Providing descriptive norms during engineering design can encourage more sustainable infrastructure

Engineering design decisions can produce more sustainable civil infrastructure systems, but cognitive barriers to innovative thinking often inhibit such outcomes. Existing research shows how descriptive norms that provide decision-makers with information about how others decide in a given context, can encourage more sustainable choices among users. Research described in this article shows that descriptive norms can encourage more sustainable choices among designers of civil infrastructure. We asked research participants to complete a simulated design exercise after randomly assigning them to either a modified version of the Envision rating system for sustainable infrastructure (with a positive descriptive norm reflecting high sustainability performance among other designers) or the current version of Envision (with no descriptive norm). Participants exposed to the positive descriptive norm set goals that resulted on average in 28% more sustainability points than a control group. A positive descriptive norm, in addition to being effective by itself, also added to the effect of other choice architecture interventions (defaults and role model project) known to increase sustainability goals. These results show a specific example and the potential for widespread use of descriptive norms in choice architecture interventions to support design for greater sustainability in civil infrastructure.