The Truth About Twins & Doppelgängers

What is the science behind doppelgängers? In this fun episode of SciShow, two bespectacled science YouTubers enter, one bespectacled science YouTuber leaves ... because while they may look suspiciously alike, Joe Hanson has his own channels while Hank’s gonna stick around here. The only question is who will return to their home territory with a well-earned sense of victory?