Sources of Cognitive Load
Cover image by Manfred Steger from Pixabay
By: Althea Need Kaminske
Cognitive Load Theory is an influential theory from educational psychology that describes how various factors affect our ability to use our working memory resources. We’ve done a digest about cognitive load theory here and talked about it here and here, but haven’t provided an overview of the theory so I want to give an overview here.
According to Sweller (2010), cognitive load describes the allocation of working memory resources (1). Cognitive load can be further described in terms of intrinsic, extraneous, and germane load. Intrinsic load describes working memory allocation that deals with the task itself and is influenced by the complexity of the task itself (2). For example, cooking dinner may be a simple task - reheating left overs - or a complex, multi-stage task that requires monitoring different foods and methods of preparation. The amount of cognitive load dedicated to the task would likely be greater with a more complex recipe. By contrast, extraneous load describes working memory allocation that is not intrinsic to the task itself, but how it is designed or the environment it takes place in (3). Even re-heating dinner can become challenging if containers are unmarked, appliances are moved or unplugged, and children and pets are clamoring for attention. On the surface, picking out a container and heating in in the microwave should be an easy task, but when much of your working memory is occupied trying to find which container, making sure the microwave is plugged, and responding to the demands of small creatures - it can become much more challenging.
Pie chart where extraneous load (EL) takes up 75% of working memory, while 25% is intrinsic load (IL). This is an example of low germane load.
Pie chart where intrinsic load (IL) takes up 75% of working memory, while 25% is extraneous load (EL). This is an example of high germane load.
Finally, while intrinsic and extraneous load describe sources of load, germane load describes the relative allocation of resources. When the majority of your working memory is dealing with intrinsic load, and relatively little is occupied by extraneous load, then this task has high germane load. However, if a task has a lot of extraneous load then less working memory is free to deal with the intrinsic load. In this situation there is low germane load.
Importantly, whether cognitive load is intrinsic or extraneous depends on the goals of a task. For example, “if the goal of learning is to comprehend concepts incorporated in some text, using jargon may constitute extraneous cognitive. Alternatively, if the goal is to learn the specialized language used in an area, the “jargon” is intrinsic to the task”(1). Whether your load is more or less germane depends on the goals of the task, in addition to features of the task.
Another thing to note about this model is that it assumes “that motivation is high and all available working memory resources are being devoted to dealing with intrinsic and extraneous cognitive load” (1). In other words, this is best-case scenario with people who are 100% on task. This model is not accounting for factors that may increase or decrease overall WM (i.e., stress, sleep, mood, etc.)
Sweller also describes how elements within a task affect cognitive load (1). An element is a concept or procedure that needs to be learned. Elements may have low or high interactivity. When there is low element interactivity, elements are somewhat unrelated. For example, when learning nouns in a foreign language there is low element interactivity. You can learn that chat/chatte means cat in French independently of whether you understand that chien/chienne means dog. On the other hand, when dealing with equations all items of the equation must be taken into account to understand each item. In the slope intercept formula, y = mx + b, for example, m is the slope of the line, b is the intercept, and x and y represent the distance of the line from the x-axis and y-axis. You can’t find the value of b without understanding something about x, y, or m.
The more elements that interact, the more working memory is needed to complete the task, imposing a higher intrinsic load (1). This helps to account for both the nature of the task itself as well as the background knowledge of the learner. Background knowledge can help us to chunk items together, requiring less working memory resources. When reading a text, for example, a less experienced reader may process items at the word level - each word is a separate idea yet related to other ideas. More experienced readers will process items at the phrase or sentence level. So while there is still a high degree of element interactivity, there are fewer elements, reducing the intrinsic cognitive load.
Cognitive load theory provides useful and dynamic model for how many different factors affect working memory and learning. Hopefully this post provides a useful overview of some of the main components of cognitive load!
References
Sweller, J. (2010). Element Interactivity and Intrinsic, Extraneous, and Germane Cognitive Load. Educational Psychology Review, 22, 123-138. https://doi.org/10.1007/s10648-010-9128-5
Sweller, J. (1994). Cognitive load theory, learning difficulty, and instructional design. Learning and Instruction, 4, 295-312.
Sweller, J. (2004). Instructional design consequences of an analogy between evolution by natural selection and human cognitive architecture. Instructional Science, 32, 9-31.
