Why does re-reading feel more effective than self-testing, even though it isn't?

Because re-reading produces fluency — the material looks familiar — which we mistake for actual knowledge (the illusion of competence).

When you re-read, the words flow smoothly and everything feels known. Your brain reads that fluency as "I've got this." But familiarity with seeing an answer is not the same as being able to produce it unaided.

Self-testing feels worse precisely because it exposes what you can't yet produce — which is uncomfortable but honest. Roediger & Karpicke's result is this illusion caught in the act: on an immediate test re-reading looked better (re-study ~81% vs test ~71%), but on a delayed test a week later the ranking flipped hard — the self-testers recalled about 56% while the re-readers had dropped to about 42%. The method that felt better in the moment left far less behind once real time had passed. Trust the discomfort; it's the sensation of learning.