JSTOVEMBER 19, 1886.] 



SCIEJ^CE. 



461 



tained for only about one second. The two ob- 

 servers show some individual variations, all of 

 which indicate that the processes were more 

 thoroughly reflex in Dr. Cattell's case than in that 

 of his associate. It is argued that the cortex is 

 not concerned in tlie reaction, and that perception 

 and willing also have no part in it. 



Passing to perception times, the observer is 

 asked to react only if the card which the falling 

 of the screen reveals has a white surface, and 

 simply do nothing at all if it has a black surface. 

 The additional time necessary to recognize the white- 

 ness of the surface, and to send out the volun- 

 tary impulse, was for the one observer .061 of a sec- 

 ond ; for the other, .095 of a second. This time Dr. 

 Cattell thinks should be divided equally between 

 the two operations, because in the simple reaction 

 the closing of the key was entirely automatic. 

 Of course, it no longer makes any difference how 

 the reaction is made. It, however, takes a little 

 longer, if, instead of a white surface, a colored 

 surface is used, though the observer has simply to 

 •distinguish that it is not black. If the color is to 

 be distinguishe 1, and in each case can be one of 

 two colors, then the perception-and-will time 

 was .100 and .110 of a second respectively for the 

 two observers ; if the color can be one of ten 

 colors, .105 and .117 of a second. In other words, 

 it takes about .0058 of a second longer to distin- 

 guish one of ten colors than one of two, but .033 

 of a second longer to say what the color is than 

 to say it was not black. In a similar way, if two 

 letters are to be distinguished from one another, 

 instead of two colors, the time is lengthened by 

 about .038 of a second. If a letter is to be dis- 

 tinguished out of ten letters, it matters greatly 

 what the letter is. E is the most difficult to read. 

 Tlie order of difficulty of five letters experimented 

 upon was M, A, Z, B, E. The perception time for 

 short English words is somewhere about .142 of a 

 second ; it is slightly longer for long words and 

 for words in a foreign language. A very impor- 

 tant point is, that the perception time for words is 

 only slightly longer than for letters ; thus show- 

 ing that the former, not the latter, is the reading 

 unit. Finally, if small pictures of such familiar 

 objects as a tree, hand, etc., be used instead of 

 words, the time is found to be shorter, and is 

 about equal to that for seeing a color. A picture 

 is thus a simpler, less abstract sign than a series 

 of letters. 



There remains the wiU or choice time. We 

 have seen in the series of experiments just de- 

 scribed that a will time has already entered. If we 

 change the form of experiment so that if a red 

 light appears the right hand is to react, and if a 

 blue the left hand, the time is lengthened by .026 



of a second. In the former case the same hand 

 always reacted; now the motor impulse is to be 

 sent in a certain direction.' 



A very interesting form of the experiment con- 

 sists in letting the different kinds of reaction be 

 the names of the colors, letters, pictures, or words ; 

 in other words, to measure the time necessary to 

 read, i.e., to see and name them. Four-tenths of 

 a second was thus found as the time necessary for 

 reading a letter. Similarly the time necessary for 

 reading a one-place number was found to be about 

 .360 of a second, it taking only .033 of a second 

 longer to read two-place numbers, and only .025 

 of a second longer for a three-place than a two- 

 place number. As regards words, it was found 

 that it took longer to read (not including pronun- 

 ciation) long than short, and foreign than vernac- 

 ular words. To name a short word in one's native 

 language requires .111 of a second, which is .050 

 of a second less time than it takes to name a let- 

 ter ; thus showing, that, as we constantly read 

 words and seldom letters, the association between 

 the concept and the name is much closer. An 

 interesting result as regards color is this : that, 

 while it takes less time to perceive a color than a 

 le'ter or word, it takes quite a long time (.343 of a 

 second) to find the name of the color. The associa- 

 tion between a color and its name is a loose one. 

 The names of the more familiar colors were found 

 in considerably less time. The average time for 

 naming a picture is about equal to that for nam- 

 ing a familiar color. Familiarity is again an im- 

 portant factor : it took least time to name a ' hat,' 

 longest to name a ' teapot.' By way of summary, 

 the following table will be found convenient.^ 



There have thus been recorded the times of some 

 of the simpler mental activities, and the undei*- 

 standing of the higher psychic processes has thus 

 been made more easy. The times of these pro- 

 cesses Dr. Cattell supposes will become shorter in 

 the course of evolution " and we will live so much 

 the longer in the same number of years." 



Finally, a very painstaking research by Dr. 

 Alfred Lehmann deserves mention. His object 



1 The perception pi'ocess is also slightly but not ma- 

 terially different. 



2 The final section of the paper is devoted to showing 

 that extreme attention can shorten central operations ; that 

 the effect of practice is first marked, but soon reaches its 

 limit (as automatism sets in) ; that fatigue is not as readily 

 brought on, and is not as disturbing a cause as is usually 

 supposed. 



