from the data of experiments with bees in which threshold response is employed as a means of recognizing visual discrimination between stripes of equal width alternately illuminated by intensities i ( 1 ) and i ( 2 ) , it is shown that the detectable increment of intensity deltai , where deltai = i ( 2 ) - i ( 1 ) , is directly proportional to sigma ( i2 ) ( i ( 1 ) being fixed ) .
C1425233
i ( 1
C0963236
i ( 1