The Role of Argument Strength and Informational Biases in Polarization and Bi-Polarization Effects

This simulation research explores the informational causes of polarization and bi-polarization of opinions within groups. We define 'polarization' here as a uniform change of the opinion of the whole group in the same direction, whereas 'bi-polarization' indicates a split of two subgroups towards opposite directions. For our purposes, we have expanded the model of the Argument Communication Theory of Bi-polarization. This is an argument-based multi-agent model of opinion dynamics inspired by Persuasive Argument Theory. The original model accounts for polarization as an outcome of pure informational influence and reproduces bipolarization effects by postulating an additional mechanism of homophilous selection of communication partners. The expanded model adds two dimensions: i.e., argument strength and more sophisticated protocols of informational influence (argument communication and opinion update). Adding the first dimension, allows us to investigate whether and how the presence of stronger or weaker arguments in a discussion influences polarization and bi-polarization dynamics, as suggested by the original framework of Persuasive Arguments Theory. The second feature allows us to test whether other mechanisms related to confirmation bias and epistemic vigilance can act as a driving force of bi-polarization. For the first issue, our simulations showed that argument strength has a measurable effect. For the second, our results would indicate that, in absence of homophily, only very strong types of informational bias can lead to bi-polarization.