneously or on cue.