Page:Mind (Old Series) Volume 11.djvu/384

 THE TIME TAKEN UP BY CEBEBRAL OPERATIONS. TABLE XVII. 383 ] B < ~t R V R' V R V R' V 22. XII Orange 308 91 309 11 316 47 299 21 Violet. 258 23 262 15 289 16 297 8 6.1 Black.. Pink... 267 288 35 19 262 284 26 14 278 302 16 26 275 303 9 18 7 Brown. 308 9,0 294 15 340 31 323 16 9 Gray... 283 12 287 6 397 80 367 31 10 Red.... 278 99 272 11 322 40 324 96 Blue... 287 19 280 17 291 24 228 26 Green.. Yellow 268 276 26 27 265 273 18 16 313 297 32 31 312 300 21 20 A. .. 282 9? 279 15 314 4 303 90 False... 1 5 XVII., and subtract the reaction-time and supposed will-time, we find that it took B 100, C 110.7, to distinguish one colour from another. In the series of experiments next to be given, I determine the time 'it takes to distinguish a colour from nine others, that is the real perception-time for a colour. The results of ten series in which the motion was made with the hand, and of five in which it was made with the speech-organs, are given in Table XVIII. This gives as the time needed to distinguish a colour 105<r for B, 117 for C ; respectively 5 and la longer than it took to distin- guish one colour from another, and 26 and 41o- longer than it took to see that a colour was present when it was not necessary to distinguish it. The results given in Table XVIII. (where the reaction was made with the hand) were obtained at the beginning of the investiga- tion ; the determinations were repeated after four months of constant practice, and again after a pause of three months, the results being given in Table XIX. Practice therefore shortened the perception- and will-times about 30<r for B and 20 for C, and this decrease in the length of the times was not lost by an interruption in the practice. With the same methods I found the time it takes to see or distinguish a letter. I tried in my experiments to determine the time taken up by those operations which are constantly going on in the brain ; the letters chosen therefore were such as we usually have to read (of the size in which this is printed). The time for larger letters is somewhat shorter. In the first experiments it was not necessary to distinguish the letter, only to know that a letter was present ; the conditions were consequently the same as in the first experiments (Table XV.) on colours.