Lev Kuleshov was one of the pioneers in film theory in Russia during the early years of its development. He is largely known for what is called the "Kuleshov Effect". The general concept has to do with the idea that the meaning of a clip can change drastically depending on the clip it is then juxtaposed with. To show this, the same clip of a man is edited with three other clips. Here's the experiment in action:
When the audiences of the time saw this, they were amazed by the man's performance. They, "raved about the acting... the heavy pensiveness of his mood over the forgotten soup, were touched and moved by the deep sorrow with which he looked on the dead child, and noted the lust with which he observed the woman. But we knew that in all three cases the face was exactly the same." Today as we've seen hundreds or thousands of movies in our lifetime, the effect is not as strong in that particular experiment. Understand, to the people back then, this was all borderline magic, a dream come to life. The technique though is just as effective.
Imagine an interior scene, the light is dim, we see a closeup of a tall man with a dark, dangerous expression. Eyes locked on some unseen point; he looks almost ready to spring forward. The next shot we see an infant asleep in a crib. What would you feel? Likely, fear for the child. What does this man intend to do? Is he going to harm the child? Kidnap it? Let's go back though. We see the same shot of the man, but instead of the child, we see this man's young teenage daughter and her previously unknown, to the father, boyfriend making out in the dimly lit living room. What do we feel now? The effect (depending on the tone of the whole piece) will likely be amusement or a tentative feeling. Something's going to happen to the boyfriend. Either way, he's likely about to be chased out of the house by a protective father.
Understand though, that juxtaposition works not just with shots, but with scenes. Whether something comes off as drama or comedy can have entirely to do with the way it is ordered. If you haven't seen What's Eating Gilbert Grape, you should. Currently it's on Netflix. There's a scene starting at about 1:04:14 where the family learns a son was arrested. The family goes to get him. The mother is understandably upset with the police. She is very overweight and hasn't really left the home in years. They go out to and get in their small blue car. The next shot we see the car is going down the road, but it is leaning heavily to one side. When I first watched it, there was a collective giggle from the crowd. At the end of the scene that follows, a crowd has gathered to see the huge woman they've heard came into town (small town, news travels fast). There are looks of wonder, pity, giggles, and enough shame to fill a swing pool. One man even takes a picture like, it's an exhibit. The film makers finish the scene by showing essentially the same shot of the leaning car. There's a difference now though. Instead of giggling in the crowd everyone was dead silent. Not a sound. A perfect way to bookend the scene and a way to remind the audience that just minutes before, they were the ones laughing at her.
Alfred Hitchcock was very familiar with these techniques and employed them both in cinematography and in editing. Here's an excellent interview where he cover three scenarios where juxtaposition of shots can have an emotional impact on the audience. Learn from a master. I won't expand on what he says:
Understand that these techniques span all stages of production. They are best accomplished if planned for. That way they are imagined in writing, properly covered in production, and realized in editing. Happy accidents do happen, but only sometimes. As editors it is our job to find/create as many happy accidents as possible. We can fall into the trap of setting up a scene and then loving it too much, or figuring it's adequate. If we go a little further and rearrange a few things you could discover an emotional payoff that could have been missed. Reaction shots are particularly effective for that.
In Part 2 (coming soon) I'll explore a few techniques developed by one of Kuleshov's students.