Orzack, a clinical psychologist at McLean Hospital in Massachusetts claims that 40 percent of World of Warcraft (WoW) players are addicted. Orzack says that the best way to optimize the desired behavior in the subject is to provide rewards for correct behavior, and then adjust the number of times the subject is required to exhibit that behavior before a reward is provided. For instance, if a rat must press a bar to receive food, then it will press faster and more often if it does not know how many times it needs to press the bar.