266 The Animal Mind 



of the discrimination required of the animal. A super- 

 ficial consideration of the situation might assume that if 

 one wants to teach an animal a difficult discrimination, such 

 as that between two slightly different shades of gray, one 

 ought to supply a stronger punishment stimulus than 

 would be necessary to teach it an easy discrimination, such 

 as that between black and white. The results with the 

 dancing mouse showed on the contrary that weaker pun- 

 ishments were more effective in the learning of hard dis- 

 criminations ; stronger punishments in that of easy dis- 

 criminations. The same rule was found by Dodson to 

 hold for cats (186 a) ; the hardest discriminations were 

 acquired by kittens in 82.5 trials with a moderate stimulus, 

 but 107.5 trials were required on the average with a strong 

 stimulus. Indications of a similar relation were found by 

 Cole (136) in the learning of chicks. 



The negative reaction is not the only one which may 

 show sufficient prepotency to cause the dropping off of 

 other responses. The feeding reaction, or any other in- 

 nate response, may serve : thus reward as well as punish- 

 ment is a method of training. The taming of an animal 

 by kind treatment illustrates both the simple dropping off 

 of useless movements, the getting used to a situation, and 

 the substitution of movements more valuable to the ani- 

 mal; the tamed creature on the one hand learns to rest 

 quietly in the presence of its tamer, instead of displaying 

 alarm, and on the other hand to come for food or follow for 

 companionship. A very pretty illustration of the over- 

 coming of an innate response to light by the response to 

 feeding was obtained by Wodsedalek (795) on immature 

 mayflies. These insects have an innate tendency to avoid 

 light and to remain under stones in the water. By regu- 

 larly feeding them on the upper surface of a stone the 



