6 HELEN B. HUBBERT 



of movements in two dimensions which would be practically 

 impossible to trace. We therefore selected as our problem the 

 learning of the circular maze. 



Heretofore, the only data possible on such a problem have 

 been in terms of time and errors, the time being the only reliable 

 record since it is practically impossible to evaluate and stand- 

 ardize errors. 18 With regard to this Miss Hicks 17 says: "The 

 prevalent practice of omitting all total and partial returns from 

 the error record, and of making no attempt to evaluate varying 

 degrees of error gives a curve which is not only worthless but 

 false." She says further: "The total distance criterion pre- 

 sents so many difficulties as to render it impracticable for ordi- 

 nary work. One difficulty lies in the matter of taking records 

 accurately. The rats, after a few trials, run so rapidly that it 

 is extremely difficult for one person to observe and record at 

 the same time. To do this, it is necessary to mark off the maze 

 into small segments and commit to memory some scheme of 

 representation so that records can be jotted down in a purely 

 automatic manner. The work of transcribing this record into 

 distance terms and computing the same is very laborious. 

 Eliminating these practical difficulties, the distance criterion is in 

 some ways an ideal one. (italics mine.) There can be no diver- 

 gence of practice as to what shall be omitted or included and 

 results obtained by different experiments upon the same maze 

 will be strictly comparable." " The distance and error criteria 

 are fundamentally alike. The distance curve is the better repre- 

 sentative of the progressive approximation of the act towards 

 automatic accuracy. It portrays all the details of this elimina- 

 tive process and it approximates the ideal of uniformity and 

 regularity of descent. However, it is impracticable from the 

 standpoint of recording and manipulating the data." 



These practical difficulties in " recording and manipulating 

 the data " have been overcome, at least where small animals 

 are the subjects used in the maze. The total distance can be 

 obtained accurately by means of the camera lucida attachment 

 designed by Professor Watson (see Fig. 1) for use with his 



"Watson, J. B. Noddy and Sooty Terns. Carnegie Pub., no. 103, p. 249, 

 note 1. 



17 Hicks, V. C. The Relative Values of Different Curves in Learning. Journ. 

 Animal Behav., I, 138-156. 



