175. Diagrammatic Representation of Accumulation and Diffusion of Culture Traits
The outstanding facts regarding these fourteen or fifteen culture-areas can be most vividly presented in a table allotting a column to each area. Roughly, at least, these columns can follow one another in geographical order. In each column, then, there might be entered all the culture traits found in its area. If one culture were twice as rich or complex as another, the double number of entries would pile up twice as high and impress the eye.
Actually, such a procedure is hardly practicable. The number of culture elements is too great. Often too there would be doubt whether a feature should be reckoned as one or several. Metal working comprises smelting, casting, forging, alloying, plating, soldering, and welding. These are distinct techniques. Yet they usually occur together or are all lacking. One tribe practises simple two-ply twining. Another adds three-strand, diagonal, and lattice twining and three-strand braiding, probably as developments of the original two-strand process. As between two adjacent or related basket-making peoples, this difference may be very significant; measured against cloth weaving, it is trivial.
Accordingly, in order to render the data more easily apperceived and conceptualized, only the more fundamental aspects of arts and institutions have been included in the diagram ([Fig. 35]), plus some that perhaps involve intrinsically less significant principles or faculties, but were of particular importance in the life of the peoples following them, such as the tipi or skin tent of the Plains tribes. This means that a necessarily subjective selection of traits has been made in the compilation of the table. But the reader who is not a specialist in the matter will generally be grateful for the elimination; and this elimination has at least been conducted without a conscious bias in any one direction. If anything, it would seem that the selective condensation has operated against the preëminence of the advanced areas. With every possible datum inserted, the peaks in the table would probably overshadow the valleys much more conspicuously.
Accepting the diagram, then, as affording an approximately truthful picture, it is obvious that much the greatest advancement took place in Middle America—the region from Mexico to Peru; and that on the whole the majority of culture traits found in any of the more backward areas are shared with this middle region. These are the traits below the heavy line that steps up and down across the diagram. A minority of traits—those above the heavy line—are local to the several areas. On the basic principle that a trait occurring over a continuous territory may be assumed to have originated but once and to have spread by diffusion, the bulk of the culture of most of the areas must have come into them from outside. On the principle that a people with many established arts is more likely to make a new invention than is a retarded people, the great majority of the diffused elements may therefore be attributed to a Middle American source. In this region, then, lay the focal point, the hive, of American civilization. From it, the tribes of the Lower Amazon and the upper Mississippi equally derived most of the limited culture which they possessed.
Fig. 35. Diagram illustrating the occurrence of some representative elements of culture in the various areas of America. In general, assumed early elements are below, late ones above, within each column; but for the figure as a whole, horizontal levels do not indicate contemporaneity as they do in [figure 36]. Height of columns is representative of quantity or elaboration of culture content, which towers impressively in Middle America, to fall away towards the peripheries. Hatching indicates elements that may once have existed in areas but are now lacking; stippling, elements perhaps introduced from Asia. Entries above the heavy line are local developments.
In South America, the diffusion proceeded broadside from the length of the Andes. In North America, it radiated fanwise from the south Mexican angle, the Southwest serving as the gateway or first relaying station that let through most but not all of what it received. One area alone, the Northwest Coast, was reached but imperfectly by Middle American influences, yet attained a tolerable development through its own creative force, supplemented in some measure by the drift into it of sporadic culture element migrants from Asia. Here only, then, there occurred a markedly independent growth of civilization, though definitely secondary to the great evolution of Middle America which in the main determined the culture of the twin continents.