No previous studies have examined temporal discounting of losses during smoking abstinence��surprising since discounting of negative outcomes may best model the negative reinforcement that occurs when abstinent smokers smoke to avoid or remove withdrawal symptoms. Probability Discounting The value of outcomes http://www.selleckchem.com/products/Gemcitabine-Hydrochloride(Gemzar).html also decreases as a function of the probability of occurrence: $10 with a .5 probability is worth less than $10 with certainty for most people. Some researchers have proposed that probabilistic events occur with a relative frequency over a series of repeated opportunities and as such, that temporal and probability discounting are conceptually related and possibly a function of the same or very similar underlying process (Green & Myerson, 1996; Prelec & Loewenstein, 1991; Rachlin, Raineri, & Cross, 1991; Stevenson, 1986).

Support for this hypothesis has been mixed. The research supporting this hypothesis reveals (a) that the mathematical model that describes temporal discounting also describes probability discounting (Rachlin et al., 1991), (b) rates of temporal and probability discounting are positively correlated (Myerson, Green, Hansen, Holt, & Estle, 2003; Richards, Zhang, Mitchell, & de Wit, 1999), and (c) that temporal discounting differences observed between smokers and nonsmokers are similarly observed with probability discounting (Mitchell, 2004; Reynolds et al., 2004; Yi, Chase, & Bickel, 2007).

The research that does not support the common process hypothesis is based primarily on the different effects of magnitude observed across the types of discounting; temporal discounting decreases and probability discounting increases as the magnitude of the outcome increases (Christensen, Parker, Silbergeld, & Hursh, 1998; Myerson et al., 2003; see an excellent review in Green & Myerson, 2004). To date, this divergence of effects of magnitude Anacetrapib has only been observed in normal individuals, and we are not aware of any research that has examined this in drug-dependent individuals. And while Mitchell (2004) previously found no difference in the probability discounting of smokers as a function of smoking abstinence, extrapolating the conflicting results obtained in temporal discounting by smokers in the same study, a replication of this effect appears pertinent. No studies have previously examined probability discounting of losses by smokers during smoking abstinence. Present Study Given the importance of generalized changes in intertemporal decision making during smoking abstinence and the current uncertainty on whether possible changes during smoking abstinence are generalized to nondrug rewards, the current study examined temporal and probability discounting of gains and losses during acute smoking abstinence.