TL;DR

This Veritasium video unpacks the magic behind the “six degrees of separation,” showing how just a few random cross-links turn a tangled web of friends into a surprisingly tight “small world.” You’ll learn why weak ties often carry the biggest punch, how diseases can race around the planet in hours, and what makes a handful of “hub” nodes dominate real networks.

Along the way we meet the pioneers—Duncan Watts’s small-world model, Steve Strogatz’s witty storytelling and Barabási’s scale-free hubs—and run simulations of epidemics, network growth and even the Prisoner’s Dilemma. Bottom line: your own choices ripple through the global network, shaping everything from viral memes to collective cooperation.

Watch on YouTube