We present an agent-based model for studying the societal implications of theories of attitude change in psychological theory. For experimenting with theories, various psychological theories of persuasive communication are implemented. The model allows for investigating the effects of contagion and assimilation, motivated cognition, polarity, source credibility, and idiosyncratic attitude formation. The simulations show that different theories produce different characteristic macro-level patterns. Central mechanisms for generating consensus can be contagion and assimilation. However, the former generates a radicalized consensus. Motivated cognition tends to cause societal polarization of attitudes. Polarity and source credibility have comparatively little effect on the societal distribution of attitudes. We discuss how the simulations provide a bridge between micro-level psychological theories and the aggregated macro level studied by sociology. This, in turn, enables complementing experimental studies by new types of evidence for evaluating social psychological theory.