The constant flux and caprice of mental events do not admit of the establishment of stable experimental conditions.

The amount of detailed information which an individual has at his command and his theoretical elaborations of the same are mutually dependent; they grow in and through each other.

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

Mental states of every kind, - sensations, feelings, ideas, - which were at one time present in consciousness and then have disappeared from it, have not with their disappearance absolutely ceased to exist.

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.

The constant flux and caprice of mental events do not admit of the establishment of stable experimental conditions.

Series of syllables which have been learned by heart, forgotten, and learned anew must be similar as to their inner conditions at the times when they can be recited.