As we navigate the world, a neurological “notification center” alerts us to novel or unexpected changes in the environment and integrates this information into a new list of world experiences – similar to the notification center of a smartphone or computer. This neurological mechanism enables us to recognize and remember helpful things which are worth repeating (e.g. apples from the green tree are delicious or this coffee makes me feel good) as well as things which are harmful or unpleasant and worth avoiding (e.g. apples from the red tree are too sour or too much coffee makes me feel sick). Unfortunately, drugs of abuse including cocaine, heroin, nicotine, and alcohol also activate this neurological notification center and, in turn, can reinforce habits that are hard for people to break. While the notification signal for an environmental change is brief, the signals activated by drugs of abuse are long-lasting and disproportionately strong by comparison. With repeated experiences, this overactivationbuilds up the contextual importance of the environment associated with drug taking. Eventually, the environmental cues (e,g, location, drug taking tools, sounds or sensory information, and even people) that predict drug availability can promote drug-seeking behavior as strongly as the drug itself. Worse yet, the recurring inclination to take drugs in response to re-exposure to such cues persists after many years of abstinence. The challenge is to disentangle the pervasive and costly problems of drug abuse and addiction from the same neurological mechanisms that help nonaddicted, healthy individuals navigate from one apple to the next.