By Trisha Prabhu, as told to April Daley

Two and a half years ago, Trisha Prabhu began work on ReThink, an anti-cyberbullying app that prompts adolescents to reconsider messages they’re about to text or post. Here, the 15-year-old Illinois student explains how she created a product that could maybe, finally make the Internet a safe space for teens.

In 2013, I read an article about 12-year-old Rebecca Sedwick, who jumped off her town’s water tower because she’d been cyberbullied. I was heartbroken. I started looking up other stories, reading about kids hanging themselves in their bedrooms after being told the world would be a better place without them. It hit me in the gut.

I’ve always been fascinated with the brain. It controls so much of what we do, and we understand so little about it. I came across another article about how the adolescent brain develops from the back to the front. Scientifically speaking, the reason young people are more likely to act impulsively is because the part of the brain that is supposed to control decision-making skills isn’t fully developed until age 26.

I decided to explore the link between that and bullying. I thought, “What if I give people a few extra seconds to pause and think about the consequences of their actions? What if I give kids a rethink word—almost force them to do it?”

That’s when the experimenting began. I spent months after school recruiting students, and gathered over 1500 trials’ worth of data. Adolescents were presented with offensive messages and then asked to choose, “Would you post this?” or “Would you not post this?” If they said, “Sure, I’ll post ‘You are so ugly’ on social media,” we went, “Hold on! Are you sure you want to do this?” We found that over 93 percent of the time adolescents changed their minds. The overall willingness to post a message actually dropped from 71 percent to 4 percent. I knew I was onto something.

I entered the Google Science Fair and was chosen as a global finalist, one of the top 15. It was the first time Google had accepted a behavioral science project into the finals. I lost, but it hit me: Maybe people could use this. I ended up creating ReThink.

I released two apps this past August, ReThink for Android and ReThink for iOS. It helps that I have parents with a tech background and have been coding since I was 10. I also have fantastic mentors.

We’re now working with school districts, parents, guidance counselors, and teachers. Our goal: to build a coalition of ReThink Ambassador schools to help download the app onto school computers and students’ mobile devices. ReThink could become more than a solution. It could become a movement, a mind-set, a call to action.