THE PERMANENCE OF INTERESTS 455 



for interest and for ability over the whole period from, say, the age of 

 eleven to the age of twenty-one. Thus, in the sample chosen, the com- 

 bined ranks give : 



Sum of Ranks for Sum of Ranks for 



Interest, All Three Ability, All Three 



Periods Periods 



Mathematics 10 7 



History 6 5 



Literature 6 6 



Science 8 12 



Music 17 17 



Drawing 17 18 



Other hand-work 20 19 



Turning these into positions from 1 to 7, we have : 



General Rank General Rank 



for Interest for Ability 



Mathematics 4 3 



History 1£ 1 



Literature U 2 



Science 3 4 



Music 5\ 5 



Drawing 5i 6 



Other hand-work 7 7 



The differences in the order are then 1, \, \, 1, \, \ and 0, their sum 

 being 4. 



I have made the calculation for each of the hundred individuals. 

 On the average this sum of differences is approximately 4^, and 

 corresponds to a coefficient of correlation of .91. The individual whose 

 interests follow his capacities least closely still shows a substantial 

 resemblance (nearly .5). The correlation between an individual's order 

 of subjects for interest and his order for ability is in fact one of the 

 closest of any that are known. A person's relative interests are an 

 extraordinarily accurate symptom of his relative capacities. 



The effect which the errors to which the original reports are subject 

 is on the whole probably to make this obtained degree of resemblance 

 between interest and capacity too low. Errors due to accident, careless- 

 ness, and inability to distinguish or to remember slight differences in 

 interest or in capacity, would make the sums of difference in the long 

 run greater — and the degree of resemblance obtained, less — than the true 

 facts, would have given. The only sort of error that could make the 

 obtained resemblance greater than the true fact would be an error 

 whereby either order was falsified to make it more like the other, 

 notably, the possible tendency to rate oneself higher than one should 

 for ability in a subject which one likes. On the whole, the resemblance 



