I would not call it a smirk. It is that little smile you get when observing the cute reaction of youngsters in the discovery of something new to them. It is their delight and satisfaction in the experience and recognizing that you have known the same feelings that generate this smile.
This is how I now react to educators first discovering coding, project/problem-based learning, and the personalization of learning. The expression “been there, done that” comes to mind, but it would likely be interpreted as the typical reaction of an old guy. The stereotype typically describes those of us in reaction to so many “new” things by claiming “we tried that and it didn’t work”. Stereotypes are interesting. They tend to be based on an exaggeration and over-extension of some element of truth. Some at my age do react in this way to too many things. However, labeling any reaction of someone more experienced than yourself in this way to anything you find interesting is also likely based on anecdotal experiences you are generalizing as an assumed personality trait. Think about an issue carefully before you generalize.
Here is a perspective I would encourage learners to take. Interesting ideas in education have a way of resurfacing. This is a fact. Coding to learn (computational thinking) is not new. Neither is project-based learning or the individualization of learning. Ask yourself, what happened last time? I would suggest there are several very reasonable possibilities. Perhaps it was an interesting idea, but actually did not work. Perhaps it was an interesting idea, but not practical at the time. Perhaps it was an interesting idea, but the idea needed some tweaking. It is very likely making the effort to get beyond the surface level excitement and digging a little deeper into what happened last time would be helpful. Without this effort, the cycle that sees ideas come and go and come and go will be repeated.
Coding makes a great example. I read pretty much everything Seymour Papert wrote on logo, the roots of logo within Piagetian theory, and computation as a form of understanding. I regard Papert as an “idea guy”. What idea guys connect with at one point in time are likely the same characteristics that resurface again and again. The “coding for all” trend in K-12 has rediscovered some of these characteristics. The excitement associated with these ideas generated a great deal of research in the last cycle. Researchers are not necessarily idea guys and they take a more pragmatic approach that attempts to determine whether the ideas as implemented at the time seem to work (according to the standards of the time) are beneficial. I think the research of the time did a reasonable job of differentiating what constituted a productive from an unproductive approach to engaging learners with programming experiences. If you are unaware of this work, you do not know whether your efforts are likely to fall into the productive or unproductive approach. Good science has a way of progressing. Interesting ideas without good science have a way of surfacing and disappearing.
One of the ideas that first interested me in education and educational research was mastery learning. This form of individualization seemed to hold out hope for optimizing the learning of all students. The interesting ideas did generate lots of research, but the ideas of a mastery approach also did seem to fade away. We now see similar ideas resurfacing in reincarnations such as the Kahn Academy. In this case, my explanation would be that mastery learning was a good idea when applied in certain situations (content that builds on itself), but faded because it was impractical to implement (unless you could afford a tutor). Technology may have changed this situation, but we need to think carefully about how we mix in mastery experiences with other learning experiences.
I apologize for my reaction to your present enthusiasm for coding, project based learning, etc. These interesting ideas are not new, but I can remember having similar reactions to what you are experiencing at this time. What I would suggest based on the wisdom of experience is that you think about the question of “why it will be different this time?” The “we tried that and it didn’t work” reaction of those my age should not discorage you, but it should encourage you to recognize that others have experienced the same enthusiasm and we now encourage you to start from what is already known to move these ideas forward. Ignore this advice and twenty years from now the youngsters you encounter will regard you as an old curmudgeon.
On a related topic, see “the emerging age bias” by Pernille Ripp.