Effects of nicotine on cooperative responding among abstinent male smokers.

The effects of nicotine on human cooperative responding in abstinent male smokers were examined. During episodes occurring at random times through a session, concurrently available cooperative and independent responses were maintained by points exchangeable for money. Cooperative responses simultaneously added points to counters marked "Your Earnings" and "Other's Earnings" only if the subject's and another person's responses ostensibly coincided. Independent responses added points only to the counter marked "Your Earnings". After the first daily session abstinent subjects smoked ad libitum, received either 0, 2 or 4mg nicotine gum or abstained from smoking. Increases from this first session in time allocated to the cooperative response option, proportion of cooperative responses and cooperative response rate were significantly greater following ad libitum smoking or acute administration of 4mg nicotine. No effects of nicotine abstinence were observed on independent response rate. These results suggest effects on sociability may maintain nicotine use and increase relapse risk in abstinent smokers.