Final answer:
The element that differentiates diffusion from other types of communication research, according to Everett Rogers, is time. Diffusion encompasses the technology adoption lifecycle and shows how innovations are adopted by society over time, causing cultural and generational shifts.
Step-by-step explanation:
According to sociologist Everett Rogers and his model of the diffusion of innovations, the element that differentiates diffusion from other types of communication research is time. Diffusion is the process by which an innovation is communicated over time among the participants in a social system. This concept encompasses the spread of both material and nonmaterial culture, and it includes the technology adoption lifecycle, where innovations reach varying levels of saturation within a society. Rogers's theory emphasizes how over time, innovations are adopted by different groups, creating generation gaps and cultural shifts as the rate of acceptance and integration into society can vary greatly.