In attempt to mobilise action against an environmental problem, communicators often incorporate normative information in their persuasive appeals. These messages can be either effective or ineffective because they can normalise either desirable or undesirable conduct. There are two types of social norms that affect human motivation: the injunctive norm and the descriptive norm. Injunctive norms express how the majority of people feel about a certain issue. For example, most people think that wasting water is bad.
Descriptive norms describe what is done rather than what should be done. Cialdini outlines the situations in which the use of normative messages in behaviour change campaigns can backfire to increase, rather than decrease, the incidence of the problem behaviour. The message that the Petrified Forest National Park(Arizona): “Your heritage is being vandalized every day by theft losses of petrified wood of 14 tons a year, mostly a small piece at a time” displays the negative power of a descriptive norm as it convey’s the message that ‘everyone is taking it’.
Cialdini and his colleagues did an experiment which involved creating signs and aligning both descriptive and injunctive norms. On the sign, the descriptive norm read “Many past visitors have removed petrified wood from the Park, changing the natural state of the Petrified Forest” The injunctive norm read: “Please don’t remove petrified wood from the Park, in order to preserve the natural state of the Petrified Forest” Interestingly, theft rates dropped with the new signage – 7. 92% vs 1. 67%.
Only by aligning descriptive norms (what people typically do) with injunctive norms (what people typically approve or disapprove) can one enhance the power of normative appeals. Communicators who cannot see the difference between these two types of norms jeopardise their persuasive efforts. If the injunctive norm is in conflict with the descriptive norm then bad behaviours will be encouraged. As an example, let’s take littering. An anti-litter norm may be highlighted with the norm stated on a sign. Descriptive norms affect behaviour by providing information about which behaviour is most common in such a situation.
For example, a littered environment illustrates that there is a breakdown of norms and values and will therefore enhance littering. Cialdini notes that “people can be steered into criminal behaviour simply by tinkering with their social surroundings and if you know which variables to change within an environment, you can make anti social behaviour spread like wild fire”. Injunctive-norm information in a persuasive message is more successful when it is associated with a descriptive norm that is in alignment rather than in conflict with that message.
For example, a sign drawing attention to the anti-litter norm is more powerful in reducing littering when placed in a non-littered setting than when it is placed in a pre-littered setting. More and more environmental interpreters understand the importance of descriptive norms. You can still explain that a particular activity is happening. You can explain that this activity harms us and our earth. Just do not imply that participating in this harmful activity is the social norm.