Characterizing the Structure of Infants' Everyday Musical Input

Infants acculturate to their soundscape over the first year of life (e.g., Hannon & Trehub, 2005a; Werker & Tees, 1984). This perceptual tuning of early auditory skills requires integrating across experiences that repeat and vary in content and are distributed in time. Music is part of this soundscape, yet little is known about the real-world musical input available to infants as they begin learning sounds, melodies, rhythms, and words. In this dissertation, we collected and analyzed a first-of-its-kind corpus of music identified in day-long audio recordings of 6- to 12-month-old infants and their caregivers in their natural, at-home environments. We characterized the structure of this input in terms of key distributional and temporal properties that shape learning in many domains (e.g., Oakes & Spalding, 1997; Roy et al., 2015; Vlach et al., 2008; Weisleder & Fernald, 2013). This everyday sensory input serves as the data available for infants to aggregate in order to build knowledge about music. We discovered that infants encountered nearly an hour of cumulative music per day distributed across multiple instances. Infants encountered many different tunes and voices in their daily music. Within this diverse range, infants encountered consistency, such that some tunes and voices were more available than others in infants’ everyday musical input. The proportion of music produced by live voices varied widely across infants. As infants progressed in time through their days, they encountered many music instances close together in time as well as some music instances separated by much longer lulls. This bursty temporal pattern also characterized how infants encountered instances of their top tune and their top voice – the specific tune and specific voice that occurred for the longest cumulative duration in each infant’s day. Finally, infants encountered many pairs of consecutive music bouts with repeated content – the same unique tune or the same unique voice. Taken together, we discovered that infants’ everyday musical input was more consistent than random in both content and time across infants’ days at home. These findings have potential to inform theory and future research examining how the nature of early music experience shapes infants’ early learning