Notes that within (and between) cultures, people tend to agree on which parts of color space are easiest to name and what the names for these regions are. Therefore, it was hypothesized that the manipulation of ease of naming (nameability) of colors should change performance in tasks where categorization by color name is important. More specifically, highly "nameable" color sets should lead to better performance than metrically equivalent but less categorically distinct sets, when the task requires categorization. In 2 experiments, a total of 22 observers were tested on a name-based task, the naming and subsequent identification by name of color sets with up to 16 members. These sets were designed to be easy to name (nameable), maximally discriminable, or matched discriminable. It was found that sets designed to be nameable did indeed lead to superior performance as measured by response times, confidence ratings, and response accuracy. Perceptual color similarity, measured by a ΔE metric, did not predict errors. It is concluded that nameability may thus be a valid, manipulable, aspect of sets of colors, and one which is not otherwise duplicated in the metric characteristics of such sets.