PROBLEM 6. Hoiv Mankind Can Be hnprovcd 



5^1 



Fig. 459 A graph showing the liitcUigence Quo- 

 tient (I.Q.) of poj children. ULmt I.Q. is char- 

 acteristic of the greater nimiber of children? 

 (adapted from l. m. term an) 



56-65 



.33% 



66-75 



2.3% 



76-85 86-95 96-105 106-115 116-125 126-135 136-145 

 8.6% 20.1% 33.9% 23.1% 9.0%, 2.3% .55% 



Feeble-mindedness is vaguely defined 

 as intelligence so lo\\^ that the person is 

 unable to meet the conditions of life 

 satisfactorily. But there are all degrees of 

 feeble-mindedness. The scores of the 

 lower grades of feeble-minded are not 

 even shown in Figure 459. Such individ- 

 uals never go to school. They need super- 

 vision and care throughout their lives 

 since they never advance, mentally, be- 

 yond the age of a very young child. 

 There are many institutions where the 

 feeble-minded are cared for and taught 

 by specially trained teachers so that in 

 their own institution they may be use- 

 ful citizens. There are not only all de- 

 grees of feeble-mindedness but there are 

 apparently several causes, about which 

 \\& know little. 



Inheritance of mental traits. Since 

 mental traits depend on physical struc- 

 ture, it seems reasonable to believe that 

 they should be inherited. But so far we 

 know very little about their inheritance. 

 Pedigrees often show the reappearance in 

 each generation of special abilities or 

 skills. There are families in which great 

 skill in boat designing appears in many 



Fig. 460 This boy spends many days in a juine. 

 Would his I.Q. score be a correct estiviate of 

 his intelligence? Explain, (national child 

 labor committee) 



members for several generations. The 

 family of Johann Sebastian Bach shows 

 musical talent and even genius in several 

 generations. Such facts are often used 

 as evidence that mental traits are inher- 

 ited. Do you think it is good evidence.- 

 A famous pedigree you may read about 

 is that of Deborah Kallikak, a feeble- 

 minded girl whose real name is withheld. 

 Her ancestry was traced back to Revo- 

 lutionary times when Martin Kallikak, a 



