It’s been understood since the 1950’s that human cognitive processing capacity is severely limited. In fact, you can put a more or less precise number on the amount of discrete pieces of information that a person can manage in their working memory at any given time – the “magic number” of seven. (see Miller, 1956) When asked to repeat a list of random digits or tones (e.g. 5,6,2,10), most people can manage about 5 to 7 of these “chunks” of information when drawing only from their working memory. It is no accident that we can all remember our phone numbers but only the most acquisitive of us can remember our credit card numbers. Of course, it’s a complicated business of how information gets moved in and out of working memory from long term memory (the closest thing nature has to the $4.4 million hard drive, the RamSan-6200). To get into that we’d have to talk about schema theory and the expertise reversal effect and all sorts of other cognitive science concepts… so let’s keep this simple. How can a basic understanding of working memory and cognitive load theory make us into better UI designers?
Well, typically this would lead to a discussion of bad, or extraneous, cognitive load and how to avoid it in the design of multimedia materials. Attention is a resource, and a limited one at that. When users strain their ability to actively process material, they are forced to make decisions about what they do and do not pay attention to. If you ask the user to process more than a few chunks of information simultaneously, working memory is easily overloaded. Designs which add to this effect are thought to actively generate extraneous load. You can control for this by following a few basic principles, most notably those outlined in Richard Mayer’s seminal 2001 book, Multi-Media Learning. An example of a design principle that minimizes bad cognitive load is spatial contiguity.
Mayer’s Spatial Contiguity Principle – Student’s learn better when corresponding words and pictures are presented near rather than far from each other on the page or screen.
Integrated (top) vs. Separated Captions (bottom) in Multi-media Instructions. The Integrated Approach is Said to Reduce Extraneous Cognitive Load
There are many more of these principles in the book and all of them are worth reviewing. Curiously, what Mayer doesn’t explicitly lay out as an anti cognitive-load principle is one you hear all the time from clients if you are in the design game – make it “less busy,” “clean,” “less cluttered,” more googley. Surely unsightly clutter must increase extraneous cognitive load, so why doesn’t he mention this? Because reduction of complexity is not, in itself, a sound instructional design principle. Some material is just more complex – it has more elements and more types of element interactivity within it. This inherent complexity is a fact of life and is thought to generate intrinsic cognitive load. Think of this as cognitive load that the designer inherits as a baseline, only to add to it by breaking Mayer’s rules in their design process.
And now for my favorite part. Designers can actually create good, or germane cognitive load. Germane cognitive load “enhances” learning rather than interferes with it; this may be attributable to effects like motivation or increases in effort that can increase the amount of cognitive resources devoted to a task. You can tell if you are getting germane cognitive load when you have a high degree of intrinsic cognitive load but learners stay within their working memory capacity due to the intelligence of the way the materials are designed. In other words, a lot of meaningful learning activity would be impossible without cognitive load – it’s just a tougher design challenge. Mayer’s research was focused on reducing overall cognitive load, with the assumption that mostly it was extraneous load that was effectively isolated in his study design. But researchers still are looking for ways to measure the different types of cognitive load, so at the moment it’s unclear exactly what can be done to increase good cognitive load (see Kalyuga, 2009).
Edward Tufte Has Inspired A Generation to Create "Germanely" Loaded Data Displays
So why did I go into all of this? Because I think people shouldn’t complain about clutter and busy-ness in web designs without pausing to think about the benefits of considered complexity. As Don Norman has said – Simplicity is Highly Overrated. Of course, in this essay he’s talking about products mostly – and the fact that people value and are willing to pay for complexity and additional features. But simplicity is overrated in design circles too… complex things are beautiful and persuasive. Nature is complex. Sometimes the user’s task is aided by complexity in the interface. For instance, pattern recognition is a common task for a user on a product website’s list pages, which can be aided by having more information on a single screen, not less (particularly when it’s optimized for comparison tasks such as the famous Orbitz grid design for listing airfares, now universally imitated.) We may not know exactly what generates germane cognitive load, but I have a strong hunch that the work of Edward Tufte does exactly that. So let’s do both – reduce the bad cognitive load and seek to add the good stuff – and we’ll find yet another reason why we should think like an Instructional Designer.
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