No you’re right, it doesn’t say how they should be combined. My assumption—and I suspect the assumption of the authors—is that we have no good widely-accepted overarching model of the mind, and that the best we can agree on is a list of ingredients (and even that list was controversial, e.g. in the commentaries on the paper). I think that’s the reason I, implicitly, was viewing the paper as a contemporary alternative to ACT-R. But I take your point that it’s doing different things.
No you’re right, it doesn’t say how they should be combined. My assumption—and I suspect the assumption of the authors—is that we have no good widely-accepted overarching model of the mind, and that the best we can agree on is a list of ingredients (and even that list was controversial, e.g. in the commentaries on the paper). I think that’s the reason I, implicitly, was viewing the paper as a contemporary alternative to ACT-R. But I take your point that it’s doing different things.