Natural Experiments of History

The title of this essay is the same as a book edited by Jared Diamond and James A. Robinson, published in 2010 by Harvard University Press.  The book explores the general method of natural experiments applied to human societies and history.  It was tempting to title this essay “Cultural Experiments,” because the emphasis of their book is on inhabited places, social institutions, and human actions.  But the cognitive dissonance of natural, experiment, and history in one title is an appropriate mental stimulus for the message they present. 

Experiments are controlled comparisons deliberately set up to expose the effect on one or a very few variables on some structure or process.  Greatest confidence is afforded by laboratory experiments where all external conditions can be held constant, or field experiments where even the conditions outdoors are kept as constant as possible while varying the presumed cause.  A randomized comparison between a treatment and a control is still the statistically most unassailable approach.  However, even with this paragon of knowledge creation, great creativity must be brought to bear to ensure that the external conditions are indeed well known and no causative factors are left unaccounted for.  Furthermore, there is a trade off between rigor and realism in experiments.  The more controlled a situation is the greater the distance from messy reality.

What are researchers to do if they can’t control the environment and vary one or two factors at a time?  After all, history can’t be redone, and there are ethical constraints to manipulation in inhabited systems.  Many people have assumed that this means the power of experimentation is unavailable in such situations.  This would disadvantage those who are interested in complex systems, in much of human agency, and in historical causation.  What influence do the conditions of the past have on the outcomes in the present?  

This is the problem that Diamond and Robinson address.  They open and close the book with chapters outlining the issues and summarizing the successful strategies for dealing with found or natural experiments.  Indeed, the cultural and historical comparisons, and the comparisons of socio-ecological conditions that the book presents are far from some haphazard stumbling across a good comparison that has the hallmarks of an experiment.  Great care is taken in evaluating the similarities and differences among the control and the treatment historical or initial conditions.

In addition to the introductory and closing chapters, the book addresses several cases:

The chapters are written in a very approachable style while at the same time explaining the rigorous assessment of conditions to ensure the validity of the comparisons.  All repay attention.  However, perhaps of greatest relevance to the Baltimore Ecosystem Study, with our new emphasis on the transition from the sanitary to the sustainable city, is the chapter by James Belich on “Exploding Wests: Boom and Bust in Nineteenth-Century Settler Societies” (pages 53-87).  The chapter covers the American West, and the British “West” consisting of Canada, Australia, New Zealand, and South Africa.  The transfer of human, financial, and material capital from an established metropolitan area to a frontier, with an associated increase in vectors of mass transfer; media and modes of communication; and booster institutions and businesses characterize booms.  The creation of local infrastructure during a boom is a major commitment.  Busts, crashes, or panics, on the other hand are characterized by reduced human population growth and reduced economic growth.  They can last for two to ten years, and generate by an economy dominated by new or increased exports.  The “conquest of distance” is a feature of successful export recoveries.

There are repeated cycles of boom and bust throughout the global, Anglo-American Wests.  What relevance does this kind of thinking have for the transition from the post-industrial, sanitary city to the sustainable city of the future?  It’s a question we should consider.  And attention to the methodology of cultural or natural experiments in an urban LTER is also an important matter.  So this book has double relevance to BES.