A novel indirect method for capturing involuntary musical imagery under varying cognitive load

Involuntary musical imagery (INMI), or “earworms”, refers to the ubiquitous experience of a musical fragment coming into the mind without effort and then repeating. Studies have provided conflicting reports regarding the relationship between INMI and cognitive load, such the effect of a systematic cognitive load increase on INMI occurrence and duration remains unknown. In the present study, 200 participants watched and immediately evaluated two non-dialogue, music-only film trailers. Subsequently, they either closed their eyes for 5 mins (Baseline), or engaged in one of three dot tasks (Easy, Medium, and Hard) of varying challenge and attentional demand (low, medium and high cognitive load, respectively). Finally, they completed a novel “Mind Activity Questionnaire”, which allows for indirect sampling of INMI experiences rather than direct questioning. A second Mind Activity Questionnaire was completed 24 hours later. Overall, a significant negative linear trend was found. At Baseline, 65% of people reported an experience of INMI. This rate reduced to 32.5% in the Easy condition with further reductions observed in both Medium and Hard conditions, which did not differ significantly from each other. Measures of INMI frequency, the number of tunes experienced as INMI, and INMI duration followed the same pattern as the induction rates. In the 24-hour follow-up, 21% of participants reported INMI experiences. This study supports the hypothesis that INMI occurrence, frequency, and duration relate to spare cognitive capacity and demonstrates an ecologically valid laboratory paradigm for covertly inducing and documenting INMI experiences.