The Role of Melodic Contour in Linguistic Processin

Melodic contour is one of the bridges connecting language and music. It is considered as one of the basic aspects of music and easier perceptible than intervals (e.g. Edworthy, 1985; Patel, 2008). Some music phenomena, such as speech surrogates, imply that tonal information may help listeners decode messages. In this study, we investigate how pitch contours affect linguistic processing by applying one lexical decision task and one speech shadowing task.;The first experiment involved a lexical decision task, where participants were required to judge whether syllables they heard are words or non-words. The result shows musicians responded with a shorter reaction time, suggesting extended musical training makes contour processing more efficiently. Females outperformed males in speed, indicating the possible gender bias. The results indicate that it is easier to make a decision for nonwords, as they have no entry in the mental lexicon, and, it is harder to do so for pseudowords, as they are very similar to words. For non-words, the fastest responses occur when the tones do not match, suggesting that when melodic contours and non-word syllables differ in tones, it may speed up the decision process. Interestingly, a facilitatory effect was found in words only under match condition. This helps us understand how musical speech surrogates work, because many musical speech surrogates map lexical tones into whistling/instruments: as tonal information is a part of lexicon, melodic pitch contours lead to the pre-activation of the lexicon, resulting in the larger facilitation size. The second experiment involved a speech shadowing task, where participants were asked to repeat the target items. The results support the idea that tonal information facilitates linguistic processing. Musicians outperformed non-musicians in both speed and accuracy, confirming the enhanced ability and sensitivity in contour processing. One of the most important results is that timbre was a significant main factor in speech shadowing task: vocal primes generated fastest responses than instrumental and noise primes, supporting the view that the special role played by the voice in human communication contributed to an increased sensibility and attention to human voice. Vocal primes seem to activate the speech motor system, which is engaged in the vocal tract movement planning, leading to faster responses. In the shadowing task, pseudo-words were responded as fast as nonwords. We suggested that this is because of the different task requirements, as there was no need to identify the lexical status, rather, participants needed to store the input phonological sound in mind and then activate the motor system to reproduce the sounds. In both experiments, we found that different contours did not have the same priming effects, and we suggested it would be interesting to further explore what caused these difference in future studies.;This dissertation demonstrates the possibility of bridging musicology and linguistics. This interdisciplinary study gives us some new insights into the role and importance of melodic contours in linguistic processing, offering evidence and a better understanding of certain musical phenomena, e.g. how musical speech surrogates can carry messages with pitch and contour only.