Below is Dr Andrew Carroll’s  contribution to the Curriculum in Science Symposium. See here for the introduction to the symposium and links to other contributions.

In this brief paper I will attempt to illustrate how, in my role as a PGCE tutor, I have structured a PGCE course around two central ideas:

  • Learning to teach does involve the acquisition of a specific type of knowledge.
  • The knowledge for teaching can be regarded as being organised into ‘schema’ which are adaptable.

I completed my PGCE in 1996, so of course I was introduced to the ‘holy tryptic’ of Bruner, Vygotsky & Piaget. I do not regret this experience. Amongst the things I remember most from those heady days is the concept of ‘schema:’

This belief has been galvanised quite recently by reading F.C. Bartlett’s book ‘Remembering’ for the first time, which I found serendipitously abandoned in a skip:

“Circumstances which arouse memory orientations, whether they occur in the laboratory or in everyday life, always set up an attitude that is primarily towards a particular ‘schematic’ organisation.” (Bartlett, 1932 p313)

Ghosh and Gilboa (2014) offer a fascinating history of the development of the idea of mental schema, suggesting that any schema must conform to four necessary factors.

To support my argument that the knowledge for teaching can be regarded as schematic. I will consider each of Ghosh and Gilboa’s necessary factors in the context of a PGCE course.

Associative Network Structure.

I would suggest that the knowledge required to teach science is made up of interrelated units; the content, pedagogical and contextual knowledge required to teach effectively. I will go on to present a metaphor I use with PGCE biology students, also explaining the ‘molecular biology’ of my title.

Has a basis of multiple episodes.

The majority of learning on a PGCE course happens through experience. The importance placed upon ‘reflection’ on/in experience in ITE could be interpreted as searching for commonalities across events. As Bartlett (1932) suggests “the past acts as an organized mass rather than as a group of elements each of which retains its specific character.” Cited in Ghosh and Gilboa (2014)

Lack of unit detail.

If a schema is based on multiple episodes, then it follows that generalisation will be required. It is interesting to consider this in relation to teaching science, where in terms of content knowledge, an awful lot of unit detail is required. I believe this to be the liminal space where content and pedagogy collide.


I believe there is no doubting that if there is a ‘schema’ for teaching science then it is adaptable. On a time scale ranging from the sub minute to years, teachers rely on schema which are constantly being adapted. I believe that adaptive schema provide the mechanism for assessment for learning and responsive teaching.

Of course, the notion of ‘schema’ can only ever be a metaphor; we will perhaps never know ‘what is really going on’, as a human forms memories and acquires knowledge and understanding in response to environmental stimuli.

In latter times, I think @olicav  has provided one of the best visual metaphors for the role of schema in the classroom.


As Lakoff and Johnson proposed; “…metaphors allow us to understand one domain of experience in terms of another.” (Lackoff and Johnson, 2008 p117).

The metaphor is omniscient in teaching, used consistently in the classroom and in thinking about demystifying how learning happens. The meta-metaphor perhaps?

I have found the concept of Pedagogical Content Knowledge (PCK) (Shulman 1986) to be a useful framework through which to view the schema metaphor.  A recent post by @HFletcherWood, commenting on  Loewenberg Ball et al (2008)’s refinement of Shulman’s original definition,  emphasises the importance of teachers having the “the most effective representations to teach an idea” requiring “careful selection from a good stock of metaphors, models and images.”

I believe it is helpful for students to conceptualise their emerging practice as a form of knowledge as opposed to a skill, building their “good stock” of pedagogical content knowledge through practise, feedback and criticality arising from scholarly activity. It perhaps negates the ‘cult of the personality’, soothing underconfident student teachers in their “I’ll never be like Ms X, down the corridor” moments.

It is the teacher’s role to help their pupils acquire a schema, both the pieces of information within it and the connections between them. Then, it goes without saying that their own schema must be secure. In helping visualise a schema for teaching, consider the elephants (in the room) below as representing how PGCE students might think about the development of their own schema for teaching .

Novice Expert
ac2 ac3


In thinking about a curriculum which in part, aims to support PGCE students acquiring PCK schema, it has been helpful to think about the three following intentions.

  • Ensure students know where the ‘dots’, which constitute the body of knowledge, are.
  • Guide them to forge links between the ‘dots’.
  • Assure them, that with time, they will be able to ‘fill in the spaces’

With Biology PGCE students I have found it helpful to evoke an evoke an analogy with the central dogma of molecular biology. DNA to RNAs to protein. Students are asked to consider their emerging PCK schema as a eukaryotic cell. Where the core CK (DNA) is transported out of its domain, to be modified and processed by knowledge from within other ‘domains’ (RNA’s), its structure changed to provide the functional knowledge for teaching (protein). I believe the core CK is adapted through the knowledge of the pedagogy, philosophy, history and nature of science itself. Alongside knowledge of the pupils, how they learn and the context in which they are learning. Students need to know through which domains and how, their CK will be transcribed and translated.


For the sake of brevity and not over stretching a metaphor, what follows is a description of how I have constructed a curriculum based on this model.  A curriculum which needs to work for students through; lectures and assignments, and classroom practice. I am going to concentrate on:

  • The content Knowledge
  • The ‘narrative’ of that knowledge

The ‘excavation’ of pre-existing content knowledge schema

It is interesting to note that along the spectrum of theoretical opinion of how science should be best taught, from constructivism to explicit instruction, the importance of ‘prior knowledge’ or ‘existing schema’ is prominent.  The duration of the PGCE would not allow for the ground up construction of science knowledge schema. I believe the job of a PGCE curriculum is to gently excavate the pre-existing schema. We also have to recognise that potential science teachers come from a wide variety of degree backgrounds and experience. The ‘archaeological’ re-revealing of the long-lost schema for ‘photosynthesis’ for example, is going to be different for every student. This is where a knowledge-based curriculum delivered pedagogically differs from its andragogically delivered relative. We hand the re-learning over to the learner, but not entirely.

As with most PGCE providers establishing students’ content knowledge happens at the interview stage, which, in my context, involves an MCQ test. Aligned to current specifications, designed also to diagnose pre- and misconceptions, it does end with the inevitable ‘action plan’.  In supporting students in this pre-course phase, indirectly fulfilling the requirements of their action plans, I recommend the @Cam_Assessment archive of examination papers.  The question below, taken from a 1974 A level paper, has proved to be a very telling question for prospective biology teachers.


I believe it is important to always focus post observed lesson discussion on the emerging PCK and not on the personality of the student teacher. I have found that pre-lesson planning work with students can also be helped by asking them, prior to thinking about activities, to consider and describe the ‘narrative’ of the knowledge and how it will unfold before the class, as they teach.

The narrative of the Knowledge:

I do find this to be the trickiest part of my curriculum design. It requires students to have knowledge and understanding beyond the scientific domain with which they are familiar. They need to have a knowledge of the knowledge as it appears in the national curriculum and beyond. The majority of this learning happens through preparing PGCE students to write at masters’ level.  Depending on their prior experience, students often struggle with the language of the social sciences; philosophy, and history of science and education. This is recognised in our curriculum.  Where I have to admit, I often slip into a more pedagogical approach, we learn unencountered definitions and then explore the concepts, in relation to classroom practice.

As an example, students are encouraged to understand the nature of the knowledge they will be working with as teachers. We consider definitions of different types of knowledge. I have found Winch (2017) useful for students to think about their ‘applied subject knowledge’. Where it is suggested that it is important for a teacher to question the omniscience of the subject knowledge.

“Pictorially the difference is between seeing the subject as a room from the ceiling downwards on the one hand (as a putative expert) and opening a door onto the room on the other (as a novice aspiring to greater expertise)” (Winch 2017 p80/81).

Introducing PGCE students to this form of philosophical enquiry, I believe goes some way towards helping them “fill in the gaps”, incorporating their C  into PCK.

To summarise:

As we will probably never really understand what happens when teaching results in learning:

  • The empirically and philosophically endorsed concept of schema is a useful for PGCE students
  • Although it has limits when considering PCK.
  • I am suggesting a teacher’s ‘knowledge’ should have subject knowledge as its template (the DNA)
  • A template upon which is built, a knowledge of teaching and of the pupils being taught.


Bartlett, F.C., 1932. Remembering: An experimental and social study. Cambridge: Cambridge University.

Ghosh, V.E. and Gilboa, A., 2014. What is a memory schema? A historical perspective on current neuroscience literature. Neuropsychologia53, pp.104-114.

Lakoff, G. and Johnson, M., 2008. Metaphors we live by. University of Chicago press.

Loewenberg Ball, D., Thames, M.H. and Phelps, G., 2008. Content knowledge for teaching: What makes it special? Journal of teacher education59(5), pp.389-407.

Shulman, L.S., 1986. Those who understand: Knowledge growth in teaching. Educational researcher15(2), pp.4-14.

Winch, C., 2017. Teachers’ Know-How: A Philosophical Investigation. John Wiley & Sons.