Computational Creativity and Music - Computational Creativity Research: Towards Creative Machines - page 312

Fig. 15.7 Second, third, and
fourth chords of Fig. 15.6 a
with analysis

5 3 r
3 r

5

r 7 3

-1 1
-2 0
0 -1

M Mm 4

M 6

2

1) Simple,
2) data-driven,
3) and contextual.

With these three principles in mind, I believe that creativity can be achieved in a
computer program.
Since the music in Fig. 15.6 represent good examples, I will use them as a database
for a data-driven computer program acting creatively. Both of these examples are
tonal, diatonic (in C-major without any chromatic notes), and use standard voice-
leading principles as previously mentioned and detailed. Thus, the music in Fig. 15.6
is consistent and will supply all the rules for the program that I will now describe.
Figure 15.7 now presents an analysis of the second, third, and fourth chords of
Fig. 15.6 a for close inspection.
The nomenclature in Fig. 15.7 is—from top to bottom—chordmembers ('r' equals
root) in boldface, and below those three lines, interval motion (0 equaling no motion
and minus sign indicating downward motion) in italics. Underneath the music itself,
M refers to Major, mminor, with the combination of the two used for seventh chords,
the first letter the nature of the bottom triad, and the second letter the nature of
the interval of the seventh. The numbers next to these letters indicate inversions,
something that need not concern us here, but I have included for those interested
(figured bass shorthand is actually redundant due to the uppermost description of
chord members). For those familiar with music theory, I've excluded function in this
presentation to avoid confusing readers without that knowledge.
Linking Fig. 15.7 with a computer program analysis process could be accom-
plished by stating this data by voice in the following manner:

((( 5M ) − 1 ( 3Mm )) (( 3Mm ) 1 ( rM )))

read as the fifth of a major triad (M) moving downward by minor second to the
third of a major/minor seventh chord (Mm), which then (the second parenthetical
grouping) moves up a minor second to the root of a major triad. This rule can then
be used for producing new output. In other words, whenever a pitch represents the