RATE OF LEARNING IN THE WHITE RAT 7 



that this slight superiority of simultaneous presentation neces- 

 sarily proves the theory of simultaneity, but would explain it by 

 a "tendency to articulate and combine the simultaneous syllables 

 into a single word." From the introspection of his subjects he 

 found "essential agreement on three points: i) that simul- 

 taneous exposure taxes the attention more than successive, 

 2) that there is a persistent tendency toward articulation in the 

 simultaneous series, and 3) that when in successive association 

 there was an appreciable interval between the stimuli, the first 

 would remain in consciousness, though with varying degrees of 

 intensity, until the second arrived." 



In order to eliminate this persisting memory image during 

 the interval between the two stimuli in successive presentation 

 the experiment was repeated with a group of four subjects and 

 with the added condition that the subjects should read numerals 

 presented to them during the intervals between the terms of the 

 pairs, a device calculated to prevent memory survival of the 

 first term during the interval separating it from the second. In 

 this test the average percentages of right response for the simul- 

 taneous and continuous presentations and the time intervals from 

 one to five seconds were 54, 45, 34, 36, 40, 24, and 22 i. e., the 

 rate of learning decreased with an increase in the length of the 

 interval when a new activity was interpolated. This decrease in 

 the rate of learning is distinct though irregular. From these 

 data and the statement by each of his subjects that "the reading 

 of the numerals effectively and completely obliterated the memory 

 image of the preceding syllable," he concludes that association 

 may still be formed between two experiences where the first has 

 already passed out of consciousness when the second one appears. 

 This is in contrast with the findings of Bergstrom. 



Since Wohlgemuth had rejected nonsense syllables as improper 

 material for the study of association, Froeberg formed another 

 group of subjects to which he presented colors and letters of the 

 alphabet. Other details were the same as in the previous ex- 

 periments. He found under these conditions that the successive 

 was superior to the simultaneous mode of presentation. This 



