by SHEN LI, RENEE TIMMERS
Background
Abundant evidence exists of the spontaneous association of musical pitch with vertical height in adults, children and infants (Walker et al. 2009). Demonstrations are found in speeded classification tasks, spatial response tasks (Walker & Ehrenstein, 2000; Lidji, Kolinsky, Lochy, & Morais, 2007), but also free association and movement tasks (Eitan & Granot, 2006; D’ausilio, Altenmüller, Olivetti-Belardinelli, & Lotze, 2006). Although semantic coding (that is, an association between modalities because of a shared semantic meaning (high/low)) may play a role (Spence, 2011), the association is not reliant on the involvement of language or the labeling of pitches (Rusconi, Kwan, Giordano, Umilta, & Butterworth, 2005).
In contrast, horizontal representations of musical pitch seem to occur less consistently compared to vertical mappings. Studies have found that pianists associate higher pitches with right-hand space and lower pitches with left-hand space. Non-musicians displayed this horizontal mapping of pitch only when the task was pitch-related (Lidji et al., 2007; Rusconi et al., 2005). Musical training has been suggested to be directly responsible for differences in the horizontal mapping of sounds. For instance, Stewart et al., (2004) suggested that pianists exhibit stronger vertical-to-horizontal mappings compared to other musicians (woodwind or string instrument players) because the musical training of sight-reading of musical notation and playing on the piano enables them to transfer vertically represented musical scores to horizontally displaced keyboards.
However, the understanding of horizontal mapping of musical sounds and its relationship with musical training is still underdeveloped. Evidence from studies investigating action-perception coupling suggests that action movements of music-making may cause a strong association between the motion and its sensory outcomes, as related to pitch (Dross, Rieger, Brass, Gunter, & Prinz, 2005), timbre features (Drost, Rieger, & Prinz, 2007), or temporal structure perception (Phillips-Silver & Trainor, 2005). Hence, we predict that the active movement of music-making on instruments might contribute to the mental representations of sounds.
Aims
This study aimed to investigate the hypothesis that action movement during musical instrumental playing, which has a particular horizontal layout of pitches, affects the internal spatial representation of pitched sounds. Particularly, we examined differences between pianists and flautists whose instruments have opposing horizontal layout of pitch.
Method
Research design
The experiment contained two parts: a pre-training session and a perceptual task. In the first part, participants were required to play three short exercises on their instrument in order to reinforce the pitch-location mapping of the instrument. In the second perceptual task, participants sat in front of a computer screen flanked by speakers and were required to judge the pitch and location of sounds that varied in pitch height and horizontal location.
Participants
Twenty participants (male = 5, female = 15; mean age = 25.55, SD = 10.48) were recruited in this study. They were advanced pianists (N = 11, mean training years = 17.36, SD = 10.96) and flautists (N = 9, mean training years = 15.56, SD = 13.83), involving left-handed individuals (N = 1) and individuals with absolute pitch (N = 6).
Materials
In the pre-training session, the musical score contained three pieces, namely: a major scale, a major arpeggio, and a short melody. The training materials for pianists and flautists were the same, besides that the third music piece was transposed to F major for flautists due to better exercise effects with making full use of the holes on the flute. In the perceptual task, sine tones of equal loudness were presented with 9 different pitch heights and 9 different horizontal locations.
Procedure
After completing a background information sheet and consent form, participants played each musical exercise three times, but the second time solely moved their fingers without making sounds. This was followed by the perceptual task: participants estimated either pitch height or horizontal location of sounds by using keyboard numbers (1-9). Before each target sound, to facilitate judgments, two reference tones were presented that represented a position below and above the lowest and highest possible tones. Similarly, the centre of the speaker on either side of the screen functioned as a reference for the horizontal location estimation judgment. The order of the type of judgment made (pitch height or location) was counter-balanced. The order of presented tones was random.
Results
To examine the degree to which judged pitch or judged location was related to the presented pitch or presented location, individual regression analyses were run per participant and per judgment. Four regression values were obtained per participant to capture the relationship between responses (judged pitch/location) and sound features (presented pitch/location). These regression data were used as dependent variables in a mixed model ANOVA to examine between-subjects effects (absolute pitch, instruments) on these judgments and the effect of sound feature on the judgment.
Pitch height perception
The mixed-model ANOVA for pitch judgments showed a main effect of sound feature on pitch perception, F (1, 18) = 71.30, p < .010. The results showed that mean values of pitch judgment by actual pitch (M = .64, SD = .24) were significantly larger than mean values of pitch judgment by actual location (M = .02, SD = .10). In judging the perceived pitch, participants relied strongly on the actual pitch and not on the horizontal location (see Figure 1).
The first between-subjects effect defined in the mixed-model ANOVA was instrumental background. The effect of instrumental background was not significant, F (1, 18) = .12, p > .050, indicating that pianists and flautists did not differ in their tendency to make pitch judgments by sound features.
Secondly, absolute pitch was selected as a between-subjects effect. Figure 2 indicates that there were no significant differences between musicians with or without absolute pitch in terms of pitch perception of sounds, F (1, 18) = .39, p > .050.
In summary, both pianists and flautists relied only on the actual pitch and not on the spatial location of pitches when judging the pitch height of sounds. They were fairly good at estimating pitch height, as indicated by a mean regression value of .64. Pitch perception was not influenced significantly by either instrumental background or absolute pitch experience.
Location perception
The mixed-model ANOVA for location judgments showed a significant effect of sound feature on location perception, F (1, 18) = 6.23, p < .050. This indicates that mean values of location judgment by presented location (M = .53, SD = .35) were significantly larger than mean values of location judgment by presented pitch (M = .27, SD = .27). However, this effect was mediated by instrumental background, as is apparent in Figure 3 and is clear from a significant interaction between instrumental background and sound feature, F (1, 18) = 6.16, p < .050. Figure 3 displays mean regression values for each group. This shows that flautists primarily relied on actual location when judging location, while pianists equally relied on the presented pitch and the presented location.
The second background variable, absolute pitch, had no significant effect on the location judgment of sounds, F (1, 18) = .15, p > .050, nor was there an interaction between the effects of absolute pitch and sound feature, F (1, 18) = .00, p > .050. This is illustrated in Figure 4, which shows parallel results for the two groups.
In summary, location judgment was shown to interact with instrumental experience. Flautists relied primarily on the actual location in judging the location of sounds. Whereas for pianists, their location judgment was affected by the presented pitch as well as the presented location. Higher pitches were perceived as coming from the right and lower pitches as coming from the left. In other words, it was not merely an association but an actual location illusion.
Conclusions
This study provided evidence of automatic mapping of pitch onto the left-right dimension in pianists but not in flautists, after short-term training on their respective instruments. The opposite way of locating sounds in horizontal space (right-left for low-high pitches) was not found in flautists, suggesting that low-left and high-right associations between pitch and location are somehow preferred. In a previous study that did not employ the performance pre-task, this interaction between instrument and sound feature for location judgments was not found. This suggests the importance of action-perception coupling for the horizontal representation of musical pitch.
Notes
Address for correspondence: Renee Timmers, Department of Music, University of Sheffield, 34 Leavygreave Road, Sheffield.
Email: r.timmers@sheffield.ac.uk or sli37@sheffield.ac.uk.
References
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