BIOLOGY IN HUMAN AFFAIRS 



beings; modern psychology is no less interested in the ways 

 in which human beings differ. As soon as attention was 

 focused upon individual differences, it was found that 

 these were omnipresent and very large. It was found, for 

 example, that people differ far more in intellectual ability 

 than they do in height or weight or other physical traits, 

 and that the intellectual differences among school children 

 are a more important factor than pedagogical methods in 

 determining how much a given child will learn. Later, 

 experimentation was begun in the measurement of special 

 abilities and of personality traits, with the result that 

 large individual differences were found wherever a search 

 was made. 



One of the leading characteristics of present-day educa- 

 tion is the almost universal effort that is being made to 

 shape the work of the school to meet the individual needs 

 of its pupils. Such attempts are affecting not only the peda- 

 gogical methods employed, but also goals of instruction, 

 the control of curriculum, and the educational and voca- 

 tional guidance of children. Special classes are being 

 established for the gifted, the backward, and the pre- 

 delinquent. Problem children of all types are psychologi- 

 cally studied, and differential treatment is provided not 

 only in the schools but also in the courts and the reforma- 

 tories. Earlier types of impressionistic case studies are 

 being largely replaced by psychometric techniques which 

 yield quantitative measurements of general intelligence, 

 of special ability in art, music, science, and mathematics, 

 and of such personality traits as ascendency-submission 

 tendencies, inferiority feelings, introversion-extraversion 

 attitudes, mental masculinity and femininity, fairminded- 

 ness, social intelligence, emotional stability, trustworthi- 

 ness, and occupational and other interests. In all such 

 traits it is found that the range of scores made by unselected 

 children is about as great as it is for intelligence. There is 



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