Dynamical systems theory is an area of mathematics used to describe the behavior of complex systems by employing differential equations.

Proponents of the dynamical systems theory approach to cognition (see dynamicism) believe that differential equations are the most appropriate tool for modeling human behavior. These equations are interpreted to represent an agent's cognitive trajectory through state space. In other words, dynamicists argue that psychology should be (or is) the description (via differential equations) of the cognitions and behaviors of an agent under certain environmental and internal pressures. The language of chaos theory is also frequently adopted.