48 HELEN B. HUBBERT 



averages which appear below in Table X seem to show the day 

 rats slightly superior in distance and trials while the night rats 

 consumed less time and had a slightly higher final efficiency. 

 These differences are negligible, and there may be said to be no 

 difference in learning at this age between the rats run in the 

 day-time and those run at night. 



The day group of two hundred day rats consisted of two 

 males and four females numbers 18, 19, 20, 21, 23 and 24, while 

 the night group included two males and four females numbered 

 6, 7, 8, 9, 10, 15 and 17. The averages show the night group 

 to be superior to the day group in every respect save that of 

 final efficiency. Nevertheless, we are inclined to hold to our 

 previous statement that no difference is shown in learning 

 ability, for the following reason: The general average for the 

 females of this group was considerably higher than that for the 

 males except in the matter of absolute time. In the day group 

 there were only two males and four females. Were the number 

 of males the same as the number of females it is our belief that 

 the average would be considerably lowered and the day and 

 night groups prove to have practically the same ability in learn- 

 ing the maze problem. 



TABLE X 

 AVERAGES 



Time 



Trials Absolute Total Distance 



25 days: 



Day 29 5.5 sec. 207 min. 247.4 m. 



Night 31 5.4 159 261.6 



200 days: 



Day 41 6.2 461 " 373.5 



Night 34 7.2 325 267.9 



CONTINUATION OF WORK AFTER THE PROBLEM HAS BEEN LEARNED 



Another question which interested us, was, what would be 

 the effect on efficiency if rats which had learned the problem 

 were caused to continue their runs in the maze for a long period, 

 i. e., would continued practice cause a marked increase in effi- 

 ciency evinced by a lowering of the absolute time record, or had 

 the highest possible level already been reached in the last six 

 trials of the learning process ? 



