A low-dimensional descriptor that expresses co-operative relationships between the many degrees of freedom found in complex systems, and which serves to simplify this description for an external observer. Order parameters are determined by and created from the cooperation of microscopical quantities, while at the same time they govern the qualitative behavior of the whole system in a form of circular causality. Behavioral states as described for the human newborn can be considered to be analogous to order parameters.
See Behavioral state concept, Bifurcation, Catastrophe theory, Circular (or non-linear) causality, Control parameter, Degrees of freedom (or Bernstein’s) problem, Dynamical parameters, Dynamical system, Emergence, Mechanism, Open system, Phase, Process, Quantitative and qualitative change, Synergetics