Agnieszka Tymula

A substantial body of behavioral economics literature links obesity to time preferences, notably impatience—a time‐consistent preference for earlier rewards—and present bias—the disproportionate overweighting of immediate payoffs that leads to dynamic inconsistency. Unlike much previous literature, which asks whether time preferences predict weight in broader populations, we examine whether they predict subsequent weight loss among adults who already have overweight or obesity. Using clinically measured outcomes and incentivized preference data from 287 adults with obesity and pre‐diabetes enrolled in a 12‐month randomized lifestyle‐intervention trial, we find that neither impatience nor present bias predicts reductions in body fat or BMI. These findings are robust to alternative measurement strategies and are not explained by the impatience‐related attrition that we uncover. To strengthen external validity, we replicate the null relationship using self‐reported time preference measures in a nationally representative sample of 7277 adults with overweight or obesity. As baseline impatience meaningfully reduces the likelihood of trial completion, we conclude that impatience affects adherence to medically recommended programs but does not directly impede weight‐loss success among those who remain engaged. Interventions targeting impatience or self‐control alone may therefore be insufficient to promote weight loss in clinical populations.

Traditional prescriptive decision theories from Pascal’s Expected Value to Expected Utility have struggled to explain inconsistent human choices, leading to purely descriptive models like prospect theory. This paper introduces a novel approach to understand why these behaviors occur, reconciling these observed irrationalities with a simple rational objective, specifically in the domain of riskless choice when choosing between options with certain outcomes. Here, we propose that the human nervous system, faced with limited cognitive capacity (a finite representational precision for the subjective values of rewards), optimally selects a task-appropriate utility function to either maximize long-run average earnings or to minimize errors when choosing between certain outcomes. We argue that the utility functions psychologists and economists have measured empirically are tools, sculpted by knowledge of the choice environment's probabilistic structure and the decision-maker's precision level, for optimally achieving a rational objective. Our results show that almost every experimentally observed utility function can be described as a near-optimal tool for achieving a maximization of objective earnings, a goal abandoned since Bernoulli. We quantify the specific gains that result when a chooser decides to add more cognitive capacity when facing a choice and find that these gains are quite small as long as the utility function is rationally selected. Our research provides a novel framework that offers a testable and foundational explanation for why human and animal decision-makers evolved the puzzling range of utility functions and risk attitudes that have been observed empirically.

We investigate the heritability of risk, uncertainty, and time preferences using a large-scale field experiment with adult twins, complemented by a comprehensive meta-analysis of prior studies. Our research introduces a novel empirical approach that integrates behavioral genetics with structural econometrics, enabling us to directly quantify the heritability of latent preference parameters in behavioral models of decision making, without relying on observed proxies. Our incentive-compatible experiment is the first to simultaneously elicit all three types of preferences within the same individuals in a twin study. Our findings reveal a stronger genetic influence on risk and uncertainty preferences than previously reported. We demonstrate that conventional proxy measures for preferences and simplified structural models tend to overstate the influence of unique environmental factors. These results help contextualize preference heterogeneity as a driver of persistent differences in decision making across individuals, leaders, and organizations. This paper was accepted by Aurélien Baillon, behavioral economics and decision analysis. Funding: Support from the University of Technology Sydney and from the Australian Government through the Australian Research Council’s Centre of Excellence for Children and Families over the Life Course [Project IDs CE140100027 and CE200100025] is gratefully acknowledged. This research was facilitated through access to Twins Research Australia, a national resource supported by the National Health & Medical Research Council since 1981, administered by the University of Melbourne. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2025.00669 .

Unequal access to opportunity is a pervasive feature of economic life and is recognized to affect outcomes through income and wealth. We experimentally investigate whether experiencing exogenously imposed unfair chances of success alters subsequent economic decisions in unrelated contexts. Participants were randomly assigned unequal probabilities of receiving a small performance-based bonus, holding productivity constant. Despite identical post-treatment opportunities, participants exposed to low chances subsequently invested less in ambiguous assets, while risky investments were unchanged. We explore wealth, prior discrimination, and beliefs as potential moderators. We show that unfair treatment generates behavioral spillovers beyond its original context, highlighting a missing channel through which unequal opportunity can reinforce economic disadvantage.

Why do nonlinear utility and stochastic choice persist when both reduce earnings? We answer by endogenizing cognitive capacity in a model of repeated riskless choice. In our model, objective prizes are encoded as bounded, noisy subjective utilities. Higher capacity improves discrimination and reduces errors but is costly. The model captures diminishing returns to cognitive capacity and predicts endogenous and environment-specific optimal capacity and utility curvature. Changes in the range and shape of the prize distribution, as well as the number of possible prizes, and the size of the choice set influence optimal capacity and utility. We conclude that utility curvature and choice stochasticity need not reflect fixed preferences or irrationality. They can emerge jointly as an optimal response to costly cognition and the expected economic environment.

We test whether acute psychosocial stress affects time preferences in a laboratory experiment. Using a validated stress induction and an incentive-compatible elicitation of time preferences, we find no statistically detectable effect of acute stress on patience or present bias, despite strong physiological and self-reported stress responses. These results suggest that, in our laboratory setting and within the precision afforded by our sample, acute psychosocial stress does not appear to systematically alter intertemporal decision-making. They also highlight the need to examine whether chronic or domain-specific stressors have more robust effects.

This paper reports a meta-analysis of 86 studies of the two parameters of quasi-hyperbolic ([ ]) discounting, the dominant model of self-control failures in behavioral economics. The central tenet of the model is that decision makers have a “present bias,” [ ], for immediate rewards, on top of standard exponential discounting of the future, [ ]. After correcting for selective reporting, we obtain a meta-analytic estimate of [ ] for money of 0.938, with 95% confidence interval [0.905, 0.972]. For nonmonetary rewards, our estimate of [ ] is 0.750, with 95% confidence interval [0.643, 0.857], and there is no evidence of selective reporting. We find that present bias for real effort, although stronger than for money, is weaker than for other rewards such as real consumption. This paper was accepted by Manel Baucells, behavioral economics and decision analysis. Funding: This research was partly supported by the Australian Government through the Australian Research Council’s Centre of Excellence for Children and Families over the Life Course [Project IDs CE140100027 and CE200100025]. S. L. Cheung received financial support from the Australian Research Council [Grant DP160101794]. A. Tymula received financial support from the University of Sydney [Bridging Grant G199763]. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2023.04003 .

We test whether acute psychosocial stress affects time preferences in a laboratory experiment. Using a validated stress induction and an incentive-compatible elicitation of time preferences, we find no effect of acute stress on patience or present bias, despite strong physiological and self-reported stress responses. Our results suggest that acute stress may not meaningfully distort intertemporal decision-making and highlight the need to examine whether chronic or domain-specific stressors have more robust effects.

Self-control, attention, and impulsivity jointly support goal-directed behavior yet are often examined in isolation with heterogeneous measures. We integrate validated self-reported scales with a hybrid, incentivized behavioral task that synthesizes two canonical experimental designs and adds novel extensions to measure these constructs in a typical work context. Using data from a preregistered four-session online study (N = 443 adults), we characterize the cross-relationships and the relationships between different measures of self-control, attention, and impulsivity and evaluate their contributions to effort allocation over time. More broadly, the study advances an emerging research program that leverages laboratory settings with well-structured economic incentives to examine the role of personality traits and cognitive limitations in economic decision making.