The analysis of stylistic variation has always been a preoccupation of archaeologists. However, the term style has assumed numerous meanings which have not been distinguished from each other, resulting in a great deal of confusion. This paper enumerates some of these coexistent definitions and models of style and endorses the view that style is a measure of social interaction and the boundaries between social groups. Within the latter model two concepts of style are expounded: EMBLEMIC styles, which deliberately mark and maintain the boundaries between social groups, and STOCHASTIC styles, which reveal their own patterns of distribution and variation, and do not necessarily coincide with socially defined boundaries. The archaeological usefulness of these two concepts of style is evaluated through an examination of Australian rock art styles. It is concluded that an approach using the concept of stochastic styles, which does not predetermine the kinds of explanation one can propose for stylistic variation, allows a greater insight into and understanding of the data. -- AATA