Behaviour Change

PROPAGANDA FOR CHANGE is a project created by the students of Behaviour Change (ps359) and Professor Thomas Hills @thomhills at the Psychology Department of the University of Warwick. This work was supported by funding from Warwick's Institute for Advanced Teaching and Learning.

Wednesday, January 21, 2015

Are Figures Better?

In the Simpsons movie (2007), the rock band Green Day was killed in Lake Springfield – because the lake was so polluted that it dissolved the band’s boat during a performance on the lake. Concerned about the environmental problems in their town, Lisa Simpson and her crush Colin held a talk to raise awareness about the lake pollution. In the talk, Lisa presented a graph showing the pollution level in Lake Springfield, hoping to persuade people in the town to clean up the lake. As you can see from the graph, there is a sharp rise in pollution level, which looks shocking. The day after, people took action to clean up the lake.

What Lisa was trying to present is a statistical message. Statistical messages (e.g. figures and graphs) have been thought to be more persuasive than narrative messages (e.g. stories) because their content is factual, does not involve subjective judgments and is therefore harder to refute.

Does that mean it’s better for Lisa to present the graph rather than telling a story? Using a sample of female students, Greene and Brinn (2003) did a study to compare the effects of using statistical evidence and narrative persuasive messages about a risky behaviour – using a tanning bed. These students read either a statistical or narrative persuasive message concerning the negative effects of tanning bed use, or they read no message at all. They then completed questionnaires asking about their attitudes to this behaviour (actual tan behaviour, intention to tan, intention to protect their skin, perceived susceptibility to skin cancer). Results show that both types of messages have some effects: statistical message results in decreased tanning behaviour, decreased intentions to tan and increased perceived susceptibility to skin cancer. Narrative message also results in decreased intentions to tan. However, none of the messages had an effect on participant’s intention to protect their skin.

Table 1. Means for Different Types of Message Evidence

The two types of messages affect attitudes in different ways – the statistical message was rated higher on information value whereas the narrative message was found to increase perceptions of realism. This is because statistical messages create a heuristic that the larger samples are more representative and believable and therefore are more influential than an individual story. Also, people might easily dissociate themselves from the narrator in a narrative message, which merely presents information from one person’s point of view. However, narrative messages can be useful as they tend to be more vivid and therefore generate more concrete images in audience’s minds.

Greene and Brinn’s study suggests that both types of messages can change attitudes, though they work in different ways. Maybe it’s a better idea for Lisa to combine the two – not just present statistics of the pollution, but also tell stories about, say, how the fish that lives in the lake suffer.


Greene, K., & Brinn, L. S. (2003). Messages influencing college women's tanning bed use: Statistical versus narrative evidence format and a self-assessment to increase perceived susceptibility. Journal of Health Communication, 8, 443-461. 

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