A concept that comes from cognitive psychology. It refers to the mental effort expended during learning — primarily the effort used by working memory. Hereafter I'll refer to cognitive load theory as CLT.
I sometimes extend CLT beyond learning to knowledge work in general. Human working memory is severely limited, so it's better to minimize the working load in knowledge work.
In algorithmic terms, it's like solving an algorithm problem on a computer with very little RAM. So you should design your workflow to reduce space complexity rather than time complexity.
Types of cognitive load
CLT divides cognitive load into the following three types. I'll use writing as the example here.
Intrinsic load
The irreducible load inherent in the cognitive task itself.
In the writing example, this includes:
- Coming up with ideas
- The complexity that comes from the subject matter itself
- Constructing sentences
I said it can't be reduced, but over the long run it can be. If the subject is familiar to you, intrinsic load decreases. Still, it's hard to reduce intrinsic load on the spot. Think of intrinsic load as a hard core that can't be increased or decreased.
Extraneous load
Load that has nothing to do with the cognitive task itself. This load can grow or shrink, and the smaller the better. For instance, you could say that all UX aims at reducing this extraneous load.
In the writing example, this includes:
- The fatigue of editing because my handwriting is terrible
- Phone notifications arriving while I'm writing
- The load of holding the overall flow in my head instead of writing it down somewhere
Germane load
The load expended on schema construction and automation. Taking on this load lets you improve at writing itself, or grasp your subject more fully.
In the writing example, this includes:
- Converting vague thoughts into sentences
- Summarizing complicated material simply
The heart of CLT seems to lie precisely in this germane load.
Good load, bad load
In strength training, you increase the load on the target muscle and treat unrelated stimulus as something like compensation, reducing that load. In knowledge work too, designing with a clear awareness of which area you're stimulating will help you improve.
By definition of cognitive load, what you can control is extraneous load and germane load.
Here, the positive direction is to lower extraneous load and raise germane load. The negative direction is the reverse.
The problems with lowering germane load are covered here: