Very rarely do societies live in absolute isolation.
Contact between different communities can bring a delicate balancing of power as well as the fruitful exchange of knowledge and practices. Archaeologists and linguists can trace the movement of people by analysing the changing stylistic variations and influences in made things or in the changes in local dialects as a result of contact between groups.
Encounters carry negative consequences as well, as in the case of North American Plains men's material culture. Nearly all museum collections contain evidence of cross cultural contact through palimpsest: wiki:world_gallery:layered_info:encounters:africa:benin:benin_plaques|Benin Plaques depict European traders, plains beadwork and South African breastplates incorporate valuable glass beads or buckles imported from Europe and exchanged.
Another example, among the Bedamuni in Papua New Guinea demonstrates cross cultural contact between the spiritual and material worlds through gift giving, which ensures maintaining good relations between ancestors and young children, particularly boys, during initiation rites.