The Mental Life of the Monkeys 173 



INTRODUCTION 



The work to be described in this paper is a direct contin- 

 uation of the work done by the author in 1897-1898 and 

 described in Monograph Supplement No. 8 of the Psycho- 

 logical Review under the heading, 'Animal Intelligence; 

 an Experimental Study of the Associative Processes in 

 Animals.' l This monograph affords by far the best in- 

 troduction to the present discussion, and I shall therefore 

 assume an acquaintance with it on the part of my readers. 



It will be remembered that evidence was there given that 

 ordinary mammals, barring the primates, did not infer or 

 compare, did not imitate in the sense of 'learning to do an 

 act from seeing it done,' did not learn various simple acts 

 from being put through them, showed no signs of having in 

 connection with the bulk of their performances any mental 

 images. Their method of learning seemed to be the grad- 

 ual selection of certain acts in certain situations by reason 

 of the satisfaction they brought. Quantitative estimates 

 of this gradualness were given for a number of dogs and 

 cats. Nothing has appeared since the ' Experimental Study' 

 to negate any of these conclusions in the author's mind. 

 The work of Kline and Small 2 on rodents shows the same 

 general aspect of mammalian mentality. 



Adult human beings who are not notably deficient in 

 mental functions, at least all such as psychologists have 

 observed, possess a large stock of images and memories. 

 The sight of a chair, for example, may call up in their minds 

 a picture of the person who usually sits in it, or the sound 

 of his name. The sound of a bell may call up the idea of 



1 Pp. 20 to 155 of this volume. 



2 American Journal of Psychology, Vol. X, pp. 256-279; Vol. XI, pp. 80- 

 100, 131-165; Vol. XII, pp. 206-239. 



