Cover legend: Even though hue can vary continuously, human observers are quick to classify stimuli into a handful of color categories, visualized in the cover illustration as attractive wells. The neural representation of color can mimic this perceptual effect. Specifically, in human visual areas V4v and VO1, performing a color naming task adaptively alters the neural representation: patterns of activity evoked by colors belonging to the same category became more similar, while the patterns of activity evoked by color of different categories became more dissimilar. This suggests that these areas switched to a categorical representation of color to perform the task. For more information, see Brouwer and Heeger (15454–15465).