Research into ethnicity aims at identifying symbolic patterns in material culture.
"Ethnicity is a product of self and group identity that is formed in extrinsic/intrinsic contexts and social interaction. Ethnicity is not the same as nor equal to culture. Ethnicity is in part the symbolic representations of an individual or a group that are produced, reproduced,and transformed over time."
http://gbl.indiana.edu/baumann/Baumann 2004 - Defining Ethnicity.pdf