The paper in Nature Sustainability is here: http://go.nature.com/2FyE48b
Promoting sustainable consumption is not just a matter of technology or engineering, but also of behavioural sciences. This was the main point of a 2015 article in The New Yorker, which inspired our work. The article described the Omniprocessor, a processing plant in Seattle funded by the Gates foundation, which can turn sewage water into potable water. The problem is, the article mentioned, that many people are unwilling to drink recycled water. Other studies showed that Westerners are also unwilling to eat certain foods, such as insect-based food and artificial meat, whose consumption could help minimize our carbon footprint. The problem is psychological—we need to override the disgust the descriptions of these products elicit. But how can we do that?
In the target article, co-authored with Constantinos Hadjichristidis and Anne-Kathrin Klesse, we tested a language intervention: describing such products in a foreign language. By foreign language we mean a language that a person has learned and used in a classroom context, rather than by being immersed in a culture where that language is spoken. Such an intervention is not as far-fetched as it may initially appear. As a result of globalization, many citizens around the world speak two or more languages. Indeed, more people speak English as a second language than as a mother tongue.
Specifically, we tested the foreign language intervention in four studies. In the first three, we presented participants with a description of a sustainable-but-disgusting product (artificial meat, recycled water, or insect-based cookies) either in their native or a foreign language and asked them whether they would consume it (Yes/Unsure/No). Foreign language descriptions prompted more Yes and fewer No responses than native language descriptions. Importantly, our third study on insect-based cookies showed that foreign language increased intended consumption by reducing the disgust this food triggers when described in the native language. In our fourth study, we turned to real consumption. We found that foreign language use influenced the quantity of recycled water consumed once we controlled for participants’ initial thirstiness. For non-thirsty participants, foreign language descriptions promoted marginally higher recycled water consumption.
But why does a foreign language reduce emotionality? If you speak a foreign language, try this thought experiment. What is easier—saying “I love you” in your native tongue or in a foreign language? How about swearing? Research has shown that the mother tongue is more emotional than a foreign language. The main explanation is that human memory is language dependent. Memories contain traces of the language used during encoding. Thus, that language (in most cases the native tongue) is a better cue for eliciting the target experience and its emotional associations than any other language.