How challenging can my content be?

When designing a sequence of learning, there are a few things to consider before you decide how inherently complex or difficult your content can be. I wish to focus on a concept from cognitive load theory described as intrinsic load.

Intrinsic load is characterised by the complexity of the thing to be learned. It’s the load that is inherent to the task and is inescapable if we want the task to be achieved. It is what we ideally want our students’ attention to be entirely focused on. It is what consumes the working memory. However, how high or demanding this load can be is very much affected by the level of existing knowledge the learner possesses that is connected to the new information being processed.

The existing knowledge is stored in the long-term memory, and if it can be retrieved to assist in the processing of the new information, then the intrinsic load of the new task is reduced. It’s like having someone come along and help you lift some heavy weights – it’s easier when they help. When the long-term memory can assist, the inherent complexity of the task can be increased.

Let’s imagine a task that has five or six components that make up its complexity. To assist in the processing of the complexity, the working memory will search the long-term memory to see if there are any relevant connections between what is held there and the new learning. If it can’t make any connections, then the working memory is on its own, and because of its limited capacity, will not be able to process all of the components of the new context. However, if the search is fruitful, then the complexity of the five or six components can be mitigated.

Take the learning of this maths problem as a good example:

Find the value of x if 3x + 3 = 12.

The problem involves more than five components of knowledge to solve: algebraic notation, balancing equations, order of operations, multiplication, division, addition and subtraction.

It is clear that if you gave such a problem to someone with absolutely no mathematical knowledge, the problem would be impossible. However, for the student whose working memory is able to successfully search the long-term memory for understanding of addition, subtraction, multiplication, division and even order of operations, the task’s intrinsic load is now in essence related only to algebraic notation and to the balancing of equations.

The other components don’t take up valuable working memory real estate – they automatically are recalled to assist in processing the unknown components. As a result, the task is made significantly easier, relatively.

“Relatively” is the key word here. As the student accommodates this new learning into their long-term memory, then the complexity of the next task can be increased. As psychologists Ericsson and Kintsch found, the limitations of the working memory in effect disappear when the long-term memory can be used to support intrinsic load.

This has large implications for how learning sequences are designed. Understanding what level of prior knowledge your students have will determine the starting position of your sequence. But also, understanding how many steps of complexity away your students are from a desired learning goal will assist in deciding what pedagogy is relevant to helping them get there. If the relative complexity is too high and the intrinsic cognitive load of the task will overwhelm the working memory, this will result in ineffective learning. If the relative complexity of the new task is manageable for the working memory, then you have set the right amount of challenge.

Paul Moss is a learning design and capability manager at the University of Adelaide.

“Long-term working memory” is a paper by K. Anders Ericsson and Walter Kintsch published in Psychological Review.