International Society of Dynamic Games

Dynamic Games and Applications Seminar

Ultimatum game: Regret or fairness

Dec 11, 2025 11:00 AM — 12:00 PM (Montreal time)

Zoom webinar link

In the ultimatum game, the challenge is to explain why responders reject non-zero offers thereby defying classical rationality. Fairness and related concepts have been among the main explanations so far. Here, the ultimatum game is reformulated based on probabilistic lotteries, enabling other decision-making tools to be applied to this problem. We explain the rejection behavior via the following principle: if the responder regrets less about losing the offer than the proposer regrets not offering a better option, the offer is rejected. We show that several experimental results normally prescribed to fairness can be given an alternative explanation. We also propose experiments that can distinguish these two scenarios. (With Armen Allahverdyan and Lida Aleksanyan).

Dynamic Games and Applications Seminar

Discrimination in games

Dec 4, 2025 11:00 AM — 12:00 PM (Montreal time)

Zoom webinar link

We consider a finite population formed by different types of individuals. Players observe the type of their opponent but do not know their own type. This assumption is discussed in different contexts, such as biology, and medecine. The question that we address is whether in such a symmetric environment a discriminating norm may arise.

Dynamic Games and Applications Seminar

Bargaining with Investment and Endogenous Status-quo

Nov 27, 2025 11:00 AM — 12:00 PM (Montreal time)

Zoom webinar link

The novelty of this paper is to investigate bargaining games where not only the status-quo can be (fully/partially) endogenous but parties can also affect the size of the future surplus (via investment). We show that there can be phases of both over- and under-investment under a fully endogenous status-quo. Moreover, players agree to invest more when they are sufficiently patient and investment is not endogenous. Instead, with pronounced asymmetries, both farsighted and shortsighted parties invest more when investment is endogenous. We study the impact of capital depreciation, asymmetry in parties’ patience and status-quo on the equilibrium.