The value of interleaving is evidence that a lot of conventional education is about teaching people to endure boredom, and this is a very bad mistake.
It's weak evidence for the first, proposition, but I don't think it's any evidence for the second. I suspect you're right, but to play devils advocate, it could be that training/selecting for grit could be more important for future success than the learning is.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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