Page:Mind (Old Series) Volume 11.djvu/242

THE TIME TAKEN UP BY CEREBBAL OPEBATIONS. 241 TABLE IX. I 5 C i R V R' V R V R' V 27.11 148 10 149 7 155 9 155 5 28 136 139 9 9 139 139 6 6 147 143 11 12 148 142 6 6 4. IV. . 156 146 10 16 154 145 6 10 157 162 11 12 158 159 7 8 A 145 11 145 7 153 11 152 6 because he strained his attention more, and thus held the centres in more unstable equilibrium than usual in spite of the longer interval. C's time, on the other hand, is slightly lengthened, concentrated attention not shortening his times, and the delay interfering with the maximum of readiness. In like manner the interval between signal and stimulus was varied at the pleasure of the experimenter between normal and fifteen seconds. The experiments recorded in Table X. were made with both light and sound. TABLE X. LIGHT. SOUND. B C B C R R' R R' R R' R R' 27.11... 200 204 168 159 178 198 196 161 158 174 170 164 wan 184 174 168 164 ting. 181 176 184 176 168 171 158 173 173 164 171 159 174 167 154 173 170 169 166 147 166 166 28 4. IV 5 A 182 177 173 172 171 168 168 163 AV 22 14 16 11 23 13 22 13 It will be seen that the times are considerably longer than normal ; the mean variation is also large. 1 The first series made 1 On two occasions with B, I varied the series on sound with results worth noting. I let towards the end of the series the interval between signal and stimulus become regular and normal. B did not notice that any change in method had taken place, but his reaction-time after the first two trials became 40o- shorter. That is, without any conscious effort, the brain-parts concerned were put in the usual maximum state of unstable equilibrium.