Spacing effect

In the field of psychology, the spacing effect is the phenomenon whereby animals (including humans) more easily remember or learn items when they are studied a few times spaced over a long time span ("spaced presentation") rather than repeatedly studied in a short span of time ("massed presentation"). Practically, this effect suggests that "cramming" (intense, last-minute studying) the night before an exam is not likely to be as effective as studying at intervals in a longer time frame. Important to note, however, is that the benefit of spaced presentations does not appear at short retention intervals, in which massed presentations tend to lead to better memory performance.