THE INHERITANCE OF MENTAL ABILITY 107 



ability. It is quite well established that high standing in college 

 is correlated with success in later Kfe. Should it be found, there- 

 fore, that sons in the honor class have a relatively large proportion 

 of fathers in the high honor class, while sons of the ''pass" or 

 ungraduated classes have a relatively large proportion of fathers 

 in these classes also, it would offer strong evidence of hereditary 

 differences in ability. The results of the study may be summar- 

 ized in the following table : 



Scholarship of Fathers and Sons at Oxford 



Percentage of Fathers 

 Sons Obtaining Obtaining First or Second 



Class Honors 



First class honors 41.9 



Second class honors 40 . 7 



Third class honors 33 . 3 



Fourth class honors 28.1 



Pass degree 20 . i 



No degree 12.9 



The striking feature of this table is the regularity with which 

 the percentage of high scholarship among the fathers decreases 

 as the scholarship becomes lower in the sons. The correlation 

 coefficients between father and son were .29 or .31 according to 

 which of two methods of calculating the coefficients was em- 

 ployed. The correlation coefficient of brother and brother was 

 somewhat higher, viz., .405, due possibly to the fact that methods 

 of instruction, standards of grading and other circumstances 

 were more nearly alike for brothers than for fathers. 



The scholastic records of two secondary schools, Harrow and 

 Charterhouse, were investigated by much the same methods, but 

 owing to the absence of data concerning the parents the study 

 was limited to comparisons between brothers. The data which 

 were drawn from several thousand students gave a fraternal 

 correlation of .398 which is very close to what was found for the 

 students at Oxford. This correlation did not increase sensibly 

 with increasing age of the students. 



