2 JOHN LINCK ULRICH 



The effect of distribution of practise on learning has been 

 studied by Ebbinghaus (1) and extensively by Jost (2), also 

 to some extent by Leuba and Hyde (3), Munn (4), Starch (5), 

 Pyle (6, 7), Kirby (8) and Whitley (9). The subjects in all 

 of these cases were human beings, and the material was made 

 up of nonsense syllables, substitution of German script in writ- 

 ing English words, letter substitution, mental arithmetic, etc. 

 A complete summary of this work is given by Thorndike.^ 

 Pyle's conclusions are of especial interest in this connection. 

 Working with a substitution test he concludes: " On the whole, 

 30 minutes seems to be the best length of practice period. In 

 some cases, shorter periods seem a trifle more advantageous, 

 especially in the early stages of practice or habituation. But, 

 generally speaking, one gets ample returns in habituation for 

 practicing up to the point of fatigue, which in our experiments 

 proves to be 30 or 40 minutes for most subjects. Eighty minutes, 

 the longest period used, proved decidedly disadvantageous, espe- 

 cially in the early stages of habituation. Generally speaking, 

 daily practice seems to give better returns than the same number 

 of periods distributed on alternate days or in twice-a-day periods. 

 However, there is some evidence that in the early stages of 

 habituation, the second practice on the same day gives good 

 returns and that, later on, alternate days may be the best dis- 

 tribution." The small amount of work which has been done 

 upon the distribution of effort in learning in animals has been 

 summarized by Watson (10). Tests upon the dancing mouse 

 by Yerkes (11) indicate that for the white-black habit the fewer 

 the tests per day within the limits of two and one hundred, the 

 higher the efficiency of the method of training as measured in 

 terms of the total number of tests necessary for the establish- 

 ment of a perfect habit, and the lower its efficiency as measured 

 in terms of the number of series given. 



I. APPARATUS AND METHOD WHEN A SINGLE PROBLEM 

 IS LEARNED 



The apparatus used for testing the effect of the various dis- 

 tributions of practise in learning a single problem comprised 

 the latch box as shown in Fig. I, and the circular maze described 

 on p. 16. The latch box was about 28 cm. square. In the 



' Thomdike, E. L. Educational Psychology, vol. II, p. 195 ff. 



