Hippe, Hennessy, Ramirez, Zhao
Infants
are immersed in a world of sounds from the moment their auditory system
becomes functional, and experience with the auditory world shapes how their
brain processes sounds in their environment. Across cultures, speech and
music are two dominant auditory signals in infants’ daily lives. Decades of
research have repeatedly shown that both quantity and quality of speech input
play critical roles in infant language development. Less is known about the
music input infants receive in their environment. This study is the first to
compare music input to speech input across infancy by analyzing a
longitudinal dataset of daylong audio recordings collected in
English-learning infants’ home environments, at 6, 10, 14, 18, and 24 months
of age. Using a crowdsourcing approach, 643 naïve listeners annotated 12,000
short snippets (10 s) randomly sampled from the recordings using Zooniverse,
an online citizen-science platform. Results show that infants overall receive
significantly more speech input than music input and the gap widens as the
infants get older. At every age point, infants were exposed to more music
from an electronic device than an in-person source; this pattern was reversed
for speech. The percentage of input intended for infants remained the same
over time for music while that percentage significantly increased for speech.
We propose possible explanations for the limited music input compared to
speech input observed in the present (North American) dataset and discuss
future directions. We also discuss the opportunities and caveats in using a
crowdsourcing approach to analyze large audio datasets. A video abstract of
this article can be viewed at https://youtu.be/lFj_sEaBMN4