DISTRIBUTION OF EFFORT IN LEARNING IN WHITE RAT 11 



points on the abscissa represent trials, and those on the ordinate 

 the average time of all rats in a given group at any given trial. 

 A length of | mm. on the abscissa represents one trial, and 

 ^ mm. on the ordinate represents for curve A and C .006 of a 

 minute, and for curve B 0.2 of a minute. The early trials are 

 plotted in curve A and the later trials in curve B. Curve C 

 is the one for retention tests. 



In general, these curves give the best available indication of 

 the entire progress of learning. When critically considered, 

 they show not only the changes in the physiological state of 

 the organism during learning, but they also show the physio- 

 logical changes resulting from extraneous disturbances. Of 

 course, the latter are antagonistic to right reactions and inte- 

 gration. How to distinguish one kind from the other will ever 

 be a difficult matter. In reading all curves of this kind, it is 

 always necessary to assume the presence of harmful disturbances. 



Having described the construction of the curves it will now 

 be convenient to mention the characteristics of the curves of 

 learning. Consider, for example, Curve I, above. The most 

 important features are the great length, and the irregularity 

 of curves representing the three and five trial groups as com- 

 pared with the one trial group. The individual curve of the 

 five trial group shows, because of the greater number of trials 

 necessary to learn the problem, the greatest length. The 

 shortest of the curves is that of the one trial group. More- 

 over an indication of the greater lengths of curves of the 

 groups given several trials daily is evident in that part of 

 the curves before the rapid drop or descent is made. More 

 trials are here required before the drop takes place than 

 when only one trial is given. With the three and five trial 

 groups this part of the curves drops in the twelfth trial, and 

 that of the one trial in the eighth trial. And, in a similar manner, 

 the remaining portions of the three curves show differences. 

 As compared with the other two groups, that of the one trial 

 is prolonged but a short distance beyond the drop. This part 

 of the curve of the five trial group is the longest of the three. 

 So, too, the irregularities in all parts of the curves, particularly 

 in the early trials, are more prominent when several trials are 

 presented than when one trial is given. In all probability this 

 irregularity combined with the length of the curve is indicative 



