A course creator notices learners struggling with a concept and responds by adding more explanation — more examples, more elaboration, more supporting detail — a reasonable-seeming instinct that can directly backfire, because working memory has a well-documented, fairly narrow capacity limit, and once that limit is exceeded, additional material doesn't add clarity. It competes for the same limited mental space the learner needs to actually process and understand the original concept.
The specific capacity constraint at the center of this
Cognitive load theory, developed from decades of research beginning with John Sweller's work in the 1980s, is built around the well-established finding that working memory can hold and actively process only a small number of new information elements at once — a genuine hard constraint, not simply a matter of learner effort or motivation. Any instructional design that requires a learner to hold more new elements in working memory simultaneously than that capacity allows will produce comprehension failure, regardless of how clearly or thoroughly each individual element was explained on its own.
The three kinds of cognitive load, and why the distinction matters
Intrinsic load is the load inherent to the material's actual complexity — some concepts genuinely require holding more interacting elements in mind at once than others, and this load can be managed through sequencing but not eliminated. Extraneous load is load created by how the material is presented, unrelated to its actual difficulty — a cluttered slide, a confusingly organized explanation, unnecessary decorative detail — and unlike intrinsic load, extraneous load can and should be minimized because it contributes nothing to learning. Germane load is the productive mental effort actually spent building understanding, integrating the new material with existing knowledge — the load learning is actually made of, and the load that intrinsic and extraneous load are competing against for the same limited working-memory capacity.
Why adding more explanation often increases extraneous load specifically
An instructor's added explanation, offered with good intentions when a concept seems difficult, frequently introduces additional elements, examples, or tangents that themselves have to be held in working memory alongside the original concept — increasing total load rather than reducing it, and specifically increasing it in the extraneous category, since the additional material wasn't inherent to the concept itself. A learner already near their working memory capacity trying to process the original concept now has even less available capacity for the germane load of actually building understanding, because more of their limited capacity is occupied holding the extra explanatory material in mind.
What this means for how instruction should actually be designed
Effective instructional design for genuinely difficult material tends to reduce extraneous load aggressively — simplifying presentation, removing decorative or tangential detail, breaking complex material into smaller sequential steps rather than presenting it all simultaneously — specifically to free up working memory capacity for the germane load that produces real learning. This often means presenting less material more carefully sequenced, rather than more material more thoroughly explained, which runs directly counter to the intuitive instinct that struggling learners need more explanation, not a more carefully load-managed presentation of the same core material.
What this means for course creators specifically
- When learners struggle with a concept, consider reducing extraneous detail and simplifying presentation before adding more explanatory material
- Break genuinely complex material (high intrinsic load) into smaller sequential steps rather than presenting all interacting elements simultaneously
- Audit lesson materials specifically for extraneous load — decorative content, tangential examples, cluttered visual presentation — and remove it, since it competes directly with genuine learning for the same limited capacity
- Recognize that more thorough explanation and more effective instruction are not the same thing, and can actively work against each other past a learner's working memory capacity
The instinct to explain more when something seems hard is understandable, but it treats a capacity problem as an information problem — and past a certain point, more information is exactly what makes a capacity problem worse.