Master of Science / Department of Psychological Sciences / Kimberly Kirkpatrick / The present experiments examined the effect of different uncertain-reward magnitudes (i.e., gains and losses) on global and local probabilistic choice behavior in rats. In two experiments, rats were given a choice between a variable-amount certain outcome that delivered 2 or 4 pellets and a variable-amount uncertain outcome that probabilistically delivered a larger reward. In Experiment 1, the larger uncertain outcome was always 11 pellets and different groups received 1, 2, or 4 pellets for the uncertain small reward. In Experiment 2, the uncertain small reward was always 4 pellets and different groups received 6, 9, or 11 pellets for the uncertain large reward. In both experiments, the rats increased their uncertain choice behavior with the probability of uncertain food. In Experiment 1, the magnitude of the uncertain small outcome affected choice behavior; there was no such effect of the uncertain large reward magnitude in Experiment 2. The group differences in choice behavior suggest that the expected value of the certain choice served as a reference point distinguishing uncertain gains and losses, and that the rats exhibited differential sensitivities to such outcomes. As some extant theoretical frameworks of choice behavior seem unable to account for all of the present data, a possible mechanism for the present results is proposed. These results emphasize the importance of identifying the choice outcomes that constitute gains and losses in animals such that the effects of prior uncertain gains and losses on subsequent choice behavior can be adequately and comprehensively understood.

Doctor of Philosophy / Department of Psychological Sciences / Laura A. Brannon / The current research investigated strategies to reduce cell phone use while driving. Anti-distracted driving campaigns, which typically communicate risk information and target driver behavior, may produce limited effects because people tend to underestimate their risk from this behavior (e.g., Schlehofer et al., 2010). Study 1 compared the effects of messages targeting drivers to messages targeting non-drivers in order to examine the potential of discouraging people from having cell phone communication with others who are driving. Some anti-distracted driving campaigns have emphasized the potential harm to both the driver and others, but whether one approach (self-oriented or other-oriented messaging) is more persuasive than the other has not been examined empirically. Study 1 compared messages that were self-oriented, other-oriented, or neutral in terms of who could be affected by cell phone use while driving. Although cell phone use while driving generally is perceived as dangerous, people may make justifications for engaging in the behavior on at least some occasions, and these justifications may override the influence of risk knowledge on behavior. Consistent with inoculation theory (McGuire, 1961), if given the opportunity to practice refuting these justifications in a controlled setting, people will be more likely to defend themselves against justifications to engage in cell phone use while driving. Thus, Study 1 tested the prediction that participation in an inoculation task would reduce the likelihood of cell phone use while driving. Results from Study 1 suggested an advantage of targeting non-driving participants of cell phone conversations to enhance efforts for reducing on-the-road cell phone use. Study 1 also demonstrated a positive effect of inoculation, but primarily for behavior of non-driving participants of cell phone conversations. In addition to overconfidence in ability to avoid risk, habitual tendencies also may impede the influence of risk communication campaigns (Bayer & Campbell, 2012). Study 2 investigated the potential of mindfulness-based and implementation intentions techniques for helping people overcome habitual responses to their cell phone when doing so is inappropriate or inconvenient. Results indicated that pairing mindfulness-based training with risk information may be significantly more effective than risk information alone at inhibiting inappropriate cell phone use.