Review by Adam Boxer

Head of science, The Totteridge Academy

4 Oct 2020, 5:00


Cognitive Load Theory by Steve Garnett

By Steve Garnett


Crown House




30 Sep 2020

Adam Boxer finds this handy introduction is undermined by edu-publishing fetishes old and new

The edu-twitter-bloggo-bookosphere is a crowded field. Jostling for attention, anything with the word “cognitive”, “curriculum” or “powerful” in the title is sure to gather interest from a sector addicted to the next best thing. Amidst this clamour, teacher trainer Steve Garnett throws his handbook on cognitive load theory (CLT) into the ring, aiming to provide “busy teacher[s]..teaching an overcrowded curriculum in an overcrowded classroom” with a guide to one of the most important things for teachers to know.

Garnett opens with a by-now fairly standard introduction to CLT featuring old favourites: working memory/long-term memory; intrinsic/extraneous load; multimodal encoding; a quote from Daniel Willingham and the prodigious memories of grand master chess players. Where Garnett diverges from other edu-pop-cogsci-fan-books is through his welcome focus on “CLT effects”.

In my experience, most people’s understanding of CLT is limited to “break things down into small chunks” and “use pictures”, so I was glad to see that Garnett’s aim here was actually to discuss 14 evidence-based practices that can alter an individual’s cognitive load. Chunking and use of graphics are just two of these, and others, such as guidance fading, variability and transient information effect, are most definitely worthy of teachers’ attention. I’m not aware of any other teacher-facing work that attempts this and, though some of the explanations are arguably over-simplified, in general Garnett’s short introductory passages will be both new and interesting to many teachers.

If someone in my department did this I would be dragging them in for a Serious Conversation

Sadly, Garnett tries to overlay a kind of four-stage teaching cycle, and this is where things start to feel a little tenuous. First off, there is a question of whether his phases are valid in themselves. Is there really a difference between how new topics are introduced (phase 1) and how new knowledge or skills are taught (phase 2)? When students are checked for understanding (phase 3), are they not also demonstrating their understanding (phase 4)?

Pedantry aside, I’m unconvinced that the different phases match up to the different effects.  For example, Garnett talks about reducing the amount of content in phase 1 so as not to overload students, but this is surely a property of, say, individual work too (phase 4).

And the contrived structure doesn’t map on to teaching practice either. Garnett places worked examples in phase 4, but generally teachers would include those in phases 1 and 2. The collective working memory effect is the only effect in phase 3 and its implementation is presented as a version of group work. However, Garnett’s particular version is impractical, possibly not entirely honest to the research (which I don’t think is really classroom-ready), and on its own terms it simply isn’t any more relevant to “checking for understanding” than it is to “demonstrating understanding”.

Other niggles abound. One-third of the book focuses on graphic organisers but no classroom-based research is cited to support their use. Presented as models of clear instruction, some of his examples are very oddly sequenced, some very difficult to decipher and others just plain unintelligible.

Garnett’s invocation of Gestalt theory in improving design is, I think, important, but also doesn’t quite work. Technically, praising a graphic for using small icons instead of big ones when said graphic doesn’t actually have any icons isn’t great. Then, taking an information-dense knowledge organiser (which I don’t necessarily approve of) and comparing it to a chic and minimalist Gestalty table thing doesn’t work in real life either. Garnett asserts that they “contain the same facts and ideas” when they clearly don’t, and whilst Camden-studio-apartment-dwelling graphic artists might agree with his praise of “lots of white space”, if someone in my department printed out 30 copies of a knowledge organiser that had more white space than text I would be dragging them into my office for a Serious Conversation about saving the Amazon (which ironically is the subject matter of the white-space-laden Gestalty graphic organiser) and the departmental budget.

All in all, as an introduction to CLT, Garnett’s book is fine. But it would have been a lot stronger without shoehorning in an old fetish for instructional sequences and a new one for graphic organisers.

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  1. David Eckley

    Some interesting comments. Although I’ve not read this particular book I am concerned that there is a serious glut of cognitive science books on the market at the moment by self-promoting authors and Tweeters. It’s interesting how little my teaching has changed despite reading a wide range of these books in the last year. The whole dual-coding thing has also been taken way out of context, and become a campaign for black and white clipart, headed by Oliver Caviglioli and Tom Sherrington. There are still things to learn though, and I remain open to ideas and well-tested classroom-based research. What I think these authors ignore though, is that this sort of research is going on constantly in school as an implicit iterative process which we call “teaching”. The experience of good teachers all around me has taught me a lot more about how to be good at what I do than any of these much-promoted books, few of which will stand the test of time.