Page:Mind (Old Series) Volume 11.djvu/404

 ON THE TIME-SENSE. 403 found that the reproduced interval was longer than the standard when this was small, shorter when it was great ; and that between the two extremes was an interval which could be repro- duced quite accurately. This indifference-point was not the same for different individuals, but varied between 1'5 and 3 '5 sees. For himself, when the impressions were conveyed through the sense of taste, this interval was from 2-2 to 2 % 5 sees. ; when through the sense of hearing, from 3 to 3'5 sees. These values were obtained when a short time elapsed between reception and reproduction ; with the increase or diminution of this, the indiffer- ence-point was found to grow longer or shorter. According to Mach (2), whose experiments were performed according to the method of just perceptible differences, the recog- nition of the inequality of two intervals of time, one interval following immediately upon the other, is the most delicate at about '37 sec. ; and the further from this point the standard interval recedes, the greater must be the difference between the standard and the interval for comparison, in order that they be recognised as unequal. There is, however, considerable discord in his results, which detracts from the value of his conclusions. Kollert (3) began the long series of experiments that have been performed in Wundt's laboratory. His experiments were per- formed according to the method of just perceptible differences. Two metronomes were used, the pendulum of each of which was placed in an electrical circuit along with an electro-magnet, so that by the momentary opening of the current a double vibration of the pendulum of the metronome could be effected, and thus an interval of time be marked out. One of the metronomes beat at a rate which was constant for a single series of observations ; the other gave out various intervals for comparison with the standard. An intermission occurred between the two intervals, which in length was equal always to the standard. The pendulum of the second metronome was shortened, until a just perceptible difference was observed between its time and that of the first ; after which it was elongated, until the subject detected a difference between the two. The mean of these two just perceptible differences gave the error made by the individual under experiment in his estimation of the constant interval. Experiments were made upon seven indi- viduals for intervals extending from -4 to 1*5 sec. The majority of these experiments confirm the general law laid down by Vierordt, but fix the indifference-point between ? and - 8 sec. The remain- ing, which constitute about one-fourth of the total number of experiments, are called anomalous. In three of the five series of anomalous experiments, the tendency seems to be to bring the value of the indifference-point up to 1 to 1-2 sees. ; in the other two, long intervals are prolonged and short ones still further shortened. Wrong decisions were chiefly made for -4 and - 5 sec. Estel (4) and Mehner (5) have extended these investigations, using, practically, the same method, and have incidentally fixed