Bethany R. Raiff

Delay discounting of potentially real and hypothetical rewards: II. Between- and within-subject comparisons.

Prior studies comparing discounting of delayed hypothetical or potentially real rewards have reported no differences, but they used within-subjects designs. This raises the possibility that participants remembered their choices in one condition and repeated them in the other. In Experiment 1, between-subjects comparisons were made with an adjusting-amount procedure. No significant effect of reward type on delay discounting was detected. Experiment 2 increased the proportion of real rewards and made between- and within-subject comparisons. These comparisons also failed to reveal a significant effect of reward type. Although these findings are consistent with prior findings, caution is urged because choices involving hypothetical rewards have yet to be compared with choices involving real rewards (i.e., the consequences of every choice are obtained) in an experiment using forced-choice trials and steady-state methodology.

Single-Case Experimental Designs to Evaluate Novel Technology-Based Health Interventions

Technology-based interventions to promote health are expanding rapidly. Assessing the preliminary efficacy of these interventions can be achieved by employing single-case experiments (sometimes referred to as n-of-1 studies). Although single-case experiments are often misunderstood, they offer excellent solutions to address the challenges associated with testing new technology-based interventions. This paper provides an introduction to single-case techniques and highlights advances in developing and evaluating single-case experiments, which help ensure that treatment outcomes are reliable, replicable, and generalizable. These advances include quality control standards, heuristics to guide visual analysis of time-series data, effect size calculations, and statistical analyses. They also include experimental designs to isolate the active elements in a treatment package and to assess the mechanisms of behavior change. The paper concludes with a discussion of issues related to the generality of findings derived from single-case research and how generality can be established through replication and through analysis of behavioral mechanisms.

Contingency Management in the 21st Century: Technological Innovations to Promote Smoking Cessation

Information technology represents an excellent medium to deliver contingencies of reinforcement to change behavior. Recently, we have linked the Internet with a science-based, behavioral treatment for cigarette smoking: abstinence reinforcement therapy. Under abstinence reinforcement interventions, incentives are provided for objective evidence of abstinence. Several studies suggest that the intervention is effective in initiating abstinence. The intervention addresses limitations (access, cost, sustainability, and dissemination potential) inherent in traditional abstinence reinforcement delivery models. It can also be applied to vulnerable, at-risk populations, and to other behavior to promote health. Information technologies offer unprecedented and rapidly expanding opportunities to facilitate behavior change.

INTERNET-BASED CONTINGENCY MANAGEMENT TO IMPROVE ADHERENCE WITH BLOOD GLUCOSE TESTING RECOMMENDATIONS FOR TEENS WITH TYPE 1 DIABETES

The current study used Internet-based contingency management (CM) to increase adherence with blood glucose testing to at least 4 times daily. Four teens diagnosed with Type 1 diabetes earned vouchers for submitting blood glucose testing videos over a Web site. Participants submitted a mean of 1.7 and 3.1 blood glucose tests per day during the 2 baseline conditions, respectively, compared to 5.7 tests per day during the intervention. Participants and their guardians rated the program favorably on a number of dimensions. The results suggest that Internet-based CM is feasible, acceptable, and effective to increase self-monitoring of blood glucose in teens.

Prevalence of Video Game Use, Cigarette Smoking, and Acceptability of a Video Game–Based Smoking Cessation Intervention Among Online Adults

INTRODUCTION Video games may serve as an ideal platform for developing and implementing technology-based contingency management (CM) interventions for smoking cessation as they can be used to address a number of barriers to the utilization of CM (e.g., replacing monetary rewards with virtual game-based rewards). However, little is known about the relationship between video game playing and cigarette smoking. The current study determined the prevalence of video game use, video game practices, and the acceptability of a video game-based CM intervention for smoking cessation among adult smokers and nonsmokers, including health care professionals. METHODS In an online survey, participants (N = 499) answered questions regarding their cigarette smoking and video game playing practices. Participants also reported if they believed a video game-based CM intervention could motivate smokers to quit and if they would recommend such an intervention. RESULTS Nearly half of the participants surveyed reported smoking cigarettes, and among smokers, 74.5% reported playing video games. Video game playing was more prevalent in smokers than nonsmokers, and smokers reported playing more recently, for longer durations each week, and were more likely to play social games than nonsmokers. Most participants (63.7%), including those who worked as health care professionals, believed that a video game-based CM intervention would motivate smokers to quit and would recommend such an intervention to someone trying to quit (67.9%). CONCLUSIONS Our findings suggest that delivering technology-based smoking cessation interventions via video games has the potential to reach substantial numbers of smokers and that most smokers, nonsmokers, and health care professionals endorsed this approach.

Responding maintained by primary reinforcing visual stimuli is increased by nicotine administration in rats

Nicotine has been shown to increase responding maintained by turning off a houselight. To examine whether this effect extends to other primary reinforcing visual stimuli, the present study assessed whether nicotine would increase responding maintained by the illumination, and not just the darkening, of a visual stimulus. One group of rats (n=4) was initially trained to press two levers, using food as a consequence, while a separate group of rats (n=4) was initially trained to press one lever. After training, all rats pressed an active lever to turn on or turn off a houselight for 10s, while presses on an inactive lever had no programmed consequences. A third group of rats (n=4) were never trained to press either of the two levers and did not experience any programmed consequences for pressing. Although nicotine slightly increased lever pressing on both levers in the third group, nicotine resulted in much greater increases in responding maintained by the visual stimuli in the first two groups. Nicotine selectively increased responding maintained by visual stimuli, regardless of which levers were originally trained and regardless of whether those stimuli consisted of turning on or turning off a houselight, suggesting that nicotine enhances the value of primary reinforcing visual stimuli.

Effects of acute and chronic nicotine on responses maintained by primary and conditioned reinforcers in rats.

There is growing recognition that nonnicotine factors, such as the sensory stimuli associated with smoking, can play a critical role in the maintenance of cigarette smoking. However, little is known about the effects of nicotine on responding maintained by these stimuli, which are assumed to be conditioned reinforcers. The authors used an animal model to examine the acute and chronic effects of nicotine on responses maintained by food and conditioned reinforcers (i.e., lights) and responses in the absence of programmed consequences (i.e., extinction). During the acute phase, 4 male rats received 5 doses of subcutaneous nicotine. One dose of nicotine was then administered for a minimum of 60 days. Food-maintained and extinction responses did not significantly increase during the acute phase; however, food-maintained responses did increase during the chronic phase. Relative to vehicle, intermediate doses increased responses maintained by conditioned reinforcers during both phases. The results suggest that nicotine enhances responding maintained by conditioned reinforcers and possibly by food.

Breath carbon monoxide output is affected by speed of emptying the lungs: Implications for laboratory and smoking cessation research

INTRODUCTION Researchers have used breath carbon monoxide (CO) cutoff values ranging from 4 to 10 ppm to define abstinence in cigarette-smoking cessation research and reductions in CO as a measure of acute abstinence in laboratory research. The current study used a reversal design to investigate effects of exhalation speed on CO output in four groups (non-, light, moderate, and heavy smokers; n = 20 per group). METHODS In one condition, participants were instructed to empty their lungs as quickly as possible (fast), whereas in a different condition, participants were instructed to empty their lungs at a slow pace (slow). Conditions were counterbalanced and repeated twice for each participant. RESULTS For all groups, speed of exhalation was significantly lower during the slow condition than during the fast condition, and CO output was significantly higher during the slow condition than during the fast condition. Sensitivity and specificity analyses revealed that the optimal CO cutoff for smoking abstinence was 3 ppm during the fast condition versus 4 ppm during the slow condition. Additionally, when heavy smokers switched from exhaling slow to exhaling fast, they showed an approximately 30% reduction in CO. DISCUSSION The results suggest that exhalation speed should be monitored when CO is used as a measure of smoking status for laboratory and smoking cessation research. If exhalation speed is not monitored when using CO to verify smoking cessation, then more conservative CO cutoff values should be used to avoid false negative CO readings.

Smoking Abstinence-Induced Changes in Resting State Functional Connectivity with Ventral Striatum Predict Lapse During a Quit Attempt

The ventral and dorsal striatum are critical substrates of reward processing and motivation and have been repeatedly linked to addictive disorders, including nicotine dependence. However, little is known about how functional connectivity between these and other brain regions is modulated by smoking withdrawal and may contribute to relapse vulnerability. In the present study, 37 smokers completed resting state fMRI scans during both satiated and 24-h abstinent conditions, prior to engaging in a 3-week quit attempt supported by contingency management. We examined the effects of abstinence condition and smoking outcome (lapse vs non-lapse) on whole-brain connectivity with ventral and dorsal striatum seed regions. Results indicated a significant condition by lapse outcome interaction for both right and left ventral striatum seeds. Robust abstinence-induced increases in connectivity with bilateral ventral striatum were observed across a network of regions implicated in addictive disorders, including insula, superior temporal gyrus, and anterior/mid-cingulate cortex among non-lapsers; the opposite pattern was observed for those who later lapsed. For dorsal striatum seeds, 24-h abstinence decreased connectivity across both groups with several regions, including medial prefrontal cortex, posterior cingulate cortex, hippocampus, and supplemental motor area. These findings suggest that modulation of striatal connectivity with the cingulo-insular network during early withdrawal may be associated with smoking cessation outcomes.

Response-cost punishment with pigeons: further evidence of response suppression via token loss.

Four pigeons responded on a two-component multiple token-reinforcement schedule, in which tokens were produced according to a random-interval 30-sec schedule and exchanged according to a variable-ratio 4 schedule in both components. To assess the effects of contingent token loss, tokens were removed after every second response (i.e., fixed-ratio 2 loss) in one of the components. Response rates were selectively lower in the loss components relative to baseline (no-loss) conditions, as well as to the within-condition no-loss components. Response rates were decreased to a greater degree in the presence of tokens than in their absence. To control for the effects of changes in the density of token and food reinforcement, two parts consisted of additional conditions where food density and token loss were yoked to those in a previous loss condition. In the yoked-food condition, tokens were produced as usual in both components, but the overall density of food reinforcement in one of the components was yoked to that obtained during a previous token-loss condition. In the yoked token-loss condition, tokens were removed during one component of the multiple schedule at a rate that approximately matched the obtained rate of loss from a previous token-loss condition. Response rates in these yoked components were less affected than those in comparable loss components, despite similar densities of token, exchange, and food reinforcement. On the whole, the results support the conclusion that contingent token loss serves as an effective punisher with pigeons.