Our long term memory is infinite but our working memory can only hold and interpret a finite amount of information. The magic number of items working memory is able to hold is usually considered to be seven (+/-2) (Miller 1956) and around four items when processing information (Cowan 2001). In effect, our working memory acts as an empty horse race starting gate. Old information from long term memory or new information is slotted in each stall ready for learning. However, when the stalls are full any additional information begins to pile up and is left out of the race – this is considered cognitive load. When working memory can no longer store or process information any additional information is left out of the learning process which can negatively impact learning. Yet, cognitive load can be minimised with effective instructional design and in particular the use of worked examples (Sweller & Cooper 1985, Sweller 1988).
The cognitive load theory suggests that there are three types of cognitive load that can overwhelm working memory: Intrinsic, extraneous and germane load. Intrinsic load is determined by the basic structure of the information (complexity of the task) and the level of expertise of the learner (Chandler & Sweller 1991; Sweller, Ayres & Kalyuga 2011). Therefore, assessing prior knowledge plays an important role in the planning and delivery of information. Although intrinsic load cannot be altered by the teacher, it can be manipulated. For example, learning how to solve a quadratic formula is inherently more difficult then calculating basic sums (though this is true only if the student understands basic sums). However, the use of worked examples can mitigate the difficulty because it will map out each step necessary to complete the problem solving. For instance a teacher supports a student learning by providing a worked example of a quadratic equation. The worked example will allow the student to learn each step necessary to solving the problem. This increases the students’ level of understanding (expertise) which will automate the process for future application. In theory, the next time the student is faced with a quadratic formula it will still inherently more difficult than adding sums but no longer as difficult which will allow the student to divert free working memory space to more advance learning. The student has automated the necessary steps to complete a quadratic formula, therefore, freeing working memory to tack more advanced problem solving.
Whereas the teacher has little control over intrinsic load, they can control extraneous load. Extraneous load can only be exerted by the instructional design and a poor design can affect learning. If working memory is overloaded to deal with the instruction of the task then little space will be available for learning (Sweller, Ayres & Kalyuga 2011). For instance, providing a problem solving question with a number of interacting pieces of information that have to be processed can quickly fill available slots for working memory. Any additional working memory resources available will then be used by weak problem solving strategies like means-ends analysis (Sweller 1988). So, integrating resources can “chunk” information with clear step by step instructions will require less space in working memory. For example, a teacher prepares a task that includes three resources that are expected to be used to complete the task – already three slots of working memory are filled. This is because our attention is diverted to each task individually. Some may suggest that this is merely multi-tasking and should be considered as a “chuck” of information. However, studies suggest that we actually can’t multi-task but instead our attention is spread thin (DeBruyckere, Kirschner & Hulshof 2015). Therefore, high quality worked examples integrate resources and demonstrate the necessary processes to solve the problem will mitigate cognitive load which will allow the learner to use all their cognitive capacity to learning (Sweller & Cooper 1985).
Germane load is the desired affect necessary for learning. It is the load dedicated to the processing, construction and automatic of schemas. In short, it’s the action to move information from working memory to long term memory. The use of worked examples supports germane load because it removes unnecessary extraneous load and more time can be used on learning the process. For instance a physics teacher may be teaching the calculation for density. The conventional method is to demonstrate the calculation and then assign a large volume of problems for pupils to complete. However, the impact may be minimal (Zhu & Simon 1987). Instead, focusing pupils a on a couple of worked examples that are followed by only a few practice problems will deliver a marginally better outcome but will significantly reduce the time needed to learn the skill (Sweller & Cooper 1985; Zhu & Simon 1987). This is because worked examples consolidates different steps to one resource and eliminates means-end analysis. Therefore, time and resources and be focused on learning.
Memory may be infinite but our working memory is not. Though, its function in learning is invaluable. Too often in the classroom there appears to be a significant focus on the nature of the activity with little conversation on how learning tasks are constructed. As the research suggests, cognitive load can impair learning that may lead to students becoming disengaged, demotivated or jaded to learning. Therefore, in addition to selecting knowledge and skills to learn, we need to consider the impact of our resources and the delivery of the learning may have on pupils’ working memory. A start is to consider how worked examples can be used in teaching to remove unnecessary distractions to learning. As worked examples can mitigate the impact of cognitive load, allowing pupils to place more effort in what is necessary to learn to make progress.
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Miller, G. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. The psychological review, 63, 81-97.
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Zhu, X., & Simon, H. A. (1987). Leaning mathematics from examples and by doing. Cognition and Instruction, 4, 137-166.