Bloom's taxonomy was developed by Benjamin Bloom as an organized classification of levels of intellectual behavior related to learning. Bloom's taxonomy covers the three main domains of learning: cognitive, affective and psychomotor. It has been a pioneering force in education and helped form Common Core and other major curricula.
The most widely influential domain of Bloom's taxonomy is the cognitive domain, which is defined by six distinct levels with increasing degrees of difficulty; the six cognitive levels of Bloom's taxonomy are knowledge, comprehension, application, analysis, synthesis and evaluation. The increasing difficulty of the levels refers to the amount of abstract, analytical and creative thinking required to access each level of processing information.
During the 1990s, a new group of psychiatrists and educators reformed Bloom's taxonomy for the 21st century. The reformed taxonomy changed the nouns to verbs and added an additional level, re-branding the six levels as remembering, understanding, applying, analyzing, evaluating and creating.