assume that they originated in this area. Insofar the conception of an age-graded series is an independent invention. It is also fair to assume that one of the five tribes manifesting this complex is responsible for its presence.
Thus, we may generalize by stating that when a trait-complex is confined to a single area, it may be regarded as an independent invention. As such, it can be hypothetically, if not actually, assigned to a single tribe from whom it was diffused outwardly. Yet, we have seen that not one, but many such inventions seem to center in one place, or area. What, therefore, shall we say of the causes contributing to this result?
CULTURE TRAIT ASSOCIATION
Such discussions as the preceding lead ultimately to an important theoretical problem: namely, the nature of trait association within what we call a tribal culture. So far, we have used the term culture to designate the sum total of trait-complexes manifested by a social group, or tribe. We have naïvely assumed that they formed a whole, because they pertained to a single group of people and we have characterized types of culture by enumerating the most conspicuous of these traits. Such a view would, in the end, commit us to the theory that the simultaneous appearance of two or more traits was a mere coincidence, or an accident. In other words, unless we can find some other basis for this association of traits in a culture, such traits have no functional or other necessary relations to each other.
If we recall the details of trait distribution so far discussed, there come to mind many instances of whole groups of associated traits so segregated as to suggest their diffusion as a whole. In this book we have preferred to use the term trait-complex because it more accurately expresses the character of the phenomenon. For example, we have frequently referred to the maize-complex. By this term, we designate all the practices that immediately accompany maize production. Upon analysis, we find these processes to fall into unit cycles such as planting, cultivating, gathering, preserving, storing, grinding,
