This summary is presented by the IPR Behavioral Insights Research Center

Key Findings

  • Communicating descriptive and injunctive norms can influence people’s judgement and opinion.
  • Descriptive norms can increase community identification and perceptions of feasibility. People find behaviours more achievable and relatable when they know the behaviours are common within their social group.
  • People’s opinions, like support for legislation, can be swayed by injunctive norms – in other words, information about others’ approval.

Implications for Public Relations

Social norms are not only effective for encouraging behaviour change; they can also be used to change people’s judgments and opinions about a particular topic. People will adjust their beliefs if they believe it will help them be more accepted in their social group. Both descriptive and injunctive norms are effective in this regard, but they can have different effects. Public relations professionals should test different norm messages and combinations to determine the best approach.

Communicating social norms can be a powerful tool for public relations professionals, as they have been shown to be effective for changing both behaviours and beliefs. Practitioners should consider incorporating messages on social norms, particularly injunctive norms, when attempting to bolster public support on an issue. When trying to increase perceptions of feasibility for legislation, corporate strategies, or other proposed initiatives, communicating descriptive norms should be considered.

However, only accurate normative information should be used; anything else would be unethical. The communication of false social norms has been used before to mislead the public and it is imperative for professionals to recognize the potential for misuse, so that they can avoid it and know how to identify it when developing countermeasures.


Others’ behaviours and opinions have a strong influence on people’s decision-making due to a desire to fit into their social surroundings. Social norms are the behaviours that are believed to be common or accepted within a social group and serve as guidelines for people to shift their own behaviours towards. If someone realizes that their behaviour deviates from a social norm, they will usually change it, making messaging about social norms an effective communication strategy.

Cognitive research typically refers to norms as being either descriptive or injunctive. Descriptive norms indicate the prevalence of a particular behaviour, whereas injunctive norms indicate approval or disproval. Previous research has demonstrated that messaging using these norms can influence behaviour related to health and environmental impact.

Vinnell and colleagues explored the application of social norms in risk communication to encourage natural disaster preparedness. Most prior studies focused on changing behaviour, but this present study examined how communicating social norms can influence people’s attitudes and judgements, specifically support for disaster preparedness legislation. Earthquakes are a serious problem in New Zealand. Following a devastating earthquake in 2011, the government began debating legislation that would increase building standards in areas prone to seismic activity.

The researchers surveyed 690 participants about their views on earthquake legislation. Critically, the surveys varied in the presence and type of normative information. A descriptive norm described the number of earthquake-prone buildings that people are already started strengthening, while the injunctive norm described how the majority (76%) of people supported the legislation. Some participants were presented with both norms. The control version only described the dangers and potential damage of earthquakes in the area. The survey questions evaluated participants’ knowledge of earthquakes, preparedness, support for the legislation, perceptions of legislation feasibility and efficacy, concern about earthquakes, evaluations of risk, and community identification.

The results found different effects for the descriptive and injunctive norms. The descriptive norms increased judgments of the feasibility of strengthening buildings and identification with the community. Learning that building strengthening is already being done made it seem more attainable and something people wanted to identify with. Injunctive norms increased support for legislation, demonstrating that people’s opinions can be swayed by information about others’ approval. When used together, the effects of both types of norms were still present, which suggests that using both is most effective for influencing judgements related to natural disaster legislation.

The findings demonstrate that social norms can be effective for influencing complex attitudes, not just behaviour. The injunctive norm was able to change support for legislation, which is a complicated judgement with multiple considerations. This research also extends the literature on the application of social norms to risk and disaster communication.


Vinnell, L. J., Milfont, T. L., & McClure, J. (2018). Do social norms affect support for earthquake-strengthening legislation? Comparing the effects of descriptive and injunctive norms. Environment and Behavior, 51(4), 376-400.

Heidy Modarelli handles Growth & Marketing for IPR. She has previously written for Entrepreneur, TechCrunch, The Next Web, and VentureBeat.
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