24 PSYCHOLOGICAL METHODS OF TESTING INTELLIGENCE 



the selection was based upon a priori reasoning that 

 a certain capacity, e. g., retention or combination, 

 which had been assumed to belong to intelligence 

 was 'hit' by a certain kind of test. Very seldom was 

 any actual preliminary investigation made to see 

 whether this particular test was really superior to 

 so and so many others by virtue of the precision, 

 constancy and significance of the particular values 

 that it afforded. Moreover, this chance selection evi- 

 dently explains why there is so little agreement be- 

 tween the test series of different investigators: 

 every psychiatrical clinic has its own special method 

 of testing intelligence; every specialist in nervous 

 diseases, every physician in charge of classes for 

 subnormals chooses his tests to suit his fancy, and 

 thus it has been impossible, so far, to effect any real 

 comparison, corroboration and standardization of 

 the results of different investigators. 



Finally, the usual psychiatrical test-series suffer 

 from the lack of any principle by which to summar- 

 ize the results in a single value. The psychiatrists 

 recognize that it is impossible to set a value on the 

 intelligence of a person as a whole, for they apply 

 such predicates as "poor in judgment/' "mentally 

 feeble, " "imbecile/' "idiotic;" but if we watch the 

 way in which, in the individual case, they arrive at 

 the general conclusion that they draw from the data 

 of their test-series, we note a yawning gap. The 

 mosaic of test results is, and remains, only raw ma- 

 terial ; no fundamental methodological principle, but 

 only intuition, routine and subjective estimation of 

 their results, dictates the final decision concerning 

 the intelligence of the subject. In a certain sense, 



