Jeeva Somasundaram Jeeva Somasundaram

About Me

I am a tenured Associate Professor of Decision Sciences at IE Business School, Madrid, Spain. I completed my PhD in Management (Decision Sciences) at INSEAD, France, where I was also a Marie-Curie early stage researcher with the CONCORT ITN (2012–15). I was also a visiting student at the McDonough School of Business, Georgetown University.

After my PhD, I was a Research Fellow in Behavioral Economics at the National University of Singapore, also affiliated with Future Resilient Systems (ETH Zurich). My dissertation focused on decision models of anticipatory emotions.

My research centers on decision theory and behavioral economics, using mathematical modelling and randomized lab and field experiments. My work spans two streams: (i) decision making under risk and (ii) habit formation and behavioral change — establishing robust theory, testing it experimentally, and applying findings to environment, health, operations, and marketing.

Affiliations

Research

Published Papers
Journal of Economic Theory 2017 Decision Making under Risk INFORMS DAS Finalist 2014 Theory & Modeling
Regret Theory: A New Foundation
with Enrico Diecidue · vol. 172: 88–119
We present a new behavioral foundation for regret theory. The central axiom — trade-off consistency — renders regret theory observable at the individual level and makes our foundation consistent with the existing measurement method. For the first time, our behavioral foundation allows deriving a continuous regret theory representation and separating utility from regret. The axioms clarify that regret theory minimally deviates from expected utility by relaxing transitivity only.
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Journal of Risk and Uncertainty 2017 Decision Making under Risk Modeling & Lab Experiment
Regret Theory and Risk Attitudes
with Enrico Diecidue · vol. 55: 147–175
We examine risk attitudes under regret theory and derive analytical expressions for two components — the resolution and regret premiums — of the risk premium. We posit that regret-averse decision makers are risk seeking for low probabilities of gains and risk averse for high probabilities, and that feedback reinforces risk attitudes. We test these hypotheses experimentally and estimate both premiums empirically.
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Journal of Risk and Uncertainty 2022 Decision Making under Risk Lab Experiment
Risk and Time Preferences Interaction: An Experimental Measurement
with Vincent Eli · vol. 65: 215–238
We experimentally characterize and measure the interaction between risk and time preferences. Decision makers are insensitive to time delay for small probabilities of gains but become progressively more sensitive as the probability of gain increases. Models allowing probability-time interaction and capturing magnitude effect fit the data better. Accounting for this interaction also leads to lower estimated discount rates.
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Energy Economics 2023 Habit Formation & Behavioral Change Field Experiment (RCT)
Raising the Temperature in the Tropics: Gradual Targets Promote Energy Conservation Habits
with Noah Lim and Ingrid Koch · vol. 128
ACs account for a significant fraction of energy consumption in tropical countries. We conduct a randomized control trial in which people are financially rewarded for setting higher AC temperatures. The gradual treatment — raising 1°C in each of two periods — outperformed the abrupt 2°C increase in maintaining higher temperatures during and after the intervention. Energy data confirmed lower consumption as a result.
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Journal of Marketing 2024 Decision Making under Risk Modeling & Lab/Online Experiments
Adoption of New Technology Vaccines
with Laura Zimmermann and Barsha Saha · vol. 88(4): 1–21
Through four experiments (N=478) we show consumers are unduly averse to new technology vaccines (e.g., mRNA) due to higher perceived uncertainty of side effects. A herd behavior nudge — communicating increasing population vaccination rates — effectively increases uptake of new technology vaccines by alleviating perceived uncertainty rather than through social conformity or free-riding concerns.
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European Journal of Operational Research 2024 Decision Making under Risk Lab Experiment
Algorithmic Support and Newsvendor Risk Attitudes
with Matthias Seifert and Prana Narayan · vol. 322(3): 993–1004
We study how managers allocate resources in response to algorithmic recommendations programmed with specific risk aversion levels. Highly risk-averse algorithmic recommendations have a strong and persistent influence on order decisions even after removal — effects that hold regardless of whether advice comes from a human or algorithm, and regardless of decision autonomy.
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Communications Medicine · Nature 2025 Decision Making under Risk Field Study
Triggering Counterfactual Thinking Deteriorates Judgmental Performance: Evidence from COVID-19 Death Toll Predictions
with Matthias Seifert · vol. 5(1): 35
Based on 6,731 incentivized daily forecasts over 377 days, individuals who engaged in counterfactual thinking prior to forecasting exhibited greater judgmental bias — underestimating the death toll, anchoring on more favorable scenarios, and showing insensitivity to trend changes. This was also observed among individuals who had recovered from COVID-19.
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Communications Psychology · Nature 2025 Habit Formation & Behavioral Change Field Experiment (RCT)
Pledging to Counter the Boomerang Effect: Evidence from Primary School Children
with Beverly Wang · vol. 3(1): 107
A randomized field experiment (N=1,121) showed an educational show on 5-minute showers triggered a boomerang effect — children below the target increased their shower time. Private and public pledges effectively countered this, reducing overall shower time and increasing adherence by raising willingness to meet the target and ensuring greater reductions for those most willing to reduce.
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Journal of Marketing Forthcoming Habit Formation & Behavioral Change Field Experiment (RCT)
Leveraging Rational Addiction Theory to Reduce Mobile Usage
with Laura Zimmermann and Pham Quang Duc
In two pre-registered RCTs on mobile usage, subjects pre-announced future targets and incentives behaved in a forward-looking manner consistent with habit formation — reducing usage before incentives begin, sustaining reductions during the incentivized period, and maintaining lower usage after incentives are removed. This provides empirical support for rational addiction theory in the domain of digital consumption.
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Conditionally Accepted · Journal of Public Policy & Marketing Habit Formation & Behavioral Change Field Study (Longitudinal + RCT)
Make it Stick: The Role of Alternative Activities in Reducing Habitual Smartphone Consumption
with Laura Zimmermann and Pham Quang Duc
Across two longitudinal field studies (5,686 observations, 153 individuals), individuals incentivized to both adopt a beneficial activity (language learning, daily walks) and curb smartphone use showed greater long-term reductions than those targeting smartphone use alone — especially when the positive alternative occupied a higher proportion of idle time.
Working Papers
Under Review Decision Making under Risk Best Paper AMA Winter 2018 Modeling & Lab Experiment
The Reassurance Effect in Information Acquisition
with Luc Wathieu · covered by INSEAD Knowledge
We model consumers who anticipate elation and disappointment from information. Our key finding: a consumer facing a large potential loss of low probability may seek non-instrumental information purely for reassurance. This paradoxically causes a consumer less likely to face a loss to value information more than one more likely to face it — an effect that disappears at higher levels of information instrumentality.
SSRN
Under Review Decision Making under Risk Modeling & Lab Experiment
Efficiency and Equity in Repeated Games
with Konstantinos Stouras and Sanjiv Erat
We examine whether inequity persists on platforms like ride-share due to momentum in repeated contests. Momentum enables inequity to persist even long-run. Two interventions — modifying winner-take-all incentives and enabling participant communication — both reduce inequity in controlled lab experiments. The former reduces earnings asymmetry directly; the latter diminishes propensity to play momentum strategies.
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Revise & Resubmit · Social Science & Medicine Habit Formation & Behavioral Change Field Experiment (RCT)
The Power of Autonomy: Self-Selected Goals Outperform Assigned Goals in Reducing Mobile Phone Usage
with Ashish Sachdeva and Kamal Kant Sharma
Behavior change interventions often involve experimenter-assigned goals. We test whether granting individuals autonomy in goal-setting enhances motivation and behavioral change when average goal difficulty and incentives are held constant. In an eleven-week randomized field experiment (N=149), participants chose their own goal, were assigned a matched goal, or received no goal. Despite identical incentives and comparable average goal difficulty, participants who chose their own goals reduced phone use by 73% more and met their goals 11% more often than those with assigned goals, and reported lower depression, anxiety, and perceived addiction — providing causal field evidence on the motivational benefits of autonomy in goal-setting.
SSRN
Reject & Resubmit · Journal of Economic Theory Decision Making under Risk Theory & Modeling
Clarifications and Extensions to "Regret Theory: A New Foundation"
with Enrico Diecidue, Songyu He, and Shuo Li Liu
Diecidue and Somasundaram (2017) provide an axiomatic foundation for regret theory. This note shows that their original axioms are insufficient and provides the appropriate axioms that characterize regret theory. We also provide axiomatic foundations for the regret theory generalizations proposed by Loomes and Sugden (1987) and Bikhchandani and Segal (2011), defining clear boundaries between increasingly general versions of the theory.
SSRN
Under Review Decision Making under Risk Modeling & Lab Experiment
Information Demand in Innovation: The Role of Uncertainty and Signal Fidelity
with Sanjiv Erat
Managers routinely face high-stakes, irreversible go/no-go decisions when evaluating innovation projects, and often seek external advice to reduce risk. We develop a model of information acquisition that jointly incorporates project uncertainty and signal fidelity, showing that optimal information demand is non-monotonic — managers should seek the most information only when uncertainty and signal fidelity are at intermediate levels. In controlled lab experiments, however, individuals instead show a strictly monotonic "uncertainty-reduction heuristic," demanding more information as uncertainty rises rather than adapting to the optimal baseline. We design a cognitive nudge — refocusing decision-makers on the project's probability of success or failure rather than its baseline uncertainty — that realigns behavior with the optimal policy, and show via a structural model that individuals systematically underweight external advice, especially when signal fidelity is high.
Under Review Habit Formation & Behavioral Change Field Experiment (RCT)
Incentive Design Shapes the Temporal Structure of Durable Behavior
with Ashish Sachdeva and Lawrence Jin
Long-run behavior change is usually evaluated using average outcomes, but behavior also has structure in how it unfolds over time. In a 51-week randomized field experiment with 523 adults using wearable activity trackers (170,000+ daily observations), participants received one of four incentive designs — fixed gain, fixed loss, gain-based streaks, or loss-based streaks — tied to personalized daily walking goals, followed by a 12-week period without incentives. All designs increased walking during the intervention, with gains persisting afterward, but different structures shaped distinct dynamics: gain-based streaks strengthened day-to-day momentum, while loss-based streaks accelerated recovery after lapses — patterns that persisted even after incentives ended.

Teaching

IE Business School
PhD Quantitative Methods (IV) — Experimental Design and Causal Inference 2019–
MBA Data Analytics for Managers 2019–
MIM Data Analytics for Decision Making 2018–
MIM Elective on Experimental Design 2020–
Exec Self-Leadership Program: Habits and Digital Well-being 2024–
Exec Executive Program on AI and Leadership 2026–
Best Professor Award, MBA 2025 — Awarded for Teaching Excellence (rating 4.5/5 and above) at IE University for 23 courses (2020–25).  ·  Teaching ratings & accolades
INSEAD  Tutor & Teaching Assistant
TA Prices and Markets: Microeconomics for MBA Sept–Oct 2013
TA Excel Tutorial Sessions 2013–2015
TA Managerial Decision Making 2014
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Contact

Personal Email
Office Address
IE Business School, Calle María de Molina 12, 28006 Madrid, Spain