Emotion–Message Congruency in Sustainability Communication: The Interactive Effects of Discrete Emotions and Message Framing in Reducing Single-Use Plastic Consumption

Every day, roughly 67 million plastic water bottles are thrown away, joining a growing mountain of waste that does not easily disappear. While recycling helps, it cannot solve the problem alone, and the sheer volume of plastic accumulating in landfills and oceans demands that people change how they consume. For decades, scientists have tried to find the most effective way to persuade people to make better choices. One powerful tool is the way a message is framed: telling someone what they stand to lose if they do not act, or what they stand to gain if they do. Another tool is emotion. We know that feelings drive decisions, but not all feelings work the same way. Some emotions push us to avoid danger, while others pull us toward helping others. The question researchers have long debated is whether these two tools—the words we use and the feelings we stir—work best when they are mixed and matched in specific ways, or if they simply add up on their own.

A team of researchers set out to answer this by looking at how different combinations of words and feelings influence the choice to avoid single-use plastics. They focused on two specific emotions: disgust, which makes us want to pull away from something unpleasant, and sadness, which often makes us want to help those who are suffering. They also looked at how "psychological distance" changes the game. This concept describes how close or far away a problem feels to a person. A problem feels psychologically close if it is happening now, nearby, or to someone we know. It feels distant if it is happening in the future, far away, or to strangers. The researchers wanted to see if the best way to convince someone to stop using plastic bottles depended on whether that person felt the problem was right in front of them or far away.

In their first experiment, the researchers asked hundreds of people to read messages about plastic waste. Some messages focused on the benefits of stopping plastic use, while others focused on the terrible consequences of continuing to use it. A third group read neutral information. The results were clear: people who read about the negative consequences were much more likely to say they intended to avoid plastic bottles than those who read about the benefits or the neutral facts. This suggests that highlighting what we might lose is a stronger motivator than highlighting what we might gain. The researchers also examined whether this effect changed depending on how close the problem felt. While the overall interaction between message framing and psychological distance was not statistically significant, the analysis indicated that the persuasive power of the messages remained strong when the issue felt close or moderately close, though the effect weakened when the issue felt very distant.

The second study shifted from reading to feeling. Participants were shown images designed to trigger either disgust or sadness. One group saw a picture of an ocean choked with plastic trash, intended to make them feel grossed out. The other group saw an animal harmed by plastic, intended to make them feel sorrowful. Afterward, they were asked if they would donate money to a research project fighting plastic waste. Surprisingly, the people who felt sadness were far more willing to donate than those who felt disgust. The researchers found that while disgust makes us want to avoid a situation, it does not always tell us what to do next. Sadness, on the other hand, seems to open a door to helping behavior. This effect was also influenced by distance. When people felt the environmental problem was far away from them, the sadness they felt led to even larger donations, suggesting that feeling sorry for distant others is a powerful driver of generosity.

The final and most complex experiment brought these ideas together. The researchers asked hundreds of people to imagine they were buying bottled water. They had to choose between a glass bottle, which is better for the environment but costs more, and a plastic bottle, which is cheaper. The participants were first shown an image to trigger either disgust or sadness, and then they read a message that was either framed as a gain or a loss. The results revealed a precise match-up. When people felt disgust, they were most likely to choose the glass bottle if they also read a message about the losses of using plastic. When people felt sadness, they were most likely to choose the glass bottle if they read a message about the gains of using glass. The most effective combination of all was the one that paired the feeling of disgust with the message about loss. This specific mix convinced more people to buy the expensive glass bottle than any other combination.

The researchers also discovered that the feeling of distance played a unique role in this final test. For the people who felt sadness, the distance of the problem mattered greatly. Those who felt the issue was far away were much more likely to choose the glass bottle when paired with a positive message about gains. However, for the people who felt disgust, the distance of the problem did not change their choice; the disgust and loss message worked just as well whether the problem felt close or far. This suggests that disgust is such a strong, immediate reaction that it overrides the sense of distance, while sadness is more flexible and grows stronger when we think about people far away.

These findings offer a clear path for anyone trying to encourage sustainable behavior. It is not enough to simply tell people the facts or to stir up any negative feeling. The most effective approach depends on matching the emotion to the message. If the goal is to make people avoid a harmful habit, pairing a message about loss with a feeling of disgust creates a powerful urge to act. If the goal is to inspire people to help, pairing a message about positive outcomes with a feeling of sadness works best, especially when the audience feels the problem is distant. By understanding how these psychological pieces fit together, communicators can craft messages that do not just inform, but truly move people to change their habits and protect the environment.