The agent or agents responsible for creating change in a process. Sometimes used interchangeable with ‘process’, the two terms are not synonymous. In dynamical systems terminology, these are referred to as control parameters, which when scaled up beyond some critical value can result in a change of state (i.e., change from one attractor to another).
See Attractor, Behavior mechanism, Biology, Child psychology, Cognitive psychology, Control parameter, Developmental bootstrapping, Dynamical systems approaches, Model systems, Ontogenetic development, Order parameter, Process, Proximate mechanisms (or causes), Ultimate mechanisms (or causes)