I combine theory and methodology from economics, psychology, and neuroscience to understand how people decide, why they make wrong decisions, and how to make them better choosers. My research focused on how economic preferences change over the lifespan and contexts, including how thirst, being observed, outdoor luminance, as well as the structure of current and past choice affect behavior.
I have been awarded over $33 million in grants as a Chief Investigator, including ARC Centre of Excellence, DECRA, Discovery, and Linkage grants. In 2017 I received the Award from the Society for Neuroeconomics for my contributions to our understanding of decision-making.
Published papers
Kettlewell N. and Tymula A. (2024) Heritability across different domains of trust, Journal of Economic Behavior and Organization, 219:549-563
Pastore C., Schurer S., Tymula A., Fuller N, Caterson I. (2023) Economic Preferences and Obesity: Evidence from a Clinical Lab-in-Field Experiment, Health Economics, 32:2147-2167
Berger A. and Tymula A. (2022) Controlling ambiguity: The illusion of control in decision-making under risk and ambiguity [short poster presentation] Journal of Risk and Uncertainty 10.1007/s11166-022-09399-4
Cheung S. L., Tymula A., Wang X. (2022) Present Bias for Monetary and Dietary Rewards: Evidence from Chinese Teenagers, Experimental Economics, 25: 1202–1233
Guo J. and Tymula A. (2021) Waterfall illusion in risky choice, European Economic Review, 139
Tymula A. and Wang X. (2021) Increased risk-taking, not loss tolerance, drives adolescents’ propensity to gamble more under peer observation, [supplement], Journal of Economic Behaviour and Organization, 188:439-457
Weinrabe A., Chung H., Tymula A., Tranand J., Hickie I. (2020) Economic Rationality in Young People with Emerging Mood Disorder, Journal of Neuroscience, Economics, and Psychology
Tymula (2019) Adolescents are more impatient and inconsistent, not more risk-taking when observed by peers – a comprehensive study of adolescent behavior under peer observation, Journal of Economic Behavior and Organisation, 166:735-750
Chung, H., Glimcher. P.W., Tymula, A. (2019) An Experimental Comparison of Risky and Riskless Choice – Limitations of Prospect Theory and Expected Utility Theory, American Economic Journal: Micro, 11(3):34-67
Rosato A. and Tymula A. (2019) Loss Aversion and Competition in Vickrey Auctions: Money Ain’t No Good, Games and Economic Behavior, 115: 188-208
Published book chapters
Tymula A. (2019). Brain Morphometry for Economists: How do Brain Volume Constraints Affect Our Choices? in Biophysical Measurement in Experimental Social Science Research, Foster (Eds.), ELSEVIER
Other writing
Tymula A. (2016) Financial gamble? My brain made me do it. The Conversation
- featured on Scientific American Blog Network
- written for the Young Minds of the 2014 USA Science and Engineering Festival
Tymula A. (2014) Explainer: neuroeconomics, where science and economics meet. The Conversation
Book review of After Phrenology: Neural Reuse and the Interactive Brain, Michael L. Anderson. The MIT Press, Cambridge, MA, USA (2014) in Journal of Economic Psychology, Volume 51, December 2015, p. 279–280
Papers under review
Cheung S., Tymula, A. and Wang X. (2023) Quasi-hyperbolic present bias: A meta-analysis [short poster presentation] revision requested from Management Science
Quasi-hyperbolic discounting is one of the most well-known and widely-used models to capture self-control problems in the economics literature. The underlying assumption of this model is that agents have a “present bias” toward current consumption such that all future rewards are downweighed relative to rewards in the present (in addition to standard exponential discounting for the length of delay). We report a meta-analytic dataset of estimates of the present bias parameter based on searches of all major research databases (62 papers with 81 estimates in total). We find that the literature shows that people are on average present biased for both monetary rewards (beta=0.82, 95% confidence interval of [0.74, 0.90]) and non-monetary rewards (beta=0.66, 95% confidence interval of [0.51, 0.85]) but that substantial heterogeneity exists across studies. The source of this heterogeneity comes from the subject pool, elicitation methodology, geographical location, payment method, mode of data collection (e.g. laboratory or field), and reward type. There is evidence of selective reporting and publication bias in the direction of overestimating the strength of present-bias (making estimates smaller), but present bias still exists after correcting for these issues (for money beta=0.87 with 95% confidence interval of [0.82, 0.92] after correcting for selective reporting).
Kettlewell N. and Tymula A. (2024) Heritability of different types of overconfidence
Incorrect estimation of own absolute and relative abilities is common and can have detrimental effects on a person’s educational, social, employment, and financial outcomes. It is not yet fully understood from where interpersonal differences in overconfidence emerge. In this paper, we estimate the heritability of two types of overconfidence, overestimation and overplacement, in a sample of 1120 twins. We find that the genetic heritability of both types of overconfidence is about 19% and that most of the interindividual variation in overconfidence is due to individual-specific environmental factors.
Kettlewell N., Tymula, A. and Yoo H. (2023) The heritability of economic preferences
We study the heritability of risk, uncertainty, and time preferences using a field experiment with a large sample of adult twins. We also offer a meta-analysis of existing findings. Our field study introduces a novel empirical approach that marries behavioral genetics with structural econometrics. This allows us to, for the first time, quantify the heritability of economic preference parameters directly without employing proxy measures. Our incentive-compatible experiment is the first twin study to elicit all three types of preferences for the same individual. Compared to previous studies, we find a greater role of genes in explaining risk and uncertainty preferences, and of the shared familial environment in explaining time preferences. Time preferences appear more important from policy and parenting perspectives since they exhibit limited genetic variation and are more than twice as sensitive to the familial environment as risk and uncertainty preferences.
Kettlewell N., Levy J., Tymula A., Wang X. (2023) The gender reference point gap
Studies have frequently found that women are more risk averse than men. In this paper, we depart from usual practice in economics that treats risk attitude as a primitive, and instead adopt a neuroeconomic approach where risk attitude is determined by the reference point which can be easily estimated using standard econometric methods. We then evaluate whether there is a gender difference in the reference point, explaining the gender difference in risk aversion observed using traditional approaches. In our study, women make riskier choices less frequently than men. Compared to men, we find that women on average have a significantly lower reference point. By acknowledging the reference point as a potential source of gender inequality, we can begin a new discussion on how to address this important issue.
Rosato A. and Tymula A. (2021) A novel experimental test of truthful bidding in second-price auctions with real objects, revise and resubmit at the Journal of Behavioral and Experimental Economics
We present experimental evidence on bidding in second-price auctions with real objects. Our novel design, combining a second-price auction with an individual-specific binary-choice task based on the outcome of the auction, allows us to directly identify over- and under-bidding. We analyze bidding in real-object and induced-value auctions and find significant deviations from truthful bidding in both. Overall, under-bidding is somewhat more prevalent than over-bidding; yet, the latter has a bigger magnitude, especially with induced values. At the individual level, we find no relation between the tendency to deviate from truthful bidding in induced-value vs. real-object auctions.
Akbari M., Alladi V., Je H. and Tymula A (2023) Ambiguity vulnerability
We theoretically define and empirically investigate a new notion: ambiguity vulnerability. Ambiguity vulnerability posits that individuals exhibit greater risk aversion in their decisions when faced with a background (that is beyond an individual’s control) prospect that has unknown probabilities (background ambiguity) than one with known probabilities (background risk). We find empirical evidence of ambiguity vulnerability, with individuals investing 11% less when faced with background ambiguity compared to background risk. We provide evidence on the relationship between utility shape and risk and ambiguity vulnerability. Finally, our results suggest that financial stress could be perceived as a form of background uncertainty, potentially reducing individuals’ profitable investments.
Less – traditional research output
Decision-making and ageing exhibit at the Museum of the National Academy of Sciences in Washington, DC (part of the Life Lab exhibit)
- on display May 2012 – September 2018