Changing Musical Emotion through Score and Performance with a Computational Rule System
Steven Robert Livingstone · 2008
This dissertation outlines the design, testing, and application of CMERS - a Computational MusicEmotion Rule System for the control of perceived musical emotions. Musical emotion is changedthrough the application of empirically derived music-emotion rules (e.g., major mode P happy).These rules modify a work in real-time at the levels of score and performance, where existingcomputational systems have focused primarily on performance elements.Six rules relating to the score, termed the Primary Music-Emotion Structural Rules, wereexamined in Round I testing with a system prototype. The prototype successfully changed theperceived emotion of selected musical works to all four emotion categories, described as: happy,angry, sad, and tender, with an average accuracy of 63%, and a multinomial logistic regression of 2 (7) = 4128.27, p < 0.0005 (N = 11). This result supported the use of structural rules, whilehighlighting the need for performance elements.CMERS replaced the system prototype, possessing both structural and performance musicemotionrules. Expressive performance capability was also added, allowing for “humanistic”performance. In Round II testing, CMERS successfully changed the perceived emotion of selectedmusical works to all four emotion categories with an average accuracy of 78%, and a multinomiallogistic regression of 2 (9) = 11183.0, p < 0.0005 (N = 20). This result supported the use of bothstructural and performance rules when changing perceived musical emotion.In Round III testing, the accuracy of CMERS was compared with KTH’s Director Musices(DM), which focused primarily on performance rules. CMERS significantly outperformed DMacross the four emotion categories, 82% to 57% (averaged), with a multinomial logistic regressionof 2 (1) = 4.69, p = 0.0304 (N = 7). DM reported similar accuracy ratings to the system prototype inRound I, with both sharing deficits for “anger” and “tender”. These results supported the need forcontrolling both score and performance when changing perceived musical emotion.CMERS possesses real-time, fine-grained emotion modification capability allowing for its usein a variety of external application environments, such as computer gaming. As a research tool,CMERS provides a powerful mechanism for exploring the emotional and perceptual nature ofindividual music features through systematic modification.