Shulman (1986) advanced thinking about teacher knowledge by introducing the idea of pedagogical content knowledge. He claimed that the emphases on teachers subject knowledge and pedagogy were being treated as mutually exclusive domains in research concerned with these domains (1987, p.6). The practical consequence of such exclusion was production of teacher education programs in which a focus on either subject matter or pedagogy dominated. To address this dichotomy, he proposed to consider the necessary relationship between the two by introducing the notion of PCK.
This knowledge includes knowing what teaching approaches fit the content, and likewise, knowing how elements of the content can be arranged for better teaching. This knowledge is different from the knowledge of a disciplinary expert and also from the general pedagogical knowledge shared by teachers across disciplines. PCK is concerned with the representation and formulation of concepts, pedagogical techniques, knowledge of what makes concepts difficult or easy to learn, knowledge of students’ prior knowledge and theories of epistemology. It also involves knowledge of teaching strategies that incorporate appropriate conceptual representations, to address learner difficulties and misconceptions and foster meaningful understanding. It also includes knowledge of what the students bring to the learning situation, knowledge that might be either facilitative or dysfunctional for the particular learning task at hand. This knowledge of students includes their strategies, prior conceptions (both “naïve” and instructionally produced); misconceptions students are likely to have about a particular domain and potential misapplications of prior knowledge.
PCK exists at the intersection of content and pedagogy. Thus it does not refer to a simple consideration of both content and pedagogy, together but in isolation; but rather to an amalgam of content and pedagogy thus enabling transformation of content into pedagogically powerful forms. PCK represents the blending of content and pedagogy into an understanding of how particular aspects of subject matter are organized, adapted, and represented for instruction. Shulman argued that having knowledge of subject matter and general pedagogical strategies, though necessary, were not sufficient for capturing the knowledge of good teachers. To characterize the complex ways in which teachers think about how particular content should be taught, he argued for “pedagogical content knowledge” as the content knowledge that deals with the teaching process, including the “the ways of representing and formulating the subject that make it comprehensible to others” (p. 9). If teachers were to be successful they would have to confront both issues (of content and pedagogy) simultaneously, by embodying “the aspects of content most germane to its teachability” (Shulman, 1986, p. 9). At the heart of PCK is the manner in which subject matter is transformed for teaching. This occurs when the teacher interprets the subject matter, finding different ways to represent it and make it accessible to learners.
The notion of PCK has been extended (and critiqued) by scholars after Shulman (for instance see Cochran, DeRuiter, & King, 1993; van Driel, Verloop, & De Vos, 1998). In fact, Shulman’s initial description of teacher knowledge included many more categories (such as curriculum knowledge, knowledge of educational contexts, etc.). Matters are further complicated by the fact that Shulman has himself proposed multiple lists in different publications, that lack, in his own words, “great cross-article consistency” (Shulman, 1986; p. 8). Our emphasis on PCK is based on Shulman’s acknowledgement that “pedagogical content knowledge is of special interest because it identifies the distinctive bodies of knowledge for teaching. It represents the blending of content and pedagogy into an understanding of how particular topics, problems, or issues are organized, represented, and adapted to the diverse interests and abilities of learners, and presented for instruction” (p. 8). Moreover, our emphasis on PCK is consistent with the work of many other scholars and recent educational reform documents. Since its introduction in 1987, PCK has become a widely useful and used notion. For instance in the area of science education scholars such as Anderson and Mitchner (1994); Hewson and Hewson (1988); Cochran, King, and DeRuiter (1993); and professional organizations such as the National Science Teachers Association (NSTA, 1999) and National Council for the Accreditation of Teacher Education (NCATE, 1997) have all emphasized the value of PCK for teacher preparation and teacher professional development. An analysis of “Teacher Educator’s handbook: Building a knowledge base for the preparation of teachers” (Murray, 1996) shows Shulman as the fourth most cited author of the close to 1500 authors in the book’s author index with an overwhelming majority of those references made to this concept of PCK (Murray, 1996, referred by Segall, 2004). The notion of PCK, since its introduction in 1987, has permeated the scholarship that deals with teacher education in general and the subject matter education in particular (See for example, Ball, 1996; Cochran, King & DeRuiter, 1993; Grossman, 1990; Ma, 1999; Shulman, 1987; Wilson, Shulman, & Richert, 1987). It is valued as an epistemological concept that usefully blends together the traditionally separated knowledge bases of content and pedagogy.
Diagrammatically, we can represent Shulman’s contribution to the scholarship of teacher knowledge by connecting the two circles, so that their intersection represents Pedagogical Content Knowledge as the interplay between pedagogy and content. In Shulman’s words, this intersection contains within it, “the most regularly taught topics in one’s subject area, the most useful forms of representation of those ideas, the most powerful analogies, illustrations, examples, explanations, and demonstrations – in a word, the ways of representing and formulating the subject that make it comprehensible to others” (Shulman, 1986, p. 9).
Although Shulman did not discuss technology and its relationship to pedagogy and content, we do not believe that these issues were considered unimportant. Rather, the intent is to now bring explicit attention to these issues by considering how technology interacts with pedagogy as Technological Pedagogical Knowledge (TPK), with content as Technological Content Knowledge (TCK), and jointly as Technological Pedagogical Content Konwledge (TPCK).