“…Social norms are rules or standards for behavior among members of a group (Sherif, 1965;Turner, 1991) and they can be categorized in two main ways: as injunctive norms (i.e., perceptions of what people ought to do) and descriptive norms (i.e., what people actually do). We focus on descriptive norms in particular in this study, as they have been shown in previous research to predict a variety of pro-environmental behaviors, such as reduced littering (Cialdini, Reno, & Kallgren, 1990), increased recycling (Fornara, Carrus, Passafaro, & Bonnes, 2011;Nigbur, Lyons, & Uzzell, 2010;Schultz, 1999), use of public transport or bicycles rather than personal cars (Kormos, Gifford, & Brown, 2015), and energy conservation (Göckeritz et al, 2010;Nolan, Schultz, Cialdini, Goldstein, & Griskevicius, 2008).…”