Randomized clinical trial examining financial incentives for smoking cessation among mothers of young children and possible impacts on child secondhand smoke exposure.

This randomized clinical trial examined whether financial-incentives increase smoking cessation among mothers of young children and potential impacts on child secondhand-smoke exposure (SHSe). 198 women-child dyads were enrolled and assigned to one of three treatment conditions: best practices (BP, N = 68), best practices plus financial incentives (BP + FI, N = 63), or best practices, financial incentives, and nicotine replacement therapy (BP + FI + NRT, N = 67). The trial was completed in Vermont, USA between June 2015 and October 2020. BP entailed staff referral to the state tobacco quitline; financial incentives entailed mothers earning vouchers exchangeable for retail items for 12 weeks contingent on biochemically-verified smoking abstinence; NRT involved mothers receiving 10 weeks of free transdermal nicotine and nicotine lozenges/gum. Baseline, 6-, 12-, 24-, and 48-week assessments were conducted. Primary outcomes were maternal 7-day point-prevalence abstinence and child SHSe through the 24-week assessment with the 48-week assessment exploratory. Results were analyzed using mixed model repeated measures for categorical data. Odds of maternal abstinence were greater among mothers in BP + FI and BP + FI + NRT compared to BP at the 6- and 12-week assessments (ORs ≥ 7.30; 95% CIs: 2.35-22.71); only abstinence in BP + FI remained greater than BP at the 24-week assessment (OR = 2.95; 95% CIs: 1.06-8.25). Abstinence did not differ significantly between treatment conditions at the 48-week assesssment. There was a significant effect of treatment condition (F[2109] = 3.64, P = .029) on SHSe with levels in BP and BP + FI significantly below BP + FI + NRT (ts[109] ≥ -2.30, Ps ≤ 0.023). Financial incentives for smoking abstinence are efficacious for increasing maternal cessation but that alone was insufficient for reducing child SHSe. ClinicalTrials.gov:NCT05740098.

Economic analysis of financial incentives for smoking cessation during pregnancy and postpartum.

Higgins and colleagues' recently-completed randomized controlled trial and pooled data with 4 related trials of smoking cessation in pregnant women in Vermont (USA) showed that abstinence-contingent financial incentives (FI) increased abstinence over control conditions from early pregnancy through 24-weeks postpartum. Control conditions were best practices (BP) alone in the recent trial and payments provided independent of smoking status (noncontingently) in the others. This paper reports economic analyses of abstinence-contingent FI. Merging trial results with maternal and infant healthcare costs from all Vermont Medicaid deliveries in 2019, we computed incremental cost-effectiveness ratios (ICERs) for quality-adjusted life years (QALYs) and compared them to established thresholds. The healthcare sector cost (±standard error) of adding FI to BP averaged $634.76 ± $531.61 per participant. Based on this trial, the increased probability per BP + FI participant of smoking abstinence at 24-weeks postpartum was 3.17%, the cost per additional abstinent woman was $20,043, the incremental health gain was 0.0270 ± 0.0412 QALYs, the ICER was $23,511/QALY gained, and the probabilities that BP + FI was very cost-effective (ICER≤$65,910) and cost-effective (ICER≤$100,000) were 67.9% and 71.0%, respectively. Based on the pooled trials, the corresponding values were even more favorable-8.89%, $7138, 0.0758 ± 0.0178 QALYs, $8371/QALY, 98.6% and 99.3%, respectively. Each dollar invested in abstinence-contingent FI over control smoking-cessation programs yielded $4.20 in economic benefits in the recent trial and $11.90 in the pooled trials (very favorable benefit-cost ratios). Medicaid and commercial insurers may wish to consider covering financial incentives for smoking abstinence as a cost-effective service for pregnant beneficiaries who smoke. Trial Registration: ClinicalTrials.gov identifier: NCT02210832.

Using an experimental tobacco marketplace to pilot test the substitutability of JUUL e-cigarettes and other alternative nicotine and tobacco products for conventional cigarettes among vulnerable populations.

The Experimental Tobacco Marketplace (ETM) is an online research marketplace where increasing the cost of cigarettes is used to investigate the substitutability of other fixed-price tobacco products such as electronic nicotine delivery systems (ENDS). The ETM is useful for modeling effects of potential policy changes on use of various concurrently available products. To our knowledge, the ETM has not been used to investigate substitutability of newer generation e-cigarettes or populations at increased risk for smoking, heavy smoking, nicotine dependence, and smoking-attributable adverse effects. In the current pilot study, participants were 30 adult daily smokers with socioeconomic disadvantage or comorbid psychiatric conditions (substance-use disorder or mental illness). In each session, cigarette prices increased ($0.12, $0.25, $0.50, $1.00. and $2.00 per cigarette) while prices for alternative products remained fixed. Across three ETM sessions, either all products, all products except little cigars and cigarillos (LCCs), or all products except ENDS (JUUL e-cigarettes) were available. Linear regression was performed on individual participant data using log-transformed cigarette price to determine demand and substitution. Cigarette demand decreased as price increased across sessions (significantly non-zero slopes, ps ≤ 0.0001). When all products were available, ENDS substitution increased as cigarette price increased (significantly non-zero slope, p = .016). When LCCs were unavailable, ENDS again were a significant substitute (p = .008). When ENDS were unavailable, LCCs did not substitute (ps ≥ 0.48). In all sessions, participants rarely purchased other products (e.g., snus). Overall, ENDS were the most robust substitute for cigarettes, further underscoring the potential importance of ENDS availability on the impact of tobacco regulatory policies.

Randomized Controlled Trial Examining the Efficacy of Adding Financial Incentives to Best practices for Smoking Cessation Among pregnant and Newly postpartum Women.

We report results from a single-blinded randomized controlled trial examining financial incentives for smoking cessation among 249 pregnant and newly postpartum women. Participants included 169 women assigned to best practices (BP) or BP plus financial incentives (BP + FI) for smoking cessation available through 12-weeks postpartum. A third condition included 80 never-smokers (NS) sociodemographically-matched to women who smoked. Trial setting was Burlington, Vermont, USA, January, 2014 through January, 2020. Outcomes included 7-day point-prevalence abstinence antepartum and postpartum, and birth and other infant outcomes during 1st year of life. Reliability and external validity of results were assessed using pooled results from the current and four prior controlled trials coupled with data on maternal-smoking status and birth outcomes for all 2019 singleton live births in Vermont. Compared to BP, BP + FI significantly increased abstinence early- (AOR = 9.97; 95%CI, 3.32-29.93) and late-pregnancy (primary outcome, AOR = 5.61; 95%CI, 2.37-13.28) and through 12-weeks postpartum (AOR = 2.46; CI,1.05-5.75) although not 24- (AOR = 1.31; CI,0.54-3.17) or 48-weeks postpartum (AOR = 1.33; CI,0.55-3.25). There was a significant effect of trial condition on small-for-gestational-age (SGA) deliveries (χ2 [2] = 9.01, P = .01), with percent SGA deliveries (+SEM) greatest in BP, intermediate in BP + FI, and lowest in NS (17.65 + 4.13, 10.81 + 3.61, and 2.53 + 1.77, respectively). Reliability analyses supported the efficacy of financial incentives for increasing abstinence antepartum and postpartum and decreasing SGA deliveries; external-validity analyses supported relationships between antepartum cessation and SGA risk. Adding financial incentives to Best Practice increases smoking cessation among antepartum and postpartum women and improves other maternal-infant outcomes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02210832.

Use of electronic nicotine delivery systems (ENDS) among U.S. women of reproductive age: Prevalence, reported reasons for use, and toxin exposure.

Given the rapidly expanding marketplace for Electronic Nicotine Delivery Systems (ENDS), it is important to monitor patterns of use, particularly among vulnerable populations. This study examined ENDS prevalence, reasons for use (i.e., to help quit smoking and for appealing flavors), and toxin exposure among U.S. women of reproductive age using data from the Population Assessment of Tobacco and Health (PATH) Study (2013-17). Exclusive ENDS users, dual users of ENDS and cigarettes, and exclusive cigarette smokers were compared within and between pregnant and not-pregnant women. Among pregnant women, prevalence of exclusive ENDS and dual use was similar (0.8%; 95%CI = 0.4-1.2% vs. 1.4%; 95%CI = 0.9-2.0%, respectively), but exclusive ENDS use was less prevalent than dual use among not-pregnant women (1.1%; 95%CI = 0.9-1.4% vs. 3.7%; 95%CI = 3.3-4.0%, respectively). Most women reported ENDs were used to help quit smoking (66.5-90.0%) and for appealing flavors (57.6-87.4%), and endorsement rates did not differ by use pattern or pregnancy status. Except for metals, toxin exposure was substantially lower for exclusive ENDS users relative to dual users and exclusive cigarette smokers regardless of pregnancy status. Pregnant and not-pregnant U.S. women regularly report using ENDS for help with quitting smoking and for appealing flavors. Although no type or pattern of tobacco/nicotine use is safe, especially during pregnancy, using ENDS exclusively is consistent with lower overall toxin exposure for pregnant and not-pregnant women. This study advances understanding of ENDS use and toxin exposure in women of reproductive age, a population highly vulnerable to the effects of nicotine/tobacco consumption.

Smoking prevalence among U.S. national samples of pregnant women.

Several data sources exist for estimating U.S. smoking prevalence among pregnant women, yet each differs in ways that have the potential to impact the estimates. In the present study we used the Population Assessment of Tobacco and Health (PATH), the National Survey on Drug use and Health (NSDUH), and the Pregnancy Risk Assessment Monitoring System (PRAMS), three common data sources, to evaluate the following questions about estimating U.S. smoking prevalence among pregnant women: To what extent are estimates impacted by differences in whether the samples include younger (<18 years) or older (>44 years) women, represent smoking in any trimester or only the 3rd, and use data from nationally representative or more selected national samples. Among the factors examined, inclusion of younger or older women does not appear to meaningfully alter prevalence estimates. Focusing on only the third trimester likely underestimates smoking prevalence, while the influence of basing estimates on selected national subgroups of women (i.e., only women who delivered live born infants) rather than nationally representative surveys has little discernible influence. Going forward, this research area would benefit from greater consistency in explicitly discussing the sampling methods used and how these various methods may have influenced the estimates reported.

Comparing participant estimated demand intensity on the cigarette Purchase Task to consumption when usual-brand cigarettes were provided free.

Accumulating evidence suggests that the hypothetical Cigarette Purchase Task (CPT), especially its demand Intensity index (i.e., estimated cigarettes participants would smoke if free), is associated with individual differences in smoking risk. Nevertheless, few studies have examined the extent to which hypothetical CPT demand Intensity may differ from consumption when participants are provided with free cigarettes. That topic is the overarching focus of the present study. Participants were 745 adult smokers with co-morbid psychiatric conditions or socioeconomic disadvantage. CPT was administered for usual-brand cigarettes prior to providing participants with seven days of their usual-brand cigarettes free of cost and consumption was recorded daily via an Interactive Voice Response (IVR) System. Demand Intensity was correlated with IVR smoking rate (rs 0.670-0.696, ps < 0.001) but estimates consistently exceeded IVR smoking rates by an average of 4.4 cigarettes per day (ps < 0.001). Importantly, both measures were comparably sensitive to discerning well-established differences in smoking risk, including greater cigarettes per day among men versus women (F(1,732) = 18.74, p < 0.001), those with versus without opioid-dependence (F(1,732) = 168.37, p < 0.001), younger versus older adults (F(2,730) = 32.93, p < 0.001), and those with lower versus greater educational attainment (F(1,732) = 38.26, p < 0.001). Overall, CPT demand Intensity appears to overestimate consumption rates relative to those observed when participants are provided with free cigarettes, but those deviations are systematic (i.e., consistent in magnitude and direction, Fs all <1.63; ps > 0.19 for all interactions with subgroups). This suggests that demand Intensity was sensitive to established group differences in smoking rate, supporting its utility as an important measure of addiction potential.

Sensitivity of hypothetical purchase task indices when studying substance use: A systematic literature review.

Hypothetical Purchase Tasks (HPTs) simulate demand for a substance as a function of escalating price. HPTs are increasingly used to examine relationships between substance-related correlates and outcomes and demand typically characterized using a common battery of indices (Intensity, Omax, Pmax, Breakpoint, Elasticity). This review examines the relative sensitivity of the HPT indices. Reports were identified using the search term "purchase task" in PubMed and Web of Science. For inclusion, reports had to be original studies in English, examine relationships between HPT indices and substance-related correlates or outcomes, and appear in a peer-reviewed journal through December 2017. Indices were compared using effect sizes (Cohen's d) and the proportion of studies in which statistically significant relationships were observed. The search identified 1274 reports with 114 (9%) receiving full-text review and 82 (6%) meeting inclusion criteria. 41 reports examined alcohol, 34 examined cigarettes/nicotine products, and 10 examined other substances. Overall, statistically significant relationships between HPT indices and substance-related correlates and outcomes were most often reported for Intensity (88.61%, 70/79), followed by Omax (81.16%, 56/69), Elasticity (72.15%, 57/59), Breakpoint (62.12%, 41/66), and Pmax (48.08%; 25/52). The largest effect sizes were observed for Intensity (0.75 ±â€¯0.04, CI 0.67-0.84) and Omax (0.64 ±â€¯0.04, CI 0.56-0.71), followed by Elasticity (0.44 ±â€¯0.04, CI 0.37-0.51), Breakpoint (0.30 ±â€¯0.03, CI 0.25-0.36), and Pmax (0.25 ±â€¯0.04, CI 0.18-0.33). Patterns were largely consistent across substances. In conclusion, HPTs can be highly effective in revealing relationships between demand and substance-related correlates and outcomes, with Intensity and Omax exhibiting the greatest sensitivity.

Current cigarette smoking among U.S. college graduates.

Although U.S. college graduates are at relatively low risk for smoking, 12-15% of U.S. smokers (~8 million people) are college graduates. Few studies have examined smoking risk among college graduates. To address that gap, the present study examined smoking risk among U.S. college graduates and those who did not graduate from college in a nationally representative sample of adults (National Survey on Drug Use and Health 2011-2017, n = 202,137). We examined smoking risk in association with well-established risk factors: alcohol abuse/dependence, drug abuse/dependence, mental illness, age, sex, race/ethnicity, and poverty status, using group contrasts and Classification and Regression Tree (CART) modeling. Smoking prevalence among U.S. college graduates and non-graduates was 10% and 26%, respectively. College graduates initiated any smoking and daily smoking at a later age and were lighter smokers than smokers who did not graduate college. Within college graduate and non-graduate groups, prevalence rates varied by orders of magnitude across different risk-factor profiles (ranges = 3-37% and 14-73% among graduates and non-graduates, respectively). Past year drug abuse/dependence was a robust predictor of smoking prevalence in both populations. For college graduates, past year alcohol abuse/dependence and mental illness were stronger predictors of smoking compared to those who did not graduate college, for whom race/ethnicity and age were stronger predictors. Overall, smoking risk increases to surprisingly high levels, even among college graduates, when select risk factors co-occur, particularly psychiatric conditions. Socio-demographic risk factors appear to be less robust predictors of smoking risk among college graduates relative to those who did not graduate college.

Examining associations between impulsivity, opioid use disorder, and posttraumatic stress disorder: The additive relation between disorders.

Impulsivity is a key feature of opioid use disorder (OUD) and other psychiatric conditions, including posttraumatic stress disorder (PTSD). The relationship between disorders and impulsivity may be additive, such that individuals with multiple disorders exhibit greater impulsivity than those with a single disorder. However, the association between impulsivity, OUD, and PTSD is unclear. Accordingly, this study compared individuals with concurrent OUD and PTSD (OUD + PTSD; n = 55), OUD without PTSD (OUD-PTSD; n = 34), PTSD without OUD (n = 32), and healthy controls (HCs; n = 55) on the Short Urgency, Premeditation, Perseverance, Sensation Seeking, Positive Urgency Impulsive Behavior Scale (SUPPS-P), and the 27-item Monetary Choice Questionnaire (MCQ). With respect to the SUPPS-P, the OUD + PTSD, OUD-PTSD, and PTSD without OUD groups reported more impulsivity on the negative urgency, positive urgency, and lack of premeditation subscales compared to HCs (ps < .001). The OUD + PTSD group also reported greater negative urgency compared to the OUD-PTSD group (p = .001) and HCs (p < .001), but not the PTSD without OUD group (p = .07). Furthermore, participants with OUD + PTSD exhibited greater discounting of delayed rewards on the MCQ than those in the PTSD without OUD group and HCs (p's < .001). However, no significant differences were observed between the two OUD groups (p = .86). These results support impulsivity as a mechanism underlying both OUD and PTSD. Future research should examine whether interventions targeting impulsivity, emotion regulation, and delay discounting are associated with meaningful improvements in functioning among individuals with OUD and PTSD. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Resurgence during transitions from variable- to fixed-interval schedules.

The effects of local periods of extinction on resurgence following transitions from variable-interval (VI) to fixed-interval (FI) schedules were studied using four pigeons exposed to a within-session resurgence procedure. Each session was divided into a Training (T) Alternative-Reinforcement (AR), and Resurgence Test (RT) phase. During the T phase, key pecking was reinforced under a VI 60-s schedule on one key. In the AR phase, responses reinforced in the T phase were extinguished, while responses to a different key were reinforced under a VI 90-s schedule. Next, responding to the same key that produced reinforcers in the AR phase was reinforced according to four different RT conditions: RT phase I (FI 90 s), RT phase II (FI 180 s), RT phase III (FI 45 s), or RT phase IV (extinction). The frequency of resurgence generally was an inverse function of the rate of reinforcement in the RT phase. Resurgence occurred less often when reinforcers were delivered under the FI 45-s schedule and more often under leaner schedules in the RT phase, peaking under extinction. The results show that resurgence may occur during local periods of extinction, with larger and more consistent effects occurring when the rate of reinforcement in the RT condition is leaner than it was during the preceding AR phase.

Both reducing cigarettes per day and transitioning to very low-nicotine-content cigarettes decreases demand for usual-brand cigarettes.

Reducing cigarettes per day (CPD) and transitioning to very low-nicotine-content (VLNC) cigarettes appear to decrease nicotine dependence. Other well-accepted measures of the addictiveness of cigarettes involve behavioral economic simulation models, such as the cigarette purchase task (CPT), which characterizes the reinforcing efficacy of cigarettes. Currently it is unclear whether reducing CPD or reducing nicotine through VLNC cigarettes leads to greater reductions in the reinforcing efficacy of cigarettes. The current paper reports a secondary analysis of a 5-week, 2-arm unblinded randomized trial, in which participants were instructed to gradually reduce to 70%, 35%, 15%, and 3% of baseline nicotine over 4 weeks by either (a) reducing CPD (n = 32) or (b) switching to VLNC cigarettes (n = 36). Participants completed the CPT for their usual-brand cigarettes at baseline and again at a 1-month follow-up. Demand was significantly reduced for participants' usual-brand cigarettes in both the CPD, t(18) = 7.65, p < .0001, and the VLNC groups, t(18) = 7.39, p < .0001, from prereduction procedure to the 1-month follow-up. Maximum consumption at zero price (intensity), and maximum expenditure (Omax), were reduced significantly for both the CPD group, t(16) = 3.23, p = .005; t(16) = 3.71, p = .002, respectively, and the VLNC group, t(22) = 3.62, p = .002; t(22) = 3.14, p = .005, respectively, prereduction procedure to the 1-month follow-up. Thus, despite the different mechanisms by which the value of cigarettes was manipulated, both interventions reduced the reinforcing efficacy of cigarettes. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Resurgence without overall worsening of alternative reinforcement.

Three experiments were conducted with pigeons to assess discriminated periods of nonreinforcement as precipitators of resurgence. Each experiment occurred in three phases. In the Training phase, key-pecking was reinforced according to variable-interval schedules that alternated between two response keys (Experiment 1) or were concurrently available on two response keys (Experiments 2a & 2b). In the Alternative-Reinforcement phase, responding to one key was extinguished, while that to the other was reinforced according to tandem schedules. These then were replaced by chained schedules with the same programmed reinforcement rate in the Resurgence-Test phase. Resurgence occurred both when the signaled period of nonreinforcement was a darkened keylight in the terminal link of the chain schedule (Experiment 1) and a darkened keylight (Experiment 2a) or keylight color change (Experiment 2b) in the initial link of the chain schedule. Thus, signaled periods of extinction, without accompanying reductions in reinforcement rate, precipitated resurgence, suggesting that resurgence is not the result of worsening of overall reinforcement conditions, but also occurs when local conditions of reinforcement are worsened.

Does DRO type matter?: Cycle versus resetting contingencies in eliminating responding.

Following lever-press training on variable-interval 30-s schedules, rats were exposed to three types of schedules designed to eliminate lever pressing. The first two were variations on what is called a differential-reinforcement-of-other-behavior (DRO, "zero rate", or [target response] omission schedule) schedule. Under both variations, reinforcers were scheduled to occur in different conditions after either fixed or variable inter-reinforcer intervals (IRIs). Under one variation each lever press reset the time interval (i.e., "resetting DRO") and under the other a reinforcer delivery scheduled at the end of an IRI was cancelled by the first response during the IRI (i.e., "cycle DRO"). In another condition reinforcers were delivered independently of responding after fixed or variable time periods. Each of the DRO procedures reduced response rates quickly and to near zero across ten sessions. The time schedules also reduced responding, albeit at a slower rate. The results extend the analogy of omission training to freeoperant avoidance to shock-deletion avoidance schedules.

Using the Cigarette Purchase Task to examine the relative reinforcing value of cigarettes among mothers with versus without opioid dependence.

The Cigarette Purchase Task (CPT), in which participants estimate the number of cigarettes they would smoke across increasing cigarette prices, measures the relative reinforcing value of cigarettes. Although opioid-dependent individuals are particularly vulnerable to tobacco addiction, more research is needed to elucidate whether and to what extent their motivation to smoke differs from not-opioid-dependent smokers controlling for potential sociodemographic differences. Participants were 173 women (65 opioid-dependent) in an ongoing clinical trial for smoking cessation. Baseline CPT responses were compared between opioid-dependent and not-opioid-dependent women using five demand indices: Demand Intensity; Omax; Pmax; Breakpoint (BP); and α, and two latent factors: Amplitude and Persistence. Final regression models adjusted for sociodemographic characteristics differing between the two groups. Opioid-dependent women had greater demand Intensity (i.e., number of cigarettes they would smoke if they were free) than not-opioid dependent women in the adjusted model, F(1, 156) = 6.93, p = .016. No other demand indices differed significantly. Regarding latent factors, demand Amplitude (i.e., volumetric consumption), but not Persistence (i.e., price insensitivity), was greater for opioid-dependent women in the adjusted model, F(1, 146) = 4.04, p = .046. These results further demonstrate that the CPT is a highly sensitive task that can illuminate potentially important individual and population differences in the relative reinforcing value of smoking. Greater demand Intensity and Amplitude differentiated smokers with comorbid opioid dependence; thus, decreasing smoking prevalence among opioid-dependent populations may require policies and interventions that can decrease cigarette demand Intensity and Amplitude. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Behavioral economic measurement of cigarette demand: A descriptive review of published approaches to the cigarette purchase task.

The cigarette purchase task (CPT) is a behavioral economic method for assessing demand for cigarettes. Growing interest in behavioral correlates of tobacco use in clinical and general populations as well as empirical efforts to inform policy has seen an increase in published articles employing the CPT. Accordingly, an examination of the published methods and procedures for obtaining these behavioral economic metrics is timely. The purpose of this investigation was to provide a review of published approaches to using the CPT. We searched specific Boolean operators (["behavioral economic" AND "purchase task"] OR ["demand" AND "cigarette"]) and identified 49 empirical articles published through the year 2018 that reported administering a CPT. Articles were coded for participant characteristics (e.g., sample size, population type, age), CPT task structure (e.g., price framing, number and sequence of prices; vignettes, contextual factors), and data analytic approach (e.g., method of generating indices of cigarette demand). Results of this review indicate no standard approach to administering the CPT and underscore the need for replicability of these behavioral economic measures for the purpose of guiding clinical and policy decisions. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Contingency tracking during unsignaled delayed reinforcement: Effects of delay duration and d-amphetamine.

In two experiments, the role of the response-reinforcer relation in maintaining low-rate responding under unsignaled delay conditions was investigated. In both experiments pecking by pigeons on one response key, denoted the relevant key, was reinforced under an unsignaled delay-of-reinforcement procedure (defined as tandem variable-interval (VI) differential-reinforcement-of-other behavior [DRO] schedule). Responding on a second key, denoted the irrelevant key, had no programmed consequences. Between sessions, the location of the relevant key varied (after one, two, or three sessions) pseudorandomly. In Experiment 1, the delay (DRO) duration was manipulated parametrically. Overall, proportional relevant-key response rates (relevant-key response rates / [relevant-key response rates + irrelevant key response rates]) increased across 3-session sequences in which the relevant key remained in the same location and decreased as the DRO duration was changed systematically (2, 5, and 10 s). In Experiment 2, acute administration of d-amphetamine increased proportional relevant-key response rates during 1-day sequences for only the DRO 5-s duration, and results over 3-day sequences, once a discrimination had already been established, were inconsistent. Results support that the response-reinforcer relation is the primary determinant of responding, and such discriminations are relatively resistant to disruption or potentiation by behaviorally active doses of d-amphetamine.

Examining interrelationships between the Cigarette Purchase Task and delay discounting among pregnant women.

Two common behavioral economic simulation tasks used to study cigarette smoking are the Cigarette Purchase Task, a measure of cigarette demand, and delay discounting, a measure of the subjective value of rewards as a function of delays to delivery. Few studies have evaluated whether combining these tasks enhances understanding of smoking beyond either alone. The current study represents an initial evaluation of the intersection between cigarette demand indices and delay discounting among pregnant smokers by examining associations between these measures and whether a woman makes antepartum quit attempts before entering prenatal care (a reliable predictor of eventual quitting). Participants were 159 pregnant women enrolled in a smoking-cessation trial. Low O max and shallow discounting were each associated with antepartum quit attempts. Participants were next categorized into four subgroups (low O max , shallow discounting; low O max , steep discounting; high O max , shallow discounting; high O max , steep discounting) using median splits. Those with shallow discounting and low O max were more likely to have made quit attempts than each of the other three subgroups. That is, steep discounting appears to undermine the association of low O max and efforts to quit smoking during pregnancy while high O max overshadows any protective influence associated with shallow discounting.

Reinforcer magnitude and resurgence.

One experiment each was conducted with pigeons and rats to assess the effects of changes in reinforcer magnitude on resurgence. Each experiment involved three phases. In the Training phase, key pecking (Experiment 1) or lever pressing (Experiment 2) on two concurrently available operanda was reinforced according to variable-interval schedules. In the Alternative Reinforcement phase, responding to one operandum was extinguished while that to the other was reinforced with greater duration of food access (Experiment 1), greater number of pellets (Experiment 2a), or a similar number of pellets (Experiment 2b) than occurred in the Training phase. In the Resurgence Test phase, the reinforcer magnitude associated with the Alternative response was either reduced (Experiments 1 & 2a) or increased (Experiment 2b) relative to the preceding condition. Resurgence generally occurred when the reinforcer magnitude maintaining the Alternative response was reduced, but not when it was increased relative to the preceding condition. The results further support the suggestion that resurgence results from an overall "worsening" of reinforcement conditions, but not simply from a change in conditions.

Stimulus contributions to operant resurgence.

In two experiments, pigeons were exposed to a three-phase resurgence procedure (train Response A; extinguish Response A and train Response B; extinguish Response B). In the first experiment, the stimuli associated with phases were different, resulting in a resurgence procedure combined with an ABC renewal procedure. Presenting the novel stimulus, C, during extinction of both responses in the third phase resulted in minimal resurgence. Subsequently, substituting the original training Stimulus A for Stimulus C resulted in resurgence with all pigeons. In the second experiment, resurgence with the same stimuli present in all three phases of the resurgence procedure (AAA) was compared concurrently with a resurgence procedure in which the ABC renewal procedure used in Experiment 1 was superimposed. Substantially more resurgence occurred with the AAA procedure compared to the ABC procedure. Although ABC renewal in combination with the resurgence procedure generated some resurgence, such recurrent responding was attenuated relative to that observed when the stimulus conditions were constant across phases. Combined with earlier research showing the enhancing effects of combining resurgence and ABA renewal procedures, the present results elaborate on how stimuli correlated with certain behavioral histories affect the course of operant resurgence.