Music generates feelings that alter our perception of other things. In effect this is a failure of perceptual binding.

Hypothesis

Music generates feelings, but the perception of these feelings is only weakly bound to the music.

Here I use the word "bound" in the same sense as "bind" in the "binding problem".

The binding problem is the problem of explaining how the brain binds together different perceptions relating to one thing, when those perceptions are represented by activity in different parts of the brain.

For example:

A person sees a blue square and a red circle.

"Blueness" is represented by activity in a part of the brain that processes information about colour, as is "redness".

Being "square" or "circular" are represented by activity in a part of the brain that processes information about shape.

Given this perceptual scenario, we can ask:

How does the person's brain represent the perception of a blue square and a red circle, ie how does the brain know that the blueness and the squariness are bound together and the redness and the circleness are bound together? How does it bind the neural activity related to the perception of "blueness" to the neural activity related to the perception of "squariness"? How does the brain know that it is not perceiving a blue circle and a red square?

If the brain failed to bind perceptions, then a scenario like the following might happen:

A person sees a large bright blue object.

The blueness of that object "leaks" away from the object, making other things seem "blueish", even though those other things are not blue.

This does not correspond to anything in our normal experience, implying that our brains are pretty good at doing the required binding.

However, something like this does happen with music.

For example, suppose:

Some sad music is playing.

At the same time, a man is telling a sad story.

The sad music generates a sad feeling, and this sad feeling comes from the music, and we know that it comes from the music.

Nevertheless, the sadness of the music will make the story seem sadder than it would be if there was no music.

So in this case, the sadness of the music has "leaked" away from the music, and transferred itself to something else, ie the story.

The conclusion is that the human brain's ability to bind perceptions together does not apply to music, and the brain is not able to prevent the feelings generated by the music from being transferred to other perceptions.

Transferability of Music-Generated Feelings

The feelings generated by music are weakly bound, and can be transferred to other perceptions by the music listener, but there are constraints on which target perceptions those feelings can be tranferred to.

In particular:

The target perception has to be an imagined perception – music-generated feelings to do not easily alter an individual's perceptions of things that are real.

perception – music-generated feelings to do not easily alter an individual's perceptions of things that are real. The target perception must be happening at the same time that the music is playing. (That is, as soon as the music stops, the transferred feeling goes away.)

The music-generated feelings should be applicable to the target perception. So it only makes sense to play sad music while presenting a story, if that story has a sad interpretation.

to the target perception. So it only makes sense to play sad music while presenting a story, that story has a sad interpretation. The music-generated feelings will more easily bind to the target perception if the target perception is itself strongly bound to the music. Particular examples of this are: Song lyrics, bound to the melody and rhythm of the music Rap lyrics, bound to the rhythm of the music Dance, bound to the rhythm of the music Music video content that has been "edited to the beat" (ie bound to the rhythm of the music) However it is not essential that the target perception be strongly bound to the music, and it is often sufficient that the target perception simply occurs within the time period that the music is playing. Musical feelings are more strongly transferred to the meaning of song lyrics, or to the meaning of rap lyrics. But they can also be transferred to the meaning of a story told by a narrator who is telling a story while the music plays, where the narrator is speaking normally in a non-melodic and non-rhythmic manner.

However it is not essential that the target perception be strongly bound to the music, and it is often sufficient that the target perception simply occurs within the time period that the music is playing. Musical feelings are more strongly transferred to the meaning of song lyrics, or to the meaning of rap lyrics. But they can also be transferred to the meaning of a story told by a narrator who is telling a story while the music plays, where the narrator is speaking normally in a non-melodic and non-rhythmic manner.

Preventing Manipulation and Psychotic Delusion

It is quite possible that music has evolved as a mechanism of generating feelings that can be transferred to other things. (It may also be that music originally evolved to serve some different purpose, and that original purpose has become obsolete, and what we see now is a secondary purpose of music as a vestigial trait.)

If music-generated feelings could be transferred to perceptions of reality, then music would be a means by which people could easily manipulate the perceptions of other people. It would also be a means by which a person could manipulate their own perceptions of reality, leading to a state of delusion, which in the worse case would be psychotic.

This risk of manipulation and psychotic delusion is mitigated by two of the constraints listed above:

The music-generated feelings only last as long as the music lasts.

Music-generated feelings only transfer easily to imagined perceptions.

A further constraint, in earlier times, when everyone didn't have a mobile phone with access to unlimited music streaming, is that music required considerable effort and organisation to produce. Without advanced technology, it is very hard for a lone individual to perform music to the same level of quality that a group can achieve. So it would be very hard to be listening to strong music all the time, and the effects of any manipulation or self-inflicted delusion would instantly fade as soon as the music stopped.