rsely, early coins from the Middle East found their way to northern Europe. In aboriginal North America, copper objects from northern Michigan have been found in mounds in Georgia; macaw feathers from Central America turn up in archaeological sites in northern Arizona. Some Indian tribes in northwestern regions of the United States had possessed horses, originally brought into the Southwest by Spanish explorers, years before they had ever even seen white men. The wide dispersion of tobacco, corn (maize), coffee, the sweet potato, and many other traits are conspicuous examples of cultural diffusion. AcculturationDiffusion may take place between tribes or nations that are approximately equal in political and military power and of equivalent stages of cultural development, such as the spread of the sun dance among the Plains tribes of North America. But in other instances, it takes place between sociocultural systems differing widely in this respect. Conspicuous examples of this have been instances of conquest and colonization of various regions by the nations of modern Europe. In these cases it is often said that the culture of the more highly developed nation is "imposed" upon the less developed peoples and cultures, and there is, of course, much truth in this; the acquisition of foreign culture by the subject people is called acculturation and is manifested by the indigenous populations of Latin America as well as of other regions. But even in cases of conquest, traits from the conquered peoples may diffuse to those of the more advanced cultures; examples might include, in addition to the cultivated plants cited above, individual words (coyote), musical themes, games, and art motifs. One of the major problems ofethnology during the latter half of the 19th and the early decades of the 20th centuries was the question "How are cultural similarities in noncontiguous regions to be explained?" Did the concepts of pyramid building, mummificati...
