Brightness discrimination thresholds were determined at positive acceleration levels of 1, 2, 3, and 5<i>g</i> and transverse acceleration levels of 1, 2, 3, 5, and 7<i>g</i>. Four background luminance-levels, ranging from 0.03 to 31 ft-L, were studied. Contrast required to detect an increment in illumination increased with acceleration. This increase was present for both directions of acceleration and for all background levels, but was most marked for positive acceleration, and for the dimmest background. At 0.03 ft-L, 16% contrast was required to detect a target at 5<i>g</i> positive, as compared to 9% at 1g.
MYRON L. BRAUNSTEIN and WILLIAM J. WHITE, "Effects of Acceleration on Brightness Discrimination," J. Opt. Soc. Am. 52, 931-933 (1962)