Easy now is not the same as remembered later
A paragraph can look comfortably familiar while remaining difficult to explain with the page closed. Familiarity is an experience in the present. A later recall test asks a different question: what can the learner produce after a delay without the original material in front of them?
Henry Roediger and Jeffrey Karpicke's 2006 study compared restudying prose passages with taking immediate free-recall tests without feedback. At five minutes, repeated study produced better recall. At two days and one week, prior testing produced greater retention, even though restudying increased confidence about remembering. The timing of the final test changed the comparison.
Sources: s1
Testing can also be a learning event
In an accompanying account of their research programme, Roediger, Mark McDaniel and Kathleen McDermott describe tests as a possible aid to learning, not solely an assessment after learning is over. That distinction is useful: an activity used to measure memory can also change the memory being measured.
An illustrative personal check is to write a brief explanation from memory, then compare it with the source and mark omissions. The exercise makes the missing information visible. It should not be described as an exact replication of the paper, which used particular materials, timings and experimental conditions.
Preserve the limits of the finding
The study does not establish that every test format helps every learner or that rereading has no value. It supports a narrower lesson: judge a learning method against the retention interval and outcome that matter. A pleasant sense of fluency is useful experience, but it is not an independent measurement of durable recall.