Modeling Homophily: A Computational Test of Merton and Lazarsfeld’s Thought Experiment and Its Extension.

This paper focuses on the results of a computational experiment conducted with an agent-based model grounded on Merton and Lazarsfeld’s homophily the - ory . In “Friendship as a social process” the authors described homophily as “a tendency for friendship to form between those who are alike in some designated respects”, considering both status homophily and value homophily . In that es - say, two causal micro-mechanisms were presented to account for the observed macro-patterns of value homophily: selection and adjustment . Such theory was a pioneering attempt to show how macro-consequences originate from individual preferences and the two micro mechanisms have played a pivotal role in the his - tory of research on social influence and dynamic networks. Lazarsfeld developed a thought experiment to explain how homophily emerges, supposing 800 social actors linked together by 400 social ties . Using NetLogo language, we formalize and simulate an agent-based model in order to dynamically generate the pro - cess suggested in that work . Therefore, we simulate four scenarios to stress the original theory. The first scenario is from our previous formalization of Lazars - feld’s thought experiment and his description of the system of action . Here, we introduce counterfactual hypotheses formulated by the authors concerning the above-mentioned causal mechanisms . In the second scenario, agents are as - sumed to interact in a dynamic network more complex than the one conceived by the authors . In the further two scenarios, on the basis of Blau’s theory of social structure, we introduce two hypotheses concerning the impact of status homoph - ily and actor’s social position on selection and adjustment . Reading the simulation results through the four-fold typology of social ties proposed by Lazarsfeld, we can clearly recognize four macro patterns generated from the micro level by the interactions between individual agents .