A research team wanted to determine how much repetition horses need to learn a new skill. So they trained each of 20 horses to back up, lower the head, lift the hind legs, and turn the head for two days a week over six weeks. As a cue, they put pressure on parts of the body—such as the chest—and reinforced the correct behavior through release of that pressure (negative reinforcement). Each horse learned half the skills by practicing them three times per training session and half by practicing them six times per session. What do you think they found?