52 Heredity and Environment 



few minutes without heeding the eggs. The ring-neck pigeon 

 also misses the eggs and sometimes rolls one of them back into 

 the nest, but never attempts to recover more than one. The dove- 

 cote pigeon generally tries to recover both eggs. According to 

 Whitman : 



In these three grades the advance is from extreme blind uni- 

 formity of action, with little or no choice, to a stage of less rigid 

 uniformity .... Under conditions of domestication the action of 

 natural selection has been relaxed, with the result that the rigor of 

 instinctive co-ordination, which bars alternative action, is more or 

 less reduced. Not only is the door to choice thus unlocked, but 

 more varied opportunities and provocations arise, and thus the in- 

 ternal mechanism and the external conditions and stimuli work 

 both in the same direction to favor greater freedom of action. 

 When choice thus enters no new factor is introduced. There is 

 greater plasticity within and more provocation without, and hence 

 the same bird, without the addition or loss of a single nerve cell, 

 becomes capable of higher action and is encouraged and even 

 constrained *by circumstances to learn to use its privileges of 

 choice. Choice, as I conceive it, is not introduced as a little deity 

 encapsuled in the brain. . . . But increased plasticity invites great- 

 er interaction of stimuli and gives more even chances for con- 

 flicting impulses. 



(4) Conscious Choice or Will. Finally in all animals behavior 

 is modified through previous experience, just as structure is also. 

 Where several responses to a stimulus are possible and where 

 experience has taught that one response is more satisfactory than 

 another, action may be limited to this particular response, not by 

 external compulsion but by the internal impulse of experience 

 and intelligence. This is what we know as conscious choice or 

 will. Whitman says: 



Choice runs on blindly at first and ceases to be blind only in 

 proportion as the animal learns through nature's system of com- 

 pulsory education. The teleological alternatives are organically 

 provided; one is taken and fails to give satisfaction, another is 

 tried and gives contentment. This little freedom is the dawning 



