In anthropology, the transmission or borrowing of certain culture traits from the group of origin into a foreign group; usually technological elements rather than those of social organization. This term defines the spread of ideas, traits, or people from one area to another - not necessarily implying the movement of people, since trade and the adoption of new ideas from neighboring cultures are reasonable explanations of diffusion. The diffusion of new ideas can come, however, from the peaceful or warlike expansion of a population into new territory. The theory of diffusion was used in the past to explain the beginning of most new ideas: it was assumed that technological skills such as metalworking, or the building of large monumental structures, could only have begun in one place, whence they diffused to other areas. It is now clear, through the use of new dating techniques, that independent invention was certainly possible and probable for many new ideas.