When Survivor: Worlds Apart premieres on Feb. 25, we will see a battle between White Collars, Blue Collars, and No Collars. But more important than the designations, perhaps, is the number—that number being three. Survivor has started its seasons with anywhere from two to four tribes, but it has experienced some of its greatest success lately (Survivor: Philippines and Survivor: Cagayan) when it has gone with three groups of six people each.

“Three tribes gives us a few advantages,” says Probst. “One is even tough we tend to have the same amount of people out there, because they are broken down into smaller groups it appears that it is easier to get to know people more quickly, because you can capture a tribe that is only six people. So you can kind of quickly go ‘Oh I know that person and I kind of like that person.’ As opposed to looking at maybe 10 people on a single tribe. And the other thing it does is it changes the dynamics of the game because of the way the numbers play out. There’s now this triangle, and when a switch happens or the inevitable merge happens, it complicates everything. And Survivor has always been a game in which one tiny little change can really result in a big result—a sweeping result. And so that’s what we tried to do and it’s always my preference now if the creative lines up to do three tribes, because of that.”