Our experts examine the brain's internal tug of war between fear and rationalization. Whether boarding an airplane or walking down a spooky street at night, we'll see how dread and anticipation build feelings of fear. Putting our host's emotions to the test, Apollo Robbins challenges Jason Silva to a game of Russian roulette. Then, with the help of John Harlacher, co-director of one of New York City's scariest haunted houses, we "Fear Factor" a group of volunteers. Without their senses of sight, sound, or control of their limbs, see how they react to snakes, cockroaches and rats... or so they think.