Long-time lurker, first time commenting. Without necessarily disagreeing on any object-level details, I want to give an alternate perspective. I'm a PhD in computational cog sci, have interacted with most of the top cognitive science departments in the US (e.g. through job search, conferences, etc), and I know literally zero people who use ACT-R for anything. It was never mentioned in any of my grad classes, has never been brought up in any talk I've been to -- I don't even know if I've even seen it ever cited in a paper I've read. I know of it, obviously, and I know that it was super influential back in the 90s, but I'd always just assumed that the research program withered away for some reason (given how little I'd seen it actually being used in top-level research at this point).
This post made me curious how I could have such a different perspective! I don't know whether academic cognitive science is just really segregated and I'm missing all the ACT-R researchers still out there; whether ACT-R was actually amazing and people have been silly to drop it; whether "top-level" research is misleading and actually the good research is being published in lower-tier journals while flashy fad-based results get published in top journals; or whether ACT-R really did fail for some deep reason. I've asked some colleagues why nobody around us uses it anymore, but I haven't gotten any detailed responses yet.
(Also, this is a small thing, but "fitting human reaction times" is not impressive -- that's a basic feature of many, many models.)
So while I don't have any object-level disagreements with this post, it feels like helpful context to know that many, many active computational cognitive scientists would strongly disagree that ACT-R is essentially the one best-validated theory of cognition (to the point where they'd be like "huh? what are you talking about?"). This paper gives what I think is a much more contemporary overview of overarching theories of human cognition.
Thanks for the thoughtful response, that perspective makes sense. I take your point that ACT-R is unique in the ways you're describing, and that most cognitive scientists are not working on overarching models of the mind like that. I think maybe our disagreement is about how good/useful of an overarching model ACT-R is? It's definitely not like in physics, where some overarching theories are widely accepted (e.g. the standard model) even by people working on much more narrow topics -- and many of the ones that aren't (e.g. string theory) are still widely known about and commonly taught. The situation in cog sci (in my view, and I think in many people's views?) is much more that we don't have an overarching model of the mind in anywhere close to the level of detail/mechanistic specificity that ACT-R posits, and that any such attempt would be premature/foolish/not useful right now. Like, I think if you polled cognitive scientists, the vast majority would disagree with the title of your post -- not because they think there's a salient alternative, but because they think that there is no theory that even comes close to meriting the title of "best-validated theory of cognition" (even if technically one theory is ahead of the others). Do you know what I mean? Of course, even if most cognitive scientists don't believe in ACT-R in that way, that alone doesn't mean that ACT-R is wrong.. I'm curious about the evidence that Terry is talking about above. I just think the field would look really, really different if we actually had a halfway-decent paradigm/overarching model of the mind. And it's not like ACT-R is some unknown idea that is poised to take over the field once people learn about it. Everyone knew about it in the 90s, and then it fell out of widespread use -- and my prior on why that happened is that people weren't finding it super useful. (Although like I said, I'm really curious to learn more about what Terry/other contemporary people are doing with it!)