36 PSYCHOLOGICAL METHODS OF TESTING INTELLIGENCE 



in the same way, carried on tests the same afternoon in different 

 rooms. Each experimenter could deal with four or five subjects 

 in this time, and each subject was obliged to go home directly 

 after his examination ; in this way, 16 to 20 members of the class 

 were tested without there being possible any exchange of ideas 

 between them. 



For all further details of the technique of these 

 tests the directions for using them that are already 

 available for different nations must be consulted. 



Such directions have been given for the examina- 

 tions of French children by Binet and Simon in 1911 

 (35, 36), for English and American children by 

 Whipple in his Manual (28), by Wallin (67) and more 

 briefly by Huey (9), and for Italians by Treves-Saf- 

 fiotti (66). For use in Germany Lipmann first fol- 

 lowed the original instructions as precisely as possi- 

 ble, and then Bobertag (40) described very fully his 

 elaboration of them as based on practical tests 

 an elaboration that differs from Binet and Simon to 

 advantage in some particulars, e. g., in the choice of 

 pictures. The extended directions for testing and 

 questioning that Bobertag has prepared should form 

 the basis of all future investigations in Germany. 2 



2. The Resultant Values: Mental Aye, Mental Re- 

 tardation, Advance, and Arrest; Mental Quotient 



We must now pass on to note how the grade of in- 

 telligence of a subject can be derived from his per- 

 formances in the tests. 



Considering the problem schematically, we might 

 think that the grade of intelligence could be ex- 



2 The simple set of materials needed for carrying on the German 

 tests, after Bobertag (lists of questions, tests of memory span, 

 pictures, set of small boxes for weights, etc.), may be had of the 

 Institute for Applied Psychology at Klein-Glienicke. 



