34 PSYCHOLOGICAL METHODS OF TESTING INTELLIGENCE 



in the selection and arrangement of these tests pre- 

 sents a difficulty of quite another sort than as if they 

 were mere collocations of tests: for, since each of 

 these tests is a factor in the determination of the 

 final score, it is possible that a change may destroy 

 the equilibrium of the whole system. This is easy 

 to be seen in the supplementary investigation of 

 Binet and Simon themselves, when they tried to cor- 

 rect their system by the omission, insertion and 

 transference of particular tests: for trials, e. g., 

 those of Terman and Childs and of Chotzen, have 

 shown that the second edition (1911) is in many re- 

 spects less useful than the earlier form (1908). 



What remedies can be devised for this situation 

 will be discussed below (Section 5a). 



The technique of the Binet-Simon method is by no 

 means so easy as the simplicity of the material used 

 would lead one at first to suppose. It is to be recom- 

 mended that, so far as is in any way feasible, the ex- 

 aminer should always do his work with the aid of an 

 assistant to keep the record, so as to avoid the un- 

 desirable division of attention between testing and 

 recording. Both of these experimenters must have 

 gained a high degree of practise and be well used to 

 one another before they proceed to actual testing. 

 The examiner must have an almost mechanical exact- 

 ness and uniformity in the formulation of the con- 

 tinually recurring questions, in the modulation of 

 his voice, etc., yet he must be prepared for the many 

 individual variations that appear in consequence of 

 different reactions of the subjects, and must have 

 definite measures in readiness for use in these junc- 

 tures. Never must he permit it to be seen that some 



