Individual differences and their implications for color perception

•Individual differences in color sensitivity and color appearance are large and reliable.•Differences in sensitivity often fail to predict differences in appearance.•Color perception remains remarkably stable despite sensitivity variations within the observer.•Variations across different hues are uncorrelated, suggesting hue categories are learned or encoded independently. Individual differences are a conspicuous feature of color vision and arise from many sources, in both the observer and the world. These differences have important practical implications for comparing and correcting perception and performance, and important theoretical implications for understanding the design principles underlying color coding. Color percepts within and between individuals often vary less than the variations in spectral sensitivity might predict. This stability is achieved by a variety of processes that compensate perception for the sensitivity limits of the eye and brain. Yet judgments of color between individuals can also vary widely, and in ways that are not readily explained by differences in sensitivity or the environment. These differences are uncorrelated across different color categories, and could reflect how these categories are learned or represented.