Small Worlds

Six degrees of separation

An interactive lesson with 7 steps, about 6 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Social networks are small worlds: high clustering, yet short chains between almost anyone.
• A few random long-range links shrink typical distances dramatically (like log N).
• Hub-dominated networks shrug off random failures but are vulnerable to losing their hubs.

Steps

1. Letters to Boston
2. Friends of friends
3. But friends overlap
4. Add shortcuts
5. Small worlds everywhere
6. Hubs
7. A ring of 1000