Eliminating the Gap between the High and Low Students through Meta-Cognitive Strategy Instruction Min Chi and Kurt VanLehn Learning Research and Development Center & Intelligent System Program University of Pittsburgh, PA, 15260 {mic31, vanlehn+}@pitt.edu Abstract. One important goal of Intelligent Tutoring Systems (ITSs) is to bring students up to the same level of mastery. We showed that an ITS teaching a domain-independent problem-solving strategy indeed closed the gap between High and Low learners, not only in the domain where it was taught (probability) but also in a second domain where it was not taught (physics). The strategy includes two main components: one is solving problems via Backward- Chaining (BC) from goals to givens, named the BC-strategy, and the other is drawing students’ attention on the characteristics of each individual domain principle, named the principle-emphasis skill. Evidence suggests that the Low learners transferred the principle-emphasis skill to physics while the High learners seemingly already had such skill and thus mainly transferred the other skill, the BC-strategy. Surprisingly, the former learned just as effectively as the latter in physics. We concluded that the effective element of the taught strategy seemed not to be the BC-Strategy, but the principle-emphasis skill. Keywords: Intelligent Tutoring Systems, meta-cognitive skills, domain- independent Problem-Solving Strategies. 1 Introduction Bloom [2] argued that human tutors not only raised the mean of scores, but also decrease the standard deviation of scores. That is, students generally start with a wide distribution in test scores; but as they are tutored, the distribution becomes narrower— the students on the low end of the distribution begin to catch up with those on the high end. Another way to measure the same phenomenon is to split students into High and Low groups based on their incoming competence. One then measures the learning gains of both groups. According to Bloom, a good tutor should exhibit an aptitude-treatment interaction: both groups should learn, and yet the learning gains of the Low students should be so much greater than the High ones’ that their performance in the post-test ties with the High ones. That is, one benefit of tutoring is to narrow or even eliminate the gap between High and Low. Previously, we found that Pyrenees [11], an ITS that explicitly taught a problem- solving strategy, was more effective than Andes [12], an ITS that did not explicitly teach any strategy not only in the domain where it was used, but in a second domain where it was not used [3]. The strategy seemed to have lived up to our expectations and transferred from one domain to another. In this paper, we investigated whether explicit strategy instruction exhibited an aptitude-treatment interaction, that is, whether it narrows or even eliminates the gap between High and Low; moreover, whether both High and Low indeed transferred the strategy to the second domain.