The function of music in the movies is a very wide field.
Music can serve several purposes that are either important on the emotional side of the movie or help/enhance the storytelling. It is not only helpful but essential for any director/producer to keep the music in mind when planning/shooting the movie. For example collages that practically don’t work at all without film music can have a fantastic effect later with the appropriate music.
You can extend every function below by clicking on the arrow in order to read a description of this function.
The following list tries to be a comprehensive overview about possible functions of film music in a movie. Some functions overlap sometimes or some music serves several functions at other times.
This is a function that shouldn’t be overdone. Music can put a judgement on certain movie scenes, it can state that a certain battle scene is heroic, a certain dialogue is sad etc. In the early days of film music, the function of the music was most of the time to comment on the images. Nowadays we perceive this as an annoying redundancy most of the time but used cleverly it will help push the audience into the right direction.
2. Illustrating movement
Another function that feels rather old fashioned and comedy. Accenting with the music every movement seen on screen is so-called mickey-mousing (coming from a scoring technique that was often used in Mickey Mouse cartoons). Hearing xylophone “plings” when someone raises his eyebrow etc. feels very cartoony however it can be great in slapstick moments and when done well even in dramatic situations.
3. Creating plot relationships
The use of so-called leitmotifs has been established by Richard Wagner in the opera and has often be used in film context since the early days of film music. Giving certain characters/situations/places thematic identities helps to connect certain plot points together. When the villian gets a theme and later we hear that theme again when somebody talks about a “stranger” we get a very clear hint of who that stranger might be. It doesn’t need to be that obvious for leitmotifs to work, of course. However, be warned to not overdo that technique. Not every supporting role needs a motif/theme and it can quickly feel very old fashioned when using this method extensively.
4. Create atmosphere
This is one of the strongest function of music in the movies. It can set the tone of the movie. Just by the way the score comes in for the first time in the movie makes it possible to know the genre and the “level of drama” of the movie. Of course exactly this really strong function can be used to create plot twists.
5. Portray Emotions
Another very strong function. Music can serve the movie by getting into the emotions of the characters. A face with a neutral expression can be pushed into “feeling” many different things just by what kind of music is used. In the same way it works of course very well to evoke certain emotions with the audience.
6. Social/Cultural/Geographic references
Music can work very well to make clear the heritage of a character/group of characters or the geographic setting of the movie or a scene. Often so called pseudo authenticity is used that uses music that feels like a certain location to western ears as opposed to actual music that can be heard at that location (which differs quite heavily sometimes). If for example Irish sounding music can be heard during a certain scene etc. we can easily spot where it’s taking place without the need of visually establishing the location too much.
7. Time/Period references
Music can also work very well to establish a certain time or period. Music that sounds very baroque will put us back into the 18th century but references can also be more subtle. Flashbacks over a few decades for for example can be very well supported by the musical style which adapts to the time portrayed in the movie and therefore makes the flashbacks more understandable.
8. Connect scenes/montages
Music helps very well to glue scenes together. Rather harsh scene changes can be softened by adding music over the scene change. One of the extremes of these forms are montages which work beautiful with music. Even though we might have a lot of jumps in time/places or even periods, when the montage is covered under one score cue it will at the same time be glued together and understood as a whole.
One of the functions of music that is and has been used quite a lot, even though it is not one of the most noble functions of music. Doubtful contents of a movie can be pushed into the “right” direction by music as it has been seen with lots of propaganda movies from all periods of times. However it can also be used very cleverly. For example when a character that is being portrayed as “the good guy” but actually is the villain. However in this case this fact will only be revealed at the end of the movie. Any moment before where the audience might get trapped into maybe thinking that he might be the evil guy, the music can jump in and manipulate in the way of working against these doubts.
10. Alternate the perception of time
The perception of time is a fantastic playground for music. Just by altering the tempo of music, it can heavily push or drag any scene. Imagine a chase sequence where the music pushed with lots of tempo, exciting orchestration etc. compared to the same sequence with a calm, slow music. The latter one would almost feel like irreal but it would make the scene way less exciting. Same goes for any time perception. A scene where we see a person waiting which lasts only 30 seconds can be extended painfully in the perception by the music.
11. Imply a sense of space
Not only the perception of time but also the perception of space can be influenced by the music. Using a very intimate piano+violin duo on a space science fiction movie might seem just as wrong as using a full symphony orchestra in a two character movie that’s taking place in a small flat. Also by the use of register (very deep sub bass or very high violin notes as opposed to music that plays mainly in the middle registers) can leave an impression of “size”.
12. Create unreal situations
Characterizing nightmares or situations of shock or being paralyzed can be done perfectly by the music. Anything that gives the feeling of not being real can be greatly enhanced by the music. Nightmares of characters can be made much more impressive with the right music.
13. Create contradictions
Music that sounds like something that is not expected in a certain scene will create a feeling of “something is not right”. It works great for example on dialogues that are actually neutral from the content of what is being said. However having a really dark and sinister music under this scene will leave the impression that something will be happening, something might be wrong here.
Music can influence very strongly whether we find a scene to be serious or laughable. It can use this ability to create fantastic parodies of characters or situations in the movie. One very simple example would be a character who pretends to be very evil and acts like this, however the music just gives him/her a quirky wannabe-evil march.
15. Physiological conditioning
Music can also influence and stimulate our very basic emotions like fear and therefore evoke in a best case scenario every physiological consequence that comes with that emotion like racing heart, sweaty hands etc. Especially in the genre of horror and thriller, these effects are used extensively. A certain level of volume will make it impossible for the body and the conscious mind to detach from these emotions. Shock effects in scores/movies as well as terrifying buildups (cop sneaking in a dark basement – he’s approaching a corner – music gets louder and more terrifying etc.) are very common and work great, however quickly can feel like a cheap trick when used too often. It is also possible to influence into other emotional directions, which is more subtle and doesn’t have the obvious effect as fear etc.
16. Implying size relationships
A little boy walking alone through a huge city is just a scene that might be very suitable for this use of film music. In this case the music can enlarge the visual differences between these things by giving the boy a little innocent flute motif on top of a very low, boiling music which might symbolize the huge city. In this way, things that can’t be seen like that on the screen can be set into relationship. If this little innocent boy from above might actually be a really brave, heroic person who has done or is about to do big things the music might set him into another “size” dimension to the city even though the images don’t reveal that yet.
17.Psychologically uniting the audience
One of the most obvious case of such a function of music are national anthems whose function of course also is, to unite the “nation”. The same works in the music. Especially euphoric, heroic emotions can be used very effectively to get this collective emotion. Often, well known songs/music pieces can be used for that as they are easier accessable than music that the audience hears for the first time. However, even a very heroic score cue on top of a scene where the heroes of the movie walk through a crowd applauding a cheering at them after they fought the last big battle and won can create exactly this collective feeling of having been part of all that also with the audience.