Tuesday 06 Apr 2021

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Learning Principle N°6: Cognitive overload causes inefficient, ineffective learning

Article by Dr Karen L. Taylor, Director of Education and of the Institute of Learning and Teaching, Ecolint

One can hardly open one’s email these days without finding at least one unsolicited message about the latest teaching resources. We read about the importance of cognition and metacognition, of surface learning and deep learning, inquiry-based and concept-based learning. It can be challenging to separate the wheat from the chaff. At the same time, most of us want our classroom practice to be grounded in recent and valid educational research. 

Dylan Wiliam is often quoted for a tweet in which he stated that cognitive load theory is  probably “the single most important thing for teachers to know” (Wiliam, 2017). Does it really matter to student learning if the teacher takes cognitive load into account when preparing a lesson? This is, of course, a rhetorical question. The whole point of the learning sciences is to use what we know about human cognition in order to create the best possible environment for student learning. 

In preparing this article I thought long and hard about how to approach the question of cognitive load theory and the best way to visualize the relationship between theory and classroom practice. I finally decided that, in the end, it really comes down to finding the right balance between working memory and long-term memory, hence the image of the out-of-balance scale. 

As human beings, we can only process so much new information at one time. Our ability to draw from information embedded in our long-term memory, however, is almost unlimited. Andy Tharby (2019) has a useful metaphor for understanding the difference when he says that our working memory is like a page of notes while long-term memory is more like a filing cabinet. In that cabinet, we have organized information into files or schema. In other words, we can draw from that store of knowledge when we need it and we are able to apply or transfer that knowledge into new domains. 

Each time we introduce new material to students we inherently tax both their working memory and their long-term memory. If we place too great a burden on a student’s working memory, which is limited in quantity and duration, we impede learning rather than enhance it. This is one of the reasons why it is so important to know our students and to be aware of their prior knowledge, the foundation upon which we build new learning. When the information we are introducing is complex, it needs to be broken down. Not so that we oversimplify, but rather to give students the building blocks they need in order to stretch themselves. 

Imagine that you are preparing to teach a new unit on global climate types. You might consider using an image such as this:


On the other hand, you might choose something like this:


Obviously the age of the students matters but bear with me here. The first image is more sophisticated, more detailed and more complex. It may appear visually more appealing. If the notion of climate types is new to your students, however, much of that detail is potentially distracting. What is the essential information on which the students need to focus? They will have to look back and forth between the map and the key and try to decipher the coding. All of this taxes the working memory and can distract students from the point of the lesson which is to understand the difference in climate types. 

If you are planning a lesson that takes into account cognitive load theory, it might actually be preferable to choose the second image. What is perhaps most important for a teacher to keep in mind is to be explicit, to make clear what the learning objective is and help students to identify key information in order to attain that objective without being exposed to peripheral information that does not contribute to the learning. This might mean starting with the incremental steps that lead towards a whole; it might mean explaining the essential question or overarching concept first and then breaking it down. The point is that the roadmap is clear to the students. 

Another example might be teaching secondary history students how to write an essay. Take this question from a past IB examination: “Economic problems between 1980 and 1991 were the most significant reason for the end of the Cold War.” To what extent do you agree with this statement? If you were to take cognitive load theory into account then you would not simply give students the question and let them get on with trying to work out an answer. Do the students have the necessary context and content information they will need to answer the question? You would likely then break down the parts of the essay question. What kinds of economic problems might one refer to? Why the reference to 1980? What other factors besides the economic might have contributed to ending the Cold War? How does one deal with a “to what extent” question? 

It goes without saying that we wish to challenge our students and to provide the opportunity for them to stretch themselves. There are ways in which we can facilitate the development of knowledge and skills that take into account the way the human mind works. This involves keeping the scale of cognitive load in balance

Things to consider:

  • Have I planned a lesson or unit that takes into account my students’ existing knowledge base? 
  • Are the activities I develop focused on the learning objective?
  • Have I removed any distracting or irrelevant information? 
  • Do I offer students opportunities to become gradually more independent in their problem-solving skills?
  • Do I present new and complex information in more than one mode?
  • When my students have moved from novice to expert, have I encouraged them to visualize their knowledge of concepts and procedures? 
  • Have we designed the curriculum so as to promote the development of long-term memory?

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