Neural Correlates of Processing Syntax in Music and ... - PubMan

Experiment II 109
Stimuli and paradigm
The experimental paradigm was essentially the same as in Experiment I, except that
there was no second group (in which Neapolitan sixth chords were compared with tonics).
In this experiment, irregular supertonics – that did not introduce a very salient
violation – were compared to regular tonics (for a discussion, see Koelsch et al., 2007).
Figure 9-1 provides an overview of the chord sequences. It could be demonstrated that
the supertonics were acoustically more similar compared to the pitch representation of
the preceding chords than the tonics: Figure Figure 9-1D presents the results from modelling
the function of echoic memory using the IPEM-Toolbox (Leman et al., 2005). 20
This modelling determines the congruency of the actual chord with the pitch representation
established by the previous chords in the chord sequence. It revealed that supertonics
are more expected than tonics from an acoustical point of view. At the same time,
these chords are harmonically irregular and violated the expectancy of a regular musical
structure. Vice versa, the tonics do conform to the harmonic expectancies but are less
expected from an acoustical point of view.
Figure 10-1 Overview of the chord sequences used in Experiment II – IV. A-C: Examples for chord
sequences ending either on a regular tonic (A) or on an irregular supertonic (B). These sequences
were played in direct succession (C). D: Correlation of the local context (pitch representation
of the current chord) with the global context (pitch representation of the previous
chords stored in echoic memory). The music-syntactically irregular supertonics (grey line)
were more congruent with this context than the regular tonics (black line). Each line represents
the mean of all twelve major keys (small dotted lines represent the standard error of
mean). The modelling was performed using the IPEM Toolbox (Leman, Lesaffre, &
Tanghe, 2005).
20 The results of this modelling were recently published in Koelsch et al. (2007).