Pitch
Naming & Tonal Schema
Deacon (1997) claimed that
humans were unique in the use of language and that our highly developed brain
allows us to think in abstract, using symbols. In addition to language,
perceptual categorization of musical pitches also relies on symbols in numerous
human cultures. Unlike natural sounds or the spoken sound, whose fundamental
frequencies are continuously distributed, musical pitches were often
categorized into discrete entities and was given a label. For example, the
pitch names of the major mode scale in Western music are: do, re, mi, fa, sol,
la, and ti. In Chinese traditional music, these seven notes are represented by
shang (上), che (尺), gong (工), fan (凡), liu (六), wu (五), and yi (乙).
According to the mapping
rules for associative transformation from a perceived frequency to a pitch
name, systems of pitch naming (solmization) can be divided into two types, as
represented by the fixed-do solmization and the moving-do solmization in
Western music. The pitch names in the fixed-do solmization are determined by
the fundamental frequency of auditory stimuli. On the other hand, the moving-do
solmization relies on pitch relationships and is associated with the use of
musical scales.
A sung pitch name informs
us the fundamental frequency and pitch name that may be either congruent or
incongruent with regard to pitch categorization, and a few experiments have
used Stroop-like paradigms to study the congruency effect of pitch and pitch
name. An interesting finding was that the solmization strategy in possessors of
absolute pitch differs from that in possessors of relative pitch. Absolute
pitch is a rare ability to identify a musical pitch without the use of an
external reference pitch. On the other hand, relative pitch is a common ability
in musicians and non-musicians. With an auditory Stroop task, it is suggested
that absolute pitch possessors tend to use the fixed-do solmization while
relative pitch possessors use the moving-do solmization (Miyazaki, 2000).
A sung pitch name conveys
(1) the acoustic information of pitch in terms of fundamental frequency, and
(2) the semantic information of pitch in terms of the pitch name. In a magnetoencephalographic
(MEG) study, we presented participants (relative pitch possessors) with sung
pitch names, which contained congruent or incongruent information (Table 1).
Table 1: The sixteen stimuli of the pitch-semantic task. In
congruent stimuli, the pitch and pitch name were matched in a C-major context.
|
Syllables Pitch |
Pitch names |
|||
|
Congruent |
Incongruent |
|||
|
C4 |
Do |
Re |
Mi |
Sol |
|
D4 |
Re |
Do |
Mi |
Sol |
|
E4 |
Mi |
Do |
Re |
Sol |
|
G4 |
Sol |
Do |
Re |
Mi |
The earliest neuromagnetic
component showing the congruency effect of pitch naming was P2m, which was
pronounced 200-230 ms after stimulus onset and enhanced for congruent stimuli (Figure
2). To the best of our knowledge, our study is the first one reporting a
congruency-sensitive component with latency shorter than 230 ms. In the evnt-related
potential (ERP) experiment by Itoh et al. (2005), the P2 responses to the
musical stimuli with congruent pitch and pitch name appeared stronger than
incongruent stimuli when selective attention was focused on pitch. However,
they did not perform statistical analysis on the P2 amplitude.
The enhanced P2m response
to pitch congruent with pitch name may reflect the activation of short-term
memory during a rapid perceptual categorization of auditory stimuli. On the
other hand, the incongruent musical stimuli may fail to be classified due to
conflicting information, thereby inducing a weaker P2m response (Tsai et al.,
2015).
Figure 1. Neuromagnetic responses
to sung pitch names. (A) The grand-average MEG waveforms in the right and left
superior temporal regions. (B) The average topographies for two conditions of
the pitch-semantic task.
Changes in the tonal
schema (tonal modulations) have been used by composers for musical expressions
and punctuations of formal structures. A musical modulation
is accompanied by a change in key membership, and a change in the mappings
from
pitches to pitch names. We used MEG and fMRI to examine
the neural correlates of the processing of tonality changes.
[to be continued]
REFERENCES
Miyazaki, K. (2000).
Interaction in musical-pitch naming and syllable naming: an experiment on a
Stroop-like effect in hearing. In T. Nakada ed., Integrated human brain
science: theory, method, application (music) (pp. 415–423). Amsterdam:
Elsevier.
Itoh, K., Suwazono, S., Arao, H., Miyazaki, K. & Nakada, T. (2005). Electrophysiological
correlates of absolute pitch and relative pitch. Cerebral Cortex, 15, 760-769.
Tsai, C. G., Chen, C. C.,
Wen, Y. C., & Chou T. L. (2015). Neuromagnetic brain activities associated
with perceptual categorization and sound-content incongruency: a comparison of
music and speech. Frontiers in Human
Neuroscience, 9, 455.
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