Sensing Global Warming

Physical sensations—be they of warmth, hunger, or thirst—can influence people’s beliefs by helping them form clear mental images of a world where those sensations are more common. The results of the study suggest that ordinary people—including bright and educated ones—may think of global warming and other pressing environmental and social concerns in intuitive rather than intellectual ways. Scientists and researchers may be more successful in communicating their findings about climate change if they make it easier for people to imagine the urgency and consequences of this issue.

Local Warmth, Global Views

In the first experiment, students were taken outside on different days and asked to answer a series of questions, one of which solicited the strength of their views on global warming. Risen and Critcher found that students tended to believe more in global warming when it was hotter outside. Of course, their answers may have been related to factors other than their mental images of a hotter planet. Blistering heat outdoors could lead people to think that the earth’s average surface temperature is indeed rising. They may think it reasonable to infer that the global climate is changing, forgetting that global warming actually entails a gradual elevation in the earth’s average temperature—an effect that would be small compared to day-to-day changes in temperature.

But even when Risen and Critcher took the experiment indoors, where the temperature was clearly unrelated to a long-term climate trend, they found that students who were asked to complete a survey in a cubicle that had been heated to approximately 81°F were more likely to believe in global warming. Furthermore, students were asked in another experiment to what extent they thought the room they were in felt warm or cold before responding to the global warming question. Calling attention to the temperature in the room should have led students to “correct” their views if those had been unintentionally based on the room’s temperature. But the feeling of heat continued to have a significant impact on their beliefs. These results suggest that the experience of heat—rather than the information it conveyed—influenced how strongly the students felt about global warming. The actual physical experience of heat was important and more powerful than the mere mention of it.

In another experiment, the authors found that exposing students to sentences such as “the room is hot” or “the bacon is sizzling” successfully summoned the concept of heat but did not influence their beliefs in global warming.

Similarly, Risen and Critcher expanded their analysis to look at the effect of thirst on the belief in another important environmental problem, drought, and the issue of desertification that often accompanies it. They had some participants eat pretzels to become thirsty, while they showed other participants a subliminal message about thirst—they flashed the word “thirst” on a computer screen for 17 milliseconds, and had a third group of participants complete a neutral task that was unrelated to thirst. They found that the students who physically experienced thirst were more likely to believe in the threat of drought and desertification. Feeling thirsty led people to think about thirst more (as did the subliminal presentation of the word), but the actual physical experience was necessary to affect people’s views. “Jumping in the process midway, by activating the thought without having the physical experience, did not lead to a change in belief,” says Risen.

Imagining Global Warming

To test the idea that feeling warm leads people to form sharper mental images of a world becoming hotter, Risen and Critcher used a new technique that measured how easily participants in a warm room imagined a picture of a hot landscape. Students who participated in this experiment were randomly assigned to heated or roomtemperature cubicles. While in the cubicles, they were first shown a series of pictures on a computer screen that included hot and cold outdoor scenes. The hot scenes, with yellow and red tones, showed parched landscapes that depicted the world as affected by global warming. Using Microsoft Office’s picture editing features, the researchers had adjusted each image’s clarity so that the pictures were semitransparent and somewhat blurry.

In the next task, they showed the students these same images, but this time with the transparency set all the way to 100 percent, so they started off completely invisible. They asked the students to adjust the transparency of each photo until they matched the level of clarity of the photo that they had seen before. Participants stopped when the images in front of them matched the images they remembered.

Students who performed the experiment in the hot cubicle made the images of hot landscapes appear sharper, while those who were in the room-temperature cubicle remembered the images being fuzzier. This result suggests that students who felt warm were able to form clearer mental images of a hot world. To further test the idea that such sharp mental images intensify a belief in global warming, Risen and Critcher conducted another experiment in which students were shown otherwise identical landscape pictures that were either clear or blurry. They found that students who were shown clear images of hot landscapes were more likely to believe that the earth was heating up.

In all of these experiments, Risen and Critcher found that regardless of participants’ political views, participants believed more in global warming when asked about their views in a warm environment. In other words, although political ideology predicted people’s beliefs in global warming (liberals were more inclined than conservatives to believe in global warming), feeling warm still had a significant impact on their beliefs. Both liberals and conservatives were better able to imagine global warming occurring when they felt warm.

The fact that liberals and conservatives responded similarly in the experiments is in sharp contrast to the response people often have when presented with explicit claims about an issue. Previous studies have shown that after people are given mixed evidence about a topic, those who are inclined to favor a position will come to believe in it even more, while those who are skeptical will tend to become even more skeptical. Trying to convince people of something by simply delivering facts can sometimes be polarizing because it gives people something to react to, Risen says. The experience of heat seems to elicit a more universal, intuitive response.