When an animal learns to repeat an action that leads to a reward, outside factors can speed up or slow down that learning. Six hamsters were split into two groups: one listened to Mozart for 12 weeks, the other heard no music. After the listening period, each hamster ran a cardboard maze once a day for 10 days, with a sunflower seed as the reward at the finish. The Mozart hamsters finished faster than the silent group on every day of testing.