

30 PSYCHOLOGICAL METHODS OF TESTING INTELLIGENCE 



time of the child, should not impose hardship on 

 him or tire him, and yet must possess sufficient ac- 

 curacy to make possible comparison and checking of 

 the investigations undertaken by different persons ; 

 and, finally, they should make it possible to work out 

 a final value for each subject tested that could be 

 deemed a measure of his general intelligence. 



It seems, at first blush, as if the fulfilling of so 

 many different demands would raise insurmountable 

 difficulties. Above all, there was no preliminary in- 

 formation available as to what intellectual perform- 

 ance might be expected, even approximately, from a 

 child of a given age. If some time you ask a teacher 

 or some one who has been dealing with children of 

 different ages for a long time at what age a child 

 could be expected to give correctly the difference be- 

 tween two designated objects, e. g., wood and glass, 

 and at what age he would be able to explain the dif- 

 ference between two abstract concepts, e. g., lies and 

 mistakes, he would either be silent or make a blind 

 guess at it. Here, then, was virgin land to explore. 

 When to that is added the conditions that have just 

 been stated, many of which are hard to reconcile 

 with one another freedom from school training, 

 general ease of application, brevity, precision, possi- 

 bility of quantitative evaluation, there can be no 

 doubt that there was laid down here one of the hard- 

 est problems that applied psychology had set for 

 itself up to this time. 



Nevertheless, the difficulty has, in principle, been 

 overcome. Of course this does not mean that the 

 present form of the method can be regarded as a 

 final form : it will doubtless suffer so many modifica- 



