The judgment of very weak sensory stimuli : with special reference to the absolute threshold of sensation for common salt / by Warner Brown.
- Warner Brown
- Date:
- 1914
Licence: In copyright
Credit: The judgment of very weak sensory stimuli : with special reference to the absolute threshold of sensation for common salt / by Warner Brown. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![series. In the strong series she gave, out of forty cases: for water 0.0% 3 positive “salt” answers for solution 0.1% 8 0.2% 1 0.3% 1 But in the weak series she gave, again out of forty eases: for water 0.0% 23 positive answers for solution 0.1% 17 0.2% 23 0.3% 23 In the strong series, which came first with her, the 50 per cent threshold stimulus is stronger than a solution of 0.6 per cent. This is considerably stronger than the strongest solution to be condensing his table we get the following: 1st day 2nd day 3d day % pos. % sail jdmt. 0.39 69 0.31 61 0.25 31 0.00 23 % pos % salt jdmt. 0.25 71 0.22 66 0.19 32 0.00 27 % pos. % salt jdmt. 0.14 64 0.12 49 0.11 28 0.00 15 4th day % pos, % salt jdmt. 0.11 32 0.10 25 0.09 8 0.00 11 From this it appears that the solution of 0.25 per cent, which was the strongest on the second day, gave as many positive judgments as were given by the solution of 0.39 per cent which was the strongest of the preceding day, and gave more than twice as many positive judgments as it had itself given on the preceding day when it was the weakest in the scries. The phenomenon continues very strong for three days, dis- appearing on the fourth; but on a later occasion a solution as weak as the w'eakest in the series of the fourth day gave 79 ])er cent of right answers for the same two observers, or more than even the strongest solu- tion of the previous days. It should be noted that the ability to detect water remains about the same from day to day, so that the increasing number of positive judgments on the weaker solutions really means a keener power of discrimination between water and salt. Camerer him- self attributes this phenomenon in part to practice, but in part to “un- conscious comparison’’ between the various solutions tasted on any one day. For these two observers the “absolute threshold” depends very largely upon the strength of the solutions entering into the series upon which the teats are made. The threshold is lower in a group of weak solutions than it is in a group of stronger solutions.](https://iiif.wellcomecollection.org/image/b22471558_0037.jp2/full/800%2C/0/default.jpg)
