 All right, irreversibility is the term. Not even a clap and a pause, yeah? I've been punished. Uh-huh. Shit. Thank you. Reinforcers. With tones like that, I don't think it's reinforcing. Good thing this is a short word, long word, short definition. Sorry, irreversibility is the word. What we're after here is the fact that I want, let me just back, irreversibility. I want you to understand that some behaviors just can't be reversed. Usually it's when you're talking about a skill, all right? For example, I'm going to get a baseline and watch you juggle. Or why don't you get a baseline and watch me juggle? I can't do it very well, all right? So then I go learn how to juggle in the intervention condition. You teach me how to juggle. Now you try to reverse it. OK, Rein, guess what? Don't juggle anymore. You can't reverse that. You taught me a skill. So you cannot bring my responding back to the prior level at the baseline, even though the conditions are the same, right? The experimental conditions are the same. So behaviors that have a sort of permanent thing, right, that aren't temporary based on a condition, based on the environment that you're operating in. Once you teach someone a skill, you can't really reverse that skill. It's like trying to teach somebody to have to unwrite a bike. Good luck unwriting a bike. You know, it's not going to do it. Anyway, irreversibility. Some behaviors just can't. You can't use ABAB designs for it. That's all there's to it.