On December 6, 2022, we lost a giant in the field of experimental economics. Professor Amnon Rapoport (1936–2022) passed away at his home in Tucson, Arizona.
Amnon Rapoport was an experimentalist at heart, a psychologist by training, and a mentor of uncommon generosity. Born in Israel and educated at the Hebrew University (B.A., Philosophy and Economics) and the University of North Carolina (Ph.D., Mathematical Psychology, 1965), he spent the majority of his career at the University of North Carolina, the University of Haifa, the University of California, Riverside, and – most influentially – the University of Arizona, where he built a laboratory culture that blended mathematical precision with behavioral insight.
Professor Rapoport was one of the pioneers of experimental study and quantitative modelling of human decisions in interactive contexts. During his distinguished career, he published multiple books, edited volumes, and more than 300 peer-reviewed research papers and chapters in leading psychology, management, operation, marketing, decision theory, economics, and political science journals, and is recognized as a leading authority in many of these areas.
Amnon’s intellectual signature is the dialogue between formal game theory and laboratory evidence. Whether the topic was coalition formation, market-entry coordination, public-goods provision, or queue-departure timing, he regarded a formal model as a research tool – something to be stress-tested, refined, and sometimes rejected once confronted with human data. Colleagues recall his insistence on ‘closing the loop’ between theory and experiment: A cycle that begins with a clear equilibrium prediction, proceeds to a carefully controlled experiment, and ends with a fresh theoretical refinement that respects the behavioral regularities uncovered in the lab.
Amnon’s work focused on clarifying the conditions under which the rationality assumption provides useful predictions of behavior. It was theory-driven, and, in most cases, the theory was represented formally by mathematical (primarily, but not exclusively, game theoretical) models. He was a meticulous and rigorous, yet imaginative and creative, experimentalist, and was one of the first researchers to employ computerized experimentation to study individual and group decision making.
As Amnon’s students, colleagues, and friends, it is our distinct privilege to edit this special issue of Experimental Economics in his memory. We have solicited submissions related to Amnon’s work on topics such as coalition formation, bargaining, social dilemmas, behavioral operations management, queues, behavioral game theory, dynamic pricing, and behavior in directed networks, as well as individual decision making. We were specifically interested in contributions that clarify the conditions under which the rationality assumption provides a useful prediction of human behavior. Not surprisingly, the response was overwhelming and due to time constraints on special issues, we had to reject papers that were not ready for the publication timeline. After receiving many submissions, we were pleasantly surprised by the high number of strong papers that people had chosen to submit as a way of honoring and remembering Amnon’s contributions and the impacts that these contributions had on their own research. Given that the resulting number of accepted papers is too large for a single issue, we decided to proceed with publication in two parts. This also coincided with the transition of Experimental Economics across publishers, making it possible to proceed to publication with the set of papers accepted as part of our agreement with the original publisher. Part 1 of the special issue with nine papers was published in the 27 (2024) issue of Experimental Economics.
This volume contains the second part of the special issue, but our introduction will address the totality of papers in both issues.
1. Professor Rapoport’s broad research streams
Professor Rapoport produced more than six decades of path-breaking research, spread across psychology, management, economics, operations, political science, decision theory, and transportation. To appreciate the breadth of that legacy it is helpful to trace the inter-locking themes of his research.
These themes do not sit in isolation; they weave into a coherent credo:
• Model first, test second, refine third.
• Complex group settings are tractable if decomposed into transparent games.
• Real human regularities – risk attitudes, fairness, bounded attention – belong inside economic theory, not outside it.
Table 1 exhibits these themes, each illustrated by a handful of landmark publications and major insights.
Professor Rapoport’s 11 interlocking themes
The main difference between the approach advanced by Rapoport, and mainstream research in behavioral economics (e.g., Kahneman & Tversky (Reference Kahneman and Tversky1979) and studies that build on this influential paper), involves the tradeoff between the potential generality and the clarity of the proposed descriptive models. Mainstream behavioral economic research tends to prefer variants of descriptive models that were found to be effective in previous behavioral studies, while Rapoport highlighted the value of focusing on the simplest modification of the rational model that can capture the target results.
Rapoport’s approach has two significant advantages. The first is the clarification of the conditions under which choice behavior converges to rational choice in controlled experiments. These conditions are important as they tend to be robust. For example, if behavior converges to one of the Nash equilibria of a specific game in a short low-incentives experiment, it is natural to assume that it will also converge to this equilibrium in longer interaction with larger incentives.
A second advantage involves the fact that the focus on the prediction of rational models reduces the risk of a selection bias, and it increases the set of environments that can be analyzed. To see why Rapoport’s approach reduces the risk of a selection bias, note that researchers that try to promote a specific descriptive model are motivated to focus on choice tasks for which their favorite model provides clear predictions that are likely to be supported. Rapoport’s approach reduces selection bias, enabling the analysis of a wide range of social and behavioral themes.
Table 1 summarizes some of the interesting themes examined by Rapoport and his co-authors.
Beyond scholarship, Amnon was an extraordinary mentor. Professor Alvin Roth wrote on his Market Design blog (here) that Amnon ‘… was a man ahead of his time, and maybe situated in the wrong discipline. It seemed to him natural that psychologists should take a leading role in the experimental study of game theory, and he noted with some regret that instead that literature had been ceded to economists.’ Here’s a paragraph from the introduction to Rapoport, Amnon Experimental studies of interactive decisions. Vol. 5. Springer Science & Business Media, 2012.
The history of experimentation in psychology is rich and old. It would have been quite natural and highly desirable for psychologists to extend their scope of research and assume a major role in the study of economic decision behavior. Psychology professes to be the general study of human behavior. Most psychologists are trained to regard their discipline as an observational science; they do not have to overcome the conditioning of many economists who think of economics as an a priori science. Psychologists’ knowledge of experimental techniques is comprehensive, and their experience in conducting experiments, analyzing data, and discovering empirical regularities exceeds that of most economists. However. with the exception of research on individual choice behavior - where psychologists like Tversky, Kahneman, and Slovic have played a major role - psychologists have not contributed in any significant way to the growing research in experimental economics. Social psychologists for whom interactive behavior is the core of their discipline, have virtually abandoned the study of economic decisions in small groups to their colleagues in economics and related disciplines.
Since 2012, the field of behavioral and experimental economics has experienced significant growth, and psychologists have assumed a pivotal role in advancing the scientific understanding of economic behavior, due in large part to the influential work of Amnon and his intellectual collaborators and successors.
The papers in this Special Issue were solicited under a call that emphasized ‘classic Rapoport questions’ – strategic interaction, social dilemmas, timing, learning, etc. – examined with modern theory or experimental tools. As mentioned before, the response was overwhelming: 27 accepted manuscripts span the full spectrum of his legacy. The remainder of this introduction maps those contributions onto broad research streams that defined Amnon’s career.
2. Rapoport’s legacy and the new contributions
Amnon blended clever formal modelling with uncompromising empirical testing. The broad streams of his scholarship – coalition formation, social dilemmas, market entry, traffic networks, decision timing, probability judgment, behavioral operations, resource dilemmas, methodological innovation, cost-sharing, and sequential search – are all visible in the 27 articles assembled in this Special Issue. Below, we trace each theme in turn and show how the new studies both honor and extend Amnon’s original insights.
Coalition formation was one of Amnon’s earliest fascinations. His laboratory work on triads and larger cooperative games demonstrated that coalitions form not only around formal power indices but also around perceived fairness and the inertia of the status quo. The significance of this observation is highlighted in Michela Chessa and colleagues’ ‘An Experimental Nash Program: A Comparison of Structured versus Semi-Structured Bargaining Experiments.’ Their analysis suggests part of the failure of rationality-based methods (mechanism design) to facilitate efficient coalition formation reflects a tendency to reject unfair coalitions. Mark Ratchford and colleagues’ ‘Status Quo Bias and Poaching Avoidance in Selecting Strategic Alliance Partners’ echoes Amnon’s old Israeli-Knesset experiments: Decision makers cling to incumbent partners even when more profitable coalitions beckon.
Gneezy and colleagues’ ‘An Experimental Investigation of Lobbying and Bribes’ connects to multiple Rapoport themes – particularly Coalition Formation, Fair Allocation, and Behavioral Operations. By examining how lobbying and bribery shape collective decisions and allocations, the study extends Rapoport’s findings on fairness, and power in coalitional contexts and group decision-making processes.
In social-dilemma research Amnon is best remembered for originating the step-level public-goods paradigm, which showed that cooperation can pivot on thresholds, strategic timing, and rivalry between groups. Antoine Malezieux and Eli Spiegelman’s ‘An Anatomical Review of the Common Pool Resource Game’ explicitly situates Amnon’s 1990 resource-dilemma designs at the root of today’s literature and extends the taxonomy he proposed. Adrian Hillenbrand and colleagues’ ‘Willingness to Volunteer Among Remote Workers Is Insensitive to the Team Size’ revisits the volunteer’s dilemma in a remote-work setting; their finding that group size leaves volunteering unchanged refines Rapoport’s own mixed results on threshold sensitivity. Trust and deception intertwine in Giulia Andrighetto and colleagues’ ‘Trust and Trustworthiness in the Villain’s Dilemma: Collaborative Dishonesty With Conflicting Incentives?’ advancing the ‘fear of being gypped’ mechanism that Rapoport and Eshed-Levy first documented. Soo-Hong Chew and coauthors’ ‘Social Efficiency Orientation in Rice Culture’ pushes the cultural frontier by linking rice farming to social-efficiency orientation, much in the spirit of Rapoport’s comparative public-goods work.
Karapetian and colleagues’ ‘Risk Aversion and Social Influence’ aligns closely with Rapoport’s themes of Social Dilemmas, examining how risk preferences interact with social influence to alter collective decision outcomes.
Rapoport’s study of market-entry games reveals a large set of interactions in which the aggregate behavior is surprisingly close to the Nash equilibrium, and it also shows that the boundaries of this set can be captured by simple learning models. Yali Dong and colleagues’ ‘Coordination in a Two-Sided Market Entry Game with Endogenous Capacity: An Experimental Investigation’ extend this investigation to two-sided platform markets with endogenous capacity, finding that customers and providers coordinate – or mis-coordinate – in ways that would have felt familiar in Rapoport’s results. The posthumous article by Hironori Otsubo, Gisches, & Rapoport, ‘The Downs-Thomson Paradox with Endogenously Determined Departure Times’ merges Amnon’s queue-departure model with multi-modal transport. It examines a complex interaction that can be described as a generalized market entry game and suggests that the added complexity can trigger efficiency enhancing deviations from the Nash equilibrium. Ori Plonsky and colleagues’ ‘Underweighting of Rare Events in Strategic Games’ demonstrates that rare events are systematically underweighted in strategic interaction and refines the learning model proposed by Erev and Rapoport (Reference Erev and Rapoport1998). Yevgeny Mugerman and colleagues’ ‘The Grant-Proposal Game: An Experimental Study on Herding and Divergent Behaviors in Competition’ demonstrates that the Grant-Proposal Game is an example of a multi-location entry problem in which researchers decide which intellectual market segment to enter.
Colman and colleagues’ ‘Persistence or Decay of Strategic Asymmetric Dominance In Repeated Dyadic Games?’ Published in: EXEX, Volume 27, Issue 4 September 2024, Pages: 766–786, contribution fits within Rapoport’s work on Market Entry Games and Decision Timing, examining whether strategically dominant options persist over repeated interactions. By testing conditions under which dominance decays or is reinforced over time, this study directly addresses Rapoport’s longstanding interest in strategic stability and how learning or repetition shapes coordination.
The experimental scrutiny of traffic networks owes much to Rapoport’s laboratory verification of the Braess paradox. In this issue the Downs-Thomson paper again takes center stage: By letting travelers choose not only their route but also their departure time, it shows that improving either rail or road can yield counter-intuitive welfare effects – precisely the style of paradox Rapoport delighted in uncovering.
Decision timing became a leitmotif after Rapoport and Stein’s (Reference Rapoport and Stein1974) multistage betting game. In ‘Learning to Detect Change: An Experimental Investigation’ Ye Li and colleagues revisit the core problem of reacting neither too early nor too late to shifting environments, finding asymmetric overreaction and under-reaction patterns reminiscent of Rapoport’s duel work. A very different timing task – buying airline tickets – is analyzed by Michael Lee and Sara Chong (‘Strategies People Use Buying Airline Tickets: A Cognitive Modeling Analysis of Optimal Stopping in a Changing Environment’), Published in: EXEX, Volume 27, Issue 4 September 2024, Pages: 854–873, through cognitive modelling and optimal-stopping benchmarks. They report that on average the price people pay is above the optimal, that there is little evidence people learn over the sequence of problems, but that there are likely significant individual differences in the way people make decisions. Almog and Martin’s ‘Rational Inattention in Games: Experimental Evidence’, Published in: EXEX, Volume 27, Issue 4 September 2024, Pages: 715–742, connects closely with Rapoport’s Decision Timing theme, exploring how cognitive constraints and limited attention shape strategic behavior. Like Rapoport’s pioneering experiments on sequential risk-taking and market entry, Almog and Martin experimentally demonstrate how attention constraints cause systematic departures from classical equilibrium predictions, echoing Rapoport’s assertion that human decisions are shaped by psychological limits. Spurlino’s ‘Rationally Inattentive and Strategically (Un)Sophisticated’ also relates to Rapoport’s themes of decision timing and methodological contributions. This paper explores the impact of rational inattention on strategic sophistication. The rare-events study by Ori Plonsky and colleagues also belongs here, because underweighting extreme outcomes distorts the temporal calibration of risk.
Rapoport’s concern with how information is framed surfaces in multiple contributions. Eldad Yechiam and Dana Zeif’s ‘Calling “Gevald”: On the Emergence of Negative Election Forecasts in Partisan Communications’, Published in: EXEX, Volume 27, Issue 4 September 2024, Pages: 787–819, found that people tended to communicate favorable forecasts to others sharing their view, compared to the neutral point and to the actual election outcomes. On the other hand, negative framing reduced the positivity of forecasts in these communications to the extent that it led most participants to predict an election loss. Jana Gallus and colleagues’ ‘Awards: Tangibility, Self-Signaling and Signaling to Others’ presents a taxonomy of awards and highlights how the presentation of recognition affects effort. Qin and colleagues’ ‘Is It What You Say or How You Say It?’, Published in: EXEX, Volume 27, Issue 4 September 2024, Pages: 874–921, relates to Rapoport’s interest in Framing and Methodological Contributions. It experimentally investigates how different framings and delivery methods affect decision outcomes.
Müller-Trede and Rottenstreich’s ‘Positive Reciprocity When Motives Are Ambiguous’ connects to Rapoport’s social dilemmas, fairness, and Framing themes. By investigating how ambiguous motives influence reciprocity and cooperation, the paper enriches the findings on how subjective perceptions of fairness, ambiguity, and framing determine cooperative decisions in social and allocation contexts.
Long before ‘behavioral operations’ became a field, Rapoport and Calder embedded inventory choices in experimental economics. That lineage continues in the posthumous article by Rapoport and his colleagues’ ‘Dynamic Pricing with Multiple Consumers and Alternating Offers Under Retailer Competition: Theory and Experiment.’, Published in: EXEX, Volume 27, Issue 4 September 2024, Pages: 945–972. This paper introduces multiple consumers and alternating offers to mimic retail competition. Béatrice Boulu-Reshef and Charles Holt’s paper (‘Inventory Management with Carryover in a Laboratory Setting: Going Beyond the Newsvendor Paradigm’) address inventory with carry-over and financing costs, answering Rapoport’s early call for richer operational realism in the lab.
Common-pool-resource dilemmas were fertile ground for Rapoport’s interest in uncertainty, asymmetry and timing. The CPR review by Malezieux and Spiegelman (‘An Anatomical Review of the Common Pool Resource Game’) credits Rapoport with the very experimental architecture it surveys. Anwar and Georgalos’ ‘Position Uncertainty in a Sequential Public Goods Game: An Experiment’, Published in: EXEX, Volume 27, Issue 4 September 2024, Pages: 820–853, extends Rapoport’s influential work on Social Dilemmas and Common Pool Resource Dilemmas, specifically his sequential contribution mechanism. By introducing positional uncertainty – where players face uncertainty about their role in sequential order – this experiment further highlights how informational uncertainty and timing alter cooperative outcomes, themes strongly emphasized in Rapoport’s foundational public-goods experiments. Chew and co-authors’ rice-culture paper (‘Social Efficiency Orientation in Rice Culture’) embeds resource dilemmas in ecological context.
Rapoport was also a methodological pioneer, introducing computer-controlled protocols in the 1960s. Wei James Chen and colleagues’ ‘Measuring Higher-Order Rationality with Belief Control’ use of perfectly rational ‘robot’ confederates to parse belief from action stands squarely in that tradition, as does Ilan Fischer and colleagues’ ‘Subjective Game Structures: Eliciting Alternatives and Payoffs to Study the Properties of Social Interactions’, Published in: EXEX, Volume 27, Issue 4 September 2024, Pages: 922–944, extended elicitation to whole payoff matrices. Busemeyer and colleagues’ ‘Explaining Interference Effects in Prisoner Dilemma Games’, Published in: EXEX, Volume 27, Issue 4 September 2024, Pages: 743–765, resonates with Rapoport’s methodological contributions by introducing a novel quantum-cognitive framework to explain interference effects (contextual decision-making anomalies) in Prisoner’s Dilemma experiments.
Fair allocation fascinated Rapoport, whether in airport-cost division or facility location. The Nash program study by Chessa and colleagues (‘An Experimental Nash Program: A Comparison of Structured Versus Semi-Structured Bargaining Experiments’) tests mechanisms that implement the Shapley value, directly extends that fairness-versus-efficiency debate. Ratchford and colleagues (‘Status Quo Bias and Poaching Avoidance in Selecting Strategic Alliance Partners’) show that alliance choices are biased by incumbency and poaching concerns, reinforcing Rapoport’s insight that perceived fairness can override pure surplus maximization.
3. Concluding reflections
Taken together, the two-part Special Issue offers an arresting snapshot of experimental economics in 2025 – a field still animated by Amnon Rapoport’s conviction that rigorous modelling and behavioral evidence must advance hand-in-hand. The 27 articles gathered here affirm that his seminal questions remain vital: How do coalitions really form? When do public goods thrive or collapse? Why do markets, queues and traffic lanes so often mis-coordinate? And how can careful changes in information, timing, or institutional detail steer groups toward better outcomes?
The blend of continuity and renewal is the surest sign of an enduring legacy: Rapoport’s methods survive because they continue to generate surprising, relevant insights, and his spirit of relentless inquiry persists because each new answer begets sharper questions. We hope readers will find in these pages not only a tribute to a towering scholar but also an invitation – echoing Amnon’s own – to keep closing the loop between elegant theory, bold experimentation, and the endlessly intriguing realities of human interaction.
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