Nonlinear Dynamics, Psychology, and Life Sciences

The U.S. Federal Reserve now controls a part of the money supply, but other financial institutions, called the 'shadow' banks, issue a growing amount of the money supply, which remains outside the control of the U.S. Federal Reserve. Being unregulated, these shadow banks operate by offering highly risky amounts of credit, leading to lack of confidence and consequent run on such banks. However, due to competition with the shadow banks, the commercial banks have undergone structural change and are themselves engaged in trading the same financial assets as traded by the shadow banks...

In this work, our objective is to explain the decline in the income share of the middle class and the increase in the share of the wealthy - a global empirical phenomenon, commonly referred to as 'The Elephant' (Lakner & Milanovic, 2013; Milanovic, 2016) - by examining the different life-cycle income paths of heterogeneous income classes and the varying tax burden on labor and capital income. The model investigates the diverse life-cycle paths and their nonlinear behavior among the income classes under scrutiny...

We develop a foreign exchange market model in which a market maker adjusts the exchange rate with respect to the trading behavior of chartists, fundamentalists and a central bank. While chartists bet on the persistence of bull and bear markets, fundamentalists speculate on mean reversion. The central bank seeks to stabilize the foreign exchange market by placing buy (sell) orders when the undervaluation (overvaluation) of the exchange rate exceeds a certain threshold. Since a one-dimensional piecewise-linear discontinuous map with three branches determines the evolution of the exchange rate, we use a combination of analytical and numerical tools to explore the extent to which the central bank is able to tame the behavior of the foreign exchange market...

In this paper, we study the complex interaction between environmental damage and location in space of firms and entrepreneurial households. We use a New Economic Geography (NEG) framework, suitably extended to account for environmental damage and the two mobility processes. The resulting model is a two-dimensional piecewise smooth map with two constraints for each variable, and we use analytic and numerical tools to explore its long-run dynamics. We pay special attention to the different types of fixed points and the structure of the respective basins of attraction...

Sustainable pumping of water resource requires intervention by a public agency in order to avoid over-exploitation. We study the evolution of compliance and regulation of groundwater resource when farmers can decide whether to comply or not with pumping quotas in an imitation rule described by replicator dynamics. The public agency sets the optimal quotas and the farmers can choose between compliance or violation of them. We investigate the policy of the public agency which may impose sanctions to discourage withdrawals that deviate from the optimal quota...

This study considers dynamics generated by a three-species Lotka-Volterra competitive model with two discrete delays. The associated characteristic equation is a cubic exponential polynomial. Assuming the stability of the three-species positive stationary point in the no-delay model, we construct a stability switching curve on which the characteristic equation has a purely imaginary root. Thus, the stability may be lost. It is numerically confirmed that the stationary point bifurcates to a limit cycle via a supercritical Hopf bifurcation when the delay crosses the stability switching curve...

The use of predator-prey models in economics has a long history, and the model equations have largely evolved since the original Lotka-Volterra system towards more realistic descriptions of the economic dynamics of predation, competition, and synergy. Seminal examples in this regard are the business cycle model (Goodwin, 1967), chaotic hysteresis (Rosser, 1994), and the models of renewable resources (Clark, 1990). Given this background, this paper aims to analyse the mechanism of economic competition under different conditions, by adopting the unifying framework of niche models...

J. Barkley Rosser Jr. dedicated his career to the study of complexity and nonlinear dynamics applied to economic matters. From his extensive work, four ideas stand out: (a) relevant economic processes can be expressed under the form of relatively simple modelling apparatus; (b) low-dimensional nonlinear systems often involve complex patterns of evolution; (c) the identified nonlinearities have significant economic meaning, and (d) there is an inherent aesthetic beauty underlying the corresponding mathematical results...

The pioneering work of John Barkley Rosser Jr. (1948-2023) in various subfields of economics emphasizes the fact that economic and social phenomena are inherently nonlinear and often discontinuous. From this standpoint, Barkley has contributed substantially to a paradigm shift in economic theory and modelling. Both his influential research work and his unceasing survey work on different approaches and schools of thought in economics and social science, carried out through the lens of complexity theory, have succeeded to develop a broader view on economic thinking and continue to inspire many researchers worldwide...

This year's cover artists are members of a team of physicists and psy-chologists who create human-centered designs based on psychology experiments that investigate the positive impacts of viewing fractal patterns. These positive impacts include reduced physiological stress levels and enhanced cognitive skills. Here, the team explores the concept of 'fractal iconography' as an approach to employing computers to generate naturalistic art. Adopting this approach, three forms of fractal patterning ('fractal icons') are combined in a variety of ways to generate the rich complexity of nature's scenery...

This study evaluated cusp models of workload and fatigue experienced by teams on a dynamic decision making task. Cognitive workload is the amount of information that a person is required to process in a given way in a fixed amount of time. Fatigue, which is captured by a work curve or a cubic polynomial function, is the loss of work capacity that is produced by an extended amount of time spent on a particular cognitive or physical task. In this experiment, 32 groups of three, four or five members (136 individuals) played two matches of a first-person shooter computer game, and completed subjective measures of workload and cognitive measures of elasticity versus rigidity...

In this paper, we focus on the nonlinear dynamic behavior of fractional order love model because the fractional order can reflect the 'memory dependency' of certain dynamic processes to a certain extent. The novel fractional order love model without external environment effect investigates two aspects: first, the chaotic dynamic of the used system when the system order is 2, and second, the smallest system order of fractional order love model that can generate chaotic behaviors. The simulation results show the fractional order love model can produce different results compared to the integer order model...

Posttraumatic Growth (PTG), characterized by newfound meaning, perspective, and purpose for trauma survivors, remains enigmatic in its nature. This state is thought to arise from the dynamic interplay of biopsychosocial factors; however, the nature of this interplay is unclear. This study aimed to investigate the intricate relationship between PTG and facial affect dynamics, shedding light on the complex interplay of biopsychosocial factors that underpin this transformative process. We conducted a comprehensive investigation involving 19 wildfire survivors who provided daily self-reported PTG ratings alongside smartphone videos analyzed using Automated Facial Affect Recognition (AFAR) software...

The spread of epidemics over a landscape of several population agglomerations is presented. A continuous, system dynamics version of an epidemics model is discussed and compared to the agent-based model. The validity of the continuous Susceptible-Infected-Recovered-Susceptible (SIRS) model is questioned. The main model deficiencies are the lack of the influence of the collective memory of the population and the spatial distribution of individuals. The chaotic behavior of the agent-based model is pointed out as a better approximation of the true dynamics of an epidemic...

Situation awareness (SA) is a mental state that is instrumental to performance of complex dynamic tasks. SA within teams is thought to be supported by favorable social conditions within the team. The present study was organized in two parts: (a) causal relationships among SA, group cohesion, and autonomic synchrony, the latter being a fundamentally nonlinear process, and (b) the combined impact of the three variables on performance in a dynamic decisions task. Experimental conditions assessed changes in task difficulty, group size, and method of obtaining SA measures...

Human resilience is often considered as static traits using a reductionist approach. More recent work has demonstrated it to be a dynamic and emergent property of complex systems. This narrative review explores human resilience through a self-organizing framework with a specific emphasis on the application of nonlinear modeling approaches. Four classes of approaches are examined: univariate dynamics, bivariate coupling, topological modeling, and network modeling. Univariate dynamics capture the temporal structure and flexibility within a single time series, while bivariate coupling approaches quantify the interaction dynamics and coordination between two time series...

The Hermite wavelet method (HWM) is introduced in this study to solve a nonlinear differential equation determining the human corneal morphology. The changes in curvature of the human cornea in hypotony, normal intraocular pressure, glaucoma, and other conditions are discussed. The Hermite wavelet operational matrices of derivatives are used to generate wavelet solutions based on this technique. The solutions of the nonlinear differential equation are determined for various values of constant parameters that can appear in the diverse physical situations...

In a recent article, we presented evidence demonstrating the existence of hidden y-stories within the genomes of humans and canines. These stories were found not only in the non-protein-coding regions but also within the genetic regions and the sequence of exons. Consequently, we are now exploring whether these discoveries are unique to humans and dogs or if they are more widely distributed throughout the cellular world. To approach this question, we embarked on an investigation of the genomes of various species across Whittaker's five kingdoms, namely Animalia, Plantae, Fungi, Protista, and Monera...

Theories and studies of corruption typically focus on individual ethics and agency problems in organizations. In this paper, we use concepts from complexity science to propose a process theory that describes how corruption risk emerges from conditions of uncertainty that are intrinsic in social systems and social interactions. We posit that our theory is valid across multiple levels of scale in social systems. We theorize that corruption involves dynamics that emerge when agents in a system take actions that exploit disequilibrium conditions of uncertainty and ethical ambiguity...

This study explores the hypothesis related to a punctuated equilibrium process for conceptual change in science learning, in conjunction with the effects of four cognitive variables: logical thinking and field-dependence/field-independence, divergent and convergent thinking. The participants were fifth and sixth-grade elementary school pupils involved in different tasks, who were asked to describe and interpret chemical phenomena. Latent Class Analysis (LCA) was applied to children's responses, and three clusters or latent classes (LC1, LC2, and LC3) were identified, corresponding to hierarchical levels of conceptual understanding...