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Skip to 0 minutes and 11 seconds Let us now look into a simple cellular automaton model of opinion formation. This model is taken from the library of net logo models. Here you can see where you find it in the net logo model library.

Skip to 0 minutes and 30 seconds In this model, agents can have only two different opinions. Either you are pro or con an issue. Or, either you prefer Windows or Apple. Or, either you are Democrat or Republican in your political orientation. All agents in this model update their opinion at the same time and every cell is occupied by an agent. The local neighbourhood in this model is a Moore 3x3 neighbourhood.

Skip to 1 minute and 7 seconds To make sure that every cell has the same shape of neighbourhood, the world is, in this model, organised like a so-called torus, as you see it here. This is often done in cellular automaton modelling. That is, cells on the left border have those on the right border as their neighbours. And cells at the upper border have those on the lower border as their neighbours. In a three-dimensional representation, this looks like a doughnut.

Skip to 1 minute and 41 seconds Here you see a possible random starting configuration for our model. This is the starting configuration you get if you start this programme in net logo. The world has here 151 times 151 cells. And every cell holds an agent.

Skip to 2 minutes and 3 seconds The state change rule for these agents is very simple. If, amongst your neighbours, there is a majority for either blue or green, then you switch to the opinion of that majority. That is, if at least five neighbours have another opinion than you have, then the cell in the middle that is you will change its colour. But if opinions are equally distributed in the neighbourhood, that is, four green and four blue, then you will stick to the opinion that you already have.

Skip to 2 minutes and 40 seconds So what do you think will happen from this initial configuration? Will everyone become green? Or will everyone become blue? Will a stable distribution arise, or will things keep changing? It is not so easy to form an intuition about questions like these. That is why we have a computer model to study this simple opinion dynamic. In the next movie, you will see the computer model at work. But try to think first about the answers to these questions.

Opinion dynamics in society 1

In this video opinion formation is explained. However, the results are not yet shown. We use a cellular automata model to understand how opinion clusters self-organise.

Think for yourself, what do you think is going to happen? Will the field turn green or blue? Will it become stable or will things keep changing? Write your thoughts in the discussion section below.