My funny Valentine

Jass musicians (and likewise blues and pop musicians) never play what the score tells them to do. To be precise: they will deviate heavily from the prescribed rythm. Most notes will be played later or earlier. If one plays exactly what is written the music will sound dull, obligatory. A good example of this is when big orchestra's or choirs play well-known pop-songs (you know: London Philharmonic playing Nirvana's Smell's like teen spirit, with the heavy violin sections). What misses in these orchestra's is the 'groove' of the original song. It is because the orchestra is playing exactly what the score says.

Of course, the 'right way' of playing it, is what the performers do, not what is written down. So it is not so much that the musicians are making errors, rather than te fact that writing it down in a score is just a poor method of representing jazz.

The deviations from the score are not random, however. A researcher at the NICI once gave at talk based on having measured all deviations from all notes in the written score in several versions of Chet Baker's 'My Funny Valentine'. As it turned out, the deviations, as a whole, form a well-defined pattern. If a jazz-performer follows this pattern, the music will sound right, people will regard the music as 'a good piece of jazz'. In fact, the only version of Chet's Valentine that couldn't be mapped to this pattern was a bootleg version that Chet never wanted to bring out because he wasn't satisfied with it, for some reason.

It is interesting to see that the 'jazz flavor', which marks the difference between a dull reproduction of the written score and a lively, groovy jazz performance, is itself completely explained by a mathematical formula. In theory, we could make a computer play lively jazz if we put the pattern that the researcher discovered and the written score together. In that sense, if we take the score and the computational pattern of deviations, we have 'explained' My Funny Valentine. But does it also explain anything about how Chet actually plays My Funny Valentine? With this I mean: does it say anything about the possible *causal mechanism* that leads Chet to play MFV in this particular way? I feel not.

Of course, there is the possibility that Chet actually embodies a computational mechanism that takes the score, transforms all the notes by adding and substracting the required deviations here and there, and then outputs the result on his trumpet. To be sure, on some level of *description* Chet *does* embody such a mechanism since this *is* exactly what he outputs on his trumpet. But I propose to make a distinction between such descriptive characterisations of the mechanisms at work, and the *real* (whatever that may be) mechanisms that actually caused the notes to be played. In particular, I see no reason why networks of cells in the *brain* would actually have to form computational patterns like the one described above in order to let this same pattern emerge out of Chet's trumpet. It could very well be, for example, that certain typical parameters on the level of Chet's breathing, lip-tension, and so on, add to the emergence of this pattern. The pattern of deviations from the score (the jazziness of jazz) might emerge as a *collective property* of Chet-as-he-is-playing-the-piece. A pattern that evolves 'in the flow of things', not something that has been 'planned' by a control system. Perhaps induced by subcortical, emotional parameter-changes and body-posture, lip-tension, and so on. Such a pattern would not have to be explicitly represented as some kind of computational *program* inside the brain, even if it emerges every time Chet plays the song. (Nobody 'programs' traffic jams, still they emerge on the same hotspots almost everytime).

Most researchers are not interested or they heavily disagree with this alternative. The first group is generally not interested in 'causal mechanisms'. They simply seek to find 'patterns' in behavior. The patterns themselve are enough 'explanation'. The second group disagrees strongly with the difference between the 'descriptive computational patterns' as observed and the 'real computational patterns' that are proposed as an underlying cause. Which is sort of the same thing, really.

Your lips are laughable
Unphotographable
Yet your my favorite work of art..