MECHANISMS OF LEARNING 185 



experiments and recurring to the inclined plane latch- 

 box experiments as described by Lashley and Franz 

 in 1917, these contribute some further evidence bear- 

 ing upon the problem of cortical localization of the 

 learning process. 



These experiments are limited (p. 75) to a "deter- 

 mination of the relation of the frontal pole and dorsal 

 convexity of the cerebrum to the formation and reten- 

 tion of habits which involve chiefly responses to tac- 

 tile and kinesthetic stimulation." The frontal pole or 

 the entire dorsal convexity of the hemisphere was de- 

 stroyed and the rats were then trained in a simple 

 maze or a latch-box and their rate and manner of 

 learning compared with normal. Conversely, normal 

 animals were trained and after destruction of various 

 parts of the cortex they were tested to determine the 

 degree of retention or loss and in the latter case their 

 ability to reform the habits. 



The experiments described give no evidence of cor- 

 tical participation at all in the formation and reten- 

 tion of a simple maze habit. This habit 



may be retained after the destruction of any part or all of the 

 cortex lying in front of and above the knee of the corpus callosum 

 and after the destruction of any part of the temporal and parietal 

 regions. The maze habit may be acquired after the destruction 

 of all the cortex included within these areas, and after the de- 

 struction of one, perhaps both, of the striate nuclei [p. 133]. 



The case of the inclined plane latch-box habit is 

 quite different. The rats were taught to climb upon 



