Effects of spirometric administration of tobacco smoke containing varying amounts of nicotine on human punished and non-punished operant responding.

Lever pulling of male tobacco smokers was maintained by a variable interval 20sec schedule (VI 20) of point presentation. In experiment 1 the rate of lever pulling was suppressed by a punishment contingency which stipulated that lever pulls would produce point subtractions on a variable ratio 30 schedule (VR 30). In experiment 2 the punishment contingency was omitted. Each subject participated in eight sessions each day (Mon. through Fri.). Each block of two 20-min sessions was separated by a period during which tobacco smoke containing varying amounts of nicotine was administered by the spirometry method, which ensured a constant puff volume and deep inhalation. The tobacco smoke conditions were: (1) 0.3mg nicotine yield cigarettes (baseline condition), (2) 1.2mg nicotine yield cigarettes, (3) 2.7mg nicotine yield cigarettes and (4) a condition in which room-temperature air was administered. Subjects remained at baseline conditions until responding stabilized and were then exposed to higher nicotine yield smoke or air for an entire day. Subjects were then returned to baseline conditions before administration of higher nicotine yield smoke or air. In experiment 1 (punishment contingency) lever pulling decreased as a function of increasing nicotine content in tobacco smoke. This effect upon responding was similar to the effects of CNS stimulants on punished responding in non-human subjects. In experiment 2 (no punishment contingency), no consistent effect of tobacco smoke or non-punished responding was observed.