Part of it probably is stimulus-response psychology. Cigarette smokers usually pair smoking with a lot more different situations than cigar smokers. As a conseq

Part of it probably is stimulus-response psychology. Cigarette smokers usually pair smoking with a lot more different situations than cigar smokers. As a consequence, the smoking impulse becomes more easily generalized for cigarette smokers, while cigar smokers restrict smoking to a stable, limited set of occasions.