EDUCATIONAL PSYCHOLOGY 



Still an immense amount of work to be done in devising 

 new instruments for psychological measurements, improv- 

 ing old ones, and finding the relationships which obtain 

 among various combinations of traits. Nevertheless, the 

 psychology of personality, which only a few years ago 

 seemed too elusive to permit a scientific approach, is 

 rapidly yielding to quantitative treatment. Even tempera- 

 ment and the psychological correlates of physical types are 

 now investigated by scientific methods. 



In the use of psychometric techniques it is not necessary 

 to start with any assumption in regard to the cause of 

 the individual differences found. Their purpose is to meas- 

 ure the differences which exist, regardless of how they 

 may have originated. However, when once a satisfactory 

 technique for the measurement of a particular trait has 

 been perfected, it is then possible to investigate the relative 

 contributions of nature and nurture influences. This has 

 been done most extensively in the case of intelligence, 

 but to a less extent also in the case of certain special 

 abilities and personality traits. The existing data pertaining 

 to the relative influence of nature and nuture have been 

 judiciously summarized in Part I of the 1928 Yearbook of 

 The National Society for the Study of Education. The 

 issue is an extremely controversial one, and it is impossible 

 to review here the factual evidence in detail. My own 

 interpretation of the data will be stated in a few brief 

 paragraphs. 



In the case of intelligence, as measured by the best 

 intelligence tests, I consider the evidence overwhelming 

 that the larger differences found among children in an 

 unselected school population of a typical American com- 

 munity must be credited to nature rather than to nurture 

 factors. The mere fact that the correlations between 

 parents and offspring and those between siblings are almost 

 always between .40 and .50 in intelligence test scores, 



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