This dissertation explored the impacts of socio-economic changes in the Titicaca Basin of Bolivia and Peru during the Early Horizon (800 - 50 BC) and Early Intermediate period (50 BC - AD 600). Prior archaeological research has shown that this was a time of dramatic social and economic transformation as shown by the domestication of plants and animals, establishment of sedentary settlements, and the development of long-distance trade networks (Bandy 2004; Bruno and Whitehead 20003; Burger et al. 2000; Capriles et al. 2014; K. Chávez 1989; Chávez and Thompson 2006; Chávez 2012; Erickson 1985, 2000; Hastorf 1999; Moore et al. 1999; Moore et al. 2007; Whitehead 1999). At the same time, the first regional ritual tradition, Yaya-Mama, emerged. What remains unclear is how these economic and social changes impacted the people living in the lake basin and their relationships with each other. To investigate these socio-economic changes, the author analyzed human skeletal remains excavated from seven sites on the Copacabana Peninsula. Specifically, I observed human skeletal remains of 184 individuals for indicators of diet, disease, ancestry, and tested 40 dental enamel samples for strontium isotopes in order to reconstruct who shared access to resources, who was considered acceptable reproductive partners, and if participants at temple rituals were local or foreign. Particularly, I looked for evidence of social stratification, access to elite food items, shared ancestry, and migrants to investigate the nature of the social relationships. I also considered differences between osteological age-at-death and sex categories, to understand if particular demographic groups were over- or under- represented at certain sites or if any groups were excluded from burial at temples or community membership altogether. These measures showed that despite the emergence of complex socio-economic structures, communities on the Copacabana Peninsula were not hierarchically ranked nor exclusive. People shared food, ancestry, and movement across the peninsula, regardless of sex, age, or burial location. Disease was a risk for all groups, not an increased burden for those with the least resources. Instead of depending on social hierarchy, the socio-economic changes of the Early Horizon may have been motivated by common ancestry and communal labor.