Why is it that a man who plays a harmonica whilst playing guitar is classed as a musical genius, but put a set of cymbals between his knees and a drum on his back and he starts to look insane?

I found the above question on a forum yesterday, and it got me thinking. What is it about the alteration of one detail that can irrevocably change a whole picture?

The first line of the old song ‘Misty’ goes ‘Look at me, I’m as helpless as a kitten up a tree’. Aah, sweet: we empathise with the singer’s vulnerability straight away. Substitute ‘kitten’ for the similarly syllabled and sounding ‘chicken’ and all of a sudden things are different. A chicken is just as helpless as a kitten is up a tree, but the empathy disappears. It’d be easy to say it’s because a chicken is a ludicrous creature, but let’s look a little deeper than that. Is it because a chicken is feathered and kind of reptilian in its movements, whereas a kitten is indisputably mammalian?

All this is towards making a point about what fits, and what doesn’t, and what kind of non-fitting thing you want to put into your screenplay when the time comes to break whatever pattern the audience is currently experiencing and present them with something unusual. Huh? Well, let’s say you have a thriller. The protagonist fearfully opens the curtains in her living room to discover…a sheep looking in at her. Unexpected alright, but not the kind of unexpected that works with a thriller. Whereas, if the curtains are pulled back and a man with a knife is seen outside, then all is well with the world.

In any screenplay, you’re seeking to strike a delicate balance between the expected and the unexpected. Veer to far off track and you lose the audience with what comes across as irrelevance. (Unless you make it your trademark and you become known as a surrealist: stand up The Discreet Charm of the Bourgeoisie.) But if your concerns are more narrative and linear, there’s only so far off the path you can stray without losing your audience.

So, how do you cement a surprise into your screenplay such that it will work on screen? Part of the answer is the inner logic of the story you’re telling. Donkey Punch features assault with a deadly weapon in the form of an outboard motor engine, but the story is set at sea, the absence of the engine has featured as a plot point, and it has been seen and thus foreshadowed.

Music and sound are your friend in situations like this too. If you create an auditory cue at one point, its reappearance will be associated with whatever was happening the first time it was heard. So, let’s say you have a string section stab just before a jack-in-the-box pops open. Later in the film, all you need to do is hear the same string stab to expect an equivalent surprise.

The degree of surprise you allow for in a film depends on the nature of the genre you’re working in. You probably won’t get far writing a romcom if the protagonists hate each other at the end as much as they did in the beginning, unless there was a love story in the middle. And so on. But finding ways to create surprise is one way to keep you as a writer on your toes. And face it, if you’re not engaged by what you’re writing, what hope has anyone else got?