THE WISDOM and/or MADNESS of the CROWDS

Why is it that the same people, in different groups, can be kind, cruel, smart, stupid? In this explorable explanation, I'll show how the network of a group itself can shape the people caught in its web.

Draw a network of friends! → When you're done playing around, press "next" ↘ An example. On the right, represent binge-drinkers, and represent non-binge-drinkers. People look to their network of peers, to get a sense of how many of their friends do something.

(the number over their heads show what % of their friends, not counting themselves, are binge-drinkers. #binge_drinking_friends/#friends)

Play around to get a feel of this! Connect & disconnect people, and see how that changes their perception of how many people do X → As important as friendships are, networks can fool people. A 1991 study showed that “virtually all students reported that their friends drank more than they did”. (which, if you think about it, is logically impossible!) In fact, it's possible to fool everyone that a majority of people do X, even if people who do X are in a minority:

Puzzle! Fool everyone into thinking 50% OR MORE of their friends are binge-drinkers → But of course, networks don't just fool people, they also change people. "Contagions", like beliefs and behaviors, spread from person to person through a network.

On the right, we start with one person who believes a rumor. "Fake news", as the cool kids say. Every day, that person will pass the lie on to their friends. And they pass it on to their friends. And so on.

Click START SIM to see the "contagion" spread (note: for now, a person adopts a contagion if AT LEAST ONE FRIEND does. we'll see other possibilities later) → Now, we have a bunch of small, separate communities.

Try to infect everyone with the rumor over time! (Feel free to just hit "start sim" and try out many different networks again and again) → (note: you can't cut the pre-existing connections) (someting something compounding cascade effect, something something knocking 'em down like ever-bigger dominos)

(something something about spread of madness through crowds, like 2008 financial crisis or mass speculation or mobs or riots or whatever) When an idea/behavior just needs a minimum of one friends to spread, it's called a "simple contagion". However, some ideas are harder to grasp, some behaviors need more encouragement, and so these need multiple friends to spread — these are called "complex contagions".

A false rumor may be a simple contagion, but the complicated truth is a complex contagion. (head shows #infected_friends/#friends)

On the right, a complex contagion that needs 25% OR MORE friends to spread. Play around to get a feel for it → Puzzle! Same as before, but now you have to spread a complex idea. (a person needs AT LEAST 25% of their friends to adopt the idea, before they do too) Try "infecting" everyone now! → (again, feel free to hit "start sim" and just try a solution, as many times as you want) So, is that the way to spread more complex ideas/behaviors? Just add more connections?

Well, no. While more connections can never hurt a simple contagion, they can hurt complex contagions!

Puzzle! Same as before, but now, try to add to the network so it prevents the spread of a complex contagion! (something something about groupthink, how too many connections squashes complex contagions due to conformity pressure. example: NASA and Challenger explosion) (something something about how if you have too FEW connections, people are isolated and ideas can't spread but if you have too MANY connections, people are pressured by conformity and ideas can't grow.)

Top-left: too few connections, complex contagion doesn't spread to everyone. Top-right: too many connections, complex contagion can't spread to everyone.

Make a small group network that's the sweet spot inbetween, and spreads the complex contagion to everyone → Within-group friendships are called "bonding social capital". And you discovered, there's a sweet spot where people are connected enough to spread a complex idea, but not so much conformity squashes it. But how do ideas spread between groups? Between-group friendships are called "bridging social capital", and, likewise, there's a sweet spot.

Create a group in the top-left (remember your sweet spot?) and then create a bridge to spread the complex contagion to the other group → FINAL PUZZLE! Now, do both! Create a bunch of bonded communities and the bridges between them. → (something someting Small World Network, something something "unity AND diversity", "e pluribus unum", etc etc)

(happy ending or whatever)