Emotion/Symbolism
Emotion is a concept that a human attaches to a certain situation - a sight, an image, an incident and to music. The human brain works with the use of symbols. We look for and use symbols to think. We witness a tragic accident. Later on we create a link between a smashed up car, and the incident we saw when we were ten years old. We link a tuba playing short phrases to humor. We link a flute playing an Indian scale, to a wonder eyed musical feeling. A composer/creator begins to become aware of this connection and uses it in his/her work.
Music sometimes has a purpose, sometimes none other than to satisfy the composer/listener. When you start to write music on demand or if you've studied or written for long enough you are aware of that on some level. Sometimes music is inspired and seems to flow out of us, other times, other times we must rely on our experience of or lessons, or devices we have learnt to help us to get something done. I think good music sometimes guides us to an emotion, but tricks us by thinking we got there on our own.
How we respond to music is somewhat culturally transferred. Music being played by 16 string players, in enherantly more important that something being played by a rock quartet. Before the advent of the internet we were more isolated as to the different types of music we could hear. That has changed, now music is like a 24 all you can eat buffet. There's an extreme assortment of variety, and you can mix/match/contaminate/expound/create a different flavor.
I come for a rock/pop background. I used synthesizers (back in 60's) The synthesizer was still very crude back then, but it had an extreme range of what it could create.I often got booked to put fake strings on arrangements. Looking back, those sounds were pretty rough, and my knowledge of string arrangement pretty poor. But that synthesizer put a label of 'legitimacy' to the music. If it vaguely sounded like strings, it must be a 'legitimate' piece of music, who would go to all that trouble to adorn 'crap'.
It was then I became to realize why an orchestra sounded to good. It has had hundreds of years to evolve. It has found the right instruments, with the right harmonics, in the right proportion, to accomplish many goals.
Because we are emotional beings, we constantly look to reinforce this. We assign emotion to sounds, harmony, polyphony, rhythm, just as we do to images.
When we first heard the riff from Jaws, or Psycho, the music reinforced the fear we that was building up from plot, the actors, even our own fears. Now years later, that riff creates almost the opposite effect, because it so stereotypical, we laugh at it.