312 The Animal Mind 



acquisition of other habits. Yerkes (820) reports that 

 dancing mice which have learned one maze learn another 

 one more readily than those which have had no previous 

 training. Richardson (634) finds previous experience a 

 help also to the rat : experienced animals were more sus- 

 ceptible to stimuli and showed better coordination of their 

 activities. Hunter (349), on the other hand, found that 

 pigeons which had learned one maze were delayed in learn- 

 ing a second one, and Yoakum (832) reports a similar condi- 

 tion in the learning of puzzle-boxes by squirrels : the older 

 habits interfere with the acquisition of the newer ones. 

 Hunter and Yarbrough (355) conclude from experiments on 

 establishing auditory associations in white rats that a 

 formed habit interferes with the formation of a new one, but 

 that the new habit does not react unfavorably upon the old 

 one. This has been found true of human memorizing also. 

 Probably, when an animal seems to learn a new habit better 

 because of having previously formed a different habit, the 

 advantage is merely in the fact that it has become used to 

 being experimented upon, to the experimental situation. 



(5) The differences in individual ability among animals 

 are marked. We are inclined to think of all the animals 

 of a certain species, especially if it be a species far removed 

 from man, as equally gifted, but it is quite possible that 

 among ants and earthworms there are geniuses and dunces. 

 Turner (729, 730) reports striking individual variations in 

 the behavior of cockroaches learning a maze; two of the 

 rats tested by Small (685) with puzzle-boxes never learned 

 to get into the boxes, but merely profited by the activity 

 of their more gifted companions. Wodsedalek_ (795) 

 gives a delightful account of a specially talented Mayfly. 

 Practically every experimenter reports similar individual 

 variations. 



