ORCID Profile
0000-0002-0521-8477
Current Organisation
University of Sydney
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Experimental Economics | Applied Economics | Social Change | Public Economics- Publically Provided Goods | Demography | Family and Household Studies | Social Policy
ANZSRC Socio-Economic Objective (SEO)
Preference, Behaviour and Welfare | Expanding Knowledge through Studies of Human Society | Families and Family Services | Public Services Policy Advice and Analysis | Social Class and Inequalities |
Related Links
Publications
A neuronal prospect theory model in the brain reward circuitry
Publisher: Springer Science and Business Media LLC
Date: 04-10-2022
DOI: 10.1038/S41467-022-33579-0
Abstract: Prospect theory, arguably the most prominent theory of choice, is an obvious candidate for neural valuation models. How the activity of in idual neurons, a possible computational unit, obeys prospect theory remains unknown. Here, we show, with theoretical accuracy equivalent to that of human neuroimaging studies, that single-neuron activity in four core reward-related cortical and subcortical regions represents the subjective valuation of risky gambles in monkeys. The activity of in idual neurons in monkeys passively viewing a lottery reflects the desirability of probabilistic rewards parameterized as a multiplicative combination of utility and probability weighting functions, as in the prospect theory framework. The erse patterns of valuation signals were not localized but distributed throughout most parts of the reward circuitry. A network model aggregating these signals reconstructed the risk preferences and subjective probability weighting revealed by the animals’ choices. Thus, distributed neural coding explains the computation of subjective valuations under risk.
Let the sunshine in? The effects of luminance on economic preferences, choice consistency and dominance violations
Publisher: Public Library of Science (PLoS)
Date: 04-08-2017
Thirst-dependent risk preferences in monkeys identify a primitive form of wealth
Publisher: Proceedings of the National Academy of Sciences
Date: 09-09-2013
Abstract: We show that monkeys display similar risk preferences and rationality to those of humans, suggesting that despite concerns raised by earlier reports, they can serve as a model for human behavior. Standard experimental economic techniques have long allowed us to evaluate human risk attitudes, but we do not know how they relate to wealth levels, a critical variable in economic models. We find thirsty monkeys to be more risk averse and discuss implications for the role of wealth in human decision making.
Feedback, Self-Esteem, and Performance in Organizations
Publisher: Institute for Operations Research and the Management Sciences (INFORMS)
Date: 2012
Abstract: We examine whether private feedback about relative performance can mitigate moral hazard in competitive environments by modifying the agents' self-esteem. In our experimental setting, people work harder and expect to rank better when told that they may learn their ranking, relative to cases when feedback will not be provided. In iduals who ranked better than expected decrease output but expect a better rank in the future, whereas those who ranked worse than expected increase output but lower their future rank expectations. Feedback helps create a ratcheting effect in productivity, mainly because of the fight for dominance at the top of the rank hierarchy. Our findings suggest that organizations can improve employee productivity by changing the likelihood of feedback, the reference group used to calculate relative performance, and the informativeness of the feedback message. This paper was accepted by Brad Barber, Teck Ho, and Terrance Odean, special issue editors.
Dynamic prospect theory - two core economic decision theories coexist in the gambling behavior of monkeys
Publisher: Cold Spring Harbor Laboratory
Date: 05-04-2021
DOI: 10.1101/2021.04.04.438415
Abstract: Research in behavioral economics and reinforcement learning has given rise to two influential theories describing human economic choice under uncertainty. The first, prospect theory, assumes that decision-makers use static mathematical functions, utility and probability weighting, to calculate the values of alternatives. The second, reinforcement learning theory, posits that dynamic mathematical functions update the values of alternatives based on experience through reward prediction error (RPE). To date, these theories have been examined in isolation without reference to one another. Therefore, it remains unclear whether RPE affects a decision-maker’s utility and/or probability weighting functions, or whether these functions are indeed static as in prospect theory. Here, we propose a dynamic prospect theory model that combines prospect theory and RPE, and test this combined model using choice data on gambling behavior of captive macaques. We found that under standard prospect theory, monkeys, like humans, had a concave utility function. Unlike humans, monkeys exhibited a concave, rather than inverse-S shaped, probability weighting function. Our dynamic prospect theory model revealed that probability distortions, not the utility of rewards, solely and systematically varied with RPE: after a positive RPE, the estimated probability weighting functions became more concave, suggesting more optimistic belief about receiving rewards and over-weighted subjective probabilities at all probability levels. Thus, the probability perceptions in laboratory monkeys are not static even after extensive training, and are governed by a dynamic function well captured by the algorithmic feature of reinforcement learning. This novel evidence supports combining these two major theories to capture choice behavior under uncertainty. We propose and test a new decision theory under uncertainty by combining pre-existing two influential theories in the neuroeconomics: prospect theory from economics and prediction error theory from reinforcement learning. Collecting a large dataset (over 60,000 gambling decisions) from laboratory monkeys enables us to test the hybrid model of these two core decision theories reliably. Our results showed over-weighted subjective probabilities at all probability levels after lucky win, indicating that positive prediction error systematically bias decision-makers more optimistically about receiving rewards. This trial-by-trial prediction-error dynamics in probability perception provides outperformed performance of the model compared to the standard static prospect theory. Thus, both static and dynamic elements coexist in monkey’s risky decision-making, an evidence contradicting the assumption of prospect theory.
Dynamic prospect theory - two core decision theories coexist in the gambling behavior of monkeys and humans
Publisher: Research Square Platform LLC
Date: 09-09-2022
DOI: 10.21203/RS.3.RS-2017714/V1
Abstract: Research in the multidisciplinary field of neuroeconomics has been driven by two influential theories regarding human economic choice: prospect theory, which describes decision-making under risk, and reinforcement learning theory, which describes learning for decision-making. We hypothesized that these two distinct theories guide decision-making in a comprehensive manner. Here, we propose and test a new decision-making theory under uncertainty that combines these highly influential theories. Collecting many gambling decisions from laboratory monkeys allowed for reliable testing of our hybrid model and revealed a systematic violation of prospect theory’s assumption that probability weighting is static. Using the same experimental paradigm in humans, substantial similarities between monkey and human behavior were described by our hybrid model, which incorporates decision-by-decision learning dynamics of prediction errors into static prospect theory. Our new model provides a single unified theoretical framework for exploring the neurobiological model of economic choice in human and nonhuman primates.
Political Quid Pro Quo Agreements: An Experimental Study
Publisher: Wiley
Date: 30-01-2013
DOI: 10.1111/AJPS.12015
Present bias for monetary and dietary rewards
Publisher: Springer Science and Business Media LLC
Date: 18-03-2022
DOI: 10.1007/S10683-022-09749-8
Abstract: Economists model self-control problems through time-inconsistent preferences. Empirical tests of these preferences largely rely on experimental elicitation using monetary rewards, with several recent studies failing to find present bias for money. In this paper, we compare estimates of present bias for money with estimates for healthy and unhealthy foods. In a within-subjects longitudinal experiment with 697 low-income Chinese high school students, we find strong present bias for both money and food, and that in idual measures of present bias are moderately correlated across reward types. Our experimental measures of time preferences over both money and foods predict field behaviors including alcohol consumption and academic performance.
Neuroanatomy accounts for age-related changes in risk preferences
Publisher: Springer Science and Business Media LLC
Date: 13-12-2016
DOI: 10.1038/NCOMMS13822
Abstract: Many decisions involve uncertainty, or ‘risk’, regarding potential outcomes, and substantial empirical evidence has demonstrated that human aging is associated with diminished tolerance for risky rewards. Grey matter volume in a region of right posterior parietal cortex (rPPC) is predictive of preferences for risky rewards in young adults, with less grey matter volume indicating decreased tolerance for risk. That grey matter loss in parietal regions is a part of healthy aging suggests that diminished rPPC grey matter volume may have a role in modulating risk preferences in older adults. Here we report evidence for this hypothesis and show that age-related declines in rPPC grey matter volume better account for age-related changes in risk preferences than does age per se. These results provide a basis for understanding the neural mechanisms that mediate risky choice and a glimpse into the neurodevelopmental dynamics that impact decision-making in an aging population.
Tolerance for Ambiguity
Publisher: SAGE Publications, Inc.
Date: 2017
Adolescents’ risk-taking behavior is driven by tolerance to ambiguity
Publisher: Proceedings of the National Academy of Sciences
Date: 10-2012
Abstract: Adolescents engage in a wide range of risky behaviors that their older peers shun, and at an enormous cost. Despite being older, stronger, and healthier than children, adolescents face twice the risk of mortality and morbidity faced by their younger peers. Are adolescents really risk-seekers or does some richer underlying preference drive their love of the uncertain? To answer that question, we used standard experimental economic methods to assess the attitudes of 65 in iduals ranging in age from 12 to 50 toward risk and ambiguity. Perhaps surprisingly, we found that adolescents were, if anything, more averse to clearly stated risks than their older peers. What distinguished adolescents was their willingness to accept ambiguous conditions—situations in which the likelihood of winning and losing is unknown. Though adults find ambiguous monetary lotteries undesirable, adolescents find them tolerable. This finding suggests that the higher level of risk-taking observed among adolescents may reflect a higher tolerance for the unknown. Biologically, such a tolerance may make sense, because it would allow young organisms to take better advantage of learning opportunities it also suggests that policies that seek to inform adolescents of the risks, costs, and benefits of unexperienced dangerous behaviors may be effective and, when appropriate, could be used to complement policies that limit their experiences.
An experimental study of adolescent behavior under peer observation: Adolescents are more impatient and inconsistent, not more risk-taking, when observed by peers
Publisher: Elsevier BV
Date: 10-2019
Expected subjective value theory (ESVT): A representation of decision under risk and certainty
Publisher: Elsevier BV
Date: 03-2023
Controlling ambiguity: The illusion of control in choice under risk and ambiguity
Publisher: Springer Science and Business Media LLC
Date: 12-2022
Dynamic prospect theory: Two core decision theories coexist in the gambling behavior of monkeys and humans
Publisher: American Association for the Advancement of Science (AAAS)
Date: 19-05-2023
Abstract: Research in the multidisciplinary field of neuroeconomics has mainly been driven by two influential theories regarding human economic choice: prospect theory, which describes decision-making under risk, and reinforcement learning theory, which describes learning for decision-making. We hypothesized that these two distinct theories guide decision-making in a comprehensive manner. Here, we propose and test a decision-making theory under uncertainty that combines these highly influential theories. Collecting many gambling decisions from laboratory monkeys allowed for reliable testing of our model and revealed a systematic violation of prospect theory’s assumption that probability weighting is static. Using the same experimental paradigm in humans, substantial similarities between these species were uncovered by various econometric analyses of our dynamic prospect theory model, which incorporates decision-by-decision learning dynamics of prediction errors into static prospect theory. Our model provides a unified theoretical framework for exploring a neurobiological model of economic choice in human and nonhuman primates.
Context-dependency in valuation
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.CONB.2016.06.015
Abstract: In the last few years, work in the nascent field of neuroeconomics has advanced understanding of the brain systems involved in value-based decision making. An important modulator of valuation processes is the specific context a decision maker is facing during choice. Recently, neuroeconomics has made great progress in understanding, on both the brain and behavioral level, how context-dependent perception affects valuation and choice. Here we describe how context-sensitive value coding accounts for choice set effects, differential perceptions of gains and losses, and expectancy effects of external (economic) signals.
Like cognitive function, decision making across the life span shows profound age-related changes
Publisher: Proceedings of the National Academy of Sciences
Date: 30-09-2013
Abstract: Although largely unstudied, behavioral changes in decision making across the life span have implications for problems associated with poor decision making at different life stages, such as careless driving in adolescents and disadvantageous medical or financial decision making in older adults. We examine age-based differences in in idual decision-making characteristics—choice consistency, rationality, and preferences for known and unknown risks—in 12- to 90-y-olds. We found that even the healthiest of elders show profoundly compromised decision making, and that risk attitudes show systematic changes across the life span that have important policy implications.
The Reduction of Ventrolateral Prefrontal Cortex Gray Matter Volume Correlates with Loss of Economic Rationality in Aging
Publisher: Society for Neuroscience
Date: 05-10-2017
DOI: 10.1523/JNEUROSCI.1171-17.2017
Abstract: The population of people above 65 years old continues to grow, and there is mounting evidence that as humans age they are more likely to make errors. However, the specific effect of neuroanatomical aging on the efficiency of economic decision-making is poorly understood. We used whole-brain voxel-based morphometry analysis to determine where reduction of gray matter volume in healthy female and male adults over the age of 65 years correlates with a classic measure of economic irrationality: violations of the Generalized Axiom of Revealed Preference. All participants were functionally normal with Mini-Mental State Examination scores ranging between 26 and 30. While our elders showed the previously reported decline in rationality compared with younger subjects, chronological age per se did not correlate with rationality measures within our population of elders. Instead, reduction of gray matter density in ventrolateral prefrontal cortex correlates tightly with irrational behavior. Interestingly, using a large fMRI s le and meta-analytic tool with Neurosynth, we found that this brain area shows strong coactivation patterns with nearly all of the value-associated regions identified in previous studies. These findings point toward a neuroanatomic locus for economic rationality in the aging brain and highlight the importance of understanding both anatomy and function in the study of aging, cognition, and decision-making. SIGNIFICANCE STATEMENT Age is a crucial factor in decision-making, with older in iduals making more errors in choices. Using whole-brain voxel-based morphometry analysis, we found that reduction of gray matter density in ventrolateral prefrontal cortex correlates with economic irrationality: reduced gray matter volume in this area correlates with the frequency and severity of violations of the Generalized Axiom of Revealed Preference. Furthermore, this brain area strongly coactivates with other reward-associated regions identified with Neurosynth. These findings point toward a role for neuroscientific discoveries in shaping long-standing economic views of decision-making.
Measuring the Subjective Value of Risky and Ambiguous Options using Experimental Economics and Functional MRI Methods
Publisher: MyJove Corporation
Date: 19-09-2012
DOI: 10.3791/3724
Neuroanatomy Predicts Individual Risk Attitudes
Publisher: Society for Neuroscience
Date: 10-09-2014
DOI: 10.1523/JNEUROSCI.1600-14.2014
Abstract: Over the course of the last decade a multitude of studies have investigated the relationship between neural activations and in idual human decision-making. Here we asked whether the anatomical features of in idual human brains could be used to predict the fundamental preferences of human choosers. To that end, we quantified the risk attitudes of human decision-makers using standard economic tools and quantified the gray matter cortical volume in all brain areas using standard neurobiological tools. Our whole-brain analysis revealed that the gray matter volume of a region in the right posterior parietal cortex was significantly predictive of in idual risk attitudes. Participants with higher gray matter volume in this region exhibited less risk aversion. To test the robustness of this finding we examined a second group of participants and used econometric tools to test the ex ante hypothesis that gray matter volume in this area predicts in idual risk attitudes. Our finding was confirmed in this second group. Our results, while being silent about causal relationships, identify what might be considered the first stable biomarker for financial risk-attitude. If these results, gathered in a population of midlife northeast American adults, hold in the general population, they will provide constraints on the possible neural mechanisms underlying risk attitudes. The results will also provide a simple measurement of risk attitudes that could be easily extracted from abundance of existing medical brain scans, and could potentially provide a characteristic distribution of these attitudes for policy makers.
Young adults gamble less when observed by peers
Publisher: Elsevier BV
Date: 10-2018
Correction for Tymula et al., Like cognitive function, decision making across the life span shows profound age-related changes
Publisher: Proceedings of the National Academy of Sciences
Date: 11-09-2015
Competitive Screening of a Heterogeneous Labor Force and Corporate Teamwork Attitude
Publisher: Mohr Siebeck
Date: 2017
Flexible valuations for consumer goods as measured by the Becker–DeGroot–Marschak mechanism.
Publisher: American Psychological Association (APA)
Date: 2016
DOI: 10.1037/NPE0000057
Loss aversion and competition in Vickrey auctions: Money ain't no good
Publisher: Elsevier BV
Date: 05-2019
Are Adolescents Really Risk-Takers? Most Adults Say Yes, but the Science is Starting to Say No
Publisher: Frontiers Media SA
Date: 30-03-2015
Free choice shapes normalized value signals in medial orbitofrontal cortex
Publisher: Springer Science and Business Media LLC
Date: 11-01-2018
DOI: 10.1038/S41467-017-02614-W
Abstract: Normalization is a common cortical computation widely observed in sensory perception, but its importance in perception of reward value and decision making remains largely unknown. We examined (1) whether normalized value signals occur in the orbitofrontal cortex (OFC) and (2) whether changes in behavioral task context influence the normalized representation of value. We record medial OFC (mOFC) single neuron activity in awake-behaving monkeys during a reward-guided lottery task. mOFC neurons signal the relative values of options via a isive normalization function when animals freely choose between alternatives. The normalization model, however, performed poorly in a variant of the task where only one of the two possible choice options yields a reward and the other was certain not to yield a reward (so called: “forced choice”). The existence of such context-specific value normalization may suggest that the mOFC contributes valuation signals critical for economic decision making when meaningful alternative options are available.
Related Organisations
Related Funding Activities
Decision Making Under Risk And Over Time - Neuroeconomic Investigation
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View Funded ActivityDiscovery Early Career Researcher Award - Grant ID: DE150101032
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View Funded ActivityLinkage Projects - Grant ID: LP160100506
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