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In this between-subjects, placebo controlled, double-blind study, the investigators will examine the effects of low oral doses of nicotine on the learning and extinction of a conditioned place preference acquired in a virtual reality environment by healthy human subjects. Physiological and subjective responses to the drug will also be monitored.

External cues and contexts contribute to the development of smoking and the use of other drugs, and drugs themselves can alter the value of conditioned cues. Interestingly, nicotine increases the acquisition of new learning, and has been considered as a "cognitive enhancer". Nicotine also prolongs responding when responding is no longer rewarded, during extinction. Although many studies have examined the effects of drugs on learning (acquisition) and unlearning (extinction) in laboratory animals, few have investigated drug effects on learning in humans. Recently, novel procedures have been developed to study conditioning in humans, pairing initially neutral places with food, money or drugs. The investigators will use one of these procedures, a virtual place conditioning procedure, to study how nicotine affects the acquisition and extinction of conditioned behaviors in humans.

Inclusion Criteria:

• Subjects must have at least a high school education and be in good physical and mental health.

Exclusion Criteria:

• Individuals with current medical conditions, and/or a history of serious medical problems (e.g., cardiac, kidney, liver, and neurological).

Additional Exclusion Criteria include:

• regular medication,
• pregnancy,
• color blindness,
• left-handedness,
• consumption of 5 or more cigarettes per day,
• English non-fluency and current DSM-IV Axis 1 diagnosis excluding nicotine dependence.