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Side Projects

ACTB Model

Argument Communication Theory of Bipolartsation Model (ACTB Model)

The ACTB Model was developed by Michael Mas and was published in 2013 (see reference below). It is an agent-based mathematical model that is capable of grappling with a perplexing property of society: Individuals, left to their own devices, can become dramatically polarised in their opinions in regard to particular matters, notably in areas of politics, but also in other domains such as religion.

The work builds on Persuasive Argument Theory. PAT assumes that individuals base their opinions on a set of binary pro or con arguments and that their position on the matter at hand is simply an average of the collection of arguments they deem relevant. When a discussion occurs, an individual is exposed to the arguments that his partner values. In a group where members already have, say, a certain political sway, it is more likely that discussions within this group will surface arguments inline with that existing bias. As a result, such gatherings have the potential to draw members of the group further in the direction of their pre-existing prevailing opinion.

If we add to the mix a phenomenon called homophily - the natural tendency for people to prefer to spend time and interact with those that are similar to themselves - we have a recipe for opinion polarisation in the making. If, when people who interact in groups where members are already similar in their political opinion, mostly arguments to reinforce that prevailing position are mouthed, thus aggregating to a collective shift towards a more extreme position, and, groups are more likely to congregate in which members are already like-minded due to a perfectly human condition called homophily, then, before they know it, groups on both sides of the fence can find themselves wandering progressively away from it, with an evermore alien group on the other side.

Of course, there are many other factors at play in such a situation, but interestingly, this Argument Communication Theory of Bipolarisation presents a clear rationale for how groups can become severely separated in their positions without even a hint of what has been called negative influence. This is where an individual will shift his own opinion away from another's whom he evaluates negatively, potentially to avoid an uncomfortable state of cognitive dissonance.

Written above is only a birds-eye view description of the ACTB model's core essence. For the sake of approachability, many of the intricacies of its complete mathematical formulation have been left out. These include, for example, the equation used to calculate the probability that an interaction partner agent will be chosen from the whole population at a given simulation event, which has included in it a parameter, h, that can be used to dial the level of homophily. If you are interested in the full mathematical simulation model description, please refer to the original paper by Michael Mas (see reference below).

The live simulation seen above is a simple implementation of the ACTB simulation model. A discrete opinion scale from -1 on the left to 1 on the right is populated by a number of interaction agents. A colour state from blue to red represents the concentration of less or more agents respectively at that particular position. You will find most of the time that the population ends up entirely in the two most extreme positions depicted by red bars at either side of the canvas.

Reference