The Involuntary Musical Imagery Scale (IMIS).

This report comprises 3 studies that delineate the development and validation of the Involuntary Musical Imagery Scale (IMIS) based on data from 2,646 individuals. This new self-report inventory measures individual differences in involuntary musical imagery (“INMI,” commonly referred to as “earworms”). The first study involved exploratory factor analysis, leading to the identification of a 4-factor scale structure. The 4 factors are conceived as “Negative Valence,” “Movement,” “Personal Reflections,” and “Help.” The second study confirmed this factor structure on an independent sample and derived indices of internal validity and test–retest reliability. The third study reports on IMIS correlates with existing measures of thinking style, imagery abilities, and music-related behaviors. Results showed that the IMIS measures a unique construct compared with existing self-report inventories. Furthermore, significant correlations were found with a combination of self-reported musical behaviors on the one hand and tendencies to engage in task-unrelated thoughts on the other. Overall, these findings provide evidence that IMIS constitutes a reliable scale that captures individual differences in INMI and that its first application reveals previously uncaptured associations between INMI and certain cognitive and behavioral traits.