Humans more easily remember or learn items when they are studied a few times over a long period of time (spaced presentation), rather than studied repeatedly in a short period of time.

Mental events, it is said, are not passive happenings but the acts of a subject.

Sensorial perception, for example, certainly occurs with greater or less accuracy according to the degree of interest; it is constantly given other directions by the change of external stimuli and by ideas.

Ideas which have been developed simultaneously or in immediate succession in the same mind mutually reproduce each other, and do this with greater ease in the direction of the original succession and with a certainty proportional to the frequency with which they were together

Humans more easily remember or learn items when they are studied a few times over a long period of time (spaced presentation), rather than studied repeatedly in a short period of time.

A poem is learned by heart and then not again repeated. We will suppose that after a half year it has been forgotten: no effort of recollection is able to call it back again into consciousness.

The relation of repetitions for learning and for repeating English stanzas needs no amplification. These were learned by heart on the first day with less than half of the repetitions necessary for the shortest of the syllable series.