The ability of color defectives to judge signal lights at sea.

Measures were made of the ability of color-defective men to judge correctly the colors of navigation lights (red, green, or white) presented to them at night under realistic sea conditions. Eighty-one color-defective men were employed; they were categorized as to type and degree of defect using a battery of five color-vision tests. While the average performance of the color-defective men was considerably poorer than that of 24 color normals, there were large individual differences within each category of defect. Attempts to account for these differences in performance by variations in acuity, intelligence, and motivation failed. The extent to which the data can be accounted for by modern color-vision theory is discussed.