EFFECT OF BACKGROUND LUMINANCE ON BRIGHTNESS OF FLASHES

Interocular brightness matches were made between flashes of light, one to each eye. added to large steady uniform backgrounds of different luminances. The backgrounds were binocularly superimposed. Under these conditions, constant-brightness curves (Log ΔI vs. Log I) were of approximately the same shape as the increment threshold curve. The brightness of a flash in one eye was unaffected by a background in the other. It is argued that these experiments measure only the contribution of retinal mechanisms. Further experiments provide some evidence of central influences. The relation between retinal and central mechanisms in the perception of brightness is discussed. © 1969.