It is known that cannabinoid and dopamine receptors can be important modulators of response to nicotine and its associated cues. In this study participants will be genotyped to determine whether there is a relationship between CB1 or D3 genes and the reinforcing properties of nicotine or the subjective effects of nicotine-associated cues. In one session, participants will chose between two different cigarettes, each with different properties. In another session, physiological responses and craving will be measured when presented with cues that remind participants of nicotine. At some point during the study, blood will be collected for genotyping and this will processed to study whether CB1 or D3 genotype influences these responses to nicotine or cues.