Maurice Solomon, Victoria Summers and Melissa Visintin co-wrote this article with Rachael Pius.
Whether we like to admit it or not, many of us know the unique rush that comes from swiping a series of multicolored jelly beans in Candy Crush. We’ve experienced the thrill of landing a triple word score in Words With Friends, and we’ve known the satisfaction that comes from—of all things—successfully harvesting a field of wheat in Farmville. Gaming is a universal pursuit, triggering not only our competitive instincts but also our desires for achievement and recognition. And with the rise of app- and social-media-based games, there are more people playing than ever before: The number of online gamers is expected to reach 2.7 billion by 2021, according to gaming analytics firm NewZoo.