Dear colleagues, We would like to draw your attention to the Call for Papers for the Special Issue "Formal Models and Empirically Informed Simulations of Interpersonal Dynamics" in the journal Zeitschrift für Psychologie (a journal published in English with a German title). The submission deadline for proposals is July 15, 2026, and the submission deadline for full manuscripts is November 15, 2026. Further information can be found at: https://econtent.hogrefe.com/doi/10.1027/2151-2604/a000619 Kind regards, Stefan Westermann and Peter Dayan --- Topic of the Special Issue: Within a dyad of two interacting individuals, each serves as the environment for the other and, in turn, experiences the other as their environment. Capturing the complex interpersonal dynamics that emerge from this interdependence is a major psychological and computational challenge. Interactions become even richer given polyadic relationships and larger groups. Mathematical and computational methods offer powerful tools for uncovering the mechanisms that shape such interact ions. The topical issue "Formal models and empirically informed simulations of interpersonal dynamics" will highlight recent advances in applying such methods to the study of interpersonal processes. We invite contributions from across psychological disciplines - including social, clinical, and personality psychology - that employ frameworks such as agent-based modeling, evolutionary game theory, Bayesian modeling, active inference, and related approaches to provide formal ways of representing, simulating, and analyzing interpersonal phenomena. Both purely theory-driven, formal models and empirically informed simulations are welcome, offering insights into the emergence, maintenance, and change of interpersonal patterns.