210 EVOLUTION: THE AGES AND TOMORROW 



Lorimer and Osborn had used data from the 1930 census 

 on population distribution and fertility, and had correlated 

 them with various samplings of intelligence and economic 

 status as compiled by other psychologists. They were able 

 to show that there was a differential birth rate in six cate- 

 gories of parents: unskilled laborers, agricultural laborers, 

 semiskilled workers, skilled workers, business and clerical 

 workers, and members of the learned professions. The dif- 

 ferential, they concluded, was such as to lower the over-all 

 I.Q. average about 1 point per generation. This was the 

 minimum rate of decline shown by the over-all analysis. An 

 examination of the differential within each class where, for 

 instance, the more intelligent unskilled laborer had fewer 

 children than the less inteUigent unskilled laborer indicated 

 a larger decline than 1 point— a decline Lorimer and Osborn 

 thought might be as large as 4 points per generation. 



The United States government was given official warning 

 of the situation when a few years later the Population Com- 

 mittee of the National Resources Committee in a report to 

 the President called attention, partly on the basis of the 

 Lorimer and Osborn study, to the dangerous inverse rela- 

 tionship between intelligence and fertility— a tendency 

 carrying "social implications of such importance that they 

 cannot safely be ignored." Other warnings have reached 

 Washington in the intervening years, but so far there is no 

 sign that anyone in the government has heard them— and 

 that, in spite of very disturbing data taken from the govern- 

 ment's own census of 1940. 



Students of population have for many years been aware 

 of the trend toward the production of fewer and fewer 

 offspring by the more educated individuals of our society, 

 and this was very strikingly brought out in a United States 

 census document entitled Fopiilation: Differential Fertility y 

 1940. In this first nationwide survey of population replace- 

 ment indexes it is clearly shown that there is a reverse rela- 

 tionship between reproductive activity and educational 



