Descriptive versus injunctive[edit]
Put simply, descriptive norms depict what happens while injunctive norms describe what should happen.
Cialdini, Reno, and Kallgren (1990) define a descriptive norm as people's perceptions of what is commonly done in specific situations; it signifies what most people do, without assigning judgment. The absence of trash on the ground in a parking lot, for example, transmits the descriptive norm that most people there do not litter.[19][20] An Injunctive norm, on the other hand, transmits group approval about a particular behavior; it dictates how an individual should behave.[19][20][21][22] Watching another person pick up trash off the ground and throw it out, a group member may pick up on the injunctive norm that he ought to not litter.