462 JOHN B. WATSON AND K. S. LASHLEY 



the breeding season affect certain psychic functions not directly 

 connected with reproduction. 



Individuals differed considerably in the time of learning and 

 the frequency and extent of the periods of error. Young ani- 

 mals (nine months old) learned with far greater difficulty than 

 mature ones. Among adults three types were distinguishable 

 with respect to the time of learning and retention. Experi- 

 ments are still in progress to determine whether these types 

 are of selective and hereditary value. 



Mammals. Hicks and Carr (u) took up the comparative 

 abilities of human adults, children and white rats to learn a 

 maze. The maze for the man was placed out of doors; its 

 dimensions were fourteen by twenty feet; the alleys were two 

 feet in width, the true path seventy-eight feet in length, compli- 

 cated by nine cut de sacs. The human subject had to run the 

 maze blindfolded. One group of rats learned the Hampton 

 Court maze and another a maze especially constructed by 

 Carr. The results of these experiments show that rats can 

 learn a maze in a fewer number of trials than the human beings. 

 The authors, however, are cautious about adherence to the 

 letter of this conclusion, since the mazes were different and 

 since the criteria of master y were different, and, further, since 

 only a very small number of individuals were tested. This 

 paper further takes up rather thoroughly the relative ability of 

 the different animals to eliminate errors, distance and excess of 

 time, the relative variability of the three groups, and the rela- 

 tion of the learning curves to intelligence. Under the latter 

 head we find the most complete discussion we have at present 

 of the significance of the form of learning curves. Especially 

 discussed is the significance of the sharp initial drop we find in 

 most learning curves. Since the argument is rather closely con- 

 nected, the reader must be referred to the original paper. 



