MEMORY AND ASSOCIATION OF IDEAS. 117 



spots and cracks of a wooden floor on which it was placed. 

 But at the yellow yolk it pecked often and earnestly. He 

 then removed all tln^ee substances, and after the lapse of an 

 hour replaced them. The cliick instantly recognized them all, 

 as proved by its immediately beginning to devour them while 

 showing a complete disregard of all other and inedible objects. 

 Yet in the first experiment the chick only once tasted the 

 white of egg, and only took a single millet seed. The experi- 

 ment therefore shows how apt a young chicken is to learn by 

 its own individual experience, while in the opinion of Pro- 

 fessor Preyer the original preference shown to the yolk of 

 egg proves an inherited faculty of taste-discrimination. 



These experiments serve to introduce us to the stage of 

 Memory at which the Association of Ideas is first concerned — 

 a principle which throughout all subsequent stages consti- 

 tutes what may be termed the vital principle of ]\Iemory — 

 for the chickens which first pecked at inedible objects in tlie 

 presence of edible ones, and an hour later were able to dis- 

 tinguish between the two classes of objects, must have 

 established a definite association of ideas between each of the 

 particular objects of its former experience with reference to 

 their edible or inedible character. But it is noteworthy that, 

 as these definite associations were established so quickly and 

 as the result of only a single individual experience in each 

 case, we can scarcely avoid concluding that heredity must 

 have had a large, if not the largest, part in the process — ^.just 

 as in the case of distinguishing from the first the boiled yolk 

 of egg, we must suppose that heredity had the exclusive 

 part.* And this shows how closely the phenomena of here- 

 ditary memory are related to those of individual memory ; 

 at this stage in the evolution of mnemonics, where the simple 

 association of ideas first occurs in very young animals, it is 

 practically impossible to disentangle the effects of hereditary 

 memory from those of individual. 



Association of Ideas. 

 I shall reserve for my chapter on Imagination a full 



* It seems to me doubtful, however, wliether heredity here had reference 

 to taste-discrimination, as Preyer supposes, seeing that in nature a young 

 chicken can never have had an opportunity of tasting boiled yolk of egg. 

 Probably the bright yellow colour had something to do with the selection, as 

 many seeds are more or less yellow in tint. 



