Final answer:
Innovators represent the first 2.5% of adopters in Everett Rogers' diffusion of innovations model. They are critical to initiating the adoption lifecycle of new technologies or ideas.
Step-by-step explanation:
The adopter group that represents the first 2.5 percent to adopt an innovation are known as innovators. This concept comes from a model developed by sociologist Everett Rogers in 1962, which is called the diffusion of innovations model. Rogers outlined several categories of adopters: innovators, early adopters, early majority, late majority, and laggards. Innovators are the first to embrace new ideas, technologies, or products, followed by the early adopters who represent the next 13.5 percent. Together, these two groups play a critical role in the adoption lifecycle, influencing subsequent groups and leading the way towards wider acceptance and usage of an innovation.