Date of Graduation


Document Type


Degree Type



Eberly College of Arts and Sciences



Committee Chair

Karen G. Anderson

Committee Member

Kathryn Kestner

Committee Member

Melissa Blank


Risky choice can be operationally defined as the choice for a larger, uncertain reinforcer over a smaller, certain reinforcer. Research suggests smokers engage in more risky or maladaptive decisions when compared to nonsmokers. The relation between nicotine and risky choice could benefit from further investigation, since nicotine is the active substance of tobacco products that maintains tobacco addiction. Acute nicotine administration has shown to alter risky choice; however, since the everyday smoker uses nicotine repeatedly, more research on chronic administration is warranted and would allow for assessment of tolerance or sensitization of these effects. The present study investigated effects of acute and chronic nicotine administration on risky decision-making in Sprague-Dawley rats using a probability-discounting procedure. The probability-discounting procedure included discrete-trial choices between a small, certain reinforcer and a larger, uncertain reinforcer. The probability of larger-reinforcer delivery systematically decreased across blocks with each session. At baseline, larger-reinforcer choice systematically declined as a function of decreasing probabilities of delivery, indicating that choice was sensitive to the programmed contingencies of the procedure. Acute nicotine administration dose-dependently increased risky choice. Tolerance to nicotine’s effects on larger-reinforcer choice was observed after repeated 1.0 mg/kg nicotine administration. The results of the present study add to the existing literature that acute nicotine administration increases risky choice and demonstrate that tolerance to this effect develops after chronic exposure to the drug. Possible mechanisms behind this effect are discussed, as are suggestions for future research on nicotine and risky choice.

Embargo Reason

Publication Pending