How do composers create music that makes us think of certain characteristics?

 How do composers create music that makes us think of certain characteristics?

To start with it is quite well known that pieces of music may be recognized as emotions being expressed by the composer of the piece which then leads to us receiving those emotions and characteristics once we listen to the piece of music.Most of the time so composers add characteristics to their music and feeling to it they use several extended sound production techniques in their music,such as improvisation, musical montage, preparing instruments, using non-traditional instruments, and other methods of sound production.Other things that also give a major effect on a piece of music are melodies, countermelodies, chord progression ( which support melodies) and also instrumentation. Composers usually use different chords with different keys to convey different emotions fro example if the composer  puts a minor key with a major chord that can deliver a peaceful and hopeful feeling but maybe in the same time  it may also deliver a dark mood however if the composer  puts unusual chords in your piece you can deliver a dramatic effect on the music.Most of the time the composer has a baseline in their piece of music which then helps the listener identify the characteristics and emotions associated with the piece of music.

For example, if the composer wants to make a frightening, scary piece he would put crescendoing minor chords and loud deep chords to deliver suspense and fright the composer may also add unusual chords to make it dramatic and traumatizing feeling or characteristic to the music.the composer can also put chaotic high pitched chords to scare the listener and also add some suspense to the music.Other than that the composer can also put nonlinear chaotic noise, for example, a dissonant chord which can then emphasize the emotion in the music but mostly the suspense.On the other hand, composers also make sad,blue pieces.In this certain type, there is a very common method which is that composers use minor keys to express sadness but the most common one is the minor third.The minor third has been used to express sadness by lots of musician and composers ever since the 17 the century.The minor third is a very clear it is obviously sadness when the minor third is put into a piece it is quite easy to identify its characteristic and its emotion in the piece as it is a deep low key that clearly describes sadness.To conclude there are a lot of methods that composers use like improvisation, musical montage, and other sound production methods  when they write pieces of music that then add characteristics to it and make the audience think and feel those emotions as they listen to the piece 

References:

http://www.theatlantic.com/entertainment/archive/2010/12/what-makes-a-song-sad/67709/

http://newsfeed.time.com/2012/06/19/why-is-scary-music-scary-heres-the-science/

https://en.wikipedia.org/wiki/Musical_composition