Re-discovered this study by Fred Newmann on high school social studies classes.

The “six key indicators of thoughtfulness” are as follows:

1. Classroom discourse focuses on sustained examination of a few topics rather than superficial coverage of many.
2. The discourse is characterized by substantive coherence and continuity.
3. Students are given sufficient time to think before being required to answer questions.
4. The teacher presses students to clarify or justify their assertions, rather than accepting and reinforcing them indiscriminately.
5. The teacher models the characteristics of a thoughtful person.
6. Students generate original and unconventional ideas in the course of the interaction.

Newmann, F. (1990). Qualities of Thoughtful Social Studies Classes: An Empirical Profile. Journal of Curriculum Studies, 22, 253-275.