MEMORY. 677 



quired to relearn tlie list after it had been once learned. 

 Eouglily speaking, if it took a thousand seconds to learn 

 the list, and five hundred to relearn it, the loss between the 

 two learnings would have been one half. Measured in this 

 way, full half of the forgetting seems to occur within the 

 first half-hour, whilst only four fifths is forgotten at the 

 end of a month. The nature of this result might have 

 been anticipated, but hardly its numerical proportions. 

 Dr. Ebbinghaus says : 



" The initial rapidity, as well as the final slowness, as these were as- 

 certained under certain experimental conditions and for a particular 

 individual, . . . may well surprise us. An hour after the work of learn- 

 ing had ceased, forgetting was so far advanced that more than half of 

 the original work had to be applied again before the series of syllables 

 could once more be reproduced. Eight hours later two thirds of the 

 original labor had to be applied. Gradually, however, the process of 

 oblivion grew slower, so that even for considerable stretches of time 

 the losses were but barely ascertainable. After 24 hours a third, after 

 6 days a fourth, and after a whole month a good ufth of the original 

 labor remain in the shape of its after-effects, and made the relearning 

 by so much the more speedy." * 



But the most interesting result of all those reached by 

 this author relates to the question whether ideas are re- 

 called only by those that previously came immediately be- 

 fore them, or whether an idea can possibly recall another 

 idea with which it was never in immediate contact, without 

 passing through the intermediate mental links. The ques- 

 tion is of theoretic importance with regard to the way in 

 which the process of * association of ideas ' must be con- 

 ceived ; and Dr. Ebbinghaus's attempt is as successful as 

 (t is original, in bringing tAvo views, which seem at first 

 sight inaccessible to proof, to a direct practical test, and 

 giving the victory to one of them. His experiments con- 

 clusively show that an idea is not only ' associated ' directly 

 with the one that follows it, and with the rest through that, 

 but that it is directly associated Avith all that are near it, 

 though in unequal degrees. He first measured the time 

 needed to impress on the memory certain lists of syllables, 

 and then the time needed to imj^ress lists of the same 

 syllables with gaps betu een them. Thus, representing the 



* Op. cit., p. 103. 



