THE SOCIAL FORM OF INFLUENCE. 85 



found in the individual, but the individual must be able to recognize 

 those of his own elan, and to keep with them in time of rapid flight. A 

 near-sighted deer or cotton-tail rabbit would be in danger of losing his 

 life through losing the trail which the leaders have taken, raising their 

 tails high that they may be seen by those which follow. 



Social election is a similar principle resting on acquired habits and 

 characters. It is due to the necessity for coordination between the 

 social habits of the individual and the social standards of the com- 

 munity, in order to secure success and influence. The knowledge of 

 a common language is recognized as a fundamental need of a human 

 community, and there is a similar need in any community of animals. 

 With the lower creatures this need is largely met by inherited instincts, 

 which determine the calls and warning cries and the interpretations 

 that they receive; but in some cases the training obtained by the 

 young from the example of their elders is an important element in the 

 transmission of the language. In such cases the standard is main- 

 tained by social election. 



It is easy to understand that the red- winged blackbird mentioned 

 above, which learned to crow, but had no chance to learn the normal 

 song of the species, would not have much influence on the musical 

 attainments of the next generation of the species; and perhaps his 

 failure in this respect would lessen his influence as a leader in other 

 things. 



One reason for believing that example has no small influence in 

 shaping the songs of certain species of birds, is found in the fact that 

 Japanese, who highly appreciate the song of the uguisu (sometimes 

 called an oriole), are very careful that the young birds that are taken 

 from the nests of wild birds in the woods and brought up by hand 

 shall have opportunity to hear only the most accomplished adult 

 singers during their period of growth. 



Social isolation. — When two groups of a species have been separated 

 by geographical barriers for many generations, they are liable to gain 

 divergent social habits and instincts, and different calls, rendering 

 them unfit for being associated in the same intergenerating group 

 when brought into the same district. The geographical isolation has 

 ceased, but they continue as separate intergenerating groups through 

 the influence of social isolation. 



Social partition. — In so far as the social incompatibilities holding 

 two groups apart are due to acquired habits and tend to produce sepa- 

 rately associating habitudinal groups, the process may be called 

 social partition. 



