The Basic Idea
In colloquial usage, Bloom's taxonomy refers to a classification scheme for educational objectives. While its original formulation was somewhat more comprehensive, it is characteristically represented as a hierarchy of six cognitive capacities: knowledge, comprehension, application, analysis, synthesis, and evaluation. Although seldom mentioned, the original taxonomy developed by Bloom and his colleagues included outcomes in the affective and psychomotor domains in addition to cognitive outcomes. The conceptual framework of Bloom's six cognitive levels has become as close as anything ever has to a common core curriculum in teacher education around the world. Its impact has been tremendous.
Bloom's taxonomy was developed, in part, to facilitate communication between educators and curriculum developers. It can serve a constructive role in both curriculum design and lesson planning, insofar as it helps to draw attention to certain aspects of higher level thinking, and thereby challenging an excessive focus on the learning of content matter alone. Moreover, the taxonomy has contributed to a shift in educational thinking away from teaching as delivery of information, and towards a focus on what is learned, and the role of activity in learning.
Effectively, what the hierarchy does is to provide some scaffolding for the way we think about thinking, and in so doing, implicitly emphasizing the importance of cognitive functions which make use of information. The basic framework has been extended to include action verbs and question stems associated with each of the levels, all of which can be considered constructive in adding to the variety of learning and teaching approaches used in a given classroom.
Like most lenses, the taxonomy brings certain things into view, while obscuring others. Bloom's taxonomy has not been widely critiqued, but where it has, criticism has tended to focus on deficiencies in its scope, or the artificial structure of discrete objectives. In common parlance, the possible learning is reduced to six alternatives (or effectively two, higher and lower level learning), none of which is capable of describing anything deeper than knowledge and skills.
While the structure may provide some benefit as metacognitive scaffolding, its artificial and reductive nature distort the way in which we come to view both teaching and thinking. We become preoccupied with distinctions between the artificial levels, as if there was something immutable about them, or as if covering all levels would result in well-rounded learning. There are other problems too, such as the tendency to see the taxonomy as a progression which should start with the lowest level and work towards the highest, rather than the more natural approach of engaging curiosity (involving analysis and evaluation), and letting inquiry drive the learning of knowledge.
However, the consequences of this scheme are much more insidious than these kinds of superficial distortion. The approach of breaking down learning to discrete and verifiable objectives is a perfect complement to the industrial, utilitarian model of schooling, with its emphasis on inputs and outputs, quantifiability, accountability, and efficiency. Bloom's Taxonomy provides a blueprint for factory schooling, and fundamentally undermines more humanistic or comprehensive perspectives on what learning and development are really about.
Ultimately, this contributes to a distortion in all aspects of education, by suggesting that teaching, learning, and development can be reduced to discrete particles, and then practiced effectively. This is akin to thinking that we could brew up a healthy diet if we could just get the chemistry right. Learning and development are natural processes, and should be understood much more holistically.
The worthwhile takeaway from Bloom's Taxonomy is the notion that we should be thinking about what we are trying to achieve in education, in some kind of tangible terms that go beyond the transmission of content. Through Bloom's lens, learning is not just about a body of content, but also what students can do with and to that content. However, the benefits of the taxonomy correspond, roughly, to the extent to which we are prepared to go beyond it.
Insofar as the taxonomy assists with articulating the kind of learning we hope to see in our students, it can be useful for channeling energy towards that learning. Because education systems have become so fixated on outcomes, and are unlikely to change anytime soon, educators concerned about higher purposes such as social justice and sustainability should learn to play the game, and articulate the kind of learning which will contribute to those goals. To this end, Bloom's Taxonomy--even in its full version--should be taken as a starting point only, and with all the preceding caveats in mind. Learning in relation to these goals should not be framed around cognitive functions alone, because at the heart of these goals we are talking about character development, the affective and behaviour domains, and the internalized perspectives and schemas required to support a cultural shift. Concerned educators should take a page from Bloom (only one), and work towards clearer articulations of this kind of learning.