In 2011, Mark Bouton, a psychologist at the University of Vermont, conducted a review of the types of conditional and operant stimuli that increase a craving for a specific food or our desire to eat more generally. He found that two types of cues play an important role. On the one hand, there are food-specific cues: a certain packaging or color associated with a preferred food (say, the distinctive red and orange of a Doritos logo and bag), a certain sound (someone opening the bag), a certain smell (the scent of the chips), or a certain taste (a hint of saltiness). But equally important are environmental cues that seem unrelated to food: the couch on which you typically watch movies while eating popcorn, a social gathering like a Super Bowl party, a sporting event, a shopping mall. These cues, in turn, are very difficult to unlearn. If you have a habit of snacking on Oreos while watching “Mad Men,” it will be tough to get through an episode without craving your cookie.