Under the direction of Dr. Keith Kintigh, MS Nancy Mahoney will collect data for her doctoral dissertation. The goal of her research is to understand how prehistoric Native Americans in the Chaco region of the US achieved the high degree of social complexity which is manifest in the archaeological record. At its height in the early second millennium AD, the Chaco culture covered an area of over 120,000 square kilometers of the Colorado Plateau. Archaeologically the system is defined by a distinctive architectural style which ostensibly forms a three-tier settlement hierarchy. At its core in Chaco Canyon, several monumental `great houses` were four stories tall and contained over 600 rooms. The geometric ground plans and distinct masonry techniques suggest they required considerable planning, labor and skill to construct. Surprisingly, despite decades of study it is still not possible to determine the functions they served. At a second level smaller great houses are distributed across the wider Chaco region and associated with each are a series of small pueblo dwellings. Similarity of architectural styles, material remains and as well as traces of ancient roads which connected great houses indicates a complex culture which integrated large numbers of people in some form of hierarchical social structure. Archaeologists however do not understand the degree to which centralized power existed, how it was maintained or what practical purpose it served. Some have argued that the `Chaco Phenomenon` was primarily ritual in nature, that individual small great houses were essentially independent and that the largest great houses in Chaco Canyon itself were occupied only sporadically for religious functions. Others have postulated a much greater degree of centralized control and believe that the system worked to store and distribute subsistence resources across a desert area in which rainfall varied markedly and unpredictably from year to year and place to place. MS Mahoney has noted that very little research has been conducted at secondary great houses. She argues that through analysis of behavior at individual great houses and associated pueblos, and then comparison among great house-pueblo systems, it will be possible to reconstruct the essential aspects of the broader social organization. With NSF support she will study data from two great house-pueblo complexes and continue excavation at a third to collect comparable material. This research is important for several reasons. It will provide data of interest to many archaeologists. It will shed new light on the impressive achievements of prehistoric Native Americans and will assist in training a promising young scientist.