FACTS AND FACTORS OF DEVELOPMENT 3 1 



in cages which could be opened from the inside by turning a button, or 

 pressing upon a lever, or pulling a cord, they at first clawed around all 

 sides of the cage until by chance they happened to operate the mechan- 

 ism which opened the door. Thereafter they gradually learned by 

 experience, that is, by trial and error, and finally by trial and success, 

 just where and how to claw in order to get out at once. When a dog 

 has learned to turn a button at once and open a door we say he is in- 

 telligent, and if he can learn to apply his knowledge of any particular 

 cage to other and different cages, a thing which Thorndike denies, we 

 should be justified in saying that he reasons, though in this case intelli- 

 gence and reason are founded upon memory of many past experiences, 

 of many trials and errors and of a few trials and successes. 



There is every evidence that human beings arrive at intelligence 

 and reason by the same process, a process of many trials and errors 

 and a few trials and successes, a remembering of these past experiences 

 and an application of them to new conditions. A baby grasps for things 

 which are out of its reach, until it has learned by experience to appre- 

 ciate distances ; it tests all sorts of pleasant and unpleasant things until 

 it has learned to avoid the latter and seek the former; it experiments 

 with its own body until it has learned what it can do and what it can not 

 do. Is not this learning by experience akin to the same process in the 

 dog and more remotely to the trial and error of the earthworm or the 

 adaptive reflexes of Paramecium ? Is not intelligence and reason in all 

 of us, and upon all subjects, based upon the same processes of trial and 

 error, memory of past experiences and application of this to new con- 

 ditions? Surely this is true in all experimental and scientific work. 

 Indeed the scientific method is the method of trial and error, and finally 

 trial and success — the method recommended by St. Paul to "try all 

 things and hold fast that which is good." 



In Paramecium the reflex type of behavior is relatively complete; 

 there is no associative memory and no ability to learn by experience. In 

 the earthworm associative memory is but slightly developed and the ani- 

 mal learns but little by experience and can make no application of past 

 experiences to new conditions. In the dog associative memory is well de- 

 veloped; the animal learns by experience and can, to a limited extent, 

 apply such memory of past experiences to new conditions. In adult man 

 all of these processes are fully developed and particularly the last, viz., 

 the ability to reason. But in his development the human individual 

 passes through the more primitive stages of intelligence, represented by 

 the lower animals named ; the germ cells and embryo represent only the 

 stages of reflex behavior, to these trial and error and associative memory 

 are added in the infant and young child, and to these the application of 

 past experience to new conditions, or reason, is added in later years. 



5. Will. — Another characteristic, which many persons regard as the 

 supreme psychical faculty, is the will. This faculty also undergoes de- 



