Personalised affect-regulation playlists: A pre-registered experimental test of the iso principle in the general population

Music listening can serve an affect-regulatory function. For instance, someone who feels anxious may listen to music with the goal of evoking a different, desired feeling (e.g., calmness), labelled ‘compensatory’ listening. However, music therapists recommend starting with music matching one’s current feelings before gradually shifting to music that evokes desired feelings, following the ‘iso principle’. Some evidence supports the effectiveness of the iso principle for affect regulation in clinical populations. However, randomised experiments comparing the iso principle with other music-listening interventions are rare, especially with non-clinical participants. To address this gap, the current study compared the effectiveness of iso-principle, compensatory-principle, and unguided music listening for modulating anxiety among healthy participants ( N = 193) in a randomised experiment. Participants completed an anxiety induction before listening to a Spotify playlist in one of three randomly assigned conditions: participants in the iso and compensatory conditions listened to five-song iso- and compensatory-principle playlists respectively, curated by the researchers using participants’ self-selected songs, whereas participants in the unguided condition self-ordered their songs. Participants rated their momentary affect at baseline, post-anxiety-induction, and post-listening. Our pre-registered analyses revealed no significant difference in the affect-regulatory consequences of iso versus compensatory listening. However, post-hoc exploratory analyses revealed that participants in the guided (iso, compensatory) conditions reported significantly greater increases in calmness than unguided participants. Moreover, exploratory analyses of unguided listening sequences revealed seven distinct patterns of spontaneous music listening, which differed in perceived effectiveness. Findings from this study may inform the development of (digital) music interventions to improve well-being.