14 PSYCHOLOGICAL METHODS OF TESTING INTELLIGENCE 



the single tests, but in the construction of well-con- 

 sidered systems of tests, for which single tests 

 merely supply the raw material. So we shall con- 

 tent ourselves in this part of our essay with a cur- 

 sory survey without any pretense at all to complete- 

 ness. 2 



The varied nature of the proposals and test inves- 

 tigations thus far made is due to the fact that the 

 same problem has been approached in very different 

 ways. 



(a) For a long time we started from the errone- 

 ous presupposition that any psychological method of 

 experimentation would be really usable as a test. 

 It was thought that all that was necessary was to 

 alter the direction, so to speak, of the plan x>f in- 

 vestigation. When a large number of measurements 

 had been secured by a single method on a few per- 

 sons in the laboratory, the same method was ap- 

 plied to many persons, but only once or a few times 

 to each of them. If it turned out from such a mass 

 experiment that the more intelligent persons ob- 

 tained, all things considered, better average scores 



2 For all the literature on single tests, see my text on differential 

 psychology (1, 426 ff.) ; also in Appendix II of that book there is a 

 survey of the relation of the single tests to school performance. 

 Fifty-four different tests, with numerous sub-types are described, 

 together with their methods and chief results, in Whipple's 

 Manual (28). A very large collection of materials for testing was 

 exhibited by the Institute for Applied Psychology at the Berlin 

 Congress, Easter, 1912, for information about which Lipmann's 

 catalog in the report of the Congress may be consulted. Since 

 the meeting, this exhibit has been made a permanent one and has 

 been assigned a room in the exhibition by the Prussian Ministry of 

 Education of German material for instruction, at Berlin, 126 

 Friedrichstrasse. The exhibit can be seen at that place by pre- 

 vious appointment with the Secretary of the Institute (Dr. Lip- 

 mann, Telephone Potsdam, No. 8). 



