Simulation of a Dynamic Theory of Reasoned Action

Background The Theory of Reasoned Action (TRA) is invoked frequently when social science scholars examine messages , affect , cognition , and action . Nevertheless, the fact that the TRA is a cross-sectional model limits its utility as an explanatory mechanism for those who study relationships among these variables as they change over time. This essay addresses this limitation by developing three versions of a Dynamic Theory of Reasoned Action (DTRA). Method Simulations were conducted to examine the properties of these varying DTRA models. The extent of autoregression was varied in these simulations, and the subsequent effects on the size and stability of the model parameters, the fit of the cross-sectional TRA, and the distributional properties of the variables that comprise the model were assessed. Results Results indicate that in the absence of an external shock (such as a persuasive message ), these models reach equilibrium , and that trials to equilibrium increase as the autoregression parameters increase. The TRA fits perfectly at equilibrium , but may fail when the system is not in equilibrium, even when the DTRA fits perfectly. Finally, although starting with seed distributions closely approximating normality, distributional properties depart decidedly from normality over trials. Conclusion Implications for the fit of cross-sectional causal models and the meaning of cross-sectional associations are discussed.