John Sweller asks: what makes some problems harder than others? What makes some material harder to understand than other material? He suggests that Cognitive load theory can help us understand.
A task can be thought of as having intrinsic cognitive load—constant for a particular task, a basic component of the material; and extraneous cognitive load, which can be manipulated by instructional design. He suggests that intrinsic cognitive load is mostly a function of Element interactivity—the extent to which components of the problem must be apprehended simultaneously in order for any of them to be learned. Foreign vocabulary learning has relatively low element interactivity. By contrast, complex algebra problems might have higher element interactivity: if you’re learning to solve (a + b)/c = d for a, you need to understand several steps in sequence. The intermediate steps may not be internalizable apart from the full sequence.
Q. Sweller argues that “intellectual mastery of any subject matter is overwhelmingly dependent” on what mechanisms?
A. Schema acquisition and the transfer of learned procedures from controlled to automatic processing.
Q. Sweller conjectures that the primary determinant of intrinsic cognitive load is…?
A. Element interactivity.
The theory suggests that instructional techniques that require students to engage in activities that are not directed at schema acquisition and automation, frequently assume a processing capacity greater than our limits and so are likely to be defective.
If we’d like to control the cognitive load involved in learning tasks, we can minimize the extraneous cognitive load in various ways (see e.g. Worked example effect). But we also need to moderate the intrinsic cognitive load.
Q. Why can’t a task’s element interactivity be fully determined a priori?
A. Interactivity depends on the prior knowledge of the learner.
Sweller points out that “while extraneous cognitive load can severely reduce instructional effectiveness, it may do so only when coupled with a high intrinsic cognitive load.” All the studies done at the time of this publication involved problems with high element interactivity. So, as an instructional designer, if you’re creating low-interactivity tasks, you may not have to worry about things like Worked example effect.
However, means-ends problem solving “invariably involves high element interactivity because it requires problem solvers to simultaneously consider the goal, the current problem state, differences between them, etc…”. So even if the elements involved in your task have relatively low natural interactivity, they might have effectively high interactivity in a problem solving context.
Q. How do goal-free problems vary from traditional problems in terms of element interactivity?
A. Novices usually solve traditional problems with means-ends strategies, which effectively increase element interactivity by making the learner consider goals, problem states, their differences, and so on.
Finally, Sweller suggests that we don’t really know what “understanding” is, but it seems like our usage of that word, as opposed to just “learning”, has something to do with higher element interactivity. In the context of high-interactivity material, “if students manage to assimilate some but not all of the elements and their relations, we might say they have failed to understand the concept or only partially understood it … In contrast, if the material consists of elements that interact minimally, failure to learn some of the elements tends to be interpreted as nothing more than learning failure “