arXiv subjects

Bryce Morsky

Publications and source records attributed to Bryce Morsky.

14 recordsLinked to original sources

arXiv2026

Collective action through adaptive awareness

Collective actions emerge through the interplay between social influence and awareness. We introduce a nonlinear opinion-dynamics framework on networks in which social influence, shaped by individual interactions and community structure, promotes collective action, while awareness regulates the amount of reinforcement required for adoption. Using a degree-based mean-field reduction, we show that the competition between effective social influence and abandonment controls both the onset and persistence of collective action. Changes in awareness modify the nonlinear adoption mechanism itself, enabling populations to transition between highly responsive and weakly responsive collective states. This generates discontinuous transitions, bistability, and hysteresis, allowing collective action to persist even after the conditions that initially promoted it have weakened. We illustrate these effects through coupled disease-mitigation and resource-consumption dynamics, where external pressures act by reshaping awareness rather than social influence. More broadly, our results identify awareness as a fundamental link between environmental conditions, social interactions, and the emergence and persistence of collective action.

physics.soc-ph↗

arXiv2026

Synchronized disease and behavioural dynamics in weakly coupled populations

The spread of infectious disease is strongly influenced by social dynamics. In addition to infection risk, individuals vaccination decisions depend on prevailing social behavior: high infection levels and widespread vaccination can increase vaccine uptake, which in turn suppresses infection. This feedback can generate sustained oscillations in disease prevalence and vaccination behavior. Here, we study two such populations undergoing the same behavioral epidemiological limit cycle and introduce weak coupling between them through social influence. We show that coupling leads to synchronization of disease dynamics between the two groups. Moreover, we find that different payoff sensitivity may lead to synchronization or anti synchronization.

q-bio.PE↗

arXiv2026

Strategies for tumor elimination and control under immune evasion and chemotherapy resistance

The evolutionary and ecological dynamics of tumors under immune responses and therapeutic interventions pose major challenges to long-term treatment success. Although treatment may initially achieve short-term disease control, resistant cancer cell subpopulations often arise, leading to relapse with more aggressive and treatment-resistant forms of the disease. Here, we develop and analyze mathematical models describing the interactions among effector cells, chemo-resistant tumor cells, and immuno-resistant tumor cells under distinct immune-evasion strategies. The models incorporate competition and cooperation between resistant and sensitive tumor subpopulations. We identify threshold conditions governing tumor persistence, elimination, and phenotype dominance under varying therapeutic intensities. These findings provide a theoretical framework for designing targeted and combination therapies and offer insights into strategies for mitigating the treatment resistance.

q-bio.QM↗

arXiv2026

Dynamics of voting strategies and public good funding

We model an electorate voting on the funding of a public good in a two-party system in an evolutionary game theory framework. Voters adopt one of four strategies: Consensus-makers, Gridlockers, Party 1 Zealots, and Party 2 Zealots, which they may change via imitation. The public good benefits both individuals locally and those in neighbouring regions due to spillover effects. A system of differential equations governs the spatial movement of individuals and shifts in their voting strategies. Local social interactions drive strategy evolution, while migration occurs toward areas of higher utility, which is a function of both social and economic factors. Our results reveal bistability and significant spatial variations. Locally, populations converge to a politically gridlocked state or a mix of consensus-makers and zealots, determining public good provisioning. We find that public good spillovers generate a free-rider effect and poorly funded regions become spatially tied to, and dependent upon, well-funded ones.

physics.soc-ph↗

arXiv2025

Phage-antibiotic therapy under density dependent bacterial defenses

Phage therapy is an alternative treatment method for bacterial infections. It has shown particular promise in reducing bacterial load while preventing antibiotic resistance. Here, we develop a mathematical model of a bacterial infection within a host to study phage therapy. It incorporates interactions between phages, bacteria, the immune system, and antibiotics. Additionally, the model includes bacterial social dynamics that provide protection from treatments and the innate immune response. We analytically and numerically identify all of the equilibria of the model and derive insights regarding the overall effectiveness of phage therapy. Without phage therapy, the model exhibits bistability: bacteria populations above a threshold grow and become entrenched, while those below it can be effectively suppressed by the immune system. We find that that phages destabilize the former equilibrium, and thus in combination with the immune system are able to suppress the bacteria. We conducted bifurcation analyses, which show that the equilibrium with a suppressed population of bacteria can become unstable. In this scenario, the system undergoes oscillations. However, these oscillations -- which can be exacerbated by social dynamics -- lead to minuscule bacterial populations, and thus, in practice, phage therapy is widely effective across the parameter space. We also demonstrate how suppression can be further improved by the addition of periodic dosing of antibiotics in a combination therapy.

q-bio.PE↗

arXiv2025

The gig economy during an epidemic: coupling disease transmission with labour market dynamics

The gig economy has grown significantly in recent years, driven by the emergence of various facilitating platforms. Triggering substantial shifts to labour markets across the world, the COVID-19 pandemic has accelerated this growth. To understand the crucial role of such an epidemic on the dynamics of labour markets of both formal and gig economies, we develop and investigate a model that couples disease transmission and a search and match framework of unemployment. We find that epidemics increase gig economy employment at the expense of formal economy employment, and can increase the total long term unemployment. In the short run, large sharp fluctuations in labour market tightness and unemployment can occur, while in the long run, employment is reduced under an endemic disease equilibrium. We analyze a public policies that increase unemployment benefits or provide benefits to gig workers to mitigate these effects, and evaluate their trade-offs in mitigating disease burden and labour market disruptions.

econ.TH↗

arXiv2025

How urban scaling and resource distribution shape social welfare and migration dynamics

Many outputs of cities scale in universal ways, including infrastructure, crime, and economic activity. Through a mathematical model, this study investigates the interplay between such scaling laws in human organization and governmental allocations of resources, focusing on impacts to migration patterns and social welfare. We find that if superlinear scaling resources of cities -- such as economic and social activity -- are the primary drivers of city dwellers' utility, then cities tend to converge to similar sizes and social welfare through migration. In contrast, if sublinear scaling resources, such as infrastructure, primarily impact utility, then migration tends to lead to megacities and inequity between large and small cities. These findings have implications for policymakers, economists, and political scientists addressing the challenges of equitable and efficient resource allocation.

physics.soc-ph↗

arXiv2024

The dynamics of strategic voting: pathways to consensus and gridlock

The outcomes of democratic elections rest on individuals' decision-making that is driven by their varying preferences and beliefs. Individuals may prefer consensus to gridlock, or gridlock to consensus, and information may be fractured via echo-chambers. To understand the role of these factors in whether or not elections reach consensus, we develop and explore a computational model in which voters have varying party affiliations, preferences, beliefs, and voting strategies. Voters may change their voting strategies either by imitating others or reconsidering their strategy individually. Preferences are orderings of the following election outcomes: a voter's party winning a super-majority, the opposing party winning such a majority, and gridlock. Voters beliefs and decisions are shaped by their social networks, and thus are heterogeneous in the population. We observe a "tipping point" phenomenon wherein the voters' initial strategies and randomness impact whether the minority party voters vote to create gridlock or consensus. A positive feedback loop secures such voters into one behaviour or the other. Consensus is reached by the minority party evolving to prefer consensus, which in turn drives the majority to also prefer consensus due to the influence of social learning. Further, consensus is promoted by an uneven distribution of party affiliation, and undermined when it is even. We also find that a moderate prevalence or strength of echo-chambers can boost consensus, since they can quell voters' desires for gridlock.

physics.soc-ph↗

arXiv2024

Worst-case control via linear programming: applications to truncation selection and partially malicious players

The connection between game theory, convex optimization, and geometry is deep. There are many applications of linear programming methods and polyhedral representation conversion methods in game theory. In this paper, we discuss two more scenarios where such methods can be useful. The first scenario is predicting the results of independent truncation dynamics under the large population assumption. The second scenario is when a player's opponent in a normal form game is not completely rational but shows some degree of malice. We show how one can compute a more profitable defensive play compared to simply playing a maximin strategy. We provide detailed computation procedure and numerical results for both scenarios.

cs.GT↗

arXiv2024

Convergence of reputations under indirect reciprocity

Previous research has shown how indirect reciprocity can promote cooperation through evolutionary game theoretic models. Most work in this field assumes a separation of time-scales: individuals' reputations equilibrate at a fast time scale for given frequencies of strategies while the strategies change slowly according to the replicator dynamics. Much of the previous research has focused on the behaviour and stability of equilibria for the replicator dynamics. Here we focus on the underlying reputational dynamics that occur on a fast time scale. We describe reputational dynamics as systems of differential equations and conduct stability analyses on their equilibria. We prove that reputations converge to a unique equilibrium for each of the five standard norms whether assessments are public or private. These results confirm a crucial but previously unconfirmed assumption underlying the theory of indirect reciprocity for the most studied set of norms.

q-bio.PE↗

arXiv2023

Social and individual learning in the Minority Game

We study the roles of social and individual learning on outcomes of the Minority Game model of a financial market. Social learning occurs via agents adopting the strategies of their neighbours within a social network, while individual learning results in agents changing their strategies without input from other agents. In particular, we show how social learning can undermine efficiency of the market due to negative frequency dependent selection and loss of strategy diversity. The latter of which can lock the population into a maximally inefficient state. We show how individual learning can rescue a population engaged in social learning from such inefficiencies.

physics.soc-ph↗

arXiv2021

Suppressing evolution through environmental switching

Ecology and evolution under changing environments are important in many subfields of biology with implications for medicine. Here, we explore an example: the consequences of fluctuating environments on the emergence of antibiotic resistance, which is an immense and growing problem. Typically, high doses of antibiotics are employed to eliminate the infection quickly and minimize the time under which resistance may emerge. However, this strategy may not be optimal. Since competition can reduce fitness and resistance typically has a reproductive cost, resistant mutants' fitness can depend on their environment. Here we show conditions under which environmental varying fitness can be exploited to prevent the emergence of resistance. We develop a stochastic Lotka-Volterra model of a microbial system with competing phenotypes: a wild strain susceptible to the antibiotic, and a mutant strain that is resistant. We investigate the impact of various pulsed applications of antibiotics on population suppression. Leveraging competition, we show how a strategy of environmental switching can suppress the infection while avoiding resistant mutants. We discuss limitations of the procedure depending on the microbe and pharmacodynamics and methods to ameliorate them.

q-bio.PE↗

arXiv2018

Truncation selection and diffusion on lattices

Evolutionary games on graphs have been extensively studied. A variety of graph structures, graph dynamics, and behaviours of replicators have been explored. These models have primarily been studied in the framework of facilitation of cooperation, and much previous research has shed light on this field of study. However, there has been little attention devoted to truncation selection as most models employ proportional selection (such as in the replicator equation) or `imitate the best.' Here we systematically explore truncation selection on periodic square lattices, where replicators below a fitness threshold are culled and the reproduction probabilities are equal for all survivors. We employ two variations of this method: independent truncation, where the threshold is fixed; and dependent truncation, which is a generalization of `imitate the best.' Further, we explore the effects of diffusion in our networks in the following orders of operation: contest-diffusion-offspring (CDO), and diffusion-contest-offspring (DCO). CDO and DCO frequently facilitate and diminish cooperation, respectively. For independent truncation, we find three regimes determined by the fitness threshold: cooperation decreases as we raise the threshold; polymorphisms and extinction can occur; and the entire population goes extinct. Further, we show how an intermediate sucker's payoff maximizes cooperation in the DCO independent truncation model. We find that dependent truncation affects games differently; lower levels reduce cooperation for the Hawk Dove game and increase it for the Stag Hunt, and higher levels produce the opposite effects. We compare these truncation methods to proportional selection, and show that they can facilitate cooperation. We conclude that truncation selection can impact the prevalence of cooperation in complex ways, and therefore merit further study.

q-bio.PE↗

arXiv2017

Cheater-altruist synergy in immunopathogenic ecological public goods games

Much research has focused on the deleterious effects of free-riding in public goods games, and a variety of mechanisms that suppresses cheating behaviour. Here we argue that under certain conditions cheating behaviour can be beneficial to the population. In a public goods game, cheaters do not pay for the cost of the public goods, yet they receive the benefit. Although this free-riding harms the entire population in the long run, the success of cheaters may aid the population when there is a common enemy that antagonizes both cooperators and cheaters. Here we study models in which an immune system antagonizes a cooperating pathogen. We investigate three population dynamics models, and determine under what conditions the presence of cheaters help defeat the immune system. The mechanism of action is that a polymorphism of cheaters and altruists optimizes the average growth rate. Our results give support for a possible synergy between cooperators and cheaters in ecological public goods games.

q-bio.PE↗