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Bystander Effect

New Tools Are Nudging the Way to Prosocial Behavior

Three-step norm nudges can be powerful interventions in cases of corruption.

Key points

  • People’s behavior is powerfully influenced by the behavior of those around them.
  • "Belief shock" may stem "pluralistic ignorance."
  • Delivered correctly, norm nudges can stimulate prosocial behavior.
Source: jasperai/OpenAI
Collective pro-social behavior can be induced by the right messaging.
Source: jasperai/OpenAI

When confronted with frequent news of inhumane behavior, people often want to create change for the better but do not know how to make it happen. Institutions that want to promote prosocial behavior are eager to find effective ways to promote positive collective action.

Researchers agree that the behavior of individuals powerfully influences the behavior of people around them. Often people want to do what their peers, neighbors, or friends do, imitate highly regarded others, coordinate with others, or seek to belong to or be accepted by a group they value. Psychologists call this influence a social norm.

In 2019 Andres Casas Casas of the University of Pennsylvania’s Social Norms Group (PENNSoNG) developed a Behavioral Drivers Model to map the scientific fields, theories of behavior, and social practices uniting researchers studying approaches and interventions that influence positive behavior. Understanding social norms helps researchers create tools to influence the common good. Psychologists Bicchieri, Mercier, and Dimant study the little nudges that work best. Their work informs what follow.

When it’s important to gain buy-in from people to help collective well-being rather than self-interest, appealing to their social norms or beliefs about norms can encourage prosocial behavior. Inducing prosocial change by informing people about what others do is called "nudging."

A 2008 study by Goldstein et al., "A Room With a Viewpoint: Using Social Norms to Motivate Environmental Conservation in Hotels," concluded that sometimes a simple "this is how we roll around here" message steers individuals toward helpful behavior. The study found that most hotel guests reuse their unwashed towels when told that other guests reuse theirs. Such actions reduce water use, something that might not appeal to hotel guests’ self-interest but helps the community to conserve water.

Some Nudges Are More Difficult

Lindstrom et al. found that the commonness of observed behavior influences its moral status. When norms revolve around corruption, a simple message may not be enough to change behavior. When bribing, corruption, cheating, or other harmful behaviors are perceived as common and thus "normal" and approved of, it is hard but not impossible to reverse them. For example, when tax evasion is perceived as more common, it will also be seen as more acceptable, increasing its prevalence and leading more people to conclude that such common behavior is approved.

In corruption nudges, a two-or three-part message that includes observability and visual cues nets the best results. In cases of corruption where antisocial behavior is frequent and prosocial behavior has a cost, such as being risky, individuals do not feel obliged to obey a prosocial norm. Although the general public benefits from lower corruption, the short-term rational choice is to act in one’s self-interest, which leads to suboptimal collective outcomes.

Although people follow a norm because it aligns with their self-interest, sometimes it is possible to get them to change their behavior. When behaviors are observed, positive behavior increases and negative behavior decreases.

People’s beliefs about norms and the information available to them influence their response to nudges. Sometimes anti-corruption nudges are ineffective because people tend to reject information inconsistent with their beliefs or well-established past behavior. Such entrenchment can be moderated by introducing observability. In some cases, observability can be as simple as a mental observation, such as when thoughts about what most peers do lead those who would otherwise behave antisocially to behave better.

Consider the Source

Another consideration of corruption is that it is often not observable. People may engage in social comparison without the transparency of action, information, and communication and thus misperceive its frequency. A large silent majority may oppose a certain behavior, but their silence may lead others to assume they acquiesce. Miller and McFarland explain that a credible source can make all the difference in such instances of "pluralistic ignorance." In such cases,, a credible source of information can introduce what psychologists call a “belief shock,” in which the beliefs based on misperceptions are changed.

Based on the studies, what are the implications for everyday people who want to change a negative social trajectory? You can influence prosocial behavior by modeling positive behavior and by providing “everybody is doing it” positive observable messaging that rewards prosocial behavior and exposes antisocial behavior.


Petit, V. (2019). The Behavioural Drivers Model: A Conceptual Framework for Social and Behaviour Change Programming.UNICEF.© United Nations Children’s Fund (UNICEF), 2019

Goldstein, N. J., Cialdini, R. B., and Griskevicius, V. (2008). A Room With a Viewpoint: Using Social Norms to Motivate Environmental Conservation in Hotels. Journal of Consumer Research, 35(3), 472-482.

Lindstr¨om, B., Jangard, S., Selbing, I., and Olsson, A. (2018). The Role of a “Common is Moral” Heuristic in the Stability and Change of Moral Norms.Journal of Experimental Psychology: General, 147(2):228.

Bicchieri, C. and Mercier, H. (2014). Norms and Beliefs: How Change Occurs. The Complexity of Social Norms, pages 37–54.

Miller, D. T. and McFarland, C. (1987). Pluralistic Ignorance: When Similarity is Interpreted as Dissimilarity. Journal of Personality and Social Psychology. 53(2):298.

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