http://hdl.handle.net/2097/1260 2013-05-25T17:46:48Z http://hdl.handle.net/2097/15548 Examining the impact of consumer feedback on internet product evaluation: comparing base-rate and case history information Nettelhorst, Stephen C.; Brannon, Laura A.; Hill, W. Trey Two important pieces of information for consumers evaluating products online are consumer ratings (i.e. base-rates) and consumer reviews (i.e. case histories). While literature in cognitive psychology shows a tendency to weigh case history information more heavily than base-rate information, other consumer oriented studies show the opposite. This study examined the relative impact of each type of information by treating consumer ratings and reviews as orthogonal factors and then manipulating the valence of each type of information. Participants evaluated a novel health beverage by viewing consumer ratings and/or reading their reviews about the product. Results indicated that the valence of the base-rate information significantly affected participants’ evaluation of the product only when case history information was not presented. When case history information was presented, the valence of such information significantly affected participants’ evaluation of the product regardless of the valence of any base-rate information. These results demonstrate that base-rate neglect may bias individuals’ evaluations of products since base-rate information tends to be more representative of a population than case history information. Thus determining ways of making base-rate information more impactful in consumer settings is an important goal. 2013-04-22T00:00:00Z http://hdl.handle.net/2097/15497 Magnitude effects for experienced rewards at short delays in the escalating interest task Young, Michael E.; Webb, Tara L.; Sutherland, Steven C.; Jacobs, Eric A. A first-person shooter video game was adapted for the study of choice between smaller sooner and larger later rewards. Participants chose when to fire a weapon that increased in damage potential over a short interval. When the delay to maximum damage was shorter (5 – 8 s), people showed greater sensitivity to the consequences of their choices than when the delay was longer (17 – 20 s). Participants also evidenced a magnitude effect by waiting proportionally longer when the damage magnitudes were doubled for all rewards. The experiment replicated the standard magnitude effect with this new video game preparation over time scales similar to those typically used in nonhuman animal studies and without complications due to satiation or cost. 2013-04-12T00:00:00Z http://hdl.handle.net/2097/15495 The effects of the previous outcome on probabilistic choice in rats Marshall, Andrew T.; Kirkpatrick, Kimberly This study examined the effects of previous outcomes on subsequent choices in a probabilistic-choice task. Twenty-four rats were trained to choose between a certain outcome (one or three pellets) vs. an uncertain outcome (three or nine pellets) delivered with a probability of .1, .33, .67, and .9 in different phases. Uncertain outcome choices increased with the probability of uncertain food. Additionally, uncertain choices increased with the probability of uncertain food following both certain-choice outcomes and unrewarded uncertain choices. However, following uncertain-choice food outcomes, there was a tendency to choose the uncertain outcome in all cases, indicating that the rats continued to “gamble” after successful uncertain choices regardless of the overall probability or magnitude of food. A subsequent manipulation, in which the probability of uncertain food varied within each session as a function of the previous uncertain outcome, examined how the previous outcome and probability of uncertain food affected choice in a dynamic environment. Uncertain-choice behavior increased with the probability of uncertain food. The rats exhibited increased sensitivity to probability changes and a greater degree of win-stay / lose-shift behavior than in the static phase. Simulations of two sequential choice models were performed to explore the possible mechanisms of reward value computations. The simulation results supported an exponentially decaying value function that updated as a function of trial (rather than time). These results emphasize the importance of analyzing global and local factors in choice behavior, and suggest avenues for the future development of sequential-choice models. 2013-04-12T00:00:00Z http://hdl.handle.net/2097/15440 Impulsive choice behavior in four strains of rats: evaluation of possible models of Attention Deficit/Hyperactivity Disorder Garcia, Ana; Kirkpatrick, Kimberly Several studies have examined impulsive choice behavior in spontaneously hypertensive rats (SHRs) as a possible pre-clinical model for Attention-Deficit/Hyperactivity Disorder (ADHD). However, this strain was not specifically selected for the traits of ADHD and as a result their appropriateness as a model has been questioned. The present study investigated whether SHRs would exhibit impulsive behavior in comparison to their control strain, Wistar Kyoto (WKY) rats. In addition, we evaluated a strain that has previously shown high levels of impulsive choice, the Lewis (LEW) rats and compared them with their source strain, Wistar (WIS) rats. In the first phase, rats could choose between a Smaller-sooner (SS) reward of 1 pellet after 10 s and a Larger-later (LL) reward of 2 pellets after 30 s. Subsequently, the rats were exposed to increases in LL reward magnitude and SS delay. These manipulations were designed to assess sensitivity to magnitude and delay within the choice task to parse out possible differences in using the strains as models of specific deficits associated with ADHD. The SHR and WKY strains did not differ in their choice behavior under either delay or magnitude manipulations. In comparison to WIS, LEW showed deficits in choice behavior in the delay manipulation, and to a lesser extent in the magnitude manipulation. An examination of individual differences indicated that the SHR strain may not be sufficiently homogeneous in their impulsive choice behavior to be considered as a viable model for impulse control disorders such as ADHD. The LEW strain may be worthy of further consideration for their suitability as an animal model. 2013-04-02T00:00:00Z