Mechanistic Models in Computational Social Science Petter Holme1*, Fredrik Liljeros2 1 Department of Energy Science, Sungkyunkwan University, 440-746 Suwon, Korea 2 Department of Sociology, Stockholm University, 10961 Stockholm, Sweden * Correspondence: Petter Holme,
[email protected] Abstract Quantitative social science is not only about regression analysis or, in general, data in- ference. Computer simulations of social mechanisms have an over 60 years long his- tory. Tey have been used for many diferent purposes—to test scenarios, to test the consistency of descriptive theories (proof-of-concept models), to explore emergent phe- nomena, for forecasting, etc. In this essay, we sketch these historical developments, the role of mechanistic models in the social sciences and the infuences from the natural and formal sciences. We argue that mechanistic computational models form a natural common ground for social and natural sciences, and look forward to possible future information fow across the social-natural divide. Background In mainstream empirical social science, a result of a study often consists of two conclu- sions. First, that there is a statistically signifcant correlation between a variable de- scribing a social phenomenon and a variable thought to explain it. Second, that the correlations with other, more basic, or trivial, variables (called control, or confounding, variables) are weaker. Tere has been a trend in recent years to criticize this approach for putting too little emphasis on the mechanisms behind the correlations [Woodward 2014, Salmon 1998, Hedström Ylikoski 2010]. It is often argued that regression analysis (and the linear, additive models they assume) cannot serve as causal explanations of an open system such as usually studied in social science.