和聲對於主動聆聽轉調的影響——腦磁圖研究

Effects of Harmony on Musical Modulations during Active Listening: an MEG Study

溫雅茜(Ya-Chien Wen)

指導教授 ： 蔡振家

國立臺灣大學/文學院/音樂學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.02557

摘要

轉調是許多樂曲中相當重要的音樂事件，音樂理論已經提供新舊調性銜接及轉移的模式，但從認知科學的角度來探討聆聽轉調的認知機制，這類研究卻十分稀少。為了探討聆聽轉調的神經基礎，本研究測量受試者在主動聆聽轉調時的腦磁場，實驗結果發現四個主要的腦磁波成份：P1m、N1m、P2m、M350，其中N1m（發生於刺激音之後約120毫秒）及M350（發生於刺激音之後約350毫秒）皆與調性認知有關。
N1m的強度在主動聆聽「已經確立新調」與「準備轉入新調」的和絃時有顯著差異，這可能是因為轉軸和絃的調性較為模糊，導致N1m較弱。M350的強度在主動聆聽「剛剛進入新調」與「已經確立新調」的無和聲單旋律時有顯著差異，這可能是因為聽者在缺乏和聲的調性線索上，必須更主動地進行工作記憶更新並加以監控，故導致轉入新調的第一個音所引發的M350較強。本實驗呈現示出和聲影響轉調認知的神經表徵，其中N1m可能與和聲脈絡裡面「由下而上」的聲音處理有關，而M350則可能與無和聲脈絡裡面「由上而下」的認知控制有關，所涉及的腦區皆在右側顳葉後方區域，顯示這個腦區在調性處理所扮演的關鍵角色。

關鍵字

和聲 ； 轉調 ； 腦磁圖 ； 顳葉

並列摘要

Modulation is a significant event in music. While music theory has elucidated the principles of moving from an established tonality to a new tonality, the cognitive mechanisms underlying musical modulations are still poorly understood. To investigate the neural substrates of musical modulations, this magnetoencephalography (MEG) study recorded participants’ neural activity while they were actively listening to musical modulations. Four components of evoked magnetic field were identified and analyzed: P1m, N1m, P2m, and M350. The results suggest that N1m (latency∼120 ms) and M350 ( latency∼350 ms) may be related to the processing of musical modulations.
The amplitude of N1m differed significantly between the occurrence of the chords of “confirming the new key” and the “pivot chords”. This might be attributed to the tonal ambiguity of the pivot chords. During listening to an unharmonized melody, the amplitude of M350 differed significantly between the occurrence of the tones of “just in the new key” and the tones of “confirming the new key”. The stronger M350 evoked by the tones of “just in the new key” may be attributed to that listeners had to initiate and monitor the updating of working memory when there was no harmonic cue. The present study demonstrates how harmonization influences a modulating melody and how the schema of pitch-naming is shifted under the impact of pivot chords and under cognitive control. N1m may be related to the bottom-up processing of modulation in harmony context, whereas M350 may be related to the top-down control of modulation without harmony context. Our results also suggest the central role of the right posterior temporal lobe in the processing of tonality.

並列關鍵字

harmony ； modulation ； MEG ； temporal lobe

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