For those who don’t know, an SRS is a Spaced Repetition System. It creates longer and longer intervals between reviews when you get the answer correct. The idea is to review just before you forget, to encourage long-term memory retention.
And in this technical statement from supermemo’s Theoretical aspects of spaced repetition in learning, you’ll find both the value and the problem with Spaced Repetition Systems:
In a long-term process, for the forgetting index equal to 10%, and for a fixed daily working time, the average time spent on memorizing new items is only 5% of the total time spent on repetitions. This value is almost independent of the size of the learning material. [emphasis mine]
It’s saying that in the long term, most of your time is devoted to pushing items further into memory, to making progress – And this is good.
But note that for modeling the memory performance of the human brain as an equation, or modeling anything for that matter, when you find yourself with too many variables, you take most of them and fix them at some value so you can solve a simpler problem.
If you’ve ever heard someone say, “All things being equal” or “Ceteris paribus”, what they mean is, “There is too much change for me to understand what’s going on so I’ll just assume that everything is frozen except the one thing I want to measure.”
And this is quite reasonable. We know because the SRS model is proven to be an effective memory tool.
But that’s not the whole story. The reality is those other variables do change. Which begs the question: How much do those changes matter?
Let’s take the assumption of a “fixed daily working time”. Is this true? Of course not. Most people don’t spend exactly the same amount of time studying everyday. And even if we allot and use 1 hour, everyday, our pace, focus, concentration and motivation vary from day to day.
Fixed time has been useful for modeling the SRS methodology and proving its value, but less useful for implementation. Why? You implement in reality, not in the model.
The reality is that users skip days, their motivation wanes, circumstances consume their time, they get bored, they burnout or they forget.
And when they come back, what does an SRS do? For today’s fixed working time, it globs together the work from the previous 3 days you missed. So much for the fun of language learning, you now have real, bonafide work to do.
Which is more important: The discipline to use an SRS everyday, or the discipline to have meaningful interaction with Japanese everyday through reading, watching, listening, speaking and writing?
SRS is a powerful methodology, but it can be completely undone with a simple case of burnout.