62 



WALTER S. HUNTER AND JOS. U. YARBROUGH 



Table 7 gives data for rats 25, 26, 27 and 29. The numbers 

 represent the percentages correct in each succeeding one-tenth 

 of the learning process. 3 The first columns for each rat are 



TABLE 7 



the records for learning the original h. c. habit. The second 



columns are the records for learning B. These figures are 



secured as follows: No. 25, e.g., learned h. c. in 420 trials. 



This is divided into 10 parts of 42 each. Of the first 42, 21 or 



50% were correct. This method when applied to all members 



of the group enables us to construct a curve which throughout 



its length is representative of the group. The bottom numbers 



in each column of table 7 represent the percentages of correct 



reactions made in the last 40 trials. Sometimes this runs over 



the standard 87.5%. The values above S are from the forties 



made at or above the standard per cent. 



If the curves of figure 3 are examined, the curve for B is seen 



to start much lower than the curve for h. c. and to lag markedly 



behind throughout eight-tenths of the learning. (These curves 



are plotted from the average values in table 7.) This lag would 



be even greater, but for the accidental fact that learning h. c. 



was retarded toward the last by the fear that arose in the rats 



from punishment. The marked interference of the two habits 



is seen when the last of h. c. is compared with the first of B, 



and also when the first parts of the curves are compared. B is 



more than a new habit. It is interfered with from the start 



by h. c. 



3 This method of treating the learning process is taken from Dr. S. B. Vincent's 

 Function of the vibrissae in the behavior of the white rat. Behavior Monographs, 

 1, no. 5, p. 17, 1912. 



