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Citation |
Cobb PW. J. Exp. Psychol. 1916; 1(6): 540-566. |
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Copyright |
(Copyright © 1916, American Psychological Association) |
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DOI |
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PMID |
unavailable |
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Abstract |
Investigated the difference threshold under various conditions of brightness of field and surroundings. The observations were taken under 14 different conditions, in groups of 100 consisting of 25 different stimuli presented 4 times each. Three Ss were involved. The method of computation and the assumptions on which it was based are described. Results show that the mean threshold was one half the stimulus interval between the two points on the scale, one corresponding to the appearance of greater brightness on the left half of the field and one on the right. The diffusion of results show much greater consistency than the threshold. The left threshold was larger than the right. A minimum in the threshold existed at or near the point of equality of field and surroundings. The changes in the sensitivity of the eye due to various brightness conditions were dependent on the ratio between the field brightness and the surroundings. (PsycINFO Database Record (c) 2012 APA, all rights reserved) |