Making the invisible visible

As part of my personal development as an educator, I have been learning my way through a couple of MOOCs around innovative teaching strategies to improve my teaching in the classroom.

One of these is called Deep Learning through Transformative Pedagogy from the University of Queensland, that reintroduced me to the idea of cognitive load. Cognitive load refers to the demands placed on a learner's cognitive system when performing a task.

According to cognitive load theory, the brain has a limit on how many concepts it can process at one time. Therefore, learning should take this limit into consideration when supporting the acquisition and application of concepts (Paas, Tuovinen, Tabbers, Van Gerven, 2003). If the working memory capacity is exceeded in a learning task, this impacts negatively on learning (de Jong, 2010).

Three things contribute to the total cognitive load:
  1. Intrinsic cognitive load refers to the complexity of a task.
  2. Extraneous cognitive load refers to the load imposed by how the information is being presented.
  3. Germane cognitive load refers to the load resulting from learning processes e.g., self-explanations, mental imagery (Chinnappan & Chandler, 2010).

While teachers cannot generally lower a task's intrinsic cognitive load, it is possible to vary lessons so that extraneous cognitive load is reduced. For example:
  • Presenting information in an integrated way to avoid "split-attention" effect (where learners must process several domain elements simultaneously).
  • Using both visual and auditory parts of working memory, which increases learners' load capacity.
  • Not requiring learners to coordinate several sources of information that contain the same material (de Jong, 2010). For example, when presenting powerpoint slides to learners it is redundant to have both a good diagram and text describing the diagram.

With this in mind, I thought of ways on how I could use both the visual and auditory parts of the working memory simultaneously to reduce cognitive load. As a science teacher, my students really struggle with the abstract concepts associated with science from atoms to respiration. I had earlier stumbled across the three “thinking-levels"  model of Johnstone (1982) which had already become one motivation for the use of Office Mix video making functions in combination with the Sensavis visual learning tool to assist students in constructing mental models of scientific principles.

In his paper, Johnstone (1982) offered an explanation for why science is so difficult to learn. He proposed that as science teachers we think in three cognitive levels; an observational (what we see experimentally) level, a level in which we have a mental picture what is happening, and a symbolic level, where we apply symbols to the observations to describe them.

The observational level in science usually is something that is visible and tangible, incorporating our senses, for example, we can observe what happens when we add lead nitrate to potassium iodide. The mental picture level of understanding consists of mental images that scientists use to imagine and explain observations in terms of atoms, proteins, and photons. Observed phenomena and mental picture-level processes are then represented in terms of mathematics and/or scientific notation at the symbolic level.

In 1991 Johnstone suggested that much of the difficulty associated with learning science occurs because:
“so much of teaching takes place … where the three levels interact in varying proportions and the teacher may be unaware of the demands being made on the pupils”.  
Presenting the three thinking levels simultaneously to a student is likely to overload their working memory (Johnstone, 1991; Gabel, 1999). If the levels are introduced together, numerous opportunities should be given to relating them, so that linkages are formed in the long-term memory. So an application that can do that - link the observational to both the abstract and the symbolic should greatly enhance understanding.

Animations of the abstract world of atoms and DNA can stimulate the imagination, bringing a new dimension to learning science. One can imagine being inside a bubble of boiling water or traveling through the bloodstream.

So over the space of the last few months, I have been creating a series of Office Mix presentations incorporating animations of the abstract world, for example, what happens in a leaf when photosynthesis is occurring or what happens in the lungs during gas exchange and then linking to a class experiment and the associated scientific notation. 

So, through the use of these animations to link the three thinking levels, I was also reducing student cognitive load. I discovered in order to use the animations effectively, I needed to direct the students’ attention to the key features of the processes. This I now realize was avoiding the overloading of the students' working memory and promoting meaningful links with prior knowledge (by referencing experimental results and equations). I achieved this with the inking capabilities of my Surface - pointing out key features on the Sensavis visual learning tool while explaining, through voice over the process on screen and linking to the other two thinking levels with the new whiteboard feature.

One thing which I am now developing is encouraging students to practice their scientific understanding in new situations, and assessing this understanding at the abstract level by incorporating them into the formative assessment. In addition to questions that probe qualitative and quantitative understanding of concepts at the symbolic level, we as science teachers need to design questions that require students to articulate their mental models of abstract structures and processes.


Chinnappan, M. & Chandler, P. A. (2010). Managing cognitive load in the mathematics classroom. Australian Mathematics Teacher, 66 (1), 5-11.

de Jong, T. (2010). Cognitive load theory, educational research, and instructional design: some food for thought. Instructional Science,38(2), pp.105 - 134.

Gabel, D. (1999). Improving Teaching and Learning through Chemistry Education Research. Journal of Chemical Education, 76(4), 548–553.

Johnstone A.H., (1991), Why is science difficult to learn? Things are seldom what they seem. Journal of Computer-Assisted Learning, 7, 701–703.

Johnstone A.H., (1982), Macro and microchemistry, School Science Review, 64, 377–379.

Paas, F., Tuovinen, J., Tabbers, H., & Van Gerven, P. (2003). Cognitive Load Measurement as a Means to Advance Cognitive Load Theory. Educational Psychologist, 38(1), 63-71.


sparvell said…
This is brilliant and I have shared it widely. So glad you enjoyed the coursework
Doctor_Harves said…
Cheers, something I am trying to implement, but def the course helped solidify my thoughts.

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