Thorndike created puzzle boxes. Cats would be put inside the puzzle boxes, and they would have to figure out a series of behaviors to escape the box, such as pushing their paw on a lever, biting a string with their teeth or swishing their tail to open a door. In addition to simply escaping the box due to these behaviors, the cats were further rewarded with a dish of food. The cats were put inside the same puzzle box several times, and each time, Thorndike measured how quickly they did the series of behaviors needed to escape.