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.

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Impulsive choice, or preference for small immediate reinforcers over large delayed reinforcers, has been associated with cigarette smoking. The direct effects of nicotine on impulsive choice in laboratory animals are unknown. We examined the effects of acute and chronic nicotine injections, and the termination of injections, on impulsive choice in rats. Five rats made choices between a one- and a three-pellet reinforcer in a discrete trials procedure. The delay to the smaller reinforcer was always 1 s. A computer adjusted the delay to the larger reinforcer until the pattern of choices reflected indifference between the two alternatives. We assessed the effects of acute and chronic nicotine (vehicle, 0.03, 0.1, 0.3 and 1.0 mg/kg nicotine). The latency to make the first response of the session increased under the acute 1.0 mg/kg dose. There were no consistent differences in the effects of acute and chronic nicotine on response latency and lever pressing during the delays between choices. Acute injections of nicotine dose-dependently increased impulsive responding. After chronic injections, impulsive responding was increased equivalently regardless of dose, and it was increased even in the absence of nicotine. After drug injections were terminated, behavior remained impulsive for about 30 drug-free sessions, and then responding gradually returned to baseline levels. The results suggest that increases in impulsive choice were not due to anorectic effects, response biases or changes in conditioned reinforcement. Nicotine may have decreased the value of delayed reinforcers. Chronic nicotine exposure produced long-lasting but reversible increases in impulsive choice.

Despite the link between inactivity and premature mortality, most adults exercise less than the Centers for Disease Control and Prevention (2008) recommends; thus, interventions to increase exercise are needed. The present study employed an Internet-based intervention to increase walking in 12 sedentary adults over 50 years of age. In Experiment 1, participants received monetary consequences for meeting an increasing series of step goals on at least 3 days during consecutive 5-day blocks. Across participants, steps increased 182% from screening to the end of the intervention, and 87% of step goals were met. In Experiment 2, goals were set using the same schedule as in Experiment 1, but no monetary consequences were provided for meeting them. Across participants, steps increased 108%, and 52% of goals were met. Across both studies, 11 of 12 participants increased their steps according to experimenter-arranged criteria. These results support the efficacy of an Internet-based intervention to increase walking in sedentary adults.

The patch did not attenuate delay discounting or smoking after a period of deprivation, but contingencies for abstinence significantly decreased smoking. Higher rates of delay discounting were related to smoking in a model of abstinence reinforcement treatment.