Citation

Cobb PW. J. Exp. Psychol. 1923; 6(2): 138-160.

Copyright

(Copyright © 1923, American Psychological Association)

DOI

10.1037/h0073883

PMID

unavailable

Abstract

The present paper continues the report of an investigation into the problems of retinal sensitivity in which measurement of the shortest time of exposure of a stimulus necessary in order that there may be discrimination between stimulus and no stimulus is adopted as a criterion of sensitivity. The method and apparatus employed were similar to those previously described. There were nine different degrees of illumination of the stimulus-aperture, and five stages in the corresponding brightnesses of the field at the upper range of illumination, and four stages at the lower range. In general, if t represent the threshold time of stimulation, and B the brightness of the experimental field, the relation followed an equation of the form: 1/ t = k log B/ B0, where k and B are constants depending upon experimental conditions. This formula agrees with the laws governing critical flicker-frequency for intermittent stimulation. From Psych Bulletin 20:09:00890. (PsycINFO Database Record (c) 2012 APA, all rights reserved)