Emotion Modulation through Music after Sadness Induction—The Iso Principle in a Controlled Experimental Study

Music therapy intervention manuals suggest that individuals who suffer from affective disorders benefit from listening to music according to the iso principle. The iso principle comprises listening to music that matches the current mood of patients at first, and then to gradually shift to music that represents a desired mood. Within the current study, we investigate whether the sequence of music with different emotional valence can modulate the emotional state. All participants were healthy adults who underwent a sadness induction via a movie clip. They were subsequently divided into four experimental groups. Each was asked to listen to two pieces of music according to a specific sequence: sad-sad; sad-happy; happy-happy; happy-sad. Participants were prompt to rate their current emotional state at different stages of the experiment: prior to and after the movie clip, as well as after each of the two pieces of music. The frame used for the assessment was the Positive and Negative Affect Schedule and the Self-Assessment Manikin. The results indicate that the movie clip induced sadness. The group of participants who listened to the sad music first and the happy music afterwards ultimately reported a higher positive affect, a higher emotional valence, and a lower negative affect compared with the other groups. However, not all the between-group differences reached significance. We conclude that the sequence of music with different emotional valence affects the current emotional state. The results are generally in line with the iso principle. Directions for future research are presented.