Marcus Tay Guan Hock, Sustainability Executive at the National University of Singapore, writes in to say that Nudge “gives me hope as an environmentalist,” and explains how the school used principles of choice architecture to redesign its recycling program.

Here at the National University of Singapore (NUS), we designed our recycling bins to tackle the issue of contamination, applying what you called “Expect Error” from users.

When users throw the wrong things in the recycling bins, it wastes the efforts of those who recycled properly. For example, paper bins are often contaminated with food waste, rendering all of the paper unrecyclable.

This situation is rather serious in Singapore. A Straits Times Article on June 15, “What rubbish,” indicates non-recyclable waste found in all 80 recycling bins surveyed. At NUS, we did the following two things. They have worked wonders.   At the point of disposal, we help people decide if the item can be recycled using proper and clear labels. These labels are designed so that before users can throw trash into the bin, they will see the labels which instruct them what can and cannot be thrown.   We give people an option not to throw garbage into the recycling bin if the garbage cannot be recycled by pairing every set of recycling bins with a trash bin as well. Because some people are not yet environmentally conscious, they just want to get rid of the rubbish in their hands, whether it can be recycled or not.