It has been around for a while, I believe. The idea is not to deny a child praise, but to use praise to enhance a child’s abilities. What you actually do is to praise the child’s willingness to work or to use their imagination or to accomplish some particular goal, not to simply praise anything they do indiscriminately. In other words, don’t simply say “I like it” but instead say what you like about either the actual work or they way in which the child got to their stopping point. Say “I like the way you used the colors” or “I love how hard you have worked on this” to reinforce creativity or focusing on a task. You can even say that you love the fact that they made it for you, to reinforce doing for others. If you say you like everything a child does, or you tell every child you like their work two things can result. One is that the child quickly realizes that you don’t really mean it and so loses interest in seeking your praise for that sort of accomplishment, or secondly, the child thinks that they are someone so special that they deserve special privileges (and when they find out later that they aren’t really a great artist they can get understandably a bit dismissive of your opinion). What I do is say that I like something they have drawn especially because of the way they have used the colors, or added something original, or worked so carefully and hard on it. And then I hang it on the refrigerator.