In our main experiment, we trained participants to categorize colors across a new category boundary, separating two kinds of hue that are referred to by the same basic term in English. After participants learned this new hue categorization correctly, we tested their discrimination skills and found that their ability to discriminate between colors improved only for colors that were on different sides of the learned category boundary. In other words CP effects were induced through training, simulating the effects of color categories in natural language.