FUNCTION OF VIBRISSAE IN BEHAVIOR OF WHITE RAT 15 



two feet from the floor. The walls which should have enclosed the 

 runways were hinged to the sides so that they dropped below 

 the floor but they could be raised and hooked together if one 

 wished to enclose the paths. The food box was surrounded 

 where it faced the maze by sides 4" high. 



Upon this maze were used rats with and without vibrissae; 

 rats with the vibrissae cut on the right side, on the left side, 

 and from birth; anosmic rats with and without vibrissae; rats 

 with the fifth nerve cut, and blind rats with and without vibrissae. 

 All of these rats were two months old or as near that age as 

 possible when the experiment began. 



E. Mode of Experimentation 



The mode of experimentation was similar to that previously 

 described by others who have used the maze in this laboratory. 

 The animals were thoroughly tame, were kept . in the room 

 where they were used, and were fed in the maze three days 

 before the experiment began. The maze was kept clean and 

 was washed at the close of each day's work with a weak solution 

 of carbolic acid. The animals ran under a slight stimulus of 

 hunger, three times a day except at the very first when the 

 time taken for one run prevented more. For our puipose the 

 coordination was considered learned when the animal made 

 eight out of ten perfect runs and this record extended over a 

 period of three days. They were then usually taken from the 

 problem and this necessitates a word at this point as to the way 

 in which the graphs which show the learning process have been 

 made. 



F. The Learning Curve 



Mr. Thorn dike was the first to apply the graphic method to 

 the results of comparative psychology.^' His curves are time 

 curves in the learning processes of single animals. It has been 

 objected by others that the time curve is not truly a learning 

 curve but there are reasons for believing that this curve may 

 represent the labyrinth type of coordination better than any 

 other because this type invoves the use of the oldest and most 

 mechanized reflex and instinctive motor systems. These single 

 animal curves all showed a sudden fall at the beginning followed 



" Thorndike, E. L.: Animal Intelligence, Psychol. Rev. Mori. Sup. 1898, vol. 2, 

 no. 4. 



