To a degree: if you over-strain to recall, you’ll actually train your brain to struggle with that item. Better to limit the time you spend retrying to recall before giving up and looking up the answer.

Is there any empirical evidence for that? Not saying it's wrong, but it's unintuitive.

I think there's probably a high correlation between consistently straining to remember something, and some form of interference going on - the better option would likely be to cut short the effort to recall, and instead identify why recall was difficult, identify any interfering information and devise a way to better remember it.

So in short, I think consistently struggling to recall something is an indication that you need to build a better recall strategy for it.

I'm interested to know why you think it's unintuitive. Certainly it matches my personal experience very well. For example, I have certain Anki cards which I see and immediately think "oh God, not this card again, this one's really difficult" whether or not I actually know the answer to it.

I think its unintuitive because I have flashcards that I now have memorized pat that took me ages to recall easily.

Of course I don't think of them as bad, only "If its hard to remember, it'll be hard to forget". Aka, the ones that I have a hard time learning are the ones I always remember. I'll probably never forget the german word for security guard, die Sicherheitsbedienstete but it took me ages to memorize it.

For some odd reason that is my intuition, which appears to be not that of everyone. But my approach to learning is "failure is a good thing, its how you learn", which might be all the difference amounts to in the end.

That's a good approach. I suspect, for others (and in my experience) when one consistently comes to The Difficult Card, they might have spent more time remembering that it was hard to remember than remembering the answer.

Or, they agonize over the answer for too long, then when they flip it over, they think "Of course!" but move along almost immediately.

And I think you're right also; when you finally get it, it's hard to forget.

That gives me an idea for a personal experiment. Have a session or two where your default attitude to every card is "this is really easy" and try not to think of any card as difficult in any way. Compare your recall percentage for the session compared to previous ones (Anki's statistics are great for this). I'll try this experiment myself.

There is an inverted U relationship between cortisol levels and memory formation. Going from no stress to low stress enhances learning, but as stress levels continue to increase learning begins to degrade. This relationship is well documented in the scientific literature.