EVIDENCE OF RAPIDLY DECREASING BIRTH RATE 405 



This drop, in course of a single generation, from 6 or 7 to less than 2 chil- 

 dren per family, is the sharpest decrease I have seen mentioned anywhere. 

 Neither decennial Census Reports nor the reports of the Division of Vital 

 Statistics gives comparable figures for the general population, though such 

 figures may be obtainable for single states. The best comparison I have 

 found is with Crum's figures for the period 1700-1870, at intervals of fifty 

 years (table 1). The only figures which would probably be directly com- 

 parable with ours would be those for the decrease over corresponding 

 periods. 



Table 2, taken from sources indicated in the bibliography, shows decreases 

 in family size among families sending children to college or producing emi- 

 nent scientists, two groups which are surely above the average in intelli- 

 gence, but probably still below our group of New York City School children. 



Very interesting would be records from a control group, similar in all re- 

 spects save intelligence to our gifted group. The children of such a group 

 were used in one or two of our studies, but no family data were collected. 



I do not wish to imply that high intelligence is the sole cause of the de- 

 crease noted, nor that this decrease indicates any biological decrease in fer- 

 tility associated with high intelligence. My own prediction would be that 

 when we do obtain evidence on this point we shall find in intelligent groups 

 a somewhat higher potential fertility, associated with the somewhat greater 

 physical development and the somewhat better health which have more 

 than once been demonstrated in highly intelligent children. Many condi- 

 tions may be related to the sharp decrease in family size; among them, first, 

 the recent shift from an European, on-the-whole lower-class, or at least 

 despised, social status, to an American environment in which a highly re- 

 garded professional status is far from impossible, with a resulting shift in 

 the attitude of their own social group towards large versus small families; 

 and second, the much more general dissemination of knowledge of fairly 

 dependable methods of birth control. As a matter of fact we know that 

 many of the families in our group were voluntarily limited. In at least two 

 cases, even further restriction than that attained had been intended. 



The remedy for this differentiation of family size in relation to intelligence 

 in what, from a social point of view, we must consider the wrong direction, 

 so far as intelligence and correlated favorable traits are concerned, lies I 

 believe almost entirely in the field of education (though not to the exclusion 

 of sterilization of the obviously unfit) ; education that shall include a spread 

 of knowledge of and skill in methods of birth control in the unfavored groups 

 (motive is already there), and a development of a different social attitude 

 toward size of family, probably aided by economic assistance, in the favored 

 groups. 



