FACTS AND FACTORS OF DEVELOPMENT 33 



arms. Many responses of organisms are modified in a similar way, not 

 only by artificial limitations, but also by natural ones. 



(c) Responses which have become fixed and constant through natural 

 selection or other means of limitation may become more varied and 

 general when the compulsory limitation is relaxed. Behavior in the 

 former case is fixed and instinctive, in the latter more varied and plastic. 

 Thus "Whitman found that the behavior of domesticated pigeons is more 

 variable and their instincts less rigidly fixed than in wild species. If 

 the eggs are removed to a little distance from the nest the wild passenger 

 pigeon returns to the nest and sits down as if nothing had happened. 

 She soon finds out, not by sight but by feeling, that something is miss- 

 ing, and she leaves the nest after a 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. 



In these three grades the advance is from extreme blind uniformity of ac- 

 tion, 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 coordination, 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 internal mechan- 

 ism 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 in- 

 troduced. 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 circum- 

 stances 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 plas- 

 ticity invites greater interaction of stimuli and gives more even chances for 

 conflicting impulses. 



(d) Finally in all animals behavior is modified though previous ex- 

 perience, 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 re- 

 sponse, not by external compulsion, but by the internal impulse of experi- 

 ence 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 compulsory education. The teleo- 

 logical alterations are organically provided; one is taken and fails to give satis- 

 faction; another is tried and gives contentment. This little freedom is the 

 dawning grace of a new dispensation, in which education by experience comes 

 in as an amelioration of the law of elimination. . . . Intelligence implies varying 

 degrees of freedom of choice, but never complete emancipation from automatism. 



Freedom of action does not mean action without stimuli, but rather 

 the introduction of the results of experience and intelligence as addi- 

 vol. lxxxv. — 3. 



