Bloom's taxonomy categorizes educational objectives into three domains: cognitive, affective, and psychomotor. The cognitive domain involves knowledge and thinking skills and includes six levels from basic recall to evaluation. The affective domain deals with attitudes, values, and feelings and has five levels from awareness to characterizing beliefs. The psychomotor domain concerns physical skills and abilities, though Bloom did not define levels for this domain as he did for the cognitive and affective domains. Subsequent researchers have proposed taxonomies for the psychomotor domain involving skills from basic reflexes to complex communication. Bloom's taxonomy provides a framework for classifying learning objectives across different types of educational goals.