As it relates to nicotine, classical or Pavlovian conditioning is conditioning in which, through repetition, a person, place, thing, activity, time or emotion (a conditioned stimulus or use cue) becomes so paired with using nicotine, until encountering the conditioned use cue alone becomes sufficient to trigger urges and cravings for nicotine. Subconsciously triggered anxieties are the mind's means of commanding that we once again bring nicotine into our body. Like Pavlov's dogs, which he conditioned to expect food and begin salivating upon the ringing of a bell, we each conditioned our subconscious to expect arrival of a new supply of nicotine in specific situations. Researchers have successfully used sight, smell and hearing to establish new conditioned use cues in smokers.

 Encountering the new cue triggered use expectations and an urge to smoke, with an increase in pulse rate. Researchers found it easier to establish new cues among light smokers, who obviously had fewer existing cues than heavy smokers. If crave episodes feel real and physical in nature there’s good reason. Although nicotine-feeding cues are psychological in origin, they trigger physiological responses within the body and mind. Not only does using nicotine increase pupil size, researchers found that encountering a visual nicotine use cue will increase pupil size, an autonomic response.

Using brain scans, researchers discovered increased blood flow during cue-induced cravings in the brain’s ventral striatum, amygdala, orbitofrontal cortex, hippocampus, medial thalamus, and left insula,361 regions associated with “aaah” rewards and anxiety. They also found that the amount of blood flow (perfusion) positively correlated with the intensity of the cue induced cigarette cravings in both the prefrontal cortex and the posterior cingulate, regions known to control attention, motivation and expectancy.