Content warning: I’m writing this entirely off vibe and the feeling I get, zero empirics here (:
I’m mainly using Anki for foreign language vocab. I’m fairly sure less half of the time I press 1 I’ve actually forgotten the material of a card in some deep sense. The majority of the time, I feel like I have some surface-level occlusion of a memory. No clue how you’d test this, but I feel like if you asked me in a different room or on a different day I would be able to recall it fine.
Plugging my parameters into Anki FSRS Visualizer, it looks like it takes an incredibly long time to re-build a long period after one, possibly fluke, wrong answer. That’s got me wondering about the inductive bias of the FSRS algorithm - is it designed with a model of memory that would assume it’s possible to get a card wrong without actually forgetting, or is every 1 treated as a complete loss of that information from the user’s brain?
FSRS has a variable called memory stbaility, defined as the number of days it takes for the probability of recall to fall from 100% to 90%. Kinda like half-life, but nine-tenths-life.
When you fail a card, S doesn’t reset to the minimum value. How much it decreases exactly depends on your parameters. As a rough rule of thumb*, S after the fail is proportional to the cubic root of S before the fail. So if the stability of your card was 100 days, it will become ~4.5 days after you press “Again”.
*this rule is based on the default parameters and a lot of simplifications of the formula
As a workflow suggestion, how about burying the card when you get that feeling that you could maybe remember it? I’ve started doing that with my language vocab and do in fact occasionally (maybe 1/3 of cases?) remember the word the next day.
And as a side-note. I totally agree that recall ability is variable and also wonder, if this could somehow be included in the FSRS calculations. From my own experience, the most noticeable things that temporarily reduce ability to recall long-term memories are major sleep deprivation and being drunk.
