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SCIENCE 



[N. S. Vol. XXXI. No. 788 



lectual processes are hard to devise, since 

 much depends on the familiarity of the 

 material used. Few tests of this nature 

 have as yet been attempted on different 

 races. 



There are a number of illusions and con- 

 stant errors of judgment which are well- 

 known in the psychological laboratory, and 

 which seem to depend, not on peculiarities 

 of the sense organs, but on quirks and 

 twists in the process of judgment. A few 

 of these have been made the matter of com- 

 parative tests, with the result that peoples 

 of widely different cultures are subject to 

 the same errors, and in about the same de- 

 gree. There is an illusion which occurs 

 when an object, which looks heavier than 

 it is, is lifted by the hand ; it then feels, not 

 only lighter than it looks, but even lighter 

 than it really is. The contrast between the 

 look and the feel of the thing plays havoc 

 with the judgment. Women are, on the 

 average, more subject to this illusion than 

 men. The amount of this illusion has been 

 measured in several peoples, and found to 

 be, with one or two exceptions, about the 

 same in all. Certain visual illusions, in 

 which the apparent length or direction of 

 a line is greatly altered by the neighbor- 

 hood of other lines, have similarly been 

 found present in all races tested, and to 

 about the same degree. As far as they go, 

 these results tend to show that simple sorts 

 of judgment, being subject to the same 

 disturbances, proceed in the same manner 

 among various peoples ; so that the similar- 

 ity of the races in mental processes extends 

 at least one step beyond sensation. 



The mere fact that members of the in- 

 ferior races are suitable subjects for psy- 

 chological tests and experiments is of some 

 value in appraising their mentality. Rivers 

 and his collaborators approached the na- 

 tives of Torres Straits with some misgiv- 

 ings, fearing that they would not possess 



the necessary powers of sustained concen- 

 tration. Elaborate introspections, indeed, 

 they did not secure from these people, but, 

 in any experiment that called for straight- 

 forward observation, they found them ad- 

 mirable subjects for the psychologist. 

 Locating the blind spot, and other observa- 

 tions with indirect vision, which are usu- 

 ally accounted a strain on the attention, 

 were successfully performed. If tests are 

 put in such form as to appeal to the in- 

 terests of the primitive man, he can be 

 relied on for sustained attention. State- 

 ments sometimes met with to the effect that 

 such and such a tribe is deficient in powers 

 of attention, because, when the visitor be- 

 gan to quiz them on matters of linguistics, 

 etc., they complained of headache and ran 

 away, sound a bit naive. Much the same 

 observations could be reported by college 

 professors, regarding the natives gathered 

 in their class rooms. 



A good test for intelligence would be 

 much appreciated by the comparative psy- 

 chologist, since, in spite of equal standing 

 in such rudimentary matters as the senses 

 and bodily movement, attention and the 

 simpler sorts of judgment, it might still be 

 that great differences in mental efficiency 

 existed between different groups of men. 

 Probably no single test could do justice to 

 so complex a trait as intelligence. Two 

 important features of intelligent action are 

 quickness in seizing the key to a novel situ- 

 ation, and firmness in limiting activity to 

 the right direction, and suppressing acts 

 which are obviously useless for the purpose 

 in hand. A simple test which calls for 

 these qualities is the so-called ' ' form test. ' ' 

 There are a number of blocks of different 

 shapes, and a board with holes to match the 

 blocks. The blocks and board are placed 

 before a person, and he is told to put the 

 blocks in the holes in the shortest possible 

 time. The key to the situation is here the 



