Working Memory Can Easily Become Overwhelmed

"Appreciating how the brakes on your car work entails knowing about the interaction between a dozen components. Although the car brakes example may appear initially as a sequence, it demands far more of the mind since the relationship between components has to be understood. In a very real sense, the whole, and knowing how the system operates, amounts to far more than its constituent parts - until it is so overlearned you can see the system as a 'single idea'.

"It would be well-nigh impossible for a person who was 'non-mechanical' and unfamiliar with the car brakes operation to learn this material to mastery level within a single session or lesson. However, most adults are able to make such a lesson more meaningful by accessing existing schemata. For example, they may alreayd know about levers, what a cylinder is, what a pipe does, what presure is, and what friction does, and so on. To the extent a person can access such relevant knowledge, load is reduced, even though item interactivity will still remain high, since the issue is how the system works, rather than merely recalling the component items.

"In any complex learning situation your mind can quickly become overwhelmed by the number of interactive informational units needing to be processed simultaneously for you to achieve understanding. As a learner you are strongly motivated to maintain order and may unwittingly adopt a number of strategies to reduce your mental load. However, in terms of following the theory, it is necessary to describe the two types of load that pertain to any learning task: a) intrinsic and b) extraneous.

"Intrinsic cogntive load is fixed by the nature of the task itself. Its chief determinant is going to be a person's prior knowledge, which implies the availability of schemata at the level of the individual. Thus, learning about car brakes is inherently difficult for perople who possess no technical knowledge. But the identical task can be relatively easier for people who work regularly with machinery.

"Extraneous cognitive load refers to load imposed by the learning conditions and the instructional context itself, but which is nevertheless irrelevant to the desired learning outcome. Ideally, extraneous load is that which must be reduced, since it threatens a person's ability to focus upon the critical information needed to achieve mastery. Extraneous load is brought into lessons through introducing information that is not needed, or through placing unnecessary demands on the students at the time. For instance, many of us make the mistake of talking too much at students assuming we are 'motivating' them when we are merely adding to the sources of load they are experiencing.

"Several studies have shown how learners may tolerate relatively high levels of extraneous load in simple learning situations. But as learning gets harder, learners benefit markedly from any condition that reduces sources of extraneous load. In short, extraneous load begins to matter when either a) the number of interacting elements is high or b) the individual lacks prior knowledge."

Once again, child-centred methods are unlikely to work well when it comes to teaching advanced concepts like problem-solving, especially to disadvantaged students.

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