When Japanese researchers wanted to see if chimps could learn things from simply viewing a situation just once, they needed to create situations where apes would anticipate a noteworthy event. So they made their own horror films just for apes.
On a Friday afternoon in 1999, I went to the matinee showing of a movie that I knew barely anything about. The film ended, the credits rolled, the house lights went up, and no one moved for a very long time. As we stumbled into the daylight, someone verbalized what we were all thinking: Was that real?