Is a a-teady and marked decrease in rapidity of habit formation; 

 from the seventh to the tenth month the direction of the change 

 is reversed. These statements hold for both sexes. 



2^. Younp males acquire the habit more quickly than young 



fenalcG, but between the ages of four and ten months the females 



1 

 acquire the halit the more quickly." 



2 

 Eaecker, in work on the I'exican axolytl, found that the 



habit of distinguishing betvieen wood and meat when offered to 

 the animals in forceps, was learned with far greater difficul- 

 ty by the young (nine month) individuals than by the old ones, 



whose are is not given. 



3 

 Watson in his Animal Education, discusses work both on 



habits involving simple motor ability and on those requiring 



skill in manipulation. He concludes that "a young rat will 



solve for the first time more quickly than a mature rat any 



probler. conditioned on mere random activity, but that a problem 



involving associative activity and manipulation is more easily 



solved by the older animals." Ee found that with the simple 



saw-dust box the average time of entrance for t].e old rats was 



85.50 minutes, while that for the young ones was 6.87 minutes 



and says further, "there is a gradation in the number of use- 



1. Log. cit. p. 269. 



2. Eaecker, Arch. f.d. ges . Isych. , 2^, 1-7j5. 



3. .Vatson, J. 3., Animal Iducation, University of Chicago Press, 

 1903. 



