How to be an extremist
We present a toy model of opinion spreading in a society which combines a self-reinforcing mechanism with diffusion. The relative strength of these two mechanisms - called the affectability of the system - is a free parameter of the model. The model is run on a scale-free network and its asymptotic behaviour is investigated. A surprising emergent effect is observed: If every individual becomes more attentive to the opinions of others, the society as a whole switches from a plurality of nuanced opinions into the state of an absolute consensus on an extreme opinion. This counter-intuitive emergent behaviour may help to explain certain paradoxes in human history.