Elaine.Atkinson@A.CS.CMU.EDU (10/22/86)
SPEAKER: Prof. Kurt VanLehn, Psychology Dept., CMU TITLE: "Towards meta-level problem solving" DATE: Thursday, October 23 TIME: 4:00 p.m. PLACE: Adamson Wing, Baker Hall ABSTRACT: This talk presents preliminary evidence for a new model of procedure following. Following a mentally held procedure is a common activity. It takes about 12 procedures to fill an order at McDonalds. Perhaps 50,000 procedures are followed daily in running an aircraft carrier. Despite its ubiquity and economic importance, little is known about procedure following. The folk model is that people have an interpreter, similar to the interpreters of Lisp, OPS5 or ACT*. The most common interpreters in cognitive science are hierarchical, in that they employ a goal stack or a goal tree as part of their temporary state. A new model of procedure following will be sketched based on the idea that procedure following is meta-level problem solving. The problem is to get a procedure to execute. The operators do things like set goals, pop them, etc. The state descriptions are things like "goal1 is more recent than goal2." Different problem spaces correspond to different interpreters: the goal stack, goal tree and goal agenda are three different meta-level problem spaces. We present data based on protocols from 25 subjects executing procedures that show that (1) different subjects have different interpreters (stack and agenda are the most common) and (2) some subjects change interpretation strategy in the midst of execution. Although these data do not unequivocally refute the folk model of procedure following, they receive a simpler, more elegant interpretation under the meta-level problem solving model.