154 THE SOCIAL LIFE OF ANIMALS 



also took less time to run the maze than when the 

 same animals were members of pairs or of groups of 

 three. Turning the comparison around, paired cock- 

 roaches took longer time per trial and made more 

 errors than when isolated, and groups of three took 

 still longer and made more errors than those in pairs. 



A study of the rate of improvement shows that 

 during the early part of the training, as is indicated 

 by the slant of the graphs, so far as time spent is 

 concerned, paired cockroaches improved more rap- 

 idly than they did if isolated or in groups of three, 

 and those placed three together on the maze im- 

 proved somewhat more rapidly than they did when 

 isolated. Thus, while the presence of one or two extra 

 cockroaches slowed down the speed of reaction on the 

 maze and increased the number of errors made at all 

 times, yet the rate of improvement in speed of re- 

 action was higher when more than one was present. 

 There was, however, no significant difference in rate 

 of improvement as measured by number of errors. 



Excluding this one aspect of rate of improvement 

 in time spent on the maze, in all other phases of 

 the experiment isolated cockroaches turned in a bet- 

 ter learning performance than they showed when 

 more were present. Evidently under the conditions 

 of our experiments the tutorial system usually works 

 best with cockroaches. 



