CHAPTER XVII 

 INDIVIDUAL, AGE, AND SEX DIFFERENCES IN BEHAVIOR 



ALL dancers are alike in certain important respects, but 

 to the trained observer of animal behavior their individual 

 peculiarities are quite as evident, and even more interesting 

 than their points of resemblance. Omitting consideration 

 of the structural marks of individuality, we shall examine 

 the individual, age, and sex differences in general behavior, 

 rapidity of learning, memory, and discrimination, which have 

 been revealed by my experiments. Observations which bear 

 on the subject of differences are scattered through the pre- 

 ceding chapters, but in no case have they been given sufficient 

 prominence to force them upon the attention of those who 

 are not especially interested in individual peculiarities. It 

 has seemed worth while, therefore, to assemble all the avail- 

 able material in this chapter for systematic examination and 

 interpretation. 



In the pages which follow, individual, age, and sex pecul- 

 iarities are discussed in turn. Within each of these three 

 groups of differences I have arranged in order what Roye 

 has appropriately named the facts of discriminating sen- 

 sitiveness, docility, and initiative. Individuals of the same 

 age and sex no less than those which differ in sex or age ex- 

 hibit important differences in ability to discriminate among 

 sense impressions ("discriminative sensitiveness"), in ability 

 to profit by experience (" docility"), and in ability to try new 

 kinds of behavior (" initiative"). 



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