In designing learning environments that support student learning, there are many instructional design decisions. These include when and how to provide examples, verbal explanations, feedback, and other scaffolding features. In this paper, the authors investigate instructional guidance as it relates to Cognitive Tutor, an intelligent tutoring system that provides students with an interactive learning environment. Cognitive tutors for high school mathematics have been successful in raising students' test scores and the Cognitive Tutor Algebra curriculum is being used in over 3,000 schools nationwide. This paper reports early results from a large scale experiment evaluating different instructional conditions implemented in the Cognitive Tutor Algebra. This study explores the degree to which students can be taught without verbal explanations and tests whether the results obtained in the laboratory will generalize to real classrooms. High school students from a large rural and urban school district in West Virginia participated in this study. This study contrasted two modified tutors with the standard tutor as a control condition. To summarize the results, the authors did not find any benefits of adding verbal explanations. The explanatory and non-explanatory students did not differ in terms of number of hints or errors in any of the experimental and non-experimental units. Tables and figures are appended.