Studies of stylistic variation in prehistoric artifacts have played an important role in archaeological research since the beginning of the discipline. A variety of different types of studies have been done using a number of different methods and types of artifacts. The purpose of the majority of these studies, however, can be placed in one of two categories. First, the largest amount of research has concentrated on the discovery and description of stylistic change through time in order to date sites. Using sets of artifacts from stratigraphic sequences or from dated deposits for temporal control, it has been established in many areas that stylistic attributes changed through time. Early examples of such studies include the excavations of Kidder (1931, 1972) and Nelson (1916) in the American Southwest, Ford (1935) in the southeastern United States, Gamio (1913) and Vaillant (1930, 1931) in the Valley of Mexico, Bennett (1934) in Bolivia, and innumerable studies in Europe where stratigraphic excavations first were used as an important means of establishing temporal sequences. Such studies have continued to be important as a means of establishing new sequences, verifying old ones, or developing methods of making more precise estimates of occupation dates [e.g., the research of Drennan (1976) in the Valley of Oaxaca, Mexico, Snarkis (1976) in Costa Rica, and Thomas and others (1976) in Luxembourg].