272 JOHN D. DODSON 



periments was the same and as to the recency between trials 

 there was practically no difference. 



Vigor. The importance of the vigor with which an animal 

 performs an act has been underestimated by some students of 

 behavior. The more nearly the^whole active organism is directed 

 towards the accomplishment of the act the more rapidly will the 

 act be perfected. The subjects which chose most quickly and 

 made the greatest effort to reach the food learned in about one 

 half the time that it took for those subjects which did not seem 

 anxious to get to the food. This is evidently an important factor 

 in accounting for the difference in the time taken for animals 

 trained with twenty-four hours hunger and animals trained with 

 forty-one hours hunger to perfect the same habit. It also has its 

 bearing in the interpretation of the difference in the average num- 

 ber of trials taken by animals trained with sixty units and those 

 trained with seventy-five units. The former stimulus was too 

 weak to keep the subjects up to their greatest efficiency. The 

 directing of all energy in a single channel means efficiency in 

 acquiring any habit. Animals trained with the more favorable 

 conditions were not often interfered with by the scratch reflex 

 and like inhibitory processes. 



Satisfyingness and annoyingness. Thorndike tells us "that 

 improvement is the addition or subtraction of bonds or the addi- 

 tion or subtraction of satisfyingness and annoyingness. 7 ' But 

 how the satisfaction of eating of food after an animal has perform- 

 ed an act can lap back and in some way stamp in the act is not 

 very easy to understand. Likewise it would be a hazardous 

 science that would say that the satisfaction an animal gets from 

 JM-j eating after forty-one hours of hunger is more effective in stamp- 

 ing in a desired act than eating after forty-eight hours of hunger, 

 or that the annoyingness of an electric shock of one hundred and 

 fifty units is less effective in stamping out an undesirable act than 

 that of seventy-five units. The above illustrations are sufficient 

 to show that the principles of satisfyingness and annoyingness 

 are of no significance in an explanation of the results of this 

 experiment. 



Other principles. Though the principles of congruity and in- 

 congruity, completeness of response and the law of irradiation 



