Professor Forrester, who turned 87 this year, is the father of a field of research and analysis called system dynamics — a methodology that uses computer-based models to simulate and study the interplay of growth and equilibrium over time. Absorbing the implications of these models in ways that Professor Forrester prescribes can allow mere mortals to comprehend the obscure nature of (and counterintuitive solutions to) such knotty problems as environmental damage, the boom-and-bust pattern of economic cycles, supply chain malfunctions, and the pernicious side effects of well-intended policies everywhere.
These problems, says Professor Forrester, are all manifestations of the underlying nature of complex systems, from living cells to organisms to organizations and corporations to nations to the world at large. For example, there is generally a principle at work called compensating feedback: When someone tries to change one part of a system, it pushes back in uncanny ways, first subtly and then ferociously, to maintain its own implicit goals. Dieters know this well; a person’s body will seek to maintain its current weight, producing cravings for fattening food. Similarly, a corporate reorganization, however well designed, tends to provoke resistance as employees circumvent the new hierarchy to hang on to their old ways. To Professor Forrester, these kinds of discomfiting phenomena are innate qualities of systems, and they routinely occur when people try to instill beneficial change. If you’re attempting to shift a complex system, such as a company, and you haven’t become aware of resistance or other unintended consequences, then the problems are probably building under the surface and simply haven’t burst forth yet.
Professor Forrester’s understanding of complex systems derives in part from years designing servomechanisms — the automatic control devices that inspired the field of cybernetics in the mid-20th century — for the U.S. Navy. In his pioneering computer simulations, Professor Forrester modeled the slow-to-emerge “tipping points” (as writer Malcolm Gladwell would later call them) that make systems difficult to manage, yet can also provide hidden leverage points for effective intervention. Modeling this kind of growth and resistance requires nonlinear calculus — a form of math so intricate that even the most gifted and highly trained mathematicians are incapable of solving nonlinear equations in their heads.
Thus one of the most controversial aspects of Professor Forrester’s work is also his core premise. He argues that most social organizations, from corporations to cities, represent a far higher level of complexity and abstraction than most people can grasp on their own. And yet corporate and government leaders of all sorts persist in making decisions based on their own “mental models” — Professor Forrester’s term for the instinctive theories that most people have about the way the world works. These decisions, no matter how well intentioned or intuitively comforting, are decidedly inferior, he says, to policies and strategies based on computer models of “system dynamics” — the interplay of complex, interrelated forces over time. As a result, Professor Forrester argues, most of the pressing problems facing humanity today will elude solution until a new generation, familiar with computer models, enters leadership roles.