Not all learning requires cookies or toys; there is value in teaching your dog just for fun. When dogs learn without classic rewards, they tend to operate in a calmer manner, because learning for learning's sake does not generate drive. It does, however, force the trainer to use genuine praise and appreciation for your dog's efforts.
Learning simply to learn allows the dog to take pleasure in their abilities to overcome challenges. There is no external pressure to succeed - nothing is at stake.
Watch Lyra learn to pick up new objects and to hand them to me (I've lumped two behaviors together here). She is doing this because I asked her to; there are no classic rewards and she knows it. The reward is twofold; one, I'm genuinely appreciative on her efforts and secondly, she gets to take pride in her ability to succeed - sometimes when she thinks what I have asked is not possible. Note her attitude the first time she picks up the small rubber toy and the pen. The rubber toy is easy to pick up but she has trouble getting it into my hand without dropping it. The pen is hard to pick up off the floor - several times she looks at me and wants to give up because she does not think it is possible. After she succeeds on both of these tasks, note that she does not fail again - she stays with the task until she succeeds. She is learning that if I ask for something then it is possible, if she simply tries hard enough.
I need Lyra to understand that "get it" means get whatever I point to, and place it in my hand. Until now I've used unusual objects in her scent discrimination but she tends to drop them without handing them to me - she has the concept of pick them up but not place them in my hand. With a formal dumbbell she has both - retrieve and place it in my hand. Now I want her to take this one step further; pick up anything I ask for with a "get it" command and put it in my hand. Eventually I'll add in a formal front with any random object but that is a different step altogether.
When she has these behaviors, I can begin to formalize her scent discrimination and add in her glove retrieve - get the one I ask for and put it in my hand.