Susceptibilities and Patterning: A Primer on Linear Response in Bayesian Learning
This work investigates how to quantify the influence of data perturbations on observable quantities in Bayesian neural networks and establishes a mapping between data patterns and structural changes. Drawing on linear response theory, the authors define susceptibility via the posterior covariance and construct a susceptibility matrix that serves as the Jacobian of the map from data distribution to structural coordinates. The pseudoinverse of this matrix enables a linear solution to the inverse “patterning” problem, facilitating the design of data perturbations that induce desired structural modifications. By integrating Bayesian inference, the fluctuation–dissipation theorem, and geometric analysis of the loss landscape, this study unifies the theoretical formulations of influence functions and structural susceptibility, provides a computable framework for evaluating sensitivity, and offers an efficient linear approach to controlling neural network behavior.