In his doctoral dissertation (The Warao: A Study in Microevolution. University of California – Los Angeles, available online from HRAF), Mark Fleischman (pp. 65-66) reports on the centrality of kinship terms among the Warao:
“In small village groupings ego is unlikely to have much contact with very distant relatives. The social interdigitation of people living closely with one another would lead naturally to a greater complexity of terminology for people within the group. This specificity of kinship terminology within a small village group would negate any need for proper names for individuals, since, in most instances, the kinship term used by ego would show which individual he is addressing or talking about. Knowledge on the part of the others of all of ego’s relatives is necessary under these circumstances. Such information would be difficult to maintain in large living groups, or in groups where people are distantly, if at all, related. The Warao conform to the above expectations, and prior to missionary contact placed little importance on proper names.”
One of the key features of personal names is their referential precision. They are capable of referring to one individual and one individual only. The important point in the Warao quote above is that in small populations kinship terms possess greater specificity over personal names. It’s also noteworthy that Fleischman identifies the reason for why small populations often exhibit unusual complexity of their kinship categories and why complexity is not always of recent origin. This is the point I made in “The Genius of Kinship” when I postulated that Murdock’s “Complexly Differentiated Sibling Type” represents an evolutionary archaism and not a recent development. In a situation when other linguistic domains, such as personal names, numbers or pronouns, may be suppressed and underdifferentiated because of the lack of a strong functional need for these classifications, kinship terminological systems acquire a greater prominence as they take over some of the functions of those other linguistic domains.