What type of diffusion describes how the number of people that possess a particular culture trait increases?

Contagious diffusion is the type of diffusion that describes how the number of people having same ideas or similar cultural trait increases. It is a process by which ideas or a particular culture is spread through population instead o them being actually carried by people to various places. This type of diffusion does not require the people to be relocated from their original places which makes it different from the other types of diffusion.