Animal trainers do not reward animals for trying to do a task. The animal would get confused as to what the desired behavior was.
Humans get a lot of praise for trying. Sometimes we don't even have to try, we can get praise for just talking about trying to do something. If I tell my friends that I wanted to learn Spanish, all my friends would praise me. Even before I actually learn any Spanish, or actually try to learn Spanish, I would receive verbal praise from my friends. Iwonder if this form of praising helpful and motivating, or does it simply encourage people to talk about doing things?
If I want to adopt this technique to working with my children, I would only praise them for succeeding at a task, not for trying. But, my children need praise and I am a great cheerleader for them. I know I can't stop verbally praising them. Instead, I can try to break down the steps to a task and praise my daughters for what they have done. I can encourage them to accomplish the next step in the task.