What is the defining characteristic of hierarchical expansion diffusion?

Hierarchical expansion diffusion is characterized by the way ideas, innovations, or cultural practices spread from a source of high authority or influence to broader segments of the population. This method operates through a structured level of influence, typically moving from influential individuals or institutions, such as celebrities, political leaders, or major organizations, to the less influential members of society.

The defining aspect of this diffusion is its flow in a hierarchical manner rather than spreading simultaneously across all levels of society. For example, a fashion trend might first be adopted by high-profile designers or celebrities before trickling down to the general public through retail outlets. This pattern highlights the interconnectedness of social networks and the importance of authority in the diffusion process.

In contrast, the other possible options do not accurately reflect the hierarchical nature of the diffusion process. A hierarchical diffusion does not primarily involve common individuals influencing powerful ones, nor is it restricted to urban areas or characterized by the unchanged nature of the original concepts. Thus, the correct understanding of hierarchical expansion diffusion aligns with the idea that it spreads from top levels to wider populations, illustrating the gradient of influence inherent in this type of diffusion.