Development of a Tissue Engineered Heart Valve for Pediatrics: A Case Study in Bioengineering Ethics

The following hypothetical case study was developed for bioengineering students and is concerned with choosing between two devices used for development of a pediatric tissue engineered heart valve (TEHV). This case is intended to elicit assessment of the devices, possible future outcomes, and ramifications of the decision making. It is framed in light of two predominant ethical theories: utilitarianism and rights of persons. After the case was presented to bioengineering graduate students, they voted on which device should be released. The results revealed that these bioengineering students preferred the more reliable (and substantially more expensive) design, though this choice precludes the majority of the world from having access to this technology. This case is intended to examine and explore where the balance lies between design, cost, and adequate distribution of biomedical devices.     

Are Plans Necessary?

According to classical decision theory, an agent realises at time t the option with maximum expected utility (determined by his beliefs and desires at t), where the relevant options are possible actions performed at t. I consider an alternative according to which the relevant options are in general plans, complex courses of action extending into the future.     

People accounting: Social category-based choice

This paper presents people accounting—a hypothesis that describes how a simple numerical imbalance in representation along nominal social category lines can affect people’s choice of candidates in highly competitive situations (e.g., awards, jobs, etc.). For example, two scholarship finalists from California and New York may be equally qualified, but the award-winning chance for the California candidate will drop precipitously if 8 of the past 10 winners were from California. Studies 1-3 illustrate this effect. Study 4 links people accounting to intergroup fairness concerns and suggests that people accounting is more likely to occur when the category dimension is meaningful (e.g., Stanford/Princeton) than when it is not (e.g., left/right-handedness). Study 5 shows that candidates from overrepresented categories (e.g., “Californians”) must achieve higher minimum standards in order to be selected. The implication is that highly competitive decisions are often influenced by headcounts along mundane social category lines.     

Regulatory focus and investment decisions in small groups

Regulatory Focus Theory was applied to small interactive groups. Based on previous research, it was expected that groups with a promotion focus would discuss gain-relevant information, whereas groups with a prevention focus would be concerned with potential losses. Furthermore, promotion groups were expected to make riskier decisions than prevention groups. Regulatory focus was manipulated by rewarding good or penalizing poor group performance on a preliminary task. Subsequently, three-person groups discussed several investment funds and made a consensual investment decision. Results supported the hypotheses and suggested that regulatory focus requires time to exert its influence in groups.     

Distortion of probability and outcome information in risky decisions

Substantial evidence indicates that information is distorted during decision making, but very few studies have assessed the distortion of probability and outcome information in risky decisions. In two studies involving six binary decisions (e.g., banning blood donations from people who have visited England, because of “mad cow disease”), student and nonstudent participants distorted their evaluations of probability and outcome information in the direction of their preferred decision alternative and used these biased evaluations to update their preferences. Participants also evaluated the utilities of possible outcomes more positively when the outcomes could follow only from the preferred alternative and more negatively when they could follow only from the competing alternative. Such circular reasoning is antithetical to the normative consequentialist principles underlying decision analysis. Presenting numerical information as precise values or as ranges of values did not significantly affect information distortion, apparently because the manipulation did not affect perceived ambiguity as intended.     

Short-term gains, long-term pains: How cues about state aid learning in dynamic environments

Successful investors seeking returns, animals foraging for food, and pilots controlling aircraft all must take into account how their current decisions will impact their future standing. One challenge facing decision makers is that options that appear attractive in the short-term may not turn out best in the long run. In this paper, we explore human learning in a dynamic decision making task which places short- and long-term rewards in conflict. Our goal in these studies was to evaluate how people’s mental representation of a task affects their ability to discover an optimal decision strategy. We find that perceptual cues that readily align with the underlying state of the task environment help people overcome the impulsive appeal of short-term rewards. Our experimental manipulations, predictions, and analyses are motivated by current work in reinforcement learning which details how learners value delayed outcomes in sequential tasks and the importance that “state” identification plays in effective learning.     

Cognitive models of choice: comparing decision field theory to the proportional difference model

People often face preferential decisions under risk. To further our understanding of the cognitive processes underlying these preferential choices, two prominent cognitive models, decision field theory (DFT; Busemeyer & Townsend, 1993 ) and the proportional difference model (PD; González-Vallejo, 2002 ), were rigorously tested against each other. In two consecutive experiments, the participants repeatedly had to choose between monetary gambles. The first experiment provided the reference to estimate the models' free parameters. From these estimations, new gamble pairs were generated for the second experiment such that the two models made maximally divergent predictions. In the first experiment, both models explained the data equally well. However, in the second generalization experiment, the participants' choices were much closer to the predictions of DFT. The results indicate that the stochastic process assumed by DFT, in which evidence in favor of or against each option accumulates over time, described people's choice behavior better than the trade-offs between proportional differences assumed by PD.