 Activity-based reinforcers, although might be referred to as activity reinforcer or activity-based reinforcer, whichever way you want to say it. This is basically saying that an activity that you engage in could be a reinforcer. C. Pre-Mac Principle. All right, so Pre-Mac Principle basically covers this whole thing in depth. The really cool thing about Pre-Mac Principle that's completely over, I'm sorry, underrated is that no one completely got it, at least in my opinion, and the thing that I think is drastically important about it, which I've said twice now, is that everything is an activity. Imagine a reinforcer that you get is not anything until you touch it, play with it, eat it, smell it, other things with it. Whatever it is that you may have to do in order to engage with that reinforcer is probably an activity. However, I do believe that what Pre-Mac was originally getting at and what the definition is really about is about being able to do things like go running or go biking or something like that. Anyway.