THE PSYCHOLOGICAL METHODS OF TESTING 

 INTELLIGENCE 



INTRODUCTION 

 Nature and Problem of Intelligence Testing 



1. Intelligence and Intelligence Testing 



Modern experimental psychology, which started 

 with the study of sense-perception and then under- 

 took that of ideas and feelings, has in the last decade 

 begun to deal with intellectual functions themselves. 

 And it is worthy of note that general theoretical psy- 

 chology and differential applied psychology took this 

 step forward at the same time, though for the most 

 part independently. In the former there was devel- 

 oped a psychology of thinking, in the latter there 

 appeared the investigation of differences in intelli- 

 gence. 



Our discussion must be restricted to the second 

 problem with which alone we are concerned. To the 

 other branch of psychology we may confidently leave 

 the question of the general nature of intellectual ac- 

 tivity and the investigation of the phenomena that 

 constitute thinking as such. What we are interested 

 in is not intelligence as a phenomenon, but intelli- 

 gence as a capacity and particularly a capacity with 

 respect to which men differ one from another. And 

 intelligence testing is the determination of the de- 

 gree of this capacity in a given individual. 



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