178 research outputs found
Essays in Behavioral Economics and Game Theory
This thesis consists of three papers. Chapter 1 conducts experimental research on individual bounded rationality in games, Chapter 2 introduces a novel equilibrium solution concept in behavioral game theory, and Chapter 3 investigates confirmation bias within the framework of game theory.
In Chapter 1 (joint with Wei James Chen and Po-Hsuan Lin), we investigate individual strategic reasoning depths by matching human subjects with fully rational computer players in a lab, allowing for the isolation of limited reasoning ability from beliefs about opponent players and social preferences. Our findings reveal that when matched with robots, subjects demonstrate higher stability in their strategic thinking depths across games, in contrast to when matched with humans.
In Chapter 2 (joint with Po-Hsuan Lin and Thomas R. Palfrey), we investigate how players’ misunderstanding about the relationship between opponents’ private information and strategies influence their equilibrium behavior in dynamic environments. This theoretical study introduces a framework that extends the analysis of cursed equilibrium from the strategic form to multi-stage games and applies it to various applications in economics and political science.
In Chapter 3, I employ a game-theoretic framework to model how decision makers strategically interpret signals, particularly when they face a utility loss from holding beliefs that differ from their partners. The study reveals that the emergence of confirmation bias is positively associated with the strength of prior beliefs about a state, while the impact of signal accuracy remains ambiguous.</p
Cognitive Hierarchies in Multi-Stage Games of Incomplete Information: Theory and Experiment
Sequential equilibrium is the conventional approach for analyzing multi-stage
games of incomplete information. It relies on mutual consistency of beliefs. To
relax mutual consistency, I theoretically and experimentally explore the
dynamic cognitive hierarchy (DCH) solution. One property of DCH is that the
solution can vary between two different games sharing the same reduced normal
form, i.e., violation of invariance under strategic equivalence. I test this
prediction in a laboratory experiment using two strategically equivalent
versions of the dirty-faces game. The game parameters are calibrated to
maximize the expected difference in behavior between the two versions, as
predicted by DCH. The experimental results indicate significant differences in
behavior between the two versions, and more importantly, the observed
differences align with DCH. This suggests that implementing a dynamic game
experiment in reduced normal form (using the "strategy method") could lead to
distortions in behavior.Comment: 48 pages for the main text, 52 pages for the appendi
Relaxing the symmetry assumption in participation games: A specification test for cluster heterogeneity
Published online: 05 April 2023.
OnlinePublWe propose a novel approach to check whether individual behaviour in binary-choice participation games is consistent with the restrictions imposed by symmetric models. This approach allows in particular an assessment of how much cluster-heterogeneity a symmetric model can tolerate to remain consistent with its behavioural restrictions. We assess our approach with data from market-entry experiments which we analyse through the lens of ‘Exploration versus Exploration’ (EvE, which is equivalent to Logit-QRE) or of Impulse Balance Equilibrium (IBE). We find that when the symmetry assumption is imposed, both models are typically rejected when assuming pooled data and IBE yields more data-consistent estimates than EvE, i.e., IBE’s estimates of session and pooled data are more consistent than those of EvE. When relaxing symmetry, EvE (IBE) is rejected for 17% (42%) of the time. Although both models support cluster-heterogeneity, IBE is much less likely to yield over-parametrised specifications and insignificant estimates so it outperforms EvE in accommodating a model-consistent cluster-heterogeneity. The use of regularisation procedures in the estimations partially addresses EvE’s shortcomings but leaves our overall conclusions unchanged.Alan Kirman, François Laisney, Paul Pezanis, Christo
Re-evaluation of the risks to public health related to the presence of bisphenol A (BPA) in foodstuffs
Publisher Copyright: © 2023 European Food Safety Authority. EFSA Journal published by Wiley-VCH GmbH on behalf of European Food Safety Authority.In 2015, EFSA established a temporary tolerable daily intake (t-TDI) for BPA of 4 μg/kg body weight (bw) per day. In 2016, the European Commission mandated EFSA to re-evaluate the risks to public health from the presence of BPA in foodstuffs and to establish a tolerable daily intake (TDI). For this re-evaluation, a pre-established protocol was used that had undergone public consultation. The CEP Panel concluded that it is Unlikely to Very Unlikely that BPA presents a genotoxic hazard through a direct mechanism. Taking into consideration the evidence from animal data and support from human observational studies, the immune system was identified as most sensitive to BPA exposure. An effect on Th17 cells in mice was identified as the critical effect; these cells are pivotal in cellular immune mechanisms and involved in the development of inflammatory conditions, including autoimmunity and lung inflammation. A reference point (RP) of 8.2 ng/kg bw per day, expressed as human equivalent dose, was identified for the critical effect. Uncertainty analysis assessed a probability of 57–73% that the lowest estimated Benchmark Dose (BMD) for other health effects was below the RP based on Th17 cells. In view of this, the CEP Panel judged that an additional uncertainty factor (UF) of 2 was needed for establishing the TDI. Applying an overall UF of 50 to the RP, a TDI of 0.2 ng BPA/kg bw per day was established. Comparison of this TDI with the dietary exposure estimates from the 2015 EFSA opinion showed that both the mean and the 95th percentile dietary exposures in all age groups exceeded the TDI by two to three orders of magnitude. Even considering the uncertainty in the exposure assessment, the exceedance being so large, the CEP Panel concluded that there is a health concern from dietary BPA exposure.Peer reviewe
Agency and Organisation: The Dialectics of Nature and Life
In recent decades, there have been major theoretical changes within evolutionary biology. In this dissertation, I critically reconstruct these developments through philosophy to assess how it may inform these debates. The overall aim is to show the mutual relevance between current trends in biology and the dialectical approach to nature. I argue that the repetition of the neglected tradition of organicism is anticipated both by a dialectical tradition within science and by Hegel’s philosophy – and that these theories may together inform the ongoing shift within evolutionary biology called the Extended Evolutionary Synthesis (EES).
I stage the discussion by outlining the tenets and history of the modern synthesis (MS) and the alternative: the extended evolutionary synthesis (EES). It takes us into topics such as autonomy, organisation, reduction, and autopoiesis. Based on these discussions, I make the case that the most promising alternative to the MS is the so-called organisational approach formulated within theoretical biology and apply dialectics to strengthen this claim. In my view, they share a fundamental premise: Biology must surpass the physical worldview and adopt a more complex model to comprehend life as an ongoing regeneration of organisation and an expression of self-determination.
To bring out the philosophical stakes of this shift, I take on Hegel’s writings on nature, life, and purposiveness and relate them to contemporary thinkers. The main contribution of this work lies not in a particularly novel reading of any of the theories I examine but in bringing them together – both within philosophy and biology and between them – and systematically mapping how philosophy and the humanities should deal with the natural sciences. The new kind of naturalism suggested here, which places life at its core, also calls for another scientific ideal which strives for unification without subsumption or eradication of differences
Multi-modal and multi-model interrogation of large-scale functional brain networks
Existing whole-brain models are generally tailored to the modelling of a particular data modality (e.g., fMRI or MEG/EEG). We propose that despite the differing aspects of neural activity each modality captures, they originate from shared network dynamics. Building on the universal principles of self-organising delay-coupled nonlinear systems, we aim to link distinct features of brain activity - captured across modalities - to the dynamics unfolding on a macroscopic structural connectome. To jointly predict connectivity, spatiotemporal and transient features of distinct signal modalities, we consider two large-scale models - the Stuart Landau and Wilson and Cowan models - which generate short-lived 40 Hz oscillations with varying levels of realism. To this end, we measure features of functional connectivity and metastable oscillatory modes (MOMs) in fMRI and MEG signals - and compare them against simulated data. We show that both models can represent MEG functional connectivity (FC), functional connectivity dynamics (FCD) and generate MOMs to a comparable degree. This is achieved by adjusting the global coupling and mean conduction time delay and, in the WC model, through the inclusion of balance between excitation and inhibition. For both models, the omission of delays dramatically decreased the performance. For fMRI, the SL model performed worse for FCD and MOMs, highlighting the importance of balanced dynamics for the emergence of spatiotemporal and transient patterns of ultra-slow dynamics. Notably, optimal working points varied across modalities and no model was able to achieve a correlation with empirical FC higher than 0.4 across modalities for the same set of parameters. Nonetheless, both displayed the emergence of FC patterns that extended beyond the constraints of the anatomical structure. Finally, we show that both models can generate MOMs with empirical-like properties such as size (number of brain regions engaging in a mode) and duration (continuous time interval during which a mode appears). Our results demonstrate the emergence of static and dynamic properties of neural activity at different timescales from networks of delay-coupled oscillators at 40 Hz. Given the higher dependence of simulated FC on the underlying structural connectivity, we suggest that mesoscale heterogeneities in neural circuitry may be critical for the emergence of parallel cross-modal functional networks and should be accounted for in future modelling endeavours
Brain Computations and Connectivity [2nd edition]
This is an open access title available under the terms of a CC BY-NC-ND 4.0 International licence. It is free to read on the Oxford Academic platform and offered as a free PDF download from OUP and selected open access locations.
Brain Computations and Connectivity is about how the brain works. In order to understand this, it is essential to know what is computed by different brain systems; and how the computations are performed.
The aim of this book is to elucidate what is computed in different brain systems; and to describe current biologically plausible computational approaches and models of how each of these brain systems computes.
Understanding the brain in this way has enormous potential for understanding ourselves better in health and in disease. Potential applications of this understanding are to the treatment of the brain in disease; and to artificial intelligence which will benefit from knowledge of how the brain performs many of its extraordinarily impressive functions.
This book is pioneering in taking this approach to brain function: to consider what is computed by many of our brain systems; and how it is computed, and updates by much new evidence including the connectivity of the human brain the earlier book: Rolls (2021) Brain Computations: What and How, Oxford University Press.
Brain Computations and Connectivity will be of interest to all scientists interested in brain function and how the brain works, whether they are from neuroscience, or from medical sciences including neurology and psychiatry, or from the area of computational science including machine learning and artificial intelligence, or from areas such as theoretical physics
Strategic decision-making in multi-agent markets: The emergence of endogenous crises and volatility
Traditional economic frameworks are built upon perfectly rational agents and equilibrium outcomes. However, during times of crises, these frameworks prove insufficient. In this thesis, we take an alternative perspective based on "Complexity Economics", relaxing the assumption of perfectly rational agents and allowing for out-of-equilibrium dynamics. While many contemporary approaches explain crises and non-equilibrium market phenomena as the rational reaction to external news, the emergence of endogenous crises remains an open question.
We begin addressing this question by demonstrating how a multi-agent model of heterogeneous boundedly rational agents acting according to heuristics can reproduce and forecast key non-linear price movements in the Australian housing market, during boom and bust cycles. In order to provide foundations for such heuristic-based reasoning, we then propose a novel information-theoretic approach, Quantal Hierarchy, for modelling limitations in strategic reasoning, demonstrating how this convincingly and generically captures the decision-making of interacting agents in competitive markets outperforming existing approaches. In addition, we demonstrate how a concise generalised market model can generate important stylised facts, such as fat-tails and volatility clustering, and allow for the emergence of crises, purely endogenously. This thesis provides support to the interacting agent hypothesis, addressing a crucial question of whether crisis emergence and various stylised facts can be seen as endogenous phenomena, and provides a generic method for representing strategic agent reasoning
25th Annual Computational Neuroscience Meeting: CNS-2016
Abstracts of the 25th Annual Computational Neuroscience
Meeting: CNS-2016
Seogwipo City, Jeju-do, South Korea. 2–7 July 201
2001 July, University of Memphis bulletin
Vol. 88 of the University of Memphis bulletin containing the graduate catalog for 2001-2003.https://digitalcommons.memphis.edu/speccoll-ua-pub-bulletins/1189/thumbnail.jp
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