Music reflects and/or shapes our state of mind.
    Music can be considered as a crude mind control tool.

It has the capacity to unify a given mass of people by making them experience the same feelings. This effect has been known for a long time and can be observed routinely on any music concert although this is more striking on hard rock/techno/loud music ones. The audience jumps in rhythm, agrees to whatever the lead singer says, shouts unanimously, etc. Everybody experienced it one way or another. It ranges from the orchestra conductor who jumps up and down like a madman at the climax of a symphony to the common nightclubber.

Still, the relationship of individuals with music is often paradoxal: sad or bluesy persons will listen to quiet, sad music whereas happy ones will fill the air with energetic and uplifting tunes; however, oftentimes depressive people try to cheer themselves up with happy songs... I for instance, never listen to hard rock music except when I am really angry. In those occasions I chose unbearably loud RAW harsh and aggressive music, and it helps me to calm down...

    This effect has been used to manipulate one's feelings during meetings of all kinds. Such events can be very diverse in nature as long as they consist in a gathering of a certain number of people, they often belong to categories such as: entertainment, politics, religion, sect, corporation, etc. These events incorporate other numerous tricks of which the music is only one part in order to turn the audience into a suggestible state , convince the audience, turn the audience into a suggestible state .

    Music influence on one's behaviour is such that it could be dubbed "canned mood" as Aresds write up demonstrates strikingly. The widespread use of muzak in malls and superstores is no accident. Don't get me wrong though: Music is no Evil.

    However, it is still unclear why music has such an effect on the human psyche. Certain songs or kind of music can have memories attached to them but it does not cover all the cases. We are conditioned as well, to a certain extent, by the conventions on which stands classical music (and fully exploited in film soundtracks for instance), the tempo, the instruments and the effects they are usually associated with (think high-pitched violins and a stabbing scene or dramatic discovery in movies). But again, all is not covered by that explanation. A typical test would be to diffuse a constant loud beat of, say, 120 bpm (beats per minute) which is roughly twice the normal heartbeat. Trying to "fight the beat" is generally a bad idea as it is, in the best case, extremely unpleasant. You will notice that your heartbeat increases and that using the energy of the beat for your own purpose is extremely effective. That explains why I put fast paced tracks when I am in heavy tidying mode... But again, it depends on your mood at the time and sometimes only silence will do. Rather tricky then.

     The only sort of explanation I found was in a 1960's piece of hard science fiction ("The Black Cloud" by Fred Hoyle - 1962 - ISBN:0899683444 ). A character advances that music frequencies somehow resonate with the electric activity in the brain and would consequently affect our state of mind. However strange this idea seems, it carries more food for thought than it may appears (more on that in later nodes).