Making Assessments While Taking Sequential Risks

Making Assessments While Taking Sequential Risks Avishai Wershbale (wershbal@msu.edu) & Timothy J. Pleskac (pleskact@msu.edu) Department of Psychology, Michigan State University, East Lansing, MI 48824 postulated within the components of the model have received less direct attention. In this study, we focus on the BART and test some of the processing implications of its respective cognitive model. In particular we use inter pump times to better understand the response selection process that decision makers use to take sequential risks during the BART. Abstract This study utilized inter pump response times on a laboratory gambling task, the BART, to examine cognitive aspects of response selection during sequential risky decision making. Findings suggest a response procedure that utilizes multiple levels of processing. Amount of task exposure as well as the distance to the goal both affect the rate at which assessments are made, with task exposure decreasing assessment rate, while target distance increases assessment rate. Several alternative models are fit to the data, to determine if the behavioral results can be informative of a model that more accurately reflects differences in processing. Balloon Analogue Risk Task (BART; Lejuez et al., During the BART participants are presented with a computerized balloon, a pump button, and a stop button. Pressing the pump button inflates the balloon, and also puts money in a temporary bank. Balloons in the BART explode after a randomly predetermined amount of pumps are made. An explosion terminates the trial and all money in the temporary bank is lost. Clicking the stop button, transfers the temporary points into the permanent bank and also terminates that trial. The participant’s goal in the BART is to earn as much money as they can, but they need to take into account the chance that the balloon could pop. Participants typically complete 30 independent balloon trials. Participants are given no information about the design of the task, other than the basic reward and punishment rules, and the fact that the balloon will explode before it fills the entire screen. It is up to the participant to determine the amount of risk they are willing to incur for a given reward. Though the BART may seem simple at first, there are many processes that take place within the course of completing the task. The processes have been formally defined in the Bayesian Sequential Risk Taking model (BSR; Wallsten et al., 2005). Keywords: Psychology, Decision Making, Mathematical Modeling, Cognitive Decision Theory Introduction People take sequential risks every day. Drivers repeatedly choose to talk on the cell phone, or text while driving each time they get in their car. People every day choose to eat at their favorite fast food establishment. Smokers of all ages repeatedly choose to smoke a cigarette. In all of these situations, our choice is not a one-shot deal rather our choices occur many times sequentially over the course of a day, a week, a month, etc. Often we are even presented with the same or similar choices on multiple occasions. Sometimes these choices may even change as a function of time or even as a function our previous choices (Busemeyer & Pleskac, 2009). Despite the many instances of sequential risks in the real world, most of the laboratory analogs of risky decision making only ask participants to make one single choice (e.g., Hertwig, Barron, Weber, & Erev, 2004; Kahneman & Tversky, 1979). However, a number of laboratory-based gambling tasks have now been developed that require people to take sequential risk, such as the Iowa Gambling Task (Bechara, Damasio, & Anderson, 1994); the Balloon Analogue Risk Task (BART; Lejuez et al., 2002); or the Angling Risk Task (Pleskac, 2008). These tasks also appear to have some construct validity with real world risk taking. Risk taking in the BART, for example, correlates with smoking and drug abuse, as well as safety issues including seatbelt usage and safe sex (Lejuez et al., 2002; Lejuez, Aklin, Zvolensky, & Pedulla, 2003; Pleskac, Wallsten, Wang, & Lejuez, 2008). The overall decision making processes for these sequential risk taking tasks are also reasonably well understood. In fact, the processes have been formalized in terms of cognitive models (Busemeyer & Stout, 2002; Wallsten, Pleskac, & Lejuez, 2005). However, the processes Bayesian Sequential Risk Taking (BSR) Model We briefly review the general processes of this 4 parameter model (for a formal derivation see Pleskac, 2008; Wallsten et al., 2005). The BSR model consists of three sub processes. The first process is a reward evaluation process. During this process, participants select a target pump number to pump the balloon towards. The target selected is a function of the participant’s subjective value of a reward and their perceived chance that an explosion will occur for any pump. Participants who value the reward more will increase their target amount of pumps to be made, while an increase in the perceived chance of an explosion occurring decreases this pumping target.