LEARNING 113

He copied tlie same list 24 hours later and the times
were compared. A variable condition consisting of
the presence or absence of the odor of oil of pepper-
mint was used. Each subject practised a list with
the odor present and repeated the same list with
the odor absent; he then practised a list with the
odor present and repeated the list 24 hours later with
the odor present. He then practised the list without
the odor and repeated with the odor; and last prac-
tised without the odor and repeated without the
odor. Thirteen subjects were used, and the aver-
age saving in the time required to repeat the list was
9.4 per cent greater when the repetition took place
under the condition of the first practice.
It is highly probable that the greater retention
shown by Meumann's subjects at the end of 24 hours
depended upon the daily recurrence of conditioning
stimuli. There is a diurnal rhythm of experience
that results in a characteristic internal state at each
hour of the day. We sleep, eat, work, and play ac-
cording to a fairly rigid schedule. The resulting
periodic bodily states, present at the original learn-
ing, contribute familiar stimuli to anyone who is en-
gaged in relearning after a 24-hour period. These
stimuli come to condition the responses and facili-
tate the relearning.
