Recently, a series of bracelets have gone viral on Weibo. On these specially made bracelets are the words “Cell Phone Ninja.” 

The bracelets are actually part of an experiment carried out by Chongqing Three Gorges University that challenges students not to use cell phones in class for 21 days.

The experiment started on April 12. Each student who volunteered to participate received a bracelet. Before the first class and after the last class of each day, students were instructed to upload a photo of their bracelet to the school’s public Wechat account if they did not use their cell phones.

Over 800 students signed up for the experiment, and 400 were selected to participate. After seven days, only 103 students remained. The experiment was set for 21 days because of a claim in psychology that 21 days is the length of time required to form any habit.

According to the teachers monitoring the activity, there were no rewards or punishments in the experiment. It depended on students themselves to make the decision. Teachers hope students can form better study habits through activities like this one.