keorkssion. 



37 



REGRESSION OF PROGENY TOWARD MEDIOCRITY. 



Galton pointed out, in the case of stature, that, since correlation 

 between parents and progeny is not perfect, the progeny of selected 



parents will tend to be less extremely selected and hence more nearly 

 mediocre than their parents. It has, indeed, been shown in my Btudiee 

 on stature (1917, p. 341 ) that the progeny of tall parents do do! shew 

 this regression to mediocrity as much as the progeny of short parents. 

 This was regarded as evidence that the gametes of tall parents carried 

 fewer recessive allelomorphs than those of short parents; hence were 

 genetically ''purer" and comprise more recessive factors. What is the 

 condition in respect to the varying indices of build? 



Table 13. — Distribution of progeny of the various matings, according t<> classes of build, 

 absolute numbers, and proportions, based on Appendix table, including starred f am 



Table 14. — Average number of progi ny yielded '>.'/ melt 

 type of muting (basal on table IS). 



The answer to this question is given in table 15, which in turn is 

 based on table 12. This table shows for each of the IS matings t In- 

 average departure of the parents from mediocre build (which for the 



