Bjorks’ “desirable difficulty” principle: The harder your brain has to work to dig out a memory, the greater the increase in learning (retrieval and storage strength). Fluency, then, is the flipside of that equation. The easier it is to call a fact to mind, the smaller the increase in learning. Repeating facts right after you’ve studied them gives you nothing, no added memory benefit. The fluency illusion is the primary culprit in below-average test performances. Not anxiety. Not stupidity. Not unfairness or bad luck.
