Mental Model of User as Learner

UCD uses GOMS (Goals, Operators, Methods, and Selection Rules) to describe the mental model of a user facing an interface. A user has goals, selects an operator, and applies the methods of that operator to achieve the goal. GOMS was originally presented in the famous Card, Moran, and Newell book on Human Information Processing.

Everybody knows that GOMS doesn't work for learners – Bonnie John, an expert in GOMS, told me that herself. So what does?

SOAR does. SOAR is a child of GOMS by Newell, Laird, and Rosenbloom. SOAR assumes that there are multiple operator spaces, and that when you hit an impasse in one space, you move into a operator space selection space – what kind of problem is this? You then solve the current impasse, then pop the stack back to the old problem.

This meshes with what we see a learner doing (LCD vs. UCD). But this also suggests tons of complexity. How do you design for something as complex as Soar (Design Methods of LCD)? What kind of interface supports task switching (Interfaces to Support Task Switching)?