An applied dissertation was designed to improve the performance of sixth-grade social studies students based on content-area work and teacher-made tests. Teachers used difficult, low-level, performance-based assessment methods to identify student achievement. This indicated that students possessed very limited opportunities to think beyond the knowledge and comprehension levels defined by Bloom's Taxonomy of Cognitive Skills. If teachers incorporated high-level questions in the classroom, students were less likely to identify the vocabulary used in the questions. Thus, students and teachers were less likely to identify the nature of critical thinking and Bloom's Taxonomy. Direct-instruction sheets were developed for students to identify low-level knowledge, which they could apply to high-level activities. Philosophy was incorporated into the sixth-grade world history curriculum, providing the foundation for critical thinking. Application of vocabulary and low-level activities allowed students to think beyond the knowledge and a social science environment. Sixth-grade teachers also identified the nature of critical thinking, which they infused into their classrooms. Analysis of the results indicated that the direct-instruction sheets positively influenced student performance. The most successful strategies incorporated simple and complex questions in teaching Bloom's Taxonomy to students. These methods improved student ability to identify critical-thinking vocabulary, which allowed them to engage in high-level questions and activities. Findings showed that teachers need more incentives to decrease the number of low-level activities. Fourteen appendices include items such as the following: Pre-Implementation Teacher Survey; Instruction Sheets; Critical-Thinking Pre-Tests and Post-Tests; Pre-Surveys and Post-Surveys; Pre-Observation and Post-Observation Instrument; Rubrics; and Student Journal Responses. (Contains 70 references and 2 tables.) (Author/BT)