The Journal of 



Comparative Neurology and Psychology 



Volume XVI SEPTEMBER, 1906 Number 5 



THE IMITATIVE TENDENCY OF WHITE RATS.' 



BY 



CHARLES SCOTT BERRY. 



(From the Har-uard Psychological Laboratory.^ 



CONTENTS. 



I. Problem and Method 333 



II. Experiments: 



1 . Climbing a Wire Ladder 334 



2. Pushing Open a Swinging Door 336 



3. Digging Through Sawdust , 337 



4. Pushing Open Door in Top of Box 338 



5. Pulling a Wooden Bar 343 



6. Pulling a Knot with the Forepaws 346 



7. Pulling a Bent Wire with the Teeth and Forepaws 352 



III. Discussion of Results 356 



I. PROBLEM AND METHOD. 



This paper is an account of some experiments made for the 

 purpose of determining to what extent white rats learn by imitating 

 one another. 



The animals studied were ten white rats, whose ages and sexes 

 were as follows: 



Nos. 9 and 10 died soon after the experiments were begun. 



'This investigation was carried on under the direction of Dr Robert M. Yerkes, to whom I am greatly 

 indebted for the suggestion of the problem and general method. 



