The third of five general cultural stages proposed by G. Willey and P. Phillips in 1958 as a framework for the study of ancient communities in the Americas, broadly covering the period c.2500 bc through to ad 300. The Formative embraced communities with village agriculture and sedentary lifestyles and is therefore mainly confined in its application to southwestern parts of North America, Mesoamerica, and the central and northern west coast of South America. The term is now largely obsolete because regionally specific traditions with better chronological and cultural resolution have been defined in most areas. During the Formative Stage, the foundations are laid for the emergence of a range of complicated social traditions or civilizations and nearly all the main traits that characterize these later civilizations were established: astronomical observations, calendrical systems, monumental architecture, hieroglyphic writing, craft specialization, planned settlements, and elaborate defined ceremonial and religious centres.
The main value of the concept of the Formative Stage is the recognition that, no matter when it happened, the same basic pattern of development can be seen: sparsely scattered hamlet‐type agricultural settlements increasing in their density in the landscape, coupled with the emergence of larger more important centres. Traditionally, the Formative is followed by the Classic Stage.