LINCOLN, Neb. (AP) — A rat competition, in which psychology students condition the behavior of their lab rodents to clear a series of obstacles, is still going strong after 40 years at a Lincoln college.

About 15 rats competed in Tuesday’s Xtreme Rat Challenge at Nebraska Wesleyan University. The rodents climbed ropes, walked on a tightrope and raced through tubes.

The event was created in 1974 by former psychology professor Marty Klein. He said he crafted it as an alternative learning experiment from the “boring” psychology labs he sat through as a student.

While training the rodents, students learn techniques in how to teach them to clear the obstacles. Klein says the rats signal to students when they’re doing something wrong by becoming uninterested or not learning the desired behavior.