110 SOCIAL EVOLUTION 



painless clearness, or positive pleasure, with least dif- 

 ficulty. The line of least effort is sought out. Activities 

 proceed from the known to the unknown, and from the 

 tried to the untried. Consciousness thus seeks to avoid 

 those stimuli which experience has found to be followed 

 by painful sensations. 



In associated life, individuals stimulate one another 

 by acts and signs. In this way the phenomena of inter- 

 stimulation and response arise. But different individ- 

 uals respond differently to the same or similar stimuli. 

 These varied responses are unlike in kind, in degree, and 

 in completeness. From this unlike-response spring the 

 innumerable phenomena of antagonism, conflict, rivalry, 

 and competition. But we often observe that fellow be- 

 ings are so constituted that they respond in like ways 

 to the same stimulus. From this like-response develop 

 the phenomena of agreement and cooperation. 10 Those 

 who respond similarly to an appeal to arms become the 

 warriors. Those who are quick to seize upon new op- 

 portunities become leaders. Any who, because of poor 

 digestions or epileptic taint, dream dreams and fall into 

 fits, become the medicine-men of the tribe and its religious 

 leaders. Thus the process of interstimulation and re- 

 sponse throws together those individuals who are most 

 alike, and sorts out for contempt or disapproval all who 

 vary too far from the accustomed mode of response. 

 There is a process of differentiation, whereby, on the 

 basis of their different responses, individuals are 

 grouped; those who respond alike are drawn together, 

 are integrated, while those whose reaction varies greatly 

 from the average are regarded as uncongenial, are per- 

 secuted or driven from the group. In this way the mem- 



10 Ibid., p. 128. 



