The present study suggests three points regarding music and film: First, that both filmic and musical stimuli elicit physiological changes; second, that an additive relationship exists between simultaneously presented music and film stimuli on some self report measures; and third, that the ability of music to bind to the visual narrative of a film may play an important role in enabling music to modulate the subsequent emotional response. We have not yet, however, discussed the question that in essence makes this research possible: Why is it that people believe in the existence of music when watching films? If one were to see an on-screen orchestra and hear orchestra-like sounds, it would be said that the music is part of the visual diegesis. But what about “true” film music? Where does it come from, and why do people accept its presence? Cohen (2001) argues that one might expect non-diegetic music to detract from (rather than add to) the sense of reality within a film. The results of this and other studies, however, suggest the opposite: pairing a film with emotionally-congruent music makes the experience more salient—subjectively across the board, and physiologically under circumstances that will require elaboration by further research.

In summary, the anticipated main effects for music valence and music arousal that appeared within self-report indices of emotion were not always seen in the concomitant physiology, and the effects of music valence and music arousal found in the physiology did not always find correspondence in the self-report. The effect of music on emotional responses to viewing films, therefore, is complicated and not necessarily predictable.

Positive films prompted strong zygomatic responses (smile pattern) while negative films elicited strong corrugator responses (frown pattern). Although the figure suggests that music and film valence may have had an interactive effect on the EMG pattern score, the interaction did not approach statistical significance (F[1, 33]=1.23, p>.25). Neither film arousal (F<1) nor music arousal (F<1) had a main effect on the EMG pattern score.

Namely, films shown with NV/HA music were rated more negatively than films shown with NV/LA music overall, whereas films shown with PV/HA music were rated more positively than films shown with PV/LA music overall. Once again, paired samples t tests indicated that music arousal significantly differentiated SAM valence within both negative (t[32] =3.07, p<.005) and positive (t[32]=3.74, p<.005) films. This interaction between music valence and music arousal is similar to the interaction between film valence and arousal reported above

The dimensional model posits that every emotion can be expressed as a function of (usually) two “core” dimensions, frequently referred to as valence and arousal. Valence is described in terms of a range of response from positive (happiness, pleasure) to negative (sadness, displeasure). Arousal ranges from low (indicating calmness, peacefulness) to high (excitement, energy). These two dimensions can be aligned orthogonally so as to produce four quadrants

However, what our study does suggest is that diegetic versus nondiegetic presentation of the same piece of music can lead to dramatically different perceptions of the overall tension of a scene, the attitudes and motives and relationships of characters, and other elements of a scene that are fundamental to our understanding of the unfolding story.

Another phrase, 'nondiegetic music', refers to music external to the ‘narrative universe’ (or diegesis)—such as the dramatic music often mirroring the mood and punctuating the action of a car chase sequence. Put simply, it is not music existing within the scene as part of the world of the film characters—but simply accompanying the scene.

Film scholars use the term 'diegetic music' to refer to music that supposedly exists within the fictional universe implied by the film.  It is music produced inside the world of the characters, that they should be able to hear.  In this Minority Report scene, music is diegetic—presented as if playing inside the shopping mall where John and Agatha are on the run. 

However, we can all think of examples in which the music does not match what appears to be developing as part of the visual narrative and dialogue. For example, in the context of a slasher film, if several fun-loving teenagers are talking and laughing amongst themselves, but mid-conversation the musical score introduces an ominous, low synthesizer tone (a la Alan Howarth horror film scores), the incongruity between the laughing teenagers and the menacing musical sound will trigger an emotional response in the viewer-listener. In such situations, while the visual portion of the film may portray one meaning, the musical score is allowed to express a different (in this case, underlying psychological) meaning, providing a sense of foreboding…a harbinger of unpleasant events likely to follow.

In the survey, I asked participants to tell me whether they remembered the music during each of these scenes. If they did, I asked them to describe the musical sound in as much detail as they were capable. Interestingly, over 25% more of my respondents “remembered” the music during the scene without a musical soundtrack when compared to the other two scenes in which I had considered the music to be extremely prominent!

researchers have confirmed again and again that audience members develop expectations for the type(s) of music that are congruent with a given visual and/or narrative context. For most viewers, these expectations are generated largely at the subconscious level and are likely to be a direct result of past exposure to movies through which composers have arrived at what might be considered a set of musical “conventions.”

In a 2005 article, Dr. Kendall argues for a third type of visual-musical match which he calls iconicity. Essentially, it is a metaphoric match of which there are a few extremely common types. One is a ramp – an increase/decrease in volume and/or pitch to metaphorically parallel a camera zoom/fade or a plane taking off/landing, or a bicycle rising into the air/landing as in “E.T.” (1982)

The second kind of match is the most complicated because it is based on associations, both those you learn in the theater (intrareferential associations) and those you bring in with you (extrareferential associations). One major extrareferential association in Western culture is that major keys are happy and minor keys are sad or angry or frightening.

One simple kind of match is syntactic – when the timing of the action lines up with the beat of the music. According to Kendall, this is the simplest kind of match, and one of the two most studied kinds. Your mind is really good at using hearing and vision together to get a better understanding of the world (read more here), so it makes a syntactic match when someone is dancing, when the film cuts to a different shot on beat, and when Rocky runs on-beat through Philadelphia and up the art museum steps in “Rocky II”