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.

The acceptability of an Internet-based contingency management (CM) intervention for cigarette-smoking was evaluated in two experiments. In Experiment 1, 67 participants completed an Internet-based CM intervention and then answered questions about the intervention. Experiment 2 assessed the acceptability of the intervention among potential treatment users (smokers, n = 164), non-smokers (n = 166), and healthcare providers (n = 139), who had never used the intervention. Participants in Experiment 2 were randomly assigned to either watch a video describing the standard CM intervention (No Deposit Group) or to watch a video about the standard intervention plus a deposit incentive (Deposit Group). Overall, results of both experiments indicated high acceptability across all dimensions of the intervention. Seventy-four percent of participants in Experiment 1, and 92% of those in Experiment 2, said they would use it if they needed to quit. Eighty one percent of healthcare providers reported that they would be very likely to recommend the intervention to patients. Participants in both experiments reported that monitoring their progress and earning vouchers were strengths of the intervention. The No Deposit group rated voucher earnings, cash earnings, and cost-effectiveness of the intervention higher than the Deposit Group. Healthcare professionals did not differ in their ratings across video conditions. Overall, the results suggest that Internet-based CM is acceptable as a method to help people quit smoking.

Impulsive choice underlies several psychological disorders and can be assessed in laboratory rats using delay-discounting tasks, in which choice is for either one food pellet immediately or three food pellets after a delay. Choice for the smaller, immediate reinforcer is considered the impulsive choice. Lewis (LEW) and Fischer 344 (F344) rats differ in the number of impulsive choices made during this task when singly housed, with LEW choosing the impulsive option more often. Due to increasing recommendations to provide environmental enrichment as a component of animal-husbandry practices, a systematic replication of two previous studies was conducted using pair-housed LEW and F344. Delay discounting was assessed with pair-housed LEW and F344 and compared to previous data from singly housed LEW and F344 collected from the same laboratory. Results showed that differences in impulsive choice between the two strains were attenuated with pair housing. The main result driving this change appears to be an increase in impulsive choice in pair-housed F344 relative to singly housed F344.

Temporal Bisection and Effects of d-Amphetamine Administration in Lewis and Fischer 344 Rats Marissa Turturici Temporal control concerns the discrimination of intervals of time. Individuals with various psychological disorders have shown differences in temporal control when compared to control populations. It is unknown whether and how temporal control might be linked with impulsivity, another measure that predicts problem behavior such as attention-deficit/hyperactivity disorder. Because Lewis (LEW) rats reliably show greater impulsive choice relative to Fischer 344 (F344) rats, the present study examined responding in these two strains under a temporal-bisection procedure that assesses temporal control. In the temporal-bisection procedure, rats are trained to discriminate between two durations. Intermediate durations are subsequently presented to determine the duration at which responding is nearly equally distributed between the original training durations. This duration is the bisection point. Because LEW rats show greater impulsive choice, it was hypothesized that LEW rats would show overestimation of duration (shorter bisection points). This effect would indicate that the subjective experience of duration, or delay, is longer for LEW rats. Results indicated that LEW rats' bisection points were shorter on average than F344 rats' bisection points in the baseline phase of the experiment. The baseline difference between LEW and F344 was not replicated during a subsequent phase of the experiment, but LEW and F344 rats did show differential effects of d-amphetamine on behavior during select conditions and doses. Effects of d-amphetamine replicated previous studies that showed apparent loss of stimulus control with increasing d-amphetamine doses, as opposed to underestimation or overestimation of temporal duration. The results generally add to the evidence supporting a link between impulsivity and temporal control. Nonhuman Animal Studies .

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