What Vladimir_Nesov said. And,

How would that model do any good compressing our description of how human minds work?

That presumes we already have such a description.

We do: it's the set of all observations of human behavior. The goal of science (or rationality) is to find ever-simpler ways of explaining (describing) the data. The worst case scenario is to explain the data by simply restating it. A theory allows you describe past data without simply restating it because it gives you a generative model.

(There's probably some LW wiki entry or Eliezer_Yudkowsky post I should reference to give more background about what I'm talking about, but I think you get the idea and it's pretty uncontroversial.)

That was the standard I was holding your post to: does this description of human behavior as "tweaking outputs to track a reference" help at all to provide a concise description of human behavior? Once again, I find myself trying to side-step a definitional dispute with you (over whether humans "are control systems") by identifying the more fundamental claim you're making.

Here, your claim is that there's some epistemic profit from describing human behavior as a control system. I completely agree that it can be done, just like you can describe human behavior with a long enough computer program. But does this approach actually simplify the problem, or just rename it? I am skeptical that it simplifies because, like I said before, any reference-being-tracked in your model must itself have all the answers that you're trying to use the model for.