SINGLE TESTS AND SERIES OF TESTS 23 



f ormances of different degrees of value shall in some 

 way be compensated. 



3. Series of Tests 



The first of these positive requirements has al- 

 ready been met for a long time since; in especial, 

 since Eieger numerous test series have been used by 

 the psychiatrists for testing intelligence. These 

 series have been based as a rule upon a psycholog- 

 ical schema, though this schema has varied a good 

 deal from one investigator to another. For illus- 

 tration two such series may be mentioned, both of 

 them quite recent. 



Sommer (26), in an article just published on the methods of 

 intelligence testing, discusses in order the materials for testing 

 the following aspects of the problem: relation of memory, of 

 school information, of arithmetical ability and of association to 

 understanding, also attention, capacity to apprehend, completeness 

 of complexes, analysis of complexes, redintegration of complexes, 

 mechanical knowledge (cleverness), constructive knowledge, logi- 

 cal subordination and superordination, notion of cause and effect, 

 intellectual interests, understanding of the environment. 



Ziehen (30), in the last (3d) edition of his Prin?ii>i<>n nud MclJt- 

 oden der Intelligenzpriifunff, makes the following classification : 

 retention, development and differentiation of ideas (generalization, 

 isolation and complexion of ideas), reproduction and combination, 

 and describes the numerous forms of questions and tests used in 

 his clinic for each of these divisions. 



Although one cannot deny that these and other 

 series devised by psychiatrists are quite compre- 

 hensive, yet they are open to criticism in other re- 

 spects : the requirements that were laid down above, 

 under I and c, are met by them only partially or not 

 at all. For all these series give the impression that 

 the selection of tests may have been more a matter 

 of chance or arbitrary choice than something deter- 

 mined by actual guaging of their value. As a rule 



