Information Cascades Against Clusters

Looking at it from a distance, information cascades seem fairly simple. If the two people going before you picked a ball out of a bucket and declared that both the balls were blue, you go and state that the bucket is “majority blue” even if you pick a red ball. It’s simple right? Although we have used cascades for primitive examples for the scope of our class, information cascades and the herding effects that come with it impact our world drastically.



In 2011, an Economist article aimed to tackle the Arab Spring through herding. The author of the article quoted a paper written by Oregon Economics Professors Chris Ellis and John Fender, where they described revolutions and civil unrest through information cascades. They defined these cascades as a phenomena that forced people to “make decisions on the basis of their observations of other peoples’ actions” and observing signals through their behaviors. They believed that workers decided whether to rebel or not by observing their counterparts actions and though of other workers rebellions as a sign of the regime’s weakness. If enough of them organized and rebelled, then a good shot was born for the regime to be overthrown.

The Economist used this bit to explain the Arab spring, where information cascades both within countries and between countries, created an avalanche effect that took the whole world even the protestors themselves by surprise. Events like these are actual testimonies to just how effective and sudden information cascades can take over.

But we know that virtually every country on Earth has protestors and citizens that want to topple the government or establish the rule of a new leader or new ideology. So why can’t all these movements take off and use the avalanche effect created by cascades? Clusters.

Clusters are closely knitted communities of people that typically share the same beliefs about political issues. And each informational cascade has an innate threshold. A threshold is a magical ratio between the nodes in a person’s network that believe in a given ideology and the total number of nodes in that persons network. For an information cascade to influence an individual this threshold has to be surpassed and significant majority of the nodes in a person’s network should believe in that ideology. However clusters characteristically force people to share a tight group of neighbors and have densities that prevent these cascades from claiming one of their members. And the natural by-product of this clash between cascades and clusters is polarization.

Several posts in this blog have explained the polarization between conservatives and liberals in the US growing due to these clusters; and they are right. However, this phenomenon represents a more global trend. The Washington Post published an article that described polarization in the world and in between the different cultures and governments of the world.


We don’t need to go into the underlying details of the map, but it basically depicts different ideologies with different colors. And the vast difference between the colors of our world is striking. This is the result of a battle between information cascades that aim to create global revolutions and national clusters that want to protect their own ways of life. It will be exciting to see how this will pay out.

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