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To validate the proposed nonlinear dynamical framework and demonstrate its advantages over conventional linear formulations, a comprehensive numerical simulation study was performed (Supplementary File 2). Unless otherwise stated, all stochastic simulation results are presented as the mean ± standard deviation (SD) obtained from 30 independent realizations (n = 30). Statistical comparisons between simulation scenarios were performed using an appropriate statistical test with a significance level of p < 0.05. Exact p-values are reported where statistical comparisons were conducted. The simulations evaluated how the nonlinear stress–emotion–regulation model behaves under systematic variation of parameters and compared its structural responses with those of the traditional linear stress model. Numerical integration of the governing differential equations was conducted over sufficiently long-time horizons to ensure convergence toward steady-state or asymptotic regimes. For each experiment, identical baseline conditions were applied to both models while a single parameter was varied across a predefined range. The resulting steady emotional states, transient dynamics, and stability characteristics were recorded and visualized to highlight structural differences in system behavior. Successful implementation of the protocol was confirmed when the nonlinear system converged to bounded steady-state solutions, exhibited stable attractor structures in phase space, and maintained negative dominant Jacobian eigenvalues under baseline parameter conditions.
The comparative analysis focused on several key dynamical parameters, including the stress–emotion coupling strength (γ), stress dissipation rate (β), external forcing amplitude (F), regulation gain (κ), and emotional nonlinearity coefficient (µ). These parameters directly influence feedback intensity, stability margins, and energy redistribution within the modeled academic environment. The simulations reveal whether system responses follow proportional scaling behavior, as predicted by the linear model, or exhibit nonlinear phenomena such as saturation, resilience buffering, and multistability, as predicted by the proposed nonlinear formulation.
The sensitivity of emotional equilibrium to stress–emotion coupling strength is shown in Figure 4. When the coupling parameter γ increases, the linear model produces nearly constant emotional responses, indicating that coupling intensity does not structurally affect equilibrium outcomes. In contrast, the nonlinear formulation shows a decrease in steady emotional activation as γ increases, reflecting the influence of nonlinear interaction terms that dynamically regulate stress–emotion feedback.

Figure 4: Comparative sensitivity analysis under stress–emotion coupling strength (γ). Grouped bar comparison of steady-state emotional response as the stress–emotion coupling strength γ increases. Blue bars represent the linear model and orange bars represent the nonlinear model. The horizontal axis shows coupling strength γ, and the vertical axis shows steady emotional equilibrium. Bars represent the mean steady-state emotion values obtained from repeated simulation runs, while error bars indicate ± standard deviation (SD) around the mean. The results demonstrate that the nonlinear model exhibits saturation behavior and bounded emotional responses as coupling strength increases, whereas the linear model remains relatively insensitive to changes in coupling intensity. Bars represent mean steady-state emotional equilibrium values obtained from 30 independent simulation runs (n = 30), and error bars indicate ± standard deviation. Please click here to view a larger version of this figure.
The effect of the stress dissipation rate β on emotional equilibrium is illustrated in Figure 5. The linear model predicts a steep decline in emotional activation as dissipation increases, demonstrating strong parameter sensitivity. By contrast, the nonlinear model remains relatively stable across the same parameter range because of intrinsic regulatory damping and nonlinear feedback mechanisms.

Figure 5: Comparative area analysis under stress dissipation rate (β). Area-based comparison of steady-state emotional equilibrium as the stress dissipation rate β varies. The blue shaded region represents the linear model, and the orange shaded region represents the nonlinear model. The horizontal axis shows β, and the vertical axis shows steady emotional equilibrium. Please click here to view a larger version of this figure.
The relationship between emotional activation and external academic forcing is presented in Figure 6. The linear formulation exhibits proportional growth in emotional activation as the forcing amplitude increases. The nonlinear model instead shows a saturating response, in which emotional activation initially rises but gradually stabilizes because of nonlinear damping and adaptive regulatory effects. Under suboptimal parameter conditions, such as excessive stress–emotion coupling or insufficient regulatory gain, the system exhibited unstable trajectories, enlarged oscillations, or loss of equilibrium stability, indicating reduced system stability and potentially representing conditions associated with elevated psychological strain and increased susceptibility to burnout-like transitions.

Figure 6: Comparative response of emotional equilibrium under external forcing (F). Steady-state emotional response as a function of external forcing amplitude F. The red dashed curve represents the linear model, while the blue solid curve represents the nonlinear model. The horizontal axis shows forcing amplitude F, and the vertical axis shows steady emotional equilibrium. Please click here to view a larger version of this figure.
The robustness of the nonlinear system under stochastic perturbations is demonstrated in Figure 7, which shows the temporal evolution of emotional activation and stress energy under random disturbances. Both variables fluctuate within bounded ranges despite continuous noise injection, indicating that nonlinear feedback mechanisms maintain stability under environmental variability.

Figure 7: Stochastic stress–emotion dynamics under noise-induced perturbations. Time evolution of emotional activation E(t) (blue curve) and stress energy S(t) (orange curve) under stochastic perturbations. The horizontal axis represents simulation time steps. Both variables remain bound despite continuous noise-driven disturbances. Please click here to view a larger version of this figure.
Energy landscape analysis provides additional insight into system stability. Figure 8 illustrates the contour representation of the Lyapunov-based energy function in the emotion–regulation phase plane, where the system trajectory converges toward a stable basin of attraction. The three-dimensional representation of this energy structure is shown in Figure 9, revealing multiple potential wells that suggest the possibility of alternative stable emotional–regulatory states.

Figure 8: Energy landscape contour map with dynamical trajectory in the emotion–regulation phase plane. Contour representation of the Lyapunov-based energy landscape in the emotional activation (E) and regulatory capacity (R) phase plane. The black trajectory illustrates system evolution toward a stable basin of attraction. Please click here to view a larger version of this figure.

Figure 9: Three-dimensional nonlinear energy landscape illustrating the potential for alternative emotional–regulatory states. Three-dimensional representation of the Lyapunov energy landscape in the emotion–regulation (E–R) phase space. Multiple potential wells suggest the possibility of alternative stable emotional–regulatory states under different system conditions. The energy landscape provides a qualitative visualization of the system's stability structure; however, direct confirmation of multi-stability requires additional dynamical evidence, such as trajectory switching or bifurcation analysis. Please click here to view a larger version of this figure.
The stability properties of the nonlinear system were further analyzed using eigenvalue-based methods. Figure 10 presents a heatmap of the maximum real eigenvalue of the Jacobian matrix across different values of the stress–emotion coupling strength (γ) and regulation gain (κ). Increasing regulatory strength produces more negative eigenvalues, indicating stronger asymptotic stability, whereas excessive coupling can reduce stability if it is not balanced by sufficient regulation. Regions characterized by negative maximum real eigenvalues correspond to stable operating conditions, whereas regions approaching or exceeding zero indicate instability thresholds and potential regime transitions.

Figure 10: Stability heatmap of the nonlinear stress–emotion system based on maximum real eigenvalue. Heatmap showing the maximum real part of the Jacobian eigenvalues across stress–emotion coupling strength γ and regulation gain κ. More negative values indicate stronger asymptotic stability, whereas values approaching zero indicate reduced stability and a greater likelihood of instability. Please click here to view a larger version of this figure.
Phase-space dynamics are visualized in Figure 11, which shows the vector field and streamlines of the stress–emotion system in the S–E phase plane. The trajectories converge toward a stable equilibrium region, demonstrating attractor behavior. This convergence behavior confirms the successful implementation of the protocol and demonstrates that the nonlinear framework consistently reproduces stable stress–emotion regulation dynamics under the specified simulation conditions. The global stability structure of the system is further illustrated in Figure 12, where trajectories originating from multiple initial conditions converge toward a common attractor in the stress–emotion plane.

Figure 11: Phase-plane vector field and streamline representation of stress–emotion dynamics. Vector field and streamline representation of the nonlinear stress–emotion system in the stress energy (S) and emotional activation (E) phase plane. Streamlines converge toward a stable equilibrium region, indicating attractor behavior. Please click here to view a larger version of this figure.

Figure 12: Dense phase portrait under multiple initial conditions in the stress–emotion plane. Phase portrait generated from multiple initial conditions in the S–E phase plane. Trajectories converge toward a common attractor, demonstrating robust stability across diverse initial states. Please click here to view a larger version of this figure.
The three-dimensional attractor structure of the nonlinear system is shown in Figure 13, where trajectories evolve in the combined stress–emotion–regulation state space and approach a stable attractor. Time-domain dynamics of the coupled variables are illustrated in Figure 14, where emotional activation and stress energy exhibit transient adjustments before converging toward steady-state equilibrium values.

Figure 13: Three-dimensional nonlinear attractor in the stress–emotion–regulation state space. Three-dimensional trajectory of the nonlinear system in the state space defined by stress (S), emotional activation (E), and regulatory capacity (R). The trajectory converges toward a stable attractor representing long-term system equilibrium. Please click here to view a larger version of this figure.

Figure 14: Time-domain evolution of coupled stress and emotional states under nonlinear regulation. Temporal evolution of emotional activation E(t) (left axis) and stress energy S(t) (right axis). Both variables exhibit transient adjustment followed by convergence toward steady-state equilibrium. Please click here to view a larger version of this figure.
The effect of adaptive regulation strength on emotional equilibrium is examined in Figure 15. As the regulatory gain κ increases, the linear model predicts substantial reductions in emotional activation, whereas the nonlinear model maintains near-constant equilibrium values due to adaptive saturation mechanisms.

Figure 15: Dual-axis comparative analysis under variation of regulation gain (κ). Comparison of steady-state emotional equilibrium under varying regulation gain κ. The blue curve represents the linear model, and the red dashed curve represents the nonlinear model. The horizontal axis shows regulation gain κ. Please click here to view a larger version of this figure.
Finally, Figure 16 presents a scatter-based sensitivity comparison as the emotional nonlinearity coefficient (µ) varies. In the linear framework, emotional equilibrium remains unchanged because nonlinear terms are absent. In contrast, the nonlinear model exhibits a decreasing emotional equilibrium as µ increases, demonstrating the stabilizing influence of cubic saturation on emotional dynamics.

Figure 16: Scatter-based sensitivity comparison under emotional nonlinearity parameter (µ). Scatter comparison of steady-state emotional equilibrium as the emotional nonlinearity coefficient µ varies. Red markers represent the linear model, and blue markers represent the nonlinear model. Please click here to view a larger version of this figure.
Beyond their computational significance, the observed dynamical behaviors have meaningful interpretations within educational and psychological contexts. The bounded responses observed under stochastic perturbations suggest that adaptive regulatory mechanisms can buffer the effects of unexpected academic stressors, thereby supporting resilience and emotional stability. Similarly, the existence of stable attractors may be interpreted as psychologically balanced states in which students successfully regulate academic pressures, whereas instability regions and bifurcation thresholds may correspond to conditions under which coping resources become insufficient, increasing vulnerability to burnout, emotional exhaustion, or maladaptive stress responses. The sensitivity analyses further indicate that strengthening regulatory capacity can expand stability regions and reduce susceptibility to disruptive transitions, highlighting potential implications for interventions aimed at improving coping skills, emotional regulation, and student wellbeing. These simulation-based findings suggest that the proposed framework may serve as a useful conceptual foundation for future studies investigating stress trajectories, resilience mechanisms, and potential intervention strategies. However, validation using empirical student data is required before practical implementation can be established.
Together, these results demonstrate that the proposed nonlinear framework captures several structural properties absent from traditional linear stress models, including saturation behavior, stability buffering under perturbations, multistable energy landscapes, and resilience through adaptive regulation. Across the tested parameter ranges, the nonlinear model consistently maintained bounded emotional activation and stable attractor behavior, whereas the linear model exhibited substantially greater sensitivity to parameter variation and reduced stability margins. These properties provide a more realistic representation of stress–emotion dynamics in complex academic environments.
Supplementary File 1: MATLAB source code, governing equations, numerical implementation, and reproducibility documentation. This supplementary file includes the governing nonlinear differential equations, baseline model parameters, initial conditions, numerical solver configuration, convergence criteria, MATLAB source code, equilibrium solver, sensitivity-analysis procedures, visualization routines, software specifications, parameter ranges, and computational workflow required to reproduce all simulations, stability analyses, phase-space trajectories, sensitivity analyses, eigenvalue heatmaps, and Lyapunov energy landscapes presented in the manuscript.Please click here to download this file.
Supplementary File 2: Simulation workflow documentation, psychological variable mapping, and empirical validation framework. This supplement includes the complete simulation workflow; the mapping of mathematical state variables and model parameters to measurable psychological constructs; recommended psychological assessment instruments; guidance for parameter estimation; a proposed framework for future empirical validation and calibration using student data; and potential implementation strategies for longitudinal validation and educational applications.Please click here to download this file.