the concept of the two-sentence horror story is actually a great way to understand the similarities between horror and humor: the way both forms are based in the same neurobiological systems and thought patterns; the creation and resolution of tension; the use of the set-up/punchline structure; the way they both rely on the recognition of an incongruity, the reveal of a surprise, or a subverted expectation; the way that the subverted expectation is based on some way on a shared cultural context or common human experience; the way they both can cause a change in breathing patterns (laughing vs. gasping); the way that knowing what is coming can lessen your reaction. tbh when you break it down, the only real difference between comedy and horror is that with comedy, the incongruity the joke hinges on is in some way safe, whereas with horror, the incongruity feels dangerous.
this holds up in a lot of ways with some evolutionary theories of laughter; basically the thought is that laughter may have developed partly as a way to quickly alert fellow humans that a threat was no longer present. ex.: your tribe sees a shape in the distance that looks like a lion; once approached, a tribe member realizes it’s just a rock; and so they laugh to let their group know the coast is clear. this may be why laughter is contagious as well; a quick way to spread the message that the coast is clear.
that theory also explains nervous laughter—people may laugh instinctually when stressed as the body’s way of trying to calm itself down and tell itself that they are safe. it can also explain why some people are hurt or offended by jokes while others are not—people are hurt or offended because in some way they don’t feel that the incongruity represented in the joke is a safe one, and people that aren’t offended don’t feel threatened at all. for example, if you’re straight and all your friends are too and you’re never known a gay person and you don’t think about them a lot—if that’s you, and someone tells you a homophobic joke, your safety and the safety of your loved ones won’t feel threatened. but if you’re gay or you have gay loved ones or the joke is told by a straight person whose background of allyship is either unknown or actively nonexistent, then you might not feel safe in that situation, and you wouldn’t laugh (except possibly out of nerves). or, alternatively, if you’re gay (for example) and the same joke is told by a gay person or someone you know to be an ally, you would know that the words don’t translate into a real life threat, you would feel safe, and you would laugh.
it’s difficult because people want jokes to be either funny or not. they want a litmus test. they want to be able to point to aspects of jokes and say “this is why this is OBJECTIVELY funny/not funny.” unfortunately, that’s not how humor works (or really any aspect of human behavior). everyone has different ideas of safety, everyone has different thresholds for determining threats, and one person’s ideas and thresholds are heavily context dependent. it changes depending on their mood, their environment, the people around them, the person telling the joke, the very rhythm of the joke, etc.—things that have nothing to do with the actual wording of the joke itself.
so if you’re writing comedy, that’s something to keep in mind: if you don’t think about your audience’s sense safety, you may accidentally end up writing a horror story.
and that’s NOT to say that mixing horror and humor is bad—works that play with the line between humor and horror are often brilliant (see: barry, every movie jordan peele has ever made, what we do in the shadows, shaun of the dead, to name a few). but walking that line needs to be with intention and care.
