Empirical Test of a Psychologically Based Simulation of Collective Action
Robert Tobias
rtobias@sozpsy.unizh.ch


     The problem of organizing collective action campaigns is tackled with a multiagent simulation, in which the actor‚s decision to participate is modeled on the basis of an expansion of the social psychological Theory of Planned Behavior. The variables entering into the model of the individual‚s
decision to participate are attitude, return, subjective social norm, and perceived behavioral control. With these four variables, various social scientific theories get integrated (Elaboration Likelihood Model, Theory of Planned Behavior, Rational Choice Theory). The theories allow conceptualization of interactions among individuals and the effect of activators, seeking to recruit others to participate in a collective action can be studied. Simulations of a population of 10,000 different agents revealed the influence of several factors, though, only one or two examples can be shown in the presentation.
     The focus of the presentation will be on the empirical test of this computer model using data that was gathered during a collective action campaign in a Swiss community. Based on this data, the behavior (participation or non-participation) of each individual in the sample was calculated and the simulation results compared with the real behavior. In more than 85% of the cases, the calculated behavior equals the empirical data.
     In a second step, the sample data was extrapolated to simulate the entire community. The simulated diffusion of participation appeared to be similar to the real dynamics of the collective action campaign in the community. Thus, the model could be used to evaluate the organization of the collective action campaign.
     Though the model has to be developed further in many regards, a lot of important aspects for planning collective action campaigns can already be investigated adequately with it.