An online game teaches people to more accurately sort waste—with lasting results, a new UBC study has found. Study participants who played the game developed by UBC researchers received immediate feedback on their sorting choices. The second time they played—when feedback was no longer provided—players still improved their average accuracy from 69 percent to 84 percent. Even when a week passed between games, players still improved their accuracy.

As part of the study, researchers also exposed students living in university residences to the game, then monitored their waste bins. They observed both a slight reduction in contamination—defined as the presence of items that shouldn’t be in a particular bin—and an increase in compost weight.

“This immediate feedback increases recycling and composting accuracy over the longer term, both in the lab and in the field,” said Jiaying Zhao, assistant professor in UBC’s department of psychology and senior author of the study. “One of the big questions in psychology is how long do these effects last? Our biggest takeaways are the fact that immediate feedback works and the effects last over time.

As solid waste increases rapidly, accurate sorting is becoming imperative in North American cities where the average person throws out 700-800 kilograms of solid waste each year. In the U.S., solid waste generation per capita increased 64 percent between 1960 and 2013. One-third of landfill waste is organic and releases methane into the atmosphere. Methane is 25 times more potent than carbon dioxide in creating conditions for climate change.

Yu Luo, the lead author of the paper, noted that social norms and the convenience of waste-sorting bins have encouraged people to try dealing with waste properly, but even when they make the effort, they make mistakes.

To correct these mistakes, Yu developed a simple sorting game. Four squares representing waste categories appear across the top of the screen: food scraps, recyclable containers, paper, and garbage. Then a picture of a waste item appears below. Players must decide where it goes. They are told whether they were right or wrong. If they were wrong, they are told which bin was the correct choice. Research in cognitive psychology has shown that immediate feedback helps people learn and improves their task performance. The results of the experiment bear that out.

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