Experimental complexity in physical, social and biological systems

There are a myriad of examples of dynamical systems displaying chaos and complex behavior, from the simple double pendulum, to the much more complex human brain or any social organization. They are typically characterized by the presence of nonlinear interactions governing their often unpredictable dynamical evolution, which makes it impossible to provide a simple description of their behavior even under controlled laboratory conditions. The very first (published) evidence of chaos in an experimental system was reported in 1977 by Jack Hudson and collaborators, who observed sustained time-dependent nonperiodic oscillations in the Belousov–Zhabotinsky reaction in a continuous-flow stirred reactor [1]