People react differently to change. Everett M. Rogers (1931-2004) is best known for developing the diffusion of innovations theory. Research on the subject has included a vast range of activities, including how people go from being bystanders to participating in a riot, communities learning about family planning, and farmers adapting to hybrid seeds. Rogers breaks down people’s reactions into the following categories:

The Innovators.
The Early Adopters.
The Early Majority.
The Late Majority.
The Late Adopters.
and The Diehards.