 Objective: Environmental cues frequently induce expectancies in the course of normal daily life. When an individual smells and sees the coffee before tasting it, an expectancy of the coming experience is formed that influences the actual experience of consuming the coffee. Similarly, when an addicted individual experiences cues associated with imminent drug taking, an expectancy of the coming experience is also formed. This protocol will examine neural responses to cues predictive of a stimulus neutral or rewarding and to the subsequent receipt of the predicted stimulus. 